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WO2014194563A1 - 改进型的用回转窑规模化生产磷酸的方法 - Google Patents

改进型的用回转窑规模化生产磷酸的方法 Download PDF

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Publication number
WO2014194563A1
WO2014194563A1 PCT/CN2013/081123 CN2013081123W WO2014194563A1 WO 2014194563 A1 WO2014194563 A1 WO 2014194563A1 CN 2013081123 W CN2013081123 W CN 2013081123W WO 2014194563 A1 WO2014194563 A1 WO 2014194563A1
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WO
WIPO (PCT)
Prior art keywords
phosphoric acid
kiln
tower
flue gas
acid
Prior art date
Application number
PCT/CN2013/081123
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English (en)
French (fr)
Inventor
侯拥和
魏世发
Original Assignee
四川玖长科技有限公司
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Filing date
Publication date
Application filed by 四川玖长科技有限公司 filed Critical 四川玖长科技有限公司
Priority to RU2015144717A priority Critical patent/RU2642651C2/ru
Publication of WO2014194563A1 publication Critical patent/WO2014194563A1/zh
Priority to MA38575A priority patent/MA38575A1/fr
Priority to US14/958,893 priority patent/US10005669B2/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/01—Treating phosphate ores or other raw phosphate materials to obtain phosphorus or phosphorus compounds
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/18—Phosphoric acid
    • C01B25/185—Preparation neither from elemental phosphorus or phosphoric anhydride nor by reacting phosphate-containing material with an acid, e.g. by reacting phosphate-containing material with an ion-exchange resin or an acid salt used alone
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/12—Oxides of phosphorus
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/18—Phosphoric acid
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/18—Phosphoric acid
    • C01B25/22—Preparation by reacting phosphate-containing material with an acid, e.g. wet process
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B7/00—Rotary-drum furnaces, i.e. horizontal or slightly inclined
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B7/00—Rotary-drum furnaces, i.e. horizontal or slightly inclined
    • F27B7/20—Details, accessories or equipment specially adapted for rotary-drum furnaces
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency

Definitions

  • the invention relates to a raw material pretreatment method and equipment in a phosphoric acid production process, in particular to a raw material pretreatment method and a pretreatment process system in a kiln process phosphoric acid process (KPA).
  • KPA kiln process phosphoric acid process
  • wet process phosphoric acid that is, the phosphate rock is decomposed by sulfuric acid to obtain dilute phosphoric acid and solid waste residue (referred to as phosphogypsum) mainly composed of CaS0 4 * n3 ⁇ 40, and the dilute phosphoric acid is concentrated to obtain wet-process phosphoric acid containing about 54% of phosphoric acid.
  • the main disadvantages of this process are as follows: First, a large amount of sulfuric acid is consumed; second, the waste slag phosphogypsum cannot be effectively utilized, and the entrained sulfuric acid, phosphoric acid and soluble fluoride are all dissolved in water, and are naturally washed by rainwater, which is easy to wash. Serious pollution to the environment; Third, the product phosphoric acid has a high impurity content, generally only used to produce fertilizer; Fourth, in order to ensure the economical efficiency of the product, high-grade phosphate rock must be used.
  • the method is to finely grind phosphate rock, silica and carbonaceous reducing agent (coke powder or pulverized coal) to 50% ⁇ 85%-325 mesh, add 1% bentonite ball, and dry preheat through chain dryer.
  • the pellets in the kiln reduction to control the maximum temperature of the solids is 1400 ° C ⁇ 1500 ° C, to adjust the pellet Ca0 / Si0 2 molar ratio of 0. 26 ⁇ 0.
  • the melting point of the pellet is higher than the carbothermal reduction temperature of the phosphate ore in the pellet, and the phosphorus is volatilized from the pellet in the form of phosphorus vapor, and then The central space of the kiln is oxidized into phosphorus pentoxide by the ventilating air, and the heat released by the oxidation is in turn supplied to the reduction reaction, and finally the kiln gas containing phosphorus pentoxide is hydrated and absorbed to obtain phosphoric acid.
  • the above-mentioned kiln phosphoric acid process idea shows a good industrial application prospect, because the principle is to use the carbothermal reduction of phosphate rock to form a gas, transfer the phosphorus in the phosphate ore to the gas phase of the rotary kiln, and utilize the gas.
  • the principle of solid separation makes the phosphorus and the remaining solid matter in the pellets separate well.
  • the P 4 gas transferred to the gas phase of the rotary kiln can react with the oxygen in the gas phase of the rotary kiln to generate P 2 0 5 , which is released.
  • the rotary kiln maintains the carbon-thermal reduction temperature of the phosphate rock, the primary energy source is used, and the combustible material produced by the carbothermal reduction of the phosphate rock and the CO can be subjected to a combustion exothermic reaction inside the rotary kiln, and is supplemented and supplied to maintain the carbon heat of the phosphate rock in the rotary kiln.
  • the energy required to reduce the temperature which is significantly reduced compared to the traditional thermal process phosphoric acid process.
  • Rotary kiln is the equipment whose kiln body runs at a certain speed (0.5 r/mir! ⁇ 3r/min). It has the advantage of continuously mechanically turning and mixing the solid materials sent into the kiln to ensure the solid materials in the kiln. The uniformity of heat is everywhere, but in turn the solid material in the kiln is also subject to the mechanical friction of the material movement. If the material strength is less than the mechanical friction, it will be easily destroyed.
  • the basic principle of the KPA process proposed by the US 0RC company is to finely grind phosphate rock, silica and carbonaceous reducing agent (coke powder or pulverized coal) to 50% ⁇ 85%-325 mesh to make pellets.
  • the material pellets used in the process are equipped with a reducing agent carbon, and the carbon undergoes a rapid oxidation reaction with oxygen in the air at a temperature of more than 350 ° C to be converted into C0 2 , if a conventional metallurgical industrial pellet is used on the grate machine.
  • high temperature consolidation 900 °C
  • the reduced carbon in the pellets is completely oxidized, and the reducing agent is lost in the rotary kiln pellets.
  • the pellets entering the kiln will be pulverized in large quantities due to the mechanical friction that can not withstand the movement of the ball in the rotary kiln.
  • Phosphate powder, silica powder and carbonaceous reducing agent which form pellets after pulverization will be separated, and the phosphate rock powder which is pulverized cannot be reduced due to intimate contact with the carbonaceous reducing agent. More seriously, once the phosphate rock is separated from the silica powder, its melting point will be drastically reduced to below 1250 °C.
  • This powdered phosphate rock passes through the high temperature reduction zone of the rotary kiln (the temperature of the layer is about 1300 °C). , all will change from the solid phase to the liquid phase, and then adhere to the rotary kiln lining to form the high temperature ring of the rotary kiln, hinder the normal movement of the material in the rotary kiln, and join Most of the material of the rotary kiln overflows from the rotary kiln at the feed end of the rotary kiln, and the high temperature reduction of phosphorus cannot be achieved, resulting in process failure. It can be seen that due to the inherent defects of the raw materials entering the kiln, the above-mentioned KPA technology has not been used for any industrialization, scale or commercial application.
  • the solid material zone in the lower part of the rotary kiln belongs to the reduction zone, and the upper part of the zone is the gas flow zone of the rotary kiln, which belongs to the oxidation zone, the feed ball.
  • the group is added from the end of the rotary kiln, and is discharged from the kiln head area of the rotary kiln by its own gravity and the frictional force of the rotary kiln.
  • the burner for burning the rotary kiln is installed in the rotary kiln head, and the combustion fumes generated by the kiln are
  • the tail fan is taken out, and the micro-negative pressure is maintained in the rotary kiln, and the air flow is opposite to the moving direction of the material. Since there is no mechanical isolation zone in the reduction zone (solid layer zone) of the rotary kiln and the oxidation zone (the gas flow zone above the solid layer of the rotary kiln), the ball exposed on the surface of the solid zone zone will be in the gas stream with the oxidation zone.
  • the white shell of 5 the thickness of the shell is generally 300 ⁇ m ⁇ 1000 ⁇ m, and the content of P 2 0 5 in the shell layer can be as high as 30% or more; this will cause the transfer ball to P 2 0 5 in the gas phase to not exceed 60%. , resulting in a yield of phosphate in P 205 is low,
  • the waste of mineral resources and the significant increase in the cost of phosphoric acid production have caused the above-mentioned KPA process to lose its commercial application and industrial promotion value.
  • Some researchers hope to isolate the reduction zone in the rotary kiln through the volatilized gas in the layer. Oxidation zones, but industrial tests conducted in rotary kiln with an inner diameter of 2 m have shown that the presence of P 2 0 5 -rich white shell on the pellet surface is still unavoidable.
  • phosphoric acid is produced according to the KPA process proposed by 0RC, which is still very difficult in large-scale industrial applications and practices.
  • Joseph A. Megy has proposed some improved technical methods for the KPA process (see US Pat. No. 7,910,080 B), which is to set the stop at the discharge end of the kiln head of the rotary kiln cylinder while maintaining the basic KPA process.
  • the material ring is used to increase the solid material filling rate of the rotary kiln.
  • by increasing the diameter of the rotary kiln to reduce the surface area to volume ratio of the material layer in the rotary kiln the probability of the material layer being exposed on the surface of the solid material layer is reduced.
  • the process also adds a portion of petroleum coke to the material entering the rotary kiln, in order to utilize the reducing gas generated by the volatilization of the volatiles in the petroleum coke to cover between the material layer and the oxidation zone of the rotary kiln.
  • the material pellets to be used are double-layer composite structure, and the inner layer is made of phosphate rock, silica (or lime, limestone, etc.) and carbonaceous reducing agent after being ground and mixed.
  • the outer layer is a layer of solid fuel containing more than 20% carbon on the inner layer pellet. The inner and outer layers of the pellet are added with a binder, and the pellet is dried and consolidated.
  • Pellet inner Ca0 / Si0 2 molar ratio may be less than 0.6 or greater than 6.5, the carbonaceous reducing agent is a reducing 1 ⁇ 3 times the theoretical amount of phosphate rock, the solid fuel pellet with an outer layer of the inner layer can amount
  • the mass of the pellet is 5% to 25%;
  • the binder added to the pellet and the outer layer may be asphalt, sodium humate, ammonium humate, water glass, sulfite pulp waste liquid, syrup, lignosulfonate 2% ⁇ 15% ( ⁇ ) ⁇
  • the pellet can be dried and consolidated, the consolidation temperature is 80 ° C ⁇ 600 ° C, and the consolidation time is 3 min ⁇ 120 min.
  • the above method proposed by the method uses a high temperature resistant wrapping material containing solid carbon on the pellet, and a binder is added during the wrapping so that the outer covering can adhere well to the inner pellet.
  • the double-layer composite pellets are dried and consolidated and sent to the rotary kiln.
  • the high temperature zone of the rotary kiln 300 ° C ⁇ 140 (about TC) can achieve the carbothermal reduction of phosphate ore.
  • the surface of the sphere is artificially coated with a coating layer containing a solid reducing agent (carbonaceous material), which can align its inner layer pellets with the gas oxidization zone containing 0 2 and P 2 0 5 in the upper part of the rotary kiln layer. Effective physical isolation.
  • the carbon in the coating layer can undergo a limited oxidation reaction with 0 2 in the oxidation zone (due to the time when the material ball is exposed on the surface of the rotary kiln layer in the industrial large rotary kiln) Shorter, less complete reaction, so that 0 2 can not be transferred to the inner pellet, ensuring that the reducing agent carbon in the inner pellet is not oxidized by the oxygen in the rotary kiln gas flow, so that P 2 0 5 in the phosphate rock the restore process can be performed completely realized process P 2 0 5 in phosphate Reduction rate.
  • an upper kiln gas stream in the oxidation zone layers P 2 0 5 can not react with the carbon composite pellet surface layer and wrapping, thus preventing the formation of a phosphate or metaphosphate on the composite pellets
  • the salt compound eliminates the formation of P 2 0 5 white shell on the original KPA process sphere, ensuring that the process can obtain a higher P 2 O 5 yield.
  • the method is replaced by solid fuel or Partially replaced Gas or liquid fuel, which further reduces the production cost of phosphoric acid.
  • the pellet drying process is prone to bursting, the bursting composite pellets enter the rotary kiln in the rotary kiln high-temperature reduction belt powdering ring; 3) in the process reaction phase, the generated metaphosphoric acid and the kiln gas In the dust reaction, a complex metaphosphate is generated at the end of the rotary kiln, and a knot kiln tail is gradually formed in the tail cylinder of the rotary kiln, which seriously reduces the operating efficiency of the rotary kiln; 4) in the cooling recovery stage, the rotary kiln is released after cooling the high-temperature slag P after the ball 205 to be improved, there is no reasonable cooling heat utilized effectively, the cooling process The waste of resources and energy is more serious; 5) In the subsequent stage of phosphoric acid production, the amount of flue gas of thermal phosphoric acid is small, the flue gas flow rate of equipment is low, the equipment system is quite large, the structure is complex, and the investment and operating costs
  • the technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, and provide an improved type of slewing with reasonable optimization of process flow, small equipment investment, high economic added value, energy saving and environmental protection throughout the process, high efficiency, and excellent product quality.
  • the technical solution proposed by the present invention is an improved method for producing phosphoric acid by using a rotary kiln in a large scale, comprising the following steps:
  • Raw material pretreatment The raw carbonaceous reducing agent, phosphate rock and silica are pretreated with a carbonaceous reducing agent pretreatment system, a phosphate ore pretreatment system and a silica pretreatment system, respectively, and the carbonaceous reduction after pretreatment
  • the agent, phosphate rock and silica are fed into the inner ball mixing device for mixing and pelletizing, and the pretreated carbonaceous reducing agent and silica are additionally sent to the outer shell mixing device for mixing. Hehe.
  • step (3) The composite pellet obtained in step (3) is transferred from the feed pipe of the rotary kiln tail box into the cavity of the rotary kiln, and the fuel burner is ignited to heat the reduction zone in the rotary kiln to 1300 ° C ⁇ 145 (TC, the composite pellets in the rotary kiln are reduced by the reducing agent under high temperature conditions to form kiln flue gas, through the outlet flue setting, the kiln flue gas at the end of the rotary kiln is entering When the flue is exported, there is no large deviation in the direction of movement, which prevents the meta-phosphoric acid in the kiln flue gas from generating centrifugal physical sediment at the end of the rotary kiln, so that the meta-phosphoric acid in the kiln gas directly enters the kiln flue gas.
  • the high temperature slag ball from the rotary kiln is sent to a cooling device for comprehensive
  • Hydration and phosphorus absorption The kiln flue gas containing P 2 0 5 and fluorine is introduced into the hydration tower, and the acid circulation spray system connected with the hydration tower is opened before, and the acid liquid circulation spray is sprayed.
  • the system continuously transports the concentrated phosphoric acid solution to the spraying device in the hydration tower, and the concentrated phosphoric acid solution sprayed downward is in full contact with the kiln flue gas containing P 2 O 5 and fluorine entering the tower, and the mass transfer is carried out.
  • the spraying device of the hydration tower continues to perform circulating spraying; the flue gas discharged from the flue gas outlet passes through the phosphoric acid mist collecting tower and the defogging separation tower in order to make the phosphoric acid mist entrained in the flue gas of the effluent tower Further trapped, the phosphoric acid mist trapping tower and defogging separation
  • the dilute phosphoric acid solution formed after the capture of the phosphoric acid mist maintains the string acid with the concentrated phosphoric acid solution in the hydration tower through the pipeline arrangement; during the hydration phosphorus absorption operation, the concentrated phosphoric acid solution in the acid circulation spray system will Continuously increase the strength, the extra part is filtered as the crude phosphoric acid product, and the crude phosphoric acid product enters the subsequent phosphoric acid refining process; on the other hand, the supporting online water replenishing device implements online replenishment of the entire process, and the demisting separation tower discharges The fluorine-containing flue gas enters the subsequent
  • the carbonaceous reductant pretreatment system comprises: crushing the carbonaceous reducing agent with a single-stage crushing device to a particle size of 30 mm or less (preferably 6 mm to 30 mm), and then sending the crushed crushed stone to the carbonaceous material.
  • Reductant intermediate silo, carbonaceous reductant intermediate silo sends the crushed stone to the grinding equipment through the metering feeding equipment for grinding, after the grinding equipment grinds the feed to the required particle size (generally - 100 mesh or more, preferably -200 mesh to -325 mesh), a combined dust collector consisting of a cyclone collecting device and a bag collecting device collects powder (or separate bag collecting device) and transports it to carbon reduction.
  • a powder storage bin during the grinding process, the hot air is continuously supplemented by the configured hot air furnace to dry the moisture entrained in the powder;
  • the process of the phosphate ore pretreatment system comprises: firstly crushing the phosphate rock with a single-stage crushing device to a particle size of 30 mm or less (preferably 6 mm to 30 mm), and then sending the crushed crushed stone to the middle of the phosphate ore.
  • the silo, the phosphate ore intermediate silo is sent to the grinding equipment for grinding by the metering feeding equipment, and the grinding equipment will grind the feed to the required grain size (generally -100 mesh or more, Preferably, -100 mesh to -200 mesh), a combined dust collector consisting of a cyclone collecting device and a bag collecting device collects powder (or a bag collecting device separately) and transports it to a homogenizing bank; During the grinding process, the hot air is continuously replenished by the configured hot blast stove to dry the moisture entrained in the powder;
  • the process of the silica pretreatment system comprises: firstly crushing the silica into a single-stage crushing device or a two-stage closed-circuit crushing device to a particle size of 30 mm or less (preferably 6 mm to 30 mm), and then sending the crushed crushed stone to the silica.
  • the intermediate silo sends the crushed stone to the grinding equipment for grinding through the metering feeding equipment, and the grinding equipment grinds the feed to the required particle size (generally -100 mesh or more, preferably -100 mesh ⁇ -200 mesh), a dust collector collected by a cyclone collecting device and a bag collecting device collects the powder and transports it to the silica powder storage bin; the hot air furnace is configured through the grinding process The hot air is continuously replenished to dry the moisture entrained in the powder.
  • the required particle size generally -100 mesh or more, preferably -100 mesh ⁇ -200 mesh
  • a dust collector collected by a cyclone collecting device and a bag collecting device collects the powder and transports it to the silica powder storage bin
  • the hot air furnace is configured through the grinding process The hot air is continuously replenished to dry the moisture entrained in the powder.
  • the single-stage crushing device adopts a hammer crusher or a counter-crusher, or a combined crusher synthesized by a hammer crusher and a counter-crushing crusher;
  • the two-stage one closed-circuit crushing device is mainly connected by a tandem type a crusher, a sieving machine and a cone crusher, and the discharge port of the cone crusher is cyclically connected to the feed port of the sifter;
  • the grinding device in the carbonaceous reductant pretreatment system adopts a vertical mill or a wind sweeping coal mill;
  • the grinding equipment in the phosphate ore pretreatment system adopts a vertical mill or a wind sweep ball mill;
  • the grinding equipment in the treatment system uses a ball mill and/or a high pressure roller press;
  • the homogenization library is a gap homogenization library or a continuous homogenization library, and the homogenization library uses compressed air to agitate and homogenize the powder in the library, and the homogenization value is greater than or equal to 4.
  • the binder is a mixed solution containing sodium humate, and the mass percentage of the sodium humate in the binder 4% ⁇ 20%
  • the preparation of the binder comprises the following steps: selecting a coal containing humic acid (having a particle size of generally -20 mm) and caustic soda as a raw material, mixing the caustic soda with water in proportion Formulated into a NaOH solution (the mass concentration of the prepared sodium hydroxide solution is preferably controlled to be 1% to 10%); the coal material and the NaOH solution are ball-milled at a solid-liquid ratio of 1:3 to 10; The mixture is stirred and heated to 40 ° C to 95 ° C for synthesis reaction, the reaction time is not less than 30 min (preferably 30 min to 180 min); the reaction product is filtered, and the filtrate obtained after filtration is a binder.
  • the coal material preferably refers to weathered coal, peat and/or lignite having a
  • the intensive mixer in the step (2) and the step (3) comprises a tilting rotating mixing barrel, and the mixing barrel is equipped with a rotatable agitator, and the mixing barrel is mixed.
  • the direction of rotation is opposite to the direction of rotation of the agitator, so that the mixture in the mixing tank forms a turbulent flow therein to achieve a sufficient agitation effect.
  • the pelletizers are all disc-type pelletizers; the inner spheres which are sieved out in the step (3) and which do not meet the process requirement granularity are sent to the wheel mill or the grinding mill for crushing, crushing process
  • the inner pellets may be selectively replenished according to the material humidity requirements, and then returned to the intensive mixer or the refiner to form a closed loop.
  • the dryer used in the step (3) is a slat dryer, and the slat dryer is divided into three dryings of low temperature, medium temperature and high temperature along the conveying direction of the composite green ball.
  • the low-temperature drying section is passed through a low-temperature hot air of 100 ° C to 200 ° C to extract air from top to bottom or from bottom to top, so that low-temperature hot air passes vertically through the layer, and the composite green ball is subjected to through-flow drying;
  • the low temperature hot air is exhaust gas discharged from a high temperature hot air outlet of the high temperature drying section;
  • the medium-temperature drying section is passed through a medium-temperature hot air of 150 ° C to 250 ° C to extract air from top to bottom or blast from bottom to top, so that the medium-temperature hot air passes vertically through the layer, and the composite green ball is subjected to Dry through;
  • the high-temperature drying section is passed through a high-temperature hot air of 200 ° C to 350 ° C to extract air from top to bottom or blast from bottom to top, so that high-temperature hot air passes vertically through the layer, and the composite green ball is subjected to through-flow drying.
  • the rotary kiln comprises a kiln body, a kiln head box, a kiln tail box and a driving device for driving the rotation of the kiln body, and is provided at the kiln head of the kiln body.
  • the fuel burner a feed pipe and an outlet flue connected to the external hydration tower at the kiln tail box, the upper part of the kiln body is not provided with a duct, and the outlet flue is arranged on the axis of the rotary kiln Within the central kiln radius, the direction of flue gas transport in the exit flue is substantially parallel to the axis of the rotary kiln or at an angle of less than 45°.
  • the kiln body preferably comprises an outer cylinder shell and a kiln lining disposed on the inner side of the cylinder shell (the kiln lining is mainly composed of refractory brick or refractory castable), and the kiln body is divided along the length direction of the rotary kiln to include reduction Belt and pre-tropical zone, the reduction belt is close to the kiln head box, the pre-tropical zone is close to the kiln tail box, the length of the reduction zone is 1/3 ⁇ 3/5 of the length of the kiln body, and the length of the pre-tropical zone accounts for 2/5 of the length of the kiln body ⁇ 2/3.
  • the kiln lining is preferably mainly composed of a composite refractory brick or a composite refractory castable, and the kiln lining in the reduction belt comprises a layer of clay material close to the shell shell (small thermal conductivity) and a layer of high aluminum material close to the inner cavity of the rotary kiln (refractory High degree, high thermal conductivity); the kiln lining in the pre-tropical zone includes a layer of clay material close to the shell of the cylinder (small thermal conductivity) and a layer of silicon carbide material close to the cavity of the rotary kiln (reactive with metaphosphoric acid, The thermal conductivity is relatively large).
  • a kiln cleaning machine is arranged outside the kiln tail box, and a kiln machine is provided with a progressive extension into the rotary kiln kiln box.
  • a scraper heat-resistant stainless steel that maintains a relative scraping of the inner wall of the chamber.
  • the axis of the rotary kiln is at an angle of 1. 7 ° to 2.
  • the aspect ratio of the kiln body (3) (the ratio of the length of the rotary kiln to the inner diameter of the steel shell of the rotary kiln) is 10
  • the range of the rotary kiln is 6% to 25%, and the rotational speed of the rotary kiln is controlled to be 0.6 r / min to 3 r / min.
  • the rotary kiln is mounted with a plurality of thermocouples for monitoring the temperature in the kiln along the longitudinal direction of the kiln, and the thermocouple passes through the conductive ring or the wireless transmitting and receiving device and the temperature control device outside the rotary kiln. It is connected with a temperature display; the kiln head of the rotary kiln is equipped with an industrial television for monitoring the condition of the rotary kiln.
  • an air suction pump for extracting a gas sample is installed in the kiln trunk of the rotary kiln or on the outlet flue.
  • the method for comprehensive utilization preferably includes the following steps:
  • the cooling device comprises a supporting device, a trolley and a casing, the trolley is located on the supporting device, the casing is erected above the trolley, the raft is provided on the trolley, the feeding area of the cooling device is unloaded The zone is connected to the trolley, and the high-temperature slag ball is sent to the trolley of the cooling device; the cooling device is divided into at least two interconnected cooling sections, and each cooling section is respectively provided with a cold air inlet And a hot air outlet corresponding thereto; the air flow passage between the cold air inlet and the hot air outlet passes through the seesaw on the trolley, and the movement track of the trolley passes through the feeding zone and the plurality of Cold air inlet and discharge area;
  • the trolley carries the high-temperature slag ball into the first cooling section by rotation, and the first cooling section introduces cold air from the cold air inlet port by using a blower in a lower portion of the trolley, the cold air passing through a cooling section of the trolley and its seesaw, heat exchange with the hot slag ball on the trolley, while burning the remaining unreacted carbon in the high temperature slag ball, after the heat exchange of the first cooling section, from
  • the hot air discharged from the first hot air outlet corresponding to the first cooling section is sent to the rotary kiln head box through the first hot air conveying pipeline and then enters the rotary kiln cavity as a hot air source of the combustion reduction reaction product in the rotary kiln (specifically as combustion Phosphorus and CO combustion air);
  • the trolley carries the high-temperature slag ball from the first cooling section to the second cooling section by rotation, and the second cooling section uses the blower of the lower part of the trolley to introduce cold air from the cold air inlet.
  • the cold air passes through the trolley and the seesaw located in the second cooling section, and exchanges heat with the hot slag ball on the trolley, and after the heat exchange through the second cooling section, the second corresponding to the second cooling section
  • the hot air discharged from the hot air outlet is sent to the kiln method phosphoric acid composite composite ball dryer through the second hot air conveying pipe as a hot air source for the composite green ball drying;
  • the trolley carries the high-temperature slag ball from the second cooling section to the subsequent remaining cooling sections by rotation, and the remaining cooling sections use the blower of the lower part of the trolley to introduce cold air from the cold air inlet vent
  • the cold air passes through the trolleys and their seesaws located in the remaining cooling sections, exchanges heat with the hot slag balls on the trolleys, and after the heat exchange of the remaining cooling sections, the heat discharged from the remaining hot air outlets
  • the dust can be directly discharged or sent to the kiln method phosphoric acid composite composite ball dryer as a hot air source for the composite green ball drying; the cooled slag ball can be discharged from the discharge zone.
  • the temperature of the hot air discharged from the first hot air outlet is preferably controlled to be above 600 ° C, and the temperature of the hot air discharged from the second hot air outlet is preferably controlled at 350. Above °C.
  • the temperature of the slag ball can be lowered to 100 °C, and the temperature of the outlet hot air of the final cooling section is generally less than 150 °C.
  • the cooled slag ball is discharged from the discharge area and used as artificial ceramsite, and can be directly used as a building material or a flower cultivation soil; or the cooled slag ball is finely ground to at least 100 mesh and above 80%, and then The active material of the concrete is produced or used as a mixture for the manufacture of cement.
  • the cooling device is preferably a ring cooler or a belt cooler, the cold air inlet is disposed under the trolley, and the hot air outlet is disposed above the trolley ( Of course, it is also possible to use the upper air inlet and the lower hot air.)
  • the ring cooler is divided into the at least two interconnected cooling sections (preferably 2 to 5 cooling sections, and the length of each cooling section is preferably equal) in the circumferential direction; Separated.
  • the belt cooler is divided into at least two (preferably 2 to 5) interconnected cooling sections along the length direction; the cooling sections are separated by a partition.
  • first hot air outlet is disposed in the first cooling section adjacent to the feeding zone
  • second hot air outlet is disposed in the second cooling section adjacent to the first cooling section, and is adjacent to the remaining remaining cooling sections of the second cooling section Set the corresponding hot air outlet.
  • the spraying device in the hydration tower in the step (5) comprises at least two spray layers located at different heights of the vat chamber, and at least two sprays
  • the layer comprises a dilute phosphoric acid spray layer and a concentrated phosphoric acid spray layer, and the concentrated phosphoric acid spray layer is disposed above the dilute phosphoric acid spray layer;
  • the inlet pipe of the circulating phosphoric acid spray layer and the acid liquid circulation spray system Connected, the inlet pipe of the dilute phosphoric acid spray layer is connected with the circulating transport pipe of the dilute phosphoric acid solution in the phosphoric acid mist trapping tower to cause the dilute phosphoric acid solution in the phosphoric acid mist trapping tower to be acidized into the hydration tower.
  • the acid circulating spray system is further connected to the phosphoric acid mist trap by a pipe to cause the circulating phosphoric acid solution in the hydration column to be acid-acidized into the phosphoric acid mist trap.
  • the acid cooler in the step (5) is a heat exchange plate in which a plurality of modified graphite tubes or stainless steel tubes are arranged in a stirring tank, and circulating cooling water is introduced into the tubes.
  • the phosphoric acid solution entering the acid cooler forms forced convection heat exchange on the heat exchange plate;
  • the kiln flue gas in the step (1) is exchanged with the circulating phosphoric acid solution circulating and sprayed, and the hydration tower
  • the cooling of the internal water cooling system reduces the temperature to 75 °C ⁇ 130 °C;
  • the mass percentage concentration of the phosphoric acid solution sprayed in the hydration tower in the step (5) is 60% to 90%, and the temperature control of the concentrated phosphoric acid solution in the hydration tower is controlled.
  • the spray liquid gas ratio in the hydration tower is controlled at lL/m 3 to 20 L/m 3 .
  • the phosphoric acid purification step in the step (5) is provided with a phosphoric acid purification tank for purifying the crude phosphoric acid product, and the activated carbon, the diatomaceous earth, the desulfurizing agent and the dephosphorization agent are added to the phosphoric acid purification tank.
  • the amount of the arsenic agent, activated carbon and diatomaceous earth is controlled to 0.1% to 2% of the mass of the crude phosphoric acid product to be refined;
  • the desulfurizing agent is a soluble cerium salt, and the amount thereof is a theoretical amount (according to the chemical reaction formula) ⁇ 2 times;
  • the arsenic removal agent is hydrogen sulfide or sodium sulfide, the amount of which is theoretical 5h ⁇ 2 ⁇
  • the amount of the reaction time is 0. 5h ⁇ 2h.
  • the phosphoric acid mist trapping tower in the step (5) is a first-stage countercurrent washing tower, comprising a washing tube and a separating tank, and the flue gas discharged from the flue gas outlet of the hydrating tower enters.
  • the washing tube of the phosphoric acid mist trapping tower the circulating dilute phosphoric acid solution sprayed from the bottom up in the washing tube collides with the upstream and downward flue gas to establish a foaming zone, and the flue gas passes through the foaming zone and a large area.
  • the surface of the dilute phosphoric acid solution is continuously updated, and the accumulation of phosphoric acid mist particles, the growth of the polymerization and the heat transfer occur in the foam zone.
  • the flue gas is further cooled to 60 ° C to 90 by adiabatic evaporation of the water in the dilute phosphoric acid solution. °C ; the gas and liquid in the washing tube enter the lower separation tank for gas-liquid separation, and the separation tank also serves as a circulating acid tank (recycle tank of dilute phosphoric acid solution), and the circulating dilute phosphoric acid solution falls into the bottom of the separation tank. Most of them are returned to the washing tube by a circulating pump, and a small portion of the acid is transferred to the hydration tower; the mass concentration of the diluted phosphoric acid solution circulating in the phosphoric acid mist collecting tower is 10% to 50%.
  • the temperature of the dilute phosphoric acid solution is controlled at 40 °C ⁇ 70 °C, and the spray liquid gas ratio in the phosphoric acid mist trap tower is controlled at 3L/m 3 ⁇ 25L/m 3 . Most of the phosphoric acid mist entrained in the flue gas of the effluent tower is transferred to the circulating dilute phosphoric acid solution.
  • the flue gas discharged from the flue gas outlet in the phosphoric acid mist trapping tower in the step (5) is further introduced into the defogging separation tower for further gas-liquid separation, and the defogging separation tower
  • the lower part is designed like a phosphoric acid droplet trapping structure of a cyclone, and the grown phosphoric acid droplets are collected from the flue gas by centrifugal force, and a wire mesh mist eliminator is installed on the upper part of the defogging separation tower to set the flue gas.
  • the phosphorous droplets that have not yet grown up are further captured;
  • the online water replenishing device is installed in the defogging separation tower and is located at the flue gas outlet position above the screen mist eliminator, and on the one hand serves as a water supply device for the entire process system.
  • the phosphoric acid mist in the flue gas is further captured by washing, and serves as a flushing device for the screen defogger.
  • the fluorine recovery step in the step (5) comprises the following steps:
  • First-stage fluorine absorption First, the fluorine-containing flue gas discharged from the defogging separation tower is sent to the fluorosilicic acid washing tube of the first-stage fluorine absorption tower, and the flue gas is sprayed from top to bottom and the nozzle from bottom to top.
  • the circulating fluorosilicic acid solution undergoes sufficient gas-liquid two-phase contact, and undergoes mass transfer heat transfer and chemical reaction to form fluorosilicic acid, and the enthalpy in the flue gas is partially cooled by the adiabatic evaporation cycle of the fluorosilicic acid solution. Transfer to water vapor;
  • the first-stage fluorine absorption tower and the second-stage fluorine absorption tower are both fluidized counter-current washing towers, and the first-stage fluorine absorption tower is mainly composed of a fluorosilicate washing tube and a fluorosilicic acid separation tank, and an outlet of the fluorosilicate washing tube Connected to the middle of the fluorosilicic acid separation tank, the top of the fluorosilicic acid separation tank is provided with a flue gas outlet, and the bottom is provided with a fluorosilicic acid liquid outlet, and the fluorosilicic acid liquid outlet passes through a circulating conveying pipeline with a circulating pump and the fluorine The nozzles in the silicic acid washing tube are connected;
  • the above-mentioned secondary fluorine absorption tower is mainly composed of a secondary fluorosilicate washing tube and a secondary fluorosilicic acid separation tank, and the flue gas outlet of the first-stage fluorine absorption tower is connected to the secondary fluorosilicate washing tube through the pipeline, the secondary fluorine
  • the outlet of the silicic acid washing tube is connected to the middle of the secondary fluorosilicate separation tank, and the top of the secondary fluorosilicate separation tank is provided with a defoaming layer (the defoaming layer is periodically sprayed with a circulating fluorosilicic acid solution to keep the defoaming Effect) and flue gas outlet, the bottom is provided with a fluorosilicic acid liquid outlet, the fluorosilicic acid liquid outlet passes through a circulating conveying pipe of a circulating pump and a nozzle in the secondary fluorosilicate washing pipe and the fluorosilicic acid of the first-stage fluorine absorption tower
  • the separation tanks are connected
  • the circulating transport pipeline in the secondary fluorine absorption tower may also preferably be provided with a fluorosilicic acid cooler, and the circulating fluorosilicic acid solution entering the secondary fluorosilicate washing tube is subjected to cooling treatment by the fluorosilicic acid cooler. .
  • the first-order fluorine absorption uses a cyclic fluorosilicic acid solution having a mass percentage of 8% to 25% (more preferably 10% to 20%), and the temperature of the circulating fluorosilicic acid solution is 25 ° C ⁇ 65 ° C (more preferably 50 ° C ⁇ 65 ° C), the spray liquid to gas ratio is controlled at 3L / m 3 ⁇ 25L / m 3 (more preferably 3L / m 3 ⁇ 6L / m 3 ); The concentration of the recycled fluorosilicic acid solution is 0.5% to 5%, and the temperature of the circulating fluorosilicic acid solution is 25 ° C to 60 ° C (more preferably 45 ° C to 60 ° C).
  • the spray liquid-gas ratio is controlled to be 3 L/m 3 to 25 L/m 3 (more preferably 3 L/m 3 to 6 L/m 3 ).
  • the flue gas outlet of the secondary fluorine absorption tower is further connected to a tail suction tower, the tail suction tower is a spray empty tower, and the top of the tail suction tower is provided with a flue gas outlet.
  • a spray layer is arranged on the upper side of the tower, and an alkali absorption liquid tank is arranged at the bottom. The outlet of the alkali absorption liquid tank communicates with the spray layer in the tail suction tower through a circulation conveying pipe with a circulation pump to control the alkali absorption liquid. 11 value 8.
  • the raw material pretreatment in the present invention is an optimized and improved high crushing ratio crushing device, which not only can significantly reduce the crushing energy consumption, but also can reduce the crushing equipment investment and Process cost, improve crushing efficiency;
  • each main raw material is equipped with independent crushing equipment and grinding equipment, and by separately crushing and separately grinding and milling, the stability of the raw material formula can be largely ensured.
  • to prevent large fluctuations in the ratio of raw materials by using a grinding furnace equipped with a hot blast stove, the drying process of various ores and raw materials is eliminated, and the process flow It is more simplified, and the energy consumption of grinding is reduced by more than 20%.
  • the homogenization of phosphate ore powder adopts the method of gas flow homogenization, which is beneficial to further ensure the stability of the chemical composition of the process phosphate ore and make industrialized stable production possible.
  • the binder prepared in the invention not only has simple composition, wide source of raw materials, low cost, and good bonding effect of the binder; the consistency of the composite pellet is more easily ensured.
  • the fluctuation of the ingredients is very small (the fluctuation range of the compounding ratio in the composite pellet can be accurately controlled within 5%); in the present invention, the dryer of the composite pellet is also importantly improved and improved, firstly the dryer Divided into three drying sections, the drying process of the composite green ball is carried out from low to high.
  • the first drying section utilizes the low temperature hot gas residual heat discharged from the third drying section to dry the wet composite green ball in the initial stage of the dryer. In this aspect, the waste heat resource is utilized.
  • the air temperature of the first drying section is low, the pellets can be effectively prevented from being damaged by the bursting of the wet composite ball, and the quality of the composite pellets that are subsequently inserted into the kiln can be ensured;
  • the second drying section is connected to the medium temperature hot air without water vapor to form a high humidity difference, which accelerates the drying of the pellets while ensuring that the pellets do not burst;
  • the moisture content of the composite pellets entering the third drying section has dropped below 4%.
  • a high temperature hot air of a higher temperature can be introduced to accelerate the drying and consolidation process of the pellets without ensuring the pellets to burst;
  • the pellet moisture of the dryer can be controlled at 1.0%, the compressive strength of the pellet reaches 250KN/ball, and the drop strength reaches 20 times/1m, which can fully guarantee that it will not be damaged during operation in the reduction rotary kiln, thereby ensuring The subsequent pellet reduction process proceeds normally.
  • the invention sets the outlet of the flue gas exhaust pipe of the rotary kiln kiln in the same direction as the axis of the rotary kiln (for the convenience of arranging to the hydration tower pipe, it may also be appropriately offset), so that the rotary kiln is discharged from the kiln.
  • the flue gas enters the outlet flue, it will not make a large deviation in the moving direction, thereby preventing the centrifugal phosphoric acid from decomposing in the kiln flue gas at the kiln tail. Due to the reduction of the metaphosphoric acid that settles in the kiln, the formation cycle of the kiln tail ring is prolonged, and the operating efficiency of the rotary kiln is improved.
  • the kiln lining of the rotary kiln pre-tropical zone adopts a double-layer composite structure
  • a clay material layer is adopted in a portion close to the rotary kiln cylinder shell
  • a silicon carbide material layer is used on the inner side near the rotary kiln. Because of the difficulty in reacting the metaphosphate with the silicon carbide material, the metaphosphate deposited in the pre-tropical zone of the rotary kiln can be dropped by gravity.
  • a scraper made of heat-resistant stainless steel can be installed outside the rotary kiln kiln.
  • the material ball is returned from the kiln tail, then the fuel supply to the rotary kiln can be stopped and stopped.
  • the scraper can be gradually inserted into the rotary kiln, and the rotary kiln itself can be used to scrape off the kiln tail ring.
  • the comprehensive utilization process of the present invention makes full use of the waste heat resource of the high-temperature slag ball, and uses the waste heat as a reduction reaction heat in the kiln process phosphoric acid process to make the rotary kiln
  • the energy consumption is significantly reduced; it is also used as a heat source for the composite ball drying, which makes full use of the thermal energy resources of different temperatures in different cooling stages, so that the energy utilization of the whole kiln phosphoric acid process is more sufficient; It also achieves efficient, high value-added utilization, rather than direct efflux, which not only reduces the environmental pollution and damage of solid waste, but also makes efficient use of waste resources.
  • the present invention relates to an existing phosphoric acid plant and process
  • a lot of improvements and optimizations have been made to make the structure of the whole equipment more simplified, the process flow more reasonable, and more adaptable.
  • the existing equipment and process for recycling fluorine have also been greatly improved and optimized, so that the entire fluorine recovery equipment
  • the structure is more simplified, the process flow is more reasonable, and the process route of hydration absorption of phosphoric acid can be better matched; in the preferred technical solution, the simultaneous recovery of P 2 O 5 and fluorine in the kiln flue gas can be realized.
  • the process of the invention not only has reasonable process and optimization, but also has small equipment investment and high economic added value, and solves many technical problems existing in the existing kiln phosphoric acid process, and the whole process is energy-saving and environmentally friendly, and runs.
  • High efficiency, excellent product quality, fully applicable to the direct production of phosphoric acid in low-grade phosphate rock can fully adapt to the characteristics of flue gas containing P 2 0 5 and fluorine (especially kiln process kiln gas) and treatment needs, for a large number of low grades in China
  • the effective use of phosphate rock is of great significance.
  • FIG. 1 is a schematic diagram of a process flow for producing phosphoric acid by using a rotary kiln in a specific embodiment of the present invention.
  • FIG. 2 is a schematic diagram of a process flow of a raw material pretreatment step in a specific embodiment of the present invention.
  • FIG 3 is a schematic structural view of an intensive mixer used in a specific embodiment of the present invention.
  • Figure 4 is a cross-sectional view and the working principle of A-A in Figure 3.
  • Fig. 5 is a structural schematic view of a slat dryer used in a specific embodiment of the present invention.
  • Figure 6 is a cross-sectional view and the working principle of B-B in Figure 5.
  • Figure 7 is a schematic view showing the structure of a rotary kiln according to a specific embodiment of the present invention.
  • Figure 8 is a cross-sectional view taken along line A-A of Figure 7.
  • Figure 9 is a cross-sectional view taken along line B-B of Figure 7.
  • Figure 10 is a cross-sectional view taken along line C-C of Figure 7.
  • Figure 11 is a schematic view showing the structure of a kiln cleaning machine according to a specific embodiment of the present invention.
  • Figure 12 is a cross-sectional view taken along line D-D of Figure 11.
  • Figure 13 is a schematic view showing the operation of the kiln cleaning machine in the embodiment of the present invention.
  • Figure 14 is a cross-sectional view taken along line E-E of Figure 13.
  • Figure 15 is a working principle diagram (top view) of a high temperature slag ball cooling device in accordance with an embodiment of the present invention.
  • Figure 16 is a partial cross-sectional view taken along line B-B of Figure 15.
  • 17 is a process flow diagram of a method for comprehensive utilization of high temperature slag balls according to an embodiment of the present invention.
  • Figure 18 is a schematic view showing the structure of a process system for hydrating phosphorus and recovering fluorine in a specific embodiment of the present invention.
  • Figure 19 is a schematic enlarged view showing the structure of a hydration tower of a phosphoric acid plant in accordance with an embodiment of the present invention.
  • Figure 20 is a schematic enlarged view showing the structure of a phosphoric acid mist trapping tower of a phosphoric acid plant in accordance with an embodiment of the present invention.
  • a modified method for producing phosphoric acid in a rotary kiln as shown in Fig. 1, comprising the following steps:
  • the raw material pretreatment method of the present embodiment uses the raw material pretreatment process system of the present embodiment, and the pretreatment process system includes mutually independent carbonaceous reductant pretreatment systems, a phosphate ore pretreatment system, and
  • the silica pretreatment system, the carbonaceous reductant pretreatment system, the phosphate ore pretreatment system and the silica pretreatment system are connected to an inner ball mixing device, a carbonaceous reductant pretreatment system and silica through the first conveying device.
  • the outlet of the pretreatment system is additionally connected to an outer casing mixing device by means of a second conveying device.
  • coal material (coke powder or petroleum coke) is used as the carbonaceous reducing agent
  • the carbonaceous reducing agent pretreatment system of the embodiment mainly comprises a single-stage crushing device, a coal material intermediate silo, and a grinding device which are sequentially connected.
  • the pulverized coal storage bin and the dosing device are composed;
  • the phosphate ore pretreatment system in the embodiment is mainly composed of a single-stage crushing device, a phosphate rock intermediate silo, a grinding device, a homogenization library and a dosing device which are sequentially connected.
  • the silica pretreatment system in this embodiment is mainly composed of two sections, a closed circuit crushing device, a silica intermediate silo, a grinding equipment, a silica powder storage silo and a dosing device.
  • the single-stage crushing equipment used in the carbonaceous reductant pretreatment system and the phosphate ore pretreatment system uses a hammer crusher.
  • the two-stage one closed-circuit crushing equipment used in the silica pretreatment system is mainly connected by the tandem type.
  • the crusher, the sieving machine and the cone crusher are combined, and the discharge port of the cone crusher is cyclically connected to the inlet of the screening machine.
  • the grinding device of the carbonaceous reductant pretreatment system and the phosphate ore pretreatment system adopts vertical grinding.
  • the grinding equipment in the silica pretreatment system adopts a ball mill and/or a high pressure roller press, and each grinding device passes through respective powders.
  • the material collection and conveying device is connected to the pulverized coal storage silo, the homogenization storage tank and the silica powder storage silo.
  • Each grinding equipment is equipped with a hot blast stove that supplies hot air to the grinding process.
  • Each of the powder collecting and conveying devices comprises a cyclone collecting device, a bag collecting device and a fan connected in sequence, and the air outlets of the respective fans are connected to the hot air furnace corresponding to each pretreatment system or directly discharged.
  • the raw material pretreatment method of the present embodiment mainly processes the raw coal, phosphate rock and silica with the above-mentioned carbonaceous reducing agent pretreatment system, the phosphate ore pretreatment system and the silica pretreatment system, respectively, and the pretreated coal.
  • the powder, phosphate rock powder and silica powder are fed into the inner ball mixing device for mixing and ball forming, and the pretreated coal powder and the silica powder are further sent to the outer shell material mixing device for mixing; the raw material pretreatment method specifically comprises the following steps.
  • Coal material pretreatment The -200mm coal material (coke powder or petroleum coke) is firstly crushed to a particle size of 12mm or less by single-stage hammer crushing (also available in counter-attack or hammer-reverse-type combination crushing).
  • the metering feeding device ie, the vertical mill, or the wind sweeping coal mill Grinding, the load of the mill can be stabilized by the metering feeding device; after the vertical mill grinds the feed to -100 mesh ⁇ -325 mesh, the combination of the cyclone collecting device and the bag collecting device
  • the dust collector collects the powder (can also be collected by a high-concentration bag filter) and transports it to the pulverized coal storage bin; during the grinding process, the hot air is continuously replenished by the configured hot blast stove to dry the powder according to the moisture content of the raw material.
  • the moisture entrained in the material; the pretreatment process of the entire coal material has a high crushing ratio, which can save energy consumption and reduce investment and process costs.
  • Phosphate ore pretreatment The -200mm phosphate ore is first crushed by a single-stage hammer crushing method (also can be crushed by counter-attack or hammer-reverse type combination) to a particle size of 12mm or less, and then crushed.
  • the crushed stone is sent to the phosphate ore intermediate silo, and the phosphate ore intermediate silo is sent to the vertical mill through a metering and feeding device (which can also be used as a wind sweeping ball mill) for grinding, through the metering feeding device.
  • the powder collector is collected by a combined dust collector consisting of a cyclone collecting device and a bag collecting device (also available separately Collected by a high-concentration bag filter and transported to the homogenization store; during the grinding process, the hot air is continuously replenished through the configured hot blast stove to dry the water entrained in the powder according to the moisture content of the raw material;
  • the treatment process has a higher crushing ratio, which can further save crushing energy consumption and reduce investment.
  • silica pretreatment The silica gel of -200mm is first used in two sections and one closed circuit crushing equipment (also can be broken by single stage counterattack) Broken equipment or counter-type-hammer combined crushing method) crushed to a particle size below 12mm, and then sent the crushed crushed stone to the silica intermediate silo, the silica intermediate silo sends the crushed stone to the high pressure through the metering and feeding equipment
  • the roller press (which can also be combined with the high-pressure roller press) can be used for grinding, and the load of the mill can be stabilized by the metering feeding device; after the grinding equipment grinds the feed to -100 mesh to -200 mesh,
  • the combined dust collector consisting of a cyclone collecting device and a bag collecting device collects the powder and transports it to the silica powder storage bin; during the grinding process, the hot air is continuously supplemented by the configured hot blast stove to dry the powder according to the moisture content of the raw material. The moisture entrained in the material.
  • the homogenization library can also use a continuous homogenization library, and the homogenization value is greater than 4; the homogenization library itself serves as a storage bin for the phosphate rock powder.
  • the carbonaceous reducing agent powder obtained after the above step 1 treatment (in this embodiment, coal powder of -200 mesh or more, such as coke powder, anthracite powder or petroleum coke), phosphate rock powder (-150 mesh or more) and silica powder are used. (-150 mesh or more) It is added to an intensive mixer according to the ratio of the compound pellets. The ingredients can be weighed by an electronic scale, and the binder of this embodiment is added in the above-mentioned addition amount.
  • the preparation method of the binder used in the embodiment specifically includes the following steps: selecting weathered coal (or peat, lignite) containing humic acid and caustic soda as raw materials, and the humic acid content in the weathered coal of the embodiment is 40%. Above; mixing caustic soda (93% sodium hydroxide) with water to prepare a 2% by mass sodium hydroxide solution; ball milling of the above weathered coal and sodium hydroxide solution at a solid-liquid ratio of 1:5 Mixing, ball milling time 20min; the mixture is sent to the reaction tank with a stirrer, the stirrer is turned on to 90 ° C for synthesis reaction, the reaction time is 30 min; the reaction product is filtered, and the filtrate obtained after filtration is bonded. Agent.
  • the binder of this example was a mixed solution containing sodium humate, and the mass percentage of sodium humate in the binder was 8%.
  • the intensive mixer used in this embodiment includes a tilting rotatable mixing bucket, and the mixing tub includes a housing 74 and a rotatable agitator 73 mounted in the tub.
  • the hopper 72 and the driving member 71 are provided with a turning plough 75 on one side of the barrel and a discharge opening 76 at the bottom of the barrel; the working principle of the powerful mixer is: the rotation direction of the mixing barrel and the rotation direction of the agitator during mixing Conversely (see Fig.
  • the fully mixed mixture is fed into the silo, and the dosing device metered by the electronic scale is installed in the lower part of the silo, which
  • the metering feeding device may be a feeding device of a combination of a disc feeder and an electronic scale, and the metering is compared with the set feeding amount by the electronic scale, and the deviation is changed by the computer control system to automatically adjust the disc of the disc feeder.
  • the speed is such that the dosing amount is equal to the set value (other metering devices with electronic scales can also be used directly).
  • the molar ratio of CaO/Si0 2 is 0.3 (less than 0.6 or greater than 6.5), and the amount of carbonaceous reducing agent powder is P 2 0 5 in the phosphate rock powder.
  • the ratio of the mass ratio of the carbonaceous reducing agent powder to the silica powder is 2.
  • the thoroughly mixed mixture is sent to a disc pelletizer through a metering feeding device for pelletizing, and the binder of the present embodiment is added in the form of droplets and/or mist application during the pelleting.
  • the addition amount is 4% to 6% of the mass of the mixture, and the inner ball is obtained after the ball is completed.
  • the unqualified inner balls that are sieved out and smaller than the set particle size are sent to the wheel mill (or grinding machine) for crushing, and the materials are crushed according to the wheel mill during the crushing process.
  • the humidity requirement can be selectively added to the inner ball in the previous batching process, and then returned to the intensive mixer of step 2 above to form a closed loop to make full use of the process raw materials and reduce the waste and waste of the intermediate waste in the process.
  • the compressive strength of the composite green ball prepared in this embodiment is about 10 N/ball, and the drop strength is about 10 times/0.5 m, and the fluctuation range of the Ca0/Si0 2 molar ratio in the composite green ball of the present embodiment can Control is within 5%.
  • the slat dryer in this embodiment includes a drying furnace body 78.
  • the drying furnace body 78 is composed of a low temperature drying section 80, a medium temperature drying section 81, and a high temperature drying section 82, and the drying furnace body 78 is The top is provided with a hot air inlet 83, the bottom is provided with an air outlet 85, and the outer periphery is covered with an insulation layer 84.
  • the chamber of the drying furnace body 78 is provided with a loading trolley 77, and a plurality of loading trolleys 77 are connected to each other to form a ring shape.
  • the charging cart 77 is provided with a vent hole 86, which adopts a chain transmission, and rotates the loading trolley 77 through the belt chain to rotate continuously, so as to achieve continuous conveying and drying.
  • a dust remover 79 is provided at the bottom of the drying furnace body 78 to recover the soot generated during the drying process.
  • dry hot air is introduced from the top to the bottom in the vertical direction of the material movement to achieve the purpose of drying.
  • the specific working principle of the slat dryer in this embodiment is that the moving conveying direction of the composite ball charging cart 77 is divided into three drying sections of low temperature, medium temperature and high temperature.
  • the composite green ball first enters the low temperature drying section 80, and the low temperature drying section 80 is introduced into the low temperature hot air of 130 ° C to 200 ° C to extract air from top to bottom (or blast from bottom to top), so that the low temperature hot air passes vertically through the composite The ball layer, and the composite green ball is subjected to through-flow drying; the low-temperature hot air is exhausted from the high-temperature hot air outlet of the high-temperature drying section 82, and is led to the low-temperature drying section 80 by the fan; the low-temperature drying section 80- utilizes The low-temperature hot gas waste heat discharged from the high-temperature drying section 82, on the other hand, due to the low airflow temperature of the low-temperature drying section 80, can effectively prevent the pellet damage caused by the bursting damage of the wet composite green ball, and ensure the quality of the composite pellets that are subsequently introduced into the kiln.
  • the composite green ball dried by the low-temperature drying section 80 is then dried in the medium-temperature drying section 81, and the medium-temperature drying section 81 is passed through a medium-temperature hot air of 200 ° C to 250 ° C and is ventilated from top to bottom (or from bottom to top). Blowing), the medium-temperature hot air is vertically passed through the layer, and the composite green ball is subjected to through-flow drying; the medium-temperature drying section is fed with medium-temperature hot air without water vapor, which forms a high humidity difference, which makes Accelerate the drying of the pellets while ensuring that the pellets do not burst.
  • the composite green ball dried by the medium temperature drying section 81 is then dried in the high temperature drying section 82, and finally the composite pellets entering the high temperature drying section 82 have been reduced to below 4%, and the high temperature drying section 82 is introduced into the temperature range of 250 ° C to 350 ° C.
  • the high temperature hot air is ventilated from top to bottom (or blast from bottom to top), allowing high temperature hot air to pass vertically through the layer and final drying of the composite pellets.
  • the high-temperature hot air of the high-temperature drying section 82 is preferably from the waste heat utilization of the subsequent cooling stage of the rotary kiln discharge, and the hot air furnace can be separately provided for air supply.
  • the exhaust gas discharged from the low-temperature drying section 80 and the medium-temperature drying section 81 can be collected by a fan, and is discharged into the atmosphere through the flue after the dust removal device 79 reaches the environmental protection requirement.
  • the composite pellet obtained after drying and solidification is a core-shell structure in which the outer shell is covered with an inner ball.
  • the inner ball is mainly composed of an inner ball and a binder
  • the outer shell is mainly composed of a wrapping material and a binder;
  • Carbonaceous reducing agent powder, phosphate rock powder and silica powder, the amount of binder added to the inner sphere is 6% of the mass of the inner pellet (may be 1% ⁇ 10%) ;
  • the encapsulating material is composed of carbonaceous reducing agent powder and
  • the composition of the silica powder, the amount of the binder in the outer shell is 6% of the mass of the package (may be 1% to 10%); the inner ball and the outer shell are combined into a core-shell structure by the binder.
  • the moisture content of the composite pellet is controlled at 1.0%, the average compressive strength of the pellet reaches 2501 ⁇ /ball, and the falling strength reaches 20 times/1 meter, which can effectively ensure the composite pellets operate in the subsequent reduction rotary kiln. It is not destroyed, thus ensuring the smooth progress of the composite pellet reduction process.
  • the composite pellets after the dryer are screened through a vibrating screen (or not) to remove the composite pellets (less than 5 mm) damaged during the drying process, so as to reduce the amount of powder that subsequently enters the rotary kiln. , thereby further delaying the ring cycle of the material in the high temperature section of the rotary kiln.
  • the composite pellets after the vibrating screen are sent from the rotary kiln tail box to the rotary kiln through the lock damper through the lock damper for subsequent high temperature reduction treatment.
  • the rotary kiln used in the process of the present embodiment includes a kiln body 93, a kiln head box 91, a kiln tail box 96, and a driving device 95 for driving the kiln body 93 to rotate.
  • the driving device 95 includes The motor, the transmission pinion 94 connected to the motor, and the transmission bull gear 90 engaged with the transmission pinion 94 are additionally provided with a roller device 92 for supporting the kiln body 93.
  • Kiln head A kiln head dynamic seal 100 is used between the tank 91 and the kiln body 93, and a kiln tail dynamic seal 99 is used between the kiln tail box 96 and the kiln body 93.
  • a fuel burner 55 and a high temperature slag ball outlet are provided at the kiln head of the kiln body 93.
  • a feed pipe 98 and an outlet flue 97 connected to the external hydration tower are disposed at the kiln tail box 96 of the kiln body 93.
  • Feed tube 98 is connected to the interior of the rotary kiln.
  • the upper part of the kiln body 93 is not provided with a duct, and the outlet flue 97 is disposed on the axis of the rotary kiln, and the flue gas conveying direction in the outlet flue 97 is substantially parallel to the axial direction of the rotary kiln.
  • the kiln body 93 includes an outer cylinder shell 102 and a kiln liner 101 disposed inside the cylinder shell 102.
  • the kiln body 93 is divided along the length direction of the rotary kiln to include a reduction belt and a pre-tropic zone, and the reduction belt is adjacent to the kiln head box 91.
  • the pre-tropical zone is close to the kiln tail box 96, and the length of the reduction zone can be 1/3 to 3/5 of the length of the kiln body 93 (1/2 in this embodiment), and the length of the pre-tropical zone can account for the length of the kiln body 93. /5 to 2/3 (1/2 in this embodiment).
  • the kiln liner 101 is mainly composed of a composite refractory castable (or composite refractory brick). As shown in Fig. 9, the kiln liner 101 located in the reduction belt includes a layer of clay material 57 near the shell shell 102 and a high aluminum near the inner cavity of the rotary kiln.
  • Material layer 58 (alumina 65%); as shown in Figure 10, the kiln liner 101 in the pre-tropical zone comprises a layer of clay material 57 adjacent the barrel shell 102 and a layer of silicon carbide material 56 adjacent the inner cavity of the rotary kiln.
  • a clear kiln is arranged outside the kiln tail box 96.
  • the kiln is placed on the platform 108.
  • the bottom of the kiln is provided with wheels 109 which can roll on the platform 108.
  • the wheels 109 pass through the wheels.
  • the main body of the kiln is a frame 104.
  • a motor-driven rotating shaft 105 is mounted on the frame 104.
  • the rotating shaft 105 extends out of the frame 104 in a substantially horizontal direction, and a peripheral portion of the protruding portion is sleeved.
  • the support truss 106, the free end of the protruding portion of the rotating shaft 105 is provided with a scraper 110 which can be progressively inserted into the rotary kiln kiln box 96 (the scraper can be easily fed) and can be relatively scraped with the inner wall of the cavity (resistant Hot stainless steel).
  • the material ball is returned from the kiln tail, the fuel supply to the rotary kiln can be stopped and the feeding of the ball into the rotary kiln can be stopped, and the scraper 110 can be gradually extended into the rotary kiln, using the rotary kiln. Rotation of the kiln tail ring is scraped off by its own rotation.
  • the specific operation of the kiln reduction by using the above rotary kiln of the embodiment includes: performing the kiln phosphoric acid process by using the above rotary kiln, so that the composite pellet raw material after the above step 3 is taken from the feed pipe 98 at the end of the rotary kiln Entering the cavity of the rotary kiln, igniting the fuel burner 55, heating the reduction zone temperature in the rotary kiln to 1300 ° C ⁇ 1450 ° C, the phosphate ore raw material in the rotary kiln is reduced by the reducing agent under high temperature to form a kiln Flue gas, by setting the outlet of the rotary kiln tail exit flue 97 in the same direction as the axis of the rotary kiln (ie parallel to the axis of the rotary kiln), so that the flue gas from the kiln at the end of the rotary kiln enters the exit flue 97 When there is a
  • the rotary kiln is placed in the pre-tropical kiln lining 101 to form a double-layer composite refractory castable (or composite refractory brick), which is used in the kiln lining portion of the cylindrical shell 102 near the rotary kiln.
  • the clay material is made into a layer 57 of clay material, and the lining portion near the inner cavity of the rotary kiln is made of silicon carbide material into a silicon carbide material layer 56. Due to the difficulty in reacting the metaphosphate with the silicon carbide material, the reaction is deposited in the rotary kiln.
  • a heat-resistant stainless steel scraper 110 is installed in the clearing kiln supporting the kiln tail box 96 of the rotary kiln of the present embodiment, and the scraper 110 is progressively inserted into the rotary kiln kiln box 96.
  • the feed ball is fed internally, and the ball in the rotary kiln is drained, and then the scraper 110 in the clearing kiln is gradually extended from the rotary kiln door frame 107 into the rotary kiln, and then the rotary kiln itself is rotated to form the kiln tail ring.
  • thermocouples 113 for monitoring the temperature in the kiln are installed along the longitudinal direction of the kiln body 93, and the thermocouple 113 passes through the conductive ring or the wireless transmitting and receiving device and the temperature control device and the temperature display outside the rotary kiln. Connected.
  • the thermocouple 113 it is possible to effectively ensure that the maximum temperature of the composite pellets having a Ca0/Si0 2 molar ratio of less than 0.6 is not more than 1370 ° C; the internal pellet Ca0/Si0 2 moles The maximum temperature of the composite pellets greater than 6.5 does not exceed the reaction set temperature requirement of 1450 °C.
  • An industrial television that monitors the condition of the rotary kiln is installed in the kiln head of the rotary kiln.
  • an air pump 114 for extracting a gas sample is mounted in the outlet flue 97 of the outlet of the kiln box 96 of the rotary kiln of the present embodiment.
  • the axis of the rotary kiln and the horizontal plane are at an angle ⁇ of 1. 2 ° to 2. 9 ° (2.3 ° in this embodiment), and the aspect ratio of the kiln body 3 is 10 to 25: 1 (
  • the present embodiment is 15: 1)
  • the filling rate of the rotary kiln is 7% to 25% (13% in this embodiment)
  • the rotational speed of the rotary kiln is controlled to be 0.6 rpm to 3 rpm. Lr/min).
  • the thickness of the refractory material of the rotary kiln is preferably 200 to 280 (this embodiment is 220).
  • the high-temperature slag ball which is discharged from the rotary kiln after the above step 4 is comprehensively utilized, and specifically includes the following steps.
  • the ring cooler of the present embodiment includes a supporting device 111, a trolley 112 and a casing 43, the trolley 112 is located on the supporting device 111, and the casing 43 is erected above the trolley 112, and the cooling device
  • the feeding zone and the discharging zone are all connected to the trolley 112, and the high-temperature slag ball 49 is sent to the trolley 112 of the cooling device; the ring cooler is divided into three interconnected cooling sections along the circumference direction; The cooling sections are separated by a partition 47.
  • Each cooling section is provided with a cold air inlet 44 and a corresponding hot air outlet; a cold air inlet 44 is disposed below the trolley 112, and a hot air outlet is disposed above the trolley 112; between the cold air inlet 44 and the hot air outlet
  • the air flow passage passes through the trolley 112; the movement track of the trolley 112 sequentially passes through the feeding zone, the plurality of cold air inlets 44 and the discharge zone; each cooling section includes a first cooling section adjacent to the feeding zone and is sequentially connected a second cooling section and a third cooling section, wherein the corresponding first hot air outlet 45 in the first cooling section is connected to the cavity of the rotary kiln through the first hot air conveying pipe; the second hot air correspondingly disposed in the second cooling section Exit 46 passes through the second hot air
  • the delivery line is connected to the cavity of the dryer.
  • a third hot air outlet is correspondingly disposed in the third cooling section.
  • the trolley 112 of the 2-ring cooler rotates around the center of rotation (the trolley is driven by the motor and the reducer) to bring the high-temperature slag ball 49 into the first cooling section, and the first cooling section is cooled by the blower in the lower part of the trolley 112. Air is introduced from the cold air inlet 44, and the cold air passes through the trolley 112 located in the first cooling section to exchange heat with the hot slag ball on the trolley 112 while leaving the remaining unreacted carbon in the high temperature slag 49.
  • the hot air discharged from the first hot air outlet 45 corresponding to the first cooling section (the temperature of the hot air discharged from the first hot air outlet 45 is controlled above 600 ° C)
  • the first hot air conveying pipe is transported into the rotary kiln cavity as a source of hot air for the combustion reduction reaction in the rotary kiln;
  • the three carts 112 continue to carry the high temperature slag ball 49 from the first cooling section into the second cooling section by rotating about its center of rotation, and the second cooling section uses the blower in the lower part of the trolley 112 to take cold air from the cold air inlet 44. Introducing, the cold air passes through the trolley 112 located in the second cooling section, exchanges heat with the hot slag ball on the trolley 112, and after the heat exchange of the second cooling section, the second hot air outlet corresponding to the second cooling section 46 The hot air discharged (the temperature of the hot air discharged from the second hot air outlet 46 is controlled above 350 ° C) is transported to the kiln process phosphoric acid compound composite ball dryer through the second hot air conveying pipe as a composite green ball drying Hot air source
  • the four carts 112 continue to carry the high temperature slag ball 49 from the second cooling section into the subsequent third cooling section by rotation, and the third cooling section uses the blower in the lower part of the trolley 112 to introduce cold air from the cold air inlet 44.
  • the cold air passes through the trolley 112 located in the third cooling section, and exchanges heat with the hot slag ball on the trolley 112.
  • the hot air discharged from the third hot air outlet can be directly discharged by the chimney 48 after being dusted. (Or can also be sent to the dryer); the cooled ball can be discharged from the discharge area.
  • the cooled slag ball is discharged from the discharge area and used as artificial ceramsite and used directly as building material or flower cultivation soil; or the cooled slag ball is finely ground to at least 100 mesh and above 80%, and then used as concrete for manufacturing The active material or as a mixed additive for the manufacture of cement.
  • the hydration phosphorus uptake step of this embodiment requires the use of the following process system shown in Figure 18, which includes a phosphoric acid system and a fluorine recovery unit.
  • the phosphoric acid production system used in this embodiment includes a hydration tower 1, an acid circulation spray system, a phosphoric acid mist trap tower 3, and a defogging separation tower 4.
  • the body of the hydration tower 1 is a spray empty tower (see Fig. 19), the lower part of the hydration tower 1 is provided with a flue gas inlet 11 for discharging kiln flue gas, and the top is provided with a flue gas outlet 12 after hydration absorption.
  • a sprinkler device 13 is disposed in the cavity of the hydration tower 1 above the flue gas inlet 11, and the liquid inlet 14 of the acid circulation sprinkler system is disposed at the bottom of the hydration tower 1, and the liquid outlet of the acid circulation sprinkler system 15 is connected to the inlet pipe of the sprinkler device 13, and the acid liquid circulation sprinkling system is further provided with an acid liquid storage tank 16 and a circulation pump 2.
  • the outer wall of the cavity of the hydration tower 1 of the present embodiment is covered with a water cooling system 17, and the cooling water in the water cooling system 17 is adopted in a manner of going in and out.
  • an acid cooler 18 is disposed in the acid circulation spray system near the liquid inlet port 14; the outlet of the acid cooler 18 is connected to the inlet of the acid liquid storage tank 16, and the outlet of the acid liquid storage tank 16
  • the circulation pump 2 is connected to the inlet pipe of the shower device 13, thereby forming an acid circulation shower system.
  • Phosphorus mist capture tower 3 is a fluid state
  • the counter-current washing tower is mainly composed of a washing pipe 31 and a separating tank 32.
  • the flue gas outlet 12 of the hydrating tower 1 communicates with the inlet of the washing pipe 31 through a pipe, and the outlet of the washing pipe 31 communicates to the middle of the separating tank 32.
  • the top of the separation tank 32 is provided with a flue gas outlet 12, and the bottom is provided with an acid liquid outlet 33, which is connected to the nozzle 35 in the washing tube 31 through a circulation conveying pipe with a circulation pump 2 (see Fig. 20).
  • the separation tank 32 serves as an acid circulation tank for circulating the conveying pipe in the phosphoric acid mist collecting tower 3 at the same time.
  • the spraying device 13 of the hydration tower 1 in this embodiment is provided with three spray layers at different heights of the liquefaction tower 1, and three
  • the spray layer comprises a dilute phosphoric acid spray layer 25 and two concentrated phosphoric acid spray layers 24 (see Figure 19), and two concentrated phosphoric acid spray layers 24 are disposed above the dilute phosphoric acid spray layer 25;
  • the liquid inlet pipe of the layer 24 is in communication with the acid circulating spray system of the hydration tower 1, and the inlet pipe of the dilute phosphoric acid spray layer 25 is connected to the circulating conveying pipe of the phosphoric acid mist collecting tower 3, so that the first realization is achieved.
  • the acid liquid in the phosphoric acid mist collecting tower 3 is sent to the hydration tower 1. Further, on the conveying pipe after circulating the pump 2 in the above-mentioned acid liquid circulating spray system, it is connected to the acid liquid inlet 34 of the phosphoric acid mist collecting tower 3 through a pipe.
  • the branch pipe is provided with a packing filtering device 22, and the acid inlet of the packing filtering device 22 is connected to the acid circulating spraying system through the branch pipe, and the filtrate outlet of the packing filtering device 22 is Divided into three ways, all the way to the acid liquid inlet 34 of the phosphoric acid mist collecting tower 3, one way to the external phosphoric acid refining device 23, the other way to the acid liquid storage tank 16; the bottom outlet of the packing filter device 22 passes
  • the pipeline is connected to the feed port of the filter press device 21, and the overflow port of the filter press device 21 communicates with the acid liquid storage tank 16 in the acid circulation spray system through the pipeline to fully realize the recovery and utilization of phosphoric acid to ensure phosphoric acid. High yield.
  • the underflow of the packing filter unit 22 is periodically pumped to the filter unit 21 for filtration to remove solids present in the acid circulating shower system.
  • the flue gas outlet 12 of the phosphoric acid mist collecting tower 3 is connected to the lower portion of the defogging separation tower 4 through a pipe, and the flue gas outlet 12 is disposed at the top of the defogging separation tower 4 to discharge the flue gas after hydration and phosphorus absorption.
  • the defogging separation tower 4 is provided with an in-line water rinsing device 41, and the water added by the inline water rinsing device 41 can simultaneously serve as hydration for the entire hydration absorption phosphoric acid process, and is gradually returned to the upstream phosphoramide trapping tower 3 through a pipeline.
  • the upper portion of the defogging separation tower 4 is provided with a screen mist eliminator 42, and the lower portion is designed as a phosphor droplet collecting structure similar to a cyclone, and the on-line water rinsing device 41 is installed above the screen defogger 42.
  • the apparatus for recovering fluorine used in the present embodiment includes a primary fluorine absorption column 5 and a secondary fluorine absorption column 6. Both the first-stage fluorine absorption tower 5 and the second-stage fluorine absorption tower 6 employ a fluidized countercurrent scrubber.
  • the first-stage fluorine absorption tower 5 is mainly composed of a fluorosilicic acid washing tube 51 and a fluorosilicic acid separation tank 52, and the inlet of the fluorosilicate washing tube 51 is connected to the conveying pipe of the hydrated phosphorus-absorbing flue gas, and the fluorosilicic acid washing tube
  • the outlet of 51 is connected to the middle of the fluorosilicic acid separation tank 52, the top of the fluorosilicic acid separation tank 52 is provided with a flue gas outlet 12, the bottom is provided with a fluorosilicic acid liquid outlet 53, and the fluorosilicic acid liquid outlet 53 is passed through a belt circulation pump.
  • the circulating conveying pipe of 2 is in communication with the nozzle 35 in the fluorosilicate washing pipe 51, and the fluorosilicic acid separating tank 52 serves as an acid circulating tank of the circulating conveying pipe.
  • the structure of the secondary fluorine absorption tower 6 is similar to that of the first-stage fluorine absorption tower 5, and the secondary fluorine absorption tower 6 is mainly composed of a secondary fluorosilicate washing tube 61 and a secondary fluorine.
  • the silicic acid separation tank 62 is composed.
  • the flue gas outlet 12 of the first-stage fluorine absorption tower 5 is connected to the inlet of the secondary fluorosilicate washing tube 61 through a pipe, and the outlet of the second-stage fluorosilicate washing pipe 61 is connected to the secondary fluorosilicic acid.
  • the top of the secondary fluorosilicate separation tank 62 is provided with a flue gas outlet 12, and the bottom is provided with a fluorosilicic acid liquid outlet 53, which passes through a circulating conveying pipe of the circulating pump 2 and The nozzles 35 in the secondary fluorosilicate washing tube 61 are in communication.
  • the circulating transport pipeline of the secondary fluorine absorption tower 6 is further provided with a fluorosilic acid cooler 63, the inlet of the fluorosilicic acid cooler 63 is connected to the circulation pump 2, and the outlet is divided into two paths, one-way and two-stage fluorosilicate washing tubes.
  • the nozzles 35 in the 61 are in communication with each other, and the other is in communication with the spray layer at the top of the secondary fluorosilicate separation tank 62.
  • the secondary fluorosilicate separation tank 62 also serves as an acid circulation tank for the circulating delivery line.
  • the outlet of the circulation pump 2 of the secondary fluorine absorption tower 6 is also connected to the inlet of the fluorosilicic acid separation tank 52 of the primary fluorine absorption tower 5 through a branch pipe, whereby the fluorosilicic acid solution of the secondary fluorine absorption tower 6 can be removed.
  • the string is passed to the first-stage fluorine absorption tower 5.
  • the equipment for recovering fluorine in the present embodiment is finally connected with a tail suction tower 7, which is a spray empty tower, and the flue gas outlet 12 of the second-stage fluorine absorption tower 6 passes.
  • the pipe is connected to the flue gas inlet 11 of the tail suction tower 7.
  • the top of the tail suction tower 7 is provided with a flue gas outlet 12, a spray layer is arranged above the tower, and a sodium hydroxide absorption liquid tank is arranged at the bottom, and the sodium hydroxide absorption liquid tank outlet passes through a circulation conveying pipe with a circulation pump 2 and
  • the spray layers in the tail suction tower 7 are connected to form an exhaust gas absorption circulating spray system.
  • the above-mentioned fluorosilicic acid liquid outlet 53 is additionally connected to an external fluorosilicic acid refining device 54 (or a fluoride salt processing device) through a pipe with a feed pump, and can pass through the filter press device 21 before entering the fluorosilicic acid refining device 54.
  • the pressure filtration treatment is performed, and the overflow port of the filter press device 21 is connected to the fluorosilicic acid refining device 54 through a pipe.
  • the method for hydrating phosphorus and recovering fluorine in the kiln flue gas from the kiln phosphoric acid process of the present embodiment specifically includes the following steps:
  • the kiln flue gas (P 2 0 5 content 80 g/Nm 3 ) containing P 2 0 5 and fluorine and having a temperature above 500 ° C after the above step 4 is introduced into the flue gas inlet 11 of the lower part of the hydration tower 1
  • the circulation pump 2 of the acid circulation spray system is turned on before, and the concentrated phosphoric acid solution in the hydration tower 1 is sprayed through the upper and middle concentrated phosphoric acid spray layers 24, and the uppermost concentrated phosphoric acid spray layer 24
  • Some of the nozzles are sprayed obliquely from below to the inner wall of the tower, and the other nozzles are sprayed vertically downwards.
  • the nozzles of the middle and lower spray layers are sprayed vertically downwards, and the concentrated phosphoric acid solution sprayed and the P 2 0 5 entering the tower. It is in full contact with the flue gas of fluorine to carry out mass transfer heat transfer.
  • the P 2 0 5 in the flue gas chemically reacts with the water in the sprayed concentrated phosphoric acid solution to form phosphoric acid, and more than half of the generated phosphoric acid is absorbed into the spray liquid.
  • the rest of the phosphoric acid mist is kept in the gas phase, and the fluorine in the flue gas (such as SiF ⁇ P HF, etc.) is difficult to be absorbed into the spray liquid under concentrated phosphoric acid and higher temperature conditions;
  • the heat exchange of the sprayed lower temperature and concentrated phosphoric acid solution and the cooling of the water cooling system 17 in the hydration tower 1 reduce the temperature to 75 At °C ⁇ 130°C, the temperature of the circulating concentrated phosphoric acid solution of the effluent tower 1 is increased to 70 °C ⁇ 95 °C.
  • the mass concentration of the concentrated phosphoric acid solution sprayed in the spray can be selected from the range of 60% to 90% (in this embodiment, a phosphoric acid solution having a concentration of 70% to 85%), the hydration tower
  • the temperature of the inlet of the concentrated phosphoric acid solution is controlled to be 50 ° C to 80 ° C, and the ratio of the spray liquid to gas is controlled at 3 L/m 3 to 20 L/m 3 .
  • More in the tower smoke The phosphoric acid mist exists in the form of a mist, cannot settle in the hydration tower 1, and is taken out of the hydration tower 1 along with the flue gas.
  • the hydration tower 1 has the dual functions of cooling flue gas and hydration absorption P 2 0 5 , wherein the main chemical reactions occur as follows:
  • the concentrated phosphoric acid solution sprayed down in the hydration tower 1 finally enters the acid circulation spray system through the liquid inlet 14 and then flows into the acid cooler 18, and the structure of the acid cooler 18 is a stainless steel tube arranged in a stirring tank.
  • the heat exchanger plate is formed into a circulating cooling water, and the phosphoric acid solution entering the acid cooler 18 is forced to form a forced convection heat transfer on the heat exchange plate to improve the heat transfer efficiency and heat the concentrated phosphoric acid.
  • Partially transferred to the circulating cooling water of the acid cooler 18, the heat of the circulating concentrated phosphoric acid solution is continuously transferred by the cooling water.
  • the circulating acid flowing out from the outlet of the acid cooler 18 enters the acid liquid storage tank 16, and is again returned to the respective nozzles of the upper and middle two concentrated phosphoric acid spray layers 24 by the circulation pump 2 for circulating spraying.
  • the gas phase material i.e., flue gas
  • the gas phase material discharged from the flue gas outlet 12 at the top of the hydration tower 1 enters the washing tube 31 of the phosphoric acid mist collecting tower 3, which is a fluidized countercurrent washing tower, which is in the washing tube 31.
  • the dilute phosphoric acid solution is sprayed downward and upward, and the dilute phosphoric acid solution forms a strong turbulent region in the gas-liquid interface region after colliding with the high-speed flue gas flow from the top to the bottom, and a stable foam is established after the fluid momentum reaches equilibrium.
  • Zone foam column
  • the flue gas passes through the foam zone, and is in contact with a large surface of the continuously updated phosphoric acid solution liquid surface.
  • the phosphorous mist trapping tower of the invention can greatly reduce the power head loss of the equipment and reduce the energy consumption of the acid collecting device under the same demisting effect.
  • the acid solution circulating in the phosphoric acid mist collecting tower 3 is a dilute phosphoric acid solution having a concentration of 10% to 50% by mass, and the gas and liquid in the washing tube 31 enter the separation tank 32 in the lower portion of the column for gas-liquid separation.
  • the circulating acid liquid falls into the bottom of the separation tank 32, and the separation tank 32 of the tower also serves as a circulating acid tank, and the dilute phosphoric acid solution at the bottom is sent back to the washing tube 31 through the circulation pump 2 or the acid phosphate to the phosphating tower 1 as needed.
  • the spray layer 25 In the spray layer 25.
  • the flue gas discharged from the flue gas outlet 12 in the phosphoric acid mist trap tower 3 is further introduced into the defogging separation tower 4 for further gas-liquid separation to further remove the phosphoric acid mist in the flue gas, and the lower portion of the defogging separation tower is designed Similar to the cyclone trapping structure of the cyclone dust collector, the grown phosphoric acid droplets are collected from the flue gas by centrifugal force, and a screen demister 42 is installed in the upper part of the defogging separation tower, so that the flue gas is not yet The grown phosphorous droplets are further captured to ensure the direct yield of the device to P 2 0 5 ; the hydrated phosphorus after the defogging separation tower 4 is sent to the fluorine recovery equipment for fluorine recovery. .
  • the P 2 0 5 in the flue gas needs to consume water, and in the process of cooling the flue gas, part of the water is evaporated from the sprayed acid solution, so the hydration absorption process needs to continuously replenish water, the process of this embodiment Replenished water in the system
  • the amount is all replenished from the flue gas outlet 12 of the defogging separation tower 4, and the in-line water rinsing device 41 serves not only as a water replenishing device but also as a flushing device for the upper screen defogger of the defogging separation tower 4.
  • the bottom liquid of the defogging separation tower 4 is returned to the phosphoric acid mist collecting tower 3 through the acid liquid inlet 34 of the phosphoric acid mist collecting tower 3, so the phosphoric acid mist is trapped.
  • the concentration of circulating acid in the tower 3 will gradually decrease.
  • the hydration tower 1 continuously absorbs P 2 0 5 in the flue gas, and the circulating acid concentration will gradually increase.
  • the hydration tower 1 and The circulating acid liquid system of the phosphoric acid mist trapping tower 3 needs to carry out string acid to maintain the stability of the respective circulating acid liquid concentrations, and the acid of the hydrating tower 1 string to the phosphoric acid mist collecting tower 3 is clarified and filtered in the packing filtering device 22.
  • the acid mist collecting tower 3 is introduced, and the acid from the phosphoric acid mist collecting tower 3 to the hydrating tower 1 is directly taken out from the outlet of the circulating pump 2 of the phosphoric acid mist collecting tower 3.
  • the circulating acid in the hydration tower 1 absorbs impurities such as dust in the flue gas, in order to prevent the accumulation of these impurities, it is necessary to extract excess acid from the acid circulating spray system of the hydration tower 1 (corresponding to material balance)
  • the amount of acid produced) first to the packing filter unit 22 for clarification filtration (primary filtration), a part of the clarification liquid is acid-acidized to the phosphoric acid mist collecting tower 3, and the other part is used as a crude product of phosphoric acid to enter the refining process, adding activated carbon, diatom Soil and barium salt, remove the color of the crude phosphoric acid and S0 4 2 —, and then use the plate and frame filter unit 21 (secondary filtration) to remove impurities and purify to obtain the concentrated phosphoric acid product.
  • the hydrated phosphorus-absorbing flue gas is sent to the fluorosilicic acid washing tube 51 of the first-stage fluorine absorption tower 5, and most of the fluorine (mainly silicon tetrafluoride) in the flue gas is from the top to the bottom and the nozzle 35 is from the bottom.
  • the circulating fluorosilicic acid solution (10% ⁇ 20% by mass) is sprayed with sufficient gas-liquid two-phase contact, and mass transfer heat transfer and chemical reaction are carried out.
  • fluorosilicic acid is generated, and the heat enthalpy in the flue gas is mostly transferred to the circulating fluorosilicic acid solution by heat transfer; the flue gas is circulated by the adiabatic evaporation cycle of the fluorosilicic acid solution and heat transfer to the circulating fluorosilicic acid solution.
  • the method is further cooled to 50 ° C ⁇ 70 ° C; the main chemical reactions in this step are as follows:
  • 3SiF 4 +33 ⁇ 40 2H 2 SiF 6 + Si0 2 * 3 ⁇ 40.
  • the products finally obtained in the fluorosilicic acid washing tube 51 are all transferred to the fluorosilicic acid separation tank 52 for gas-liquid separation, and the separated gas passes through the flue gas outlet of the primary fluorine absorption tower 5 to enter the secondary fluorine absorption tower 6.
  • the separated liquid is retained in the fluorosilicic acid separation tank 52 and returned to the fluorosilicate washing tube 51 through the circulation conveying pipe with the circulation pump 2 to carry out the operation of the above step 4.
  • the flue gas entering the secondary fluorosilicate washing tube 61 (the remaining fluorine-containing substance, mainly silicon tetrafluoride) is a cyclic fluorosilicic acid solution sprayed from the top to the bottom and the nozzle 35 from the bottom up. (5% by mass of 5% ⁇ 1. 5%)
  • a sufficient gas-liquid two-phase contact occurs, and mass transfer heat transfer and chemical reaction are carried out to form fluorosilicic acid, and the heat in the flue gas passes through the heat.
  • the transfer is again transferred to the circulating fluorosilicic acid solution; the temperature of the product treated by the step (3) is further lowered to 60 ° C.
  • the chemical reaction that occurs mainly in this step is the same as in step 4.
  • the products finally obtained in the secondary fluorosilicate washing tube 61 are all transferred to the secondary fluorosilicate separation tank 62 for gas-liquid separation, and the second fluorosilicic acid separation tank 62 is provided with a defogging unit at the top to remove the flue gas.
  • the entrained mist increases the absorption rate of fluorine, and the defogging unit is sprayed by circulating the fluorosilicic acid solution through the top.
  • the separated gas passes through the flue gas outlet of the secondary fluorine absorption tower 6 and enters the subsequent tail suction tower 7 for treatment.
  • the separated liquid remains in the secondary fluorosilicate separation tank 62 and is sent back through the circulating conveying pipe with the circulation pump 2.
  • the operation of the above step 6 is performed in the secondary fluorosilicate washing tube 61, and the circulating conveying pipe is installed with a fluorosilicic acid cooler 63 to remove a part of the heat in the circulating fluorosilicic acid solution, so that the fluorine absorption reaction energy can be compared. It is carried out at a suitable temperature.
  • the circulating fluorosilicic acid solution entering the secondary fluorosilicate washing tube 61 is subjected to cooling treatment by a fluorosilicic acid cooler 63 (conventional cooling equipment); part of the excess circulating fluorosilicic acid solution can be directly discharged to the first-stage fluorine absorption tower The fluorosilicic acid separation tank 52 of 5.
  • the circulating fluorosilicic acid solution in the first-stage fluorine absorption tower 5 and the second-stage fluorine absorption tower 6 accumulates due to absorption of fluorine (mainly silicon tetrafluoride) in the flue gas, and the concentration of the fluorosilicic acid in the first-stage fluorine absorption tower 5 Due to the absorption of SiF ⁇ P HF in the flue gas, the excess circulating fluorosilicic acid solution in the secondary fluorine absorption tower 6 is discharged to the primary fluorine absorption tower 5 to maintain a constant concentration thereof, and finally the first-stage fluorine absorption tower 5
  • the excess circulating fluorosilicic acid solution is pumped to the pressure filter device 21 through a feed pump to carry out pressure filtration to remove solid materials such as silica gel, and the filtrate is refined into a fluorosilicic acid refined product (concentration is about 12%). Or processed into a fluoride salt product; the filter residue is silica gel, which is used as a by-
  • the flue gas entering the subsequent tail suction tower 7 is in countercurrent contact with the downwardly sprayed NaOH solution during the upward movement of the tail suction tower 7, and the bottom absorption tank of the tail suction tower 7 passes through the circulation pump 2 and the various sprays in the tower.
  • the shower layer is connected to form a circulating spray system; in order to maintain the absorption capacity of the absorption liquid, the pH value of the absorption liquid is maintained at 8 or more, and it is necessary to continuously add a dilute NaOH solution, and the absorption liquid is added by the dilute NaOH solution and the flue gas P 2 0 5 , the absorption of fluorine and other impurities will accumulate, need to be continuously discharged for sewage treatment, the treated water can be reused to the raw material process of kiln process phosphoric acid; the remaining pollutants in the flue gas (P 2 0 5 , SiF 4 , dust, etc.) is absorbed by the spray liquid, and the flue gas is further washed and purified to meet the national discharge standard (the gas fluorine content is reduced to 9 mg/m 3 or less), and then discharged to the chimney through the induced draft fan.
  • the main chemical reactions in this step are as follows:

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Abstract

本发明公开了一种改进型的用回转窑规模化生产磷酸的方法，包括以下步骤：先将原料碳质还原剂、磷矿石和硅石分别进行预处理，然后混合；将预处理后的碳质还原剂粉、磷矿石粉和硅石粉混合制作内球；再将碳质还原剂粉和硅石粉混匀得到包裹料；将内球和包裹料混合进行包裹处理，干燥固结，得到复合球团；将复合球团送入回转窑内进行还原反应；出回转窑的高温渣球则输送至冷却设备进行综合利用；将含P2O5和氟的出窑烟气通入一水化塔内进行水化吸磷，再依次通过磷酸雾捕集塔和除雾分离塔，除雾分离塔排出的含氟烟气则进入后续的氟回收工序。本发明的工艺流程合理优化、设备投入小、经济附加值高、整个工艺过程节能环保、运行高效、产品质量优异。

Description

改进型的用回转窑规模化生产磷酸的方法
【技术领域】
本发明涉及一种制磷酸工艺中的原料预处理方法及设备， 尤其涉及一种窑法磷酸工艺 (KPA) 中的原料预处理方法及预处理工艺系统。
【背景技术】
目前世界上工业生产磷酸的方法主要有两种。 （1 ) 湿法制磷酸： 即利用硫酸分解磷矿石 得到稀磷酸和以 CaS04* n¾0为主体的固体废渣（简称磷石膏），将稀磷酸浓缩得到含磷酸 54% 左右的湿法磷酸。 这种工艺的主要缺点： 一是要耗用大量的硫酸； 二是废渣磷石膏无法得到 有效的利用， 其中夹带的硫酸、 磷酸和可溶性氟化物均溶于水， 自然堆放后被雨水冲刷， 容 易对环境造成严重污染； 三是产品磷酸的杂质含量较高， 一般只用于生产肥料； 四是为保证 产品的经济性， 必须使用高品位磷矿。 （2 ) 热法制磷酸： 即首先将磷矿石、 硅石、 碳质固体 还原剂置于一台矿热电炉中， 用电短路形成电弧的能量， 将炉内温度加热到 1300°C以上， 将 磷矿石中的磷以 形式还原出来， 同时碳质固体还原剂被转化为 C0， 将排出矿热炉的 和 CO为主的气体用水洗涤降温， P4被冷却成固体与气相分离， 得到产品黄磷， 含 CO的废气在烟 囱出口点火燃烧后排入大气； 将得到的 加热到 80°C左右， 使其变为液相， 将其在水化塔中 与通入的空气发生氧化燃烧反应， 得到磷酸酐 P205， 再用水吸收得到磷酸。 热法制磷酸的主 要缺点： 一是要耗费大量的电能； 二是排出矿热炉后分离了 的气体还夹带有大量的氟化物 (以 SiF^P HF存在） 和少量未沉淀的气体 P4， 这将对大气环境造成严重污染； 三是含大量 CO的气体直接燃烧排空， 能源浪费很大； 四是为了保证生产的经济性， 同样需要使用高品位 磷矿石。
为了克服电能紧张、 硫铁矿资源不足和高品位磷矿石逐年减少对磷酸生产的影响， 八十 年代初美国 Occidental Research Corporation ( 0RC) 提出采用 KPA法， 即用回转窑生产 磷酸的方法（简称窑法磷酸工艺） （参见 Frederic Ledar and Won C. Park等， New Process for Technical-Grade Phosphoric Acid, Ind. Eng. Chem. Process Des. Devl985, 24, 688-697)， 并进行了 0. 84m (内） X 9. 14m回转窑中试装置的中间试验 （参见 US4389384号美国专利文 献）。 该方法是将磷矿石、 硅石和碳质还原剂（焦粉或煤粉）细磨到 50%〜85%— 325目， 配加 1%的膨润土造球， 经链式干燥机干燥预热后送入窑头燃烧天然气的回转窑中， 球团在窑内还 原， 控制最高固体温度为 1400°C〜1500°C， 调整球团 Ca0/Si02摩尔比为 0. 26〜0. 55， 使球团 熔点高于球团中磷矿石的碳热还原温度， 磷以磷蒸气的形式从球团中还原挥发出来， 然后在 窑的中部空间被通入的空气氧化成五氧化二磷， 氧化放出来的热反过来又供给还原反应， 最 后将含有五氧化二磷的窑气水化吸收即制得磷酸。
上述的窑法磷酸工艺思路显示了一种良好的工业应用前景， 因其原理是利用磷矿的碳热 还原形成 气体， 将磷矿石中的磷转移到回转窑的气相当中， 并利用气固分离原理使磷与料 球中的其余固体物质很好的进行分离， 转移到回转窑气相中的 P4气体可与回转窑气相中的氧 发生氧化放热反应生成 P205， 放出的热则供给料球中磷矿石的碳热还原 （吸热反应）， 最后将 出回转窑的含 P205的窑气水化吸收， 可获得洁净度远高于湿法磷酸的工业磷酸。 由于回转窑 维持磷矿碳热还原温度使用的是初级能源，同时磷矿碳热还原产生的可燃物质 与 CO在回转 窑内部即可进行燃烧放热反应， 补充提供给维持回转窑磷矿碳热还原温度所需能量， 这与传 统的热法制磷酸工艺相比， 其能耗得到大幅度降低。
然而， 我们的研究表明， 上述的窑法磷酸工艺在规模化的工业应用及实践中很难实现， 其主要缺陷在于：
1、 回转窑是窑体以一定速度（0. 5r/mir！〜 3r/min )运转的设备， 其优点是可以连续对送 入窑内的固体物料进行机械翻转、 混合， 保证窑内固体物料各处受热的均匀性， 但反过来窑 内固体物料亦须承受物料运动的机械摩擦力， 如果物料强度小于受到的机械摩擦力将很容易 被破坏。 美国 0RC公司提出的 KPA工艺基本原理是将磷矿石、 硅石和碳质还原剂 （焦粉或煤 粉） 细磨到 50%〜85%— 325 目后制成球团， 这三种物质必须紧密地共聚一体， 才能在混合物 中 Ca0/Si02摩尔比为 0. 26〜0. 55 的条件下， 实现混合物料在磷矿石的碳热还原温度下不熔 化， 同时， 磷矿的碳还原才能得以顺利进行。 但工艺使用的物料球团中配入了还原剂碳， 碳 在大于 350 °C温度下会与空气中的氧发生快速的氧化反应转变成 C02， 如果采用传统冶金工业 球团在链篦机上高温固结的方法 （ 900 °C )， 则球团中的还原碳会被全部氧化， 入回转窑球 团则流失了还原剂， 磷的碳热还原反应自然也无法进行， 导致工艺失败。 如果仅通过添加膨 润土作球团粘结剂在 300 °C以下进行干燥脱水， 则球团抗压强度仅为 10KN/个球左右， 落下强 度 1次 /米； 因为膨润土的作用机理主要是利用其物质结构中的层间水来调节球团干燥过程 中的水分释放速率， 提高球团在干燥过程中的爆裂温度， 其本身对提高球团强度并无显著作 用。 将这种球团送入回转窑后、 且在回转窑温度值达到 900 °C温度前， 由于承受不住回转窑 内料球运动所受到的机械摩擦力， 入窑的球团将大量粉化， 粉化后组成球团的磷矿粉、 硅石 粉和碳质还原剂等将分离， 粉化后的磷矿粉由于不能与碳质还原剂紧密接触， 将导致磷不能 被还原。 更为严重的是， 磷矿粉一旦与硅石粉分开， 其熔点将急剧降低到 1250 °C以下， 这种 粉状磷矿通过回转窑的高温还原区 （料层温度为 1300 °C左右） 时， 将全部由固相变成液相， 进而粘附在回转窑窑衬上形成回转窑的高温结圈， 阻碍物料在回转窑内的正常运动， 使加入 回转窑的大部分物料从回转窑加料端溢出回转窑， 无法实现磷的高温还原， 导致工艺失败。 可见， 由于入窑原料存在固有缺陷， 至今未见上述的 KPA技术进行过任何工业化、 规模化或 商业化的应用。
2、对于上述配碳磷矿球团的 KPA工艺而言， 在回转窑内料层下部的固体料层区属于还原 带， 料层上部则是回转窑的气流区， 属于氧化带， 进料球团从回转窑窑尾加入， 依靠其自身 重力和回转窑旋转的摩擦力从回转窑的窑头区排出， 回转窑燃烧燃料的烧嘴安装在回转窑窑 头， 产生的燃烧烟气则由窑尾的风机引出， 回转窑内维持微负压， 气流与物料的运动方向相 反。 由于在回转窑的还原带 （固体料层区） 和氧化带 （回转窑固体料层上部的气流区） 无机 械隔离区， 因此， 暴露在固体料层区表面的料球将与氧化带气流中的 、 （¾发生对流传质； 这一方面会使料球中的还原剂碳在料球被气流传热加热到磷矿石碳还原温度前被部分氧化 掉， 致使料球在回转窑还原带由于碳质还原剂的缺乏， 而得不到充分还原； 更为严重的是， 在回转窑高温区暴露于料层表面的料球， 会与窑气中已经还原生成的 P205发生进一步的化学 反应， 生成偏磷酸钙、 磷酸钙及其他的偏磷酸盐或磷酸盐， 进而导致已被还原到气相中的磷 又重新返回料球，并在料球表面形成一层富含 P205的白壳，壳层厚度一般在 300 μ m〜1000 μ m， 壳层中 P205含量可高达 30%以上； 这样会致使料球转移到气相中的 P205不超过 60%， 造成磷矿 中 P205的收率偏低， 进而造成矿产资源的浪费及磷酸生产成本的大幅度上升， 使上述的 KPA 工艺丧失商业应用和工业推广价值。 有研究人员寄望通过料层中挥发出的气体来隔离回转窑 中的还原带与氧化带， 但在内径 2m的回转窑中进行的工业试验表明， 球团表面出现富含 P205 的白壳现象仍是不可避免的。
鉴于上述提及的技术缺陷， 按照 0RC公司所提出的 KPA工艺来生产磷酸， 这在规模化的 工业应用及实践中还存在很大困难。
Joseph A. Megy对 KPA工艺提出过一些改进的技术方法 （参见 US7910080B号美国专利文 献）， 即在维持 KPA基本工艺方法不变的前提下， 通过在回转窑筒体的窑头泄料端设置挡料圈 以提高回转窑的固体物料填充率， 与此同时， 通过增大回转窑的直径以减小回转窑内料层的 表面积-体积比， 降低料层物料暴露在固体料层表面的几率， 以缩短料球中还原剂碳被回转窑 窑气中的 氧化的时间， 减少料球到达回转窑还原带前的还原剂碳的烧损， 同时减少回转窑 高温区中料球表面磷酸盐或偏磷酸盐的生成。 另外， 该工艺还通过在入回转窑的物料中加入 部分石油焦， 以希望利用石油焦中挥发分受热挥发产生的还原性气体， 使其覆盖在料层与回 转窑气流氧化区之间， 以进一步阻止回转窑气流中 、 P205与料球反应的几率， 以保证工艺的 正常进行。 然而， 提高回转窑的填充率将使料球在回转窑内承受更大的机械摩擦力， 进而将 造成料球在回转窑内更大比例的粉化， 形成更多的小于磷矿碳热还原温度的低熔点物质， 使 回转窑高温结圈更加迅速和严重， 从而更早造成工艺的失败。 而添加少量的石油焦产生的挥 发分不足以产生足够的气体， 难以在回转窑固体料层与回转窑内气流区之间形成有效的隔离 层， 若加入量过大， 则出回转窑物料中将夹带有大量的燃料， 这会导致在后续工艺的渣球冷 却机中， 剩余燃料将与冷却渣球的空气相遇并迅速燃烧， 燃烧放出的大量热量不仅增加了出 回转窑高温渣球冷却的难度， 而且又大大提高了工艺的生产成本， 使工艺的商业化、 规模化 运用变得不可实现。
鉴于上述问题， 我们经过反复研究， 曾提出过一种克服上述问题的解决方案 （参见 CN1026403C, CN1040199C 号中国专利文献）， 即采用一种双层复合球团直接还原磷矿石生产 磷酸的工艺， 具体技术解决方案是： 先将磷矿石与配入物料制成球团， 在回转窑内， 球团中 的 P205被还原成磷蒸气并挥发， 在料层上方， 磷蒸气被引入炉内的空气氧化成 P205气体， 然 后在水化装置中被吸收制得磷酸。 该技术方案的最大特点在于： 配入的物料球团采用双层复 合结构， 其内层是由磷矿石、 硅石 （或石灰、 石灰石等） 和碳质还原剂经磨碎、 混匀后造球 而成， 其外层是在内层球团上再裹上一层含碳量大于 20%的固体燃料， 球团的内、 外层配料 时添加粘结剂， 球团采用干燥固结。 球团内层 Ca0/Si02摩尔比可以小于 0. 6或大于 6. 5， 碳 质还原剂为还原磷矿石理论量的 1〜3倍，球团外层固体燃料配量可以为内层球团质量的 5%〜 25%； 球团内、 外层添加的粘结剂可以是沥青、 腐植酸钠、 腐植酸铵、 水玻璃、 亚硫酸盐纸浆 废液、糖浆、木质素磺酸盐中的一种或多种的组合，其添加量为被添加物料重量的 0. 2%〜15% (干基）。 该球团可以采用干燥固结， 固结温度为 80°C〜600°C， 固结时间为 3min〜120min。
我们提出的上述方法采用在球团上裹一层含固体碳的耐高温包裹料，包裹时添加粘结剂， 以使外层包裹料能良好地附着在内层球团上。 将这种双层复合球团经干燥固结后送入回转窑 中， 在回转窑高温带 （1300°C〜140(TC左右） 可以很好地实现磷矿石的碳热还原。 由于在料 球表面人为包覆了一层含固体还原剂 （碳质物料） 的包裹层， 该包裹层可将其内层球团与回 转窑料层上部的含 02和 P205的气流氧化区进行有效地物理隔离。 当这种复合球团在回转窑固 体料层中随回转窑的旋转运动上升到回转窑固体料层表面， 并与回转窑固体料层上部的含 02 和 P205的气流氧化区接触发生对流传质时， 包裹层中的碳便可与氧化区中的 02发生有限的氧 化反应 （因在工业大型回转窑中料球暴露在回转窑料层表面的时间较短， 反应不完全）， 使 02不能传递到内层球团， 保证了内层球团中的还原剂碳不被回转窑气流中的氧所氧化， 使磷 矿石中 P205的还原过程能进行彻底， 实现了工艺过程中磷矿 P205的高还原率。 另一方面， 回 转窑料层上部气流氧化区中的 P205也不可能与复合球团表层包裹层中的碳反应， 因而阻止了 在复合球团上形成磷酸盐或偏磷酸盐化合物， 消除了原有 KPA工艺料球上富含 P205白壳的生 成， 确保了工艺可获得较高的 P2O5收率。 与此同时， 该方法中以固体燃料取代或部分取代了 气体或液体燃料， 这可进一步降低磷酸的生产成本。
此外， 我们提出的上述方法中在造球时还加入了有机粘结剂， 这可使复合球团在干燥脱 水后 （低于球团中碳氧化温度）， 仍可以达到 200kN/个球以上的抗压强度和 10次 /米以上的 落下强度， 因此， 该复合球团可以抵抗在回转窑内受到的机械摩擦力而不被粉碎， 克服了原 有 KPA工艺存在的球团强度差等缺陷， 也克服了球团中碳在回转窑预热带过早氧化的现象， 使复合球团在窑内不出现粉化， 进而避免了粉料造成的回转窑高温结圈致使工艺失败， 保证 了工艺能在设定的条件下顺利进行。
然而，在我们后续的研究过程中，又发现了一系列新的技术问题，这些技术问题包括： 1 ) 在原料预处理阶段， 工艺成本和能耗相对较高， 送入回转窑的原料成分波动较大， 原料的混 合不够均匀， 这会进一步加重回转窑内粉料的高温结圈问题； 2 )作为工艺原料的复合球团的 力学性能和机械强度不够稳定， 复合球团干燥没有可选的工业设备和合适的干燥方法， 球团 干燥过程容易出现爆裂， 爆裂的复合球团进入回转窑在回转窑高温还原带粉化结圈； 3 )在工 艺反应阶段， 生成的偏磷酸会与窑气中的粉尘反应， 在回转窑窑尾生成复杂的偏磷酸盐， 并 逐渐在回转窑尾部筒体内形成结窑尾圈， 严重降低回转窑的作业效率； 4) 在冷却回收阶段， 出回转窑释放完 P205后的高温渣球的冷却效果有待改善， 冷却的热能没有得到合理有效地利 用， 冷却过程中对资源和能源的浪费比较严重； 5 )在后续的制磷酸阶段， 热法磷酸的烟气量 小， 设备的烟气流速低， 设备系统相当庞大， 结构复杂， 而且投资和运行成本均较高； 窑法 磷酸的烟气杂质含量复杂， 出窑烟气还含有对人体有害的含氟物质（以 SiF^P HF形态存在）， 这需要加以回收利用， 同时避免对环境的污染。
因此， 为了解决现有窑法磷酸工艺中出现的一系列技术问题， 为了能更稳定、 更节能、 更环保、 低成本和高效率地进行长周期生产， 现有的窑法磷酸整体工艺还亟待本领域技术人 员进行大量的改进和完善。
【发明内容】
本发明要解决的技术问题是克服现有技术的不足， 提供一种工艺流程合理优化、 设备投 入小、 经济附加值高、 整个工艺过程节能环保、 运行高效、 产品质量优异的改进型的用回转 窑规模化生产磷酸的方法。
为解决上述技术问题， 本发明提出的技术方案为一种改进型的用回转窑规模化生产磷酸 的方法， 包括以下步骤：
( 1 )原料预处理： 将原料碳质还原剂、 磷矿石和硅石分别用碳质还原剂预处理系统、 磷 矿石预处理系统和硅石预处理系统进行预处理， 预处理后的碳质还原剂、 磷矿石和硅石送入 内球料混合装置进行混合造球， 预处理后的碳质还原剂和硅石另送入外壳料混合装置进行混 合.
( 2) 内球的制备： 将经过步骤 （1 ) 处理后得到的碳质还原剂粉、 磷矿石粉和硅石粉按 配比要求加入一强力混合机或润磨机中， 同时添加粘结剂， 充分混匀后的混合料通过计量给 料设备送入造球机进行造球处理， 造球时以滴状和 /或雾状施加形式补加所述粘结剂， 补加量 为所述混合料质量的 1%〜10%， 造球完成后得到内球；
( 3) 复合球团的成型： 将经过步骤 （1 ) 处理后得到的碳质还原剂粉和硅石粉按配比要 求加入另一强力混合机或润磨机中， 同时添加粘结剂， 充分混匀后得到包裹料； 将步骤 （2) 中得到的内球进行双层辊式筛分处理， 筛分出符合工艺要求粒度的内球送入另一进行包裹处 理的造球机中， 向该造球机中 （由电子计量给料装置按与内球料的设定对应比例） 通入所述 包裹料， 在包裹处理过程中以滴状和 /或雾状施加形式补加所述粘结剂， 补加量为所述包裹料 质量的 1%〜12%， 包裹处理完成后得到复合生球； 复合生球送入干燥机进行干燥固结， 最终 成型得到复合球团；
(4) 窑法还原： 将步骤 （3) 中得到的复合球团从回转窑窑尾箱的进料管处进入回转窑 的腔体内， 点燃燃料烧嘴， 使回转窑内还原带温度加热到 1300°C〜145(TC， 回转窑中的复合 球团在高温条件下经还原剂还原后生成出窑烟气， 通过所述出口烟道的设置使回转窑窑尾的 出窑烟气在进入出口烟道时不在运动方向上发生较大偏移， 进而阻止出窑烟气中的偏磷酸在 回转窑窑尾处产生离心物理沉降， 使窑气中偏磷酸直接随出窑烟气进入到后续的水化塔中； 出回转窑的高温渣球则输送至一冷却设备进行综合利用；
( 5)水化吸磷： 将含 P205和氟的出窑烟气通入一水化塔内， 此前开启与水化塔相连接的 酸液循环喷淋系统， 酸液循环喷淋系统将浓磷酸溶液不断输送到水化塔内的喷淋装置中， 向 下喷淋的浓磷酸溶液与进入塔内的含 P2O5和氟的出窑烟气逆流充分接触， 进行传质传热， 烟 气中的 P2O5与喷淋的浓磷酸溶液中的水发生化学反应生成磷酸并被吸收进喷淋液中， 其余部 分形成磷酸雾保持在气相中， 水化塔中剩余烟气通过其烟气出口排出； 水化塔中喷淋落下的 磷酸溶液进入酸液循环喷淋系统中， 先流入酸冷器， 从酸冷器出口流出的循环磷酸溶液再通 过循环泵回送到所述水化塔的喷淋装置继续进行循环喷淋； 从所述烟气出口排出的烟气再依 次通过磷酸雾捕集塔和除雾分离塔， 使出水化塔烟气中夹带的磷酸雾被进一步捕集， 所述磷 酸雾捕集塔和除雾分离塔捕集磷酸雾后形成的稀磷酸溶液通过管道布置与所述水化塔中的浓 磷酸溶液保持串酸； 在水化吸磷的操作过程中， 酸液循环喷淋系统中的浓磷酸溶液会不断增 力口， 多出的部分经过滤后作为粗磷酸产品， 粗磷酸产品进入后续的磷酸精制工序； 另一方面， 配套的在线补水装置对整个工艺过程实施在线补水， 除雾分离塔排出的含氟烟气则进入后续 的氟回收工序。 上述本发明的方法， 所述步骤 （1 ) 中， 优选的，
所述碳质还原剂预处理系统的工艺过程包括： 将碳质还原剂先采用单段破碎设备破碎至 粒度在 30mm以下 （优选 6mm〜30mm)， 然后将破碎后的碎石料送至碳质还原剂中间料仓， 碳 质还原剂中间料仓通过计量给料设备将碎石料送至磨矿设备进行粉磨， 待磨矿设备将进料粉 磨至工艺要求的粒度后 （一般为 -100目以上， 优选 -200目〜 -325目）， 由旋风收粉设备和布 袋收粉设备组成的组合式收尘器收集粉料（或单独用布袋收粉设备）， 并输送至碳质还原剂粉 储料仓； 所述粉磨过程中通过配置的热风炉不断补充热风以干燥粉料中夹带的水分；
所述磷矿石预处理系统的工艺过程包括： 将磷矿石先采用单段破碎设备破碎至粒度在 30mm以下（优选 6mm〜30mm)， 然后将破碎后的碎石料送至磷矿石中间料仓， 磷矿石中间料仓 通过计量给料设备将碎石料送至磨矿设备进行粉磨， 待磨矿设备将进料粉磨至工艺要求的粒 度后 （一般为 -100目以上， 优选 -100目〜 -200目）， 由旋风收粉设备和布袋收粉设备组成的 组合式收尘器收集粉料（或单独用布袋收粉设备）， 并输送至均化库； 所述粉磨过程中通过配 置的热风炉不断补充热风以干燥粉料中夹带的水分；
所述硅石预处理系统的工艺过程包括： 将硅石先采用单段破碎设备或两段一闭路破碎设 备破碎至粒度在 30mm以下 （优选 6mm〜30mm)， 然后将破碎后的碎石料送至硅石中间料仓， 硅石中间料仓通过计量给料设备将碎石料送至磨矿设备进行粉磨， 待磨矿设备将进料粉磨至 工艺要求的粒度后 （一般为 -100目以上， 优选 -100目〜 -200目）， 由旋风收粉设备和布袋收 粉设备组成的组合式收尘器收集粉料， 并输送至硅石粉储料仓； 所述粉磨过程中通过配置的 热风炉不断补充热风以干燥粉料中夹带的水分。
上述本发明的方法， 所述步骤 （1 ) 中， 优选的，
所述单段破碎设备采用锤式破碎机或反击式破碎机， 或者采用锤式破碎机和反击式破碎 机组合成的联合式破碎机； 所述两段一闭路破碎设备主要由依次相连的颚式破碎机、 筛分机 和圆锥破碎机组成， 且圆锥破碎机的出料口循环连接至筛分机的进料口；
所述碳质还原剂预处理系统中的磨矿设备采用立式磨或风扫煤磨； 所述磷矿石预处理系 统中的磨矿设备采用立式磨或风扫球磨； 所述硅石预处理系统中的磨矿设备采用球磨机和 / 或高压辊压机；
所述均化库为间隙均化库或连续均化库， 所述均化库采用压缩空气对库内粉料进行搅拌 均化， 且均化值大于或等于 4。
上述本发明的方法， 所述步骤 （2 ) 和步骤 （3 ) 中， 优选的， 所述粘结剂为含腐植酸钠 的混合溶液， 所述粘结剂中腐植酸钠的质量百分浓度为 4%〜20%， 所述粘结剂的制备包括以 下步骤： 选用含腐植酸的煤料（粒度一般为 -20mm)和烧碱作为原料， 将烧碱与水混合按比例 配制成 NaOH溶液 （配制得到的氢氧化钠溶液的质量百分浓度优选控制在 1%〜10%)； 将所述 煤料和 NaOH溶液按 1 : 3〜10的固液比进行球磨混合； 将混合料搅拌加热到 40 °C〜95 °C进行 合成反应， 反应时间不小于 30min (优选 30min〜180min ) ; 将反应产物进行过滤， 过滤后得 到的滤液即为粘结剂。 所述煤料优选是指腐植酸含量在 20%以上的风化煤、 泥煤和 /或褐煤。
上述本发明的方法， 优选的， 所述步骤 （2 ) 和步骤 （3 ) 中的强力混合机包括一倾斜旋 转的混合桶， 混合桶内安装有可旋转式搅拌器， 混合时所述混合桶的旋转方向与所述搅拌器 的旋转方向相反， 使混合桶内的混合料在其中形成紊流达到充分搅拌的效果。 所述造球机均 为圆盘式造球机； 所述步骤（3 )中筛分出的不符合工艺要求粒度的内球均送入轮碾机或润磨 机中碾碎， 碾碎过程中根据物料湿度要求可选择性补入所述内球料， 然后返回到所述强力混 合机或润磨机中形成闭路循环。
上述本发明的方法， 优选的， 所述步骤（3 ) 中用到的干燥机为鳞板干燥机， 该鳞板干燥 机沿复合生球的输送方向共分为低温、 中温和高温三个干燥段；
所述低温干燥段通入 100 °C〜200 °C的低温热风由上至下进行抽风或由下至上进行鼓风， 使低温热风垂直穿过料层， 并对复合生球进行穿流干燥； 所述低温热风是源自所述高温干燥 段的高温热风出口处排出的废气；
所述中温干燥段通入 150 °C〜250 °C的中温热风由上至下进行抽风或由下至上进行鼓风， 使中温热风垂直穿过料层， 并对复合生球进行穿流干燥；
所述高温干燥段通入 200 °C〜350 °C的高温热风由上至下进行抽风或由下至上进行鼓风， 使高温热风垂直穿过料层， 并对复合生球进行穿流干燥。
上述本发明的方法， 优选的， 所述步骤（4 ) 中， 所述回转窑包括窑体、 窑头箱、 窑尾箱 和驱动窑体转动的驱动装置， 在窑体的窑头处设有燃料烧嘴， 在窑尾箱处设有进料管和一连 接至外部水化塔的出口烟道， 所述窑体的上部不设置风管， 所述出口烟道设于以回转窑轴线 为中心的窑体半径范围内， 且出口烟道中的烟气输送方向与回转窑的轴线方向基本平行或呈 小于 45 ° 的夹角。 所述窑体优选包括外部的筒体壳和设于筒体壳内侧的窑衬 （所述窑衬主要 由耐火砖或耐火浇注料构成）， 所述窑体沿回转窑长度方向被划分包括还原带和预热带， 还原 带靠近窑头箱， 预热带靠近窑尾箱， 还原带长度占窑体长度的 1/3〜3/5， 预热带长度占窑体 长度的 2/5〜2/3。 所述窑衬优选主要由复合耐火砖或复合耐火浇注料构成， 位于还原带的窑 衬包括靠近筒体壳的黏土材料层（导热系数小）和靠近回转窑内腔的高铝材料层（耐火度高， 导热系数相对大）； 位于预热带的窑衬则包括靠近筒体壳的黏土材料层（导热系数小）和靠近 回转窑内腔的碳化硅材料层 （与偏磷酸反应程度低， 导热系数相对大）。 更进一步的， 所述步 骤（4 ) 中， 所述窑尾箱外配套设有一清窑机， 清窑机中设有一可渐进式伸入回转窑窑尾箱内 并可与其腔体内壁保持相对刮蹭的刮刀 （耐热不锈钢制）。 所述回转窑的轴线与水平面呈 1. 7 ° 〜2. 9 ° 的夹角， 且窑体 （3 ) 的长径比 （指回转窑长度和回转窑筒体钢壳内径的比值） 为 10〜25： 1范围； 回转窑的填充率为 7%〜25%， 回转窑的转速控制为 0. 6 r/min〜3r/min。
上述回转窑中， 优选的， 所述回转窑沿窑体长度方向上安装有多个监控窑内温度的热电 偶， 所述热电偶通过导电环或无线发送接收装置与回转窑外的温度控制装置及温度显示器相 连； 所述回转窑的窑头安装有监控回转窑内炉况的工业电视。
上述回转窑中， 优选的， 所述回转窑的窑尾箱内或出口烟道上安装有抽取气样的抽气泵。 上述本发明的方法， 所述步骤 （4) 中， 所述综合利用的方法优选包括以下步骤：
( a)将窑法磷酸工艺中出回转窑高温渣球（释放完 P205的渣球， 一般温度高达 1000°C〜 1300°C ) 输送至一冷却设备的进料区处， 所述冷却设备包括支撑装置、 台车和罩壳， 所述台 车位于支撑装置上， 所述罩壳架设于台车上方， 台车上设有蓖板， 所述冷却设备的进料区、 卸料区均与所述台车相通， 所述高温渣球被送进冷却设备的台车上； 所述冷却设备被划分成 至少两个相互连接的冷却段， 各冷却段分别设置有冷空气进风口和与之对应的热风出口； 所 述冷空气进风口与热风出口之间的气流通道穿过所述台车上的蓖板， 所述台车的运动轨迹依 次经过所述进料区、 多个冷空气进风口和卸料区；
(b )所述台车通过转动将高温渣球带入第一冷却段， 第一冷却段利用台车下部的鼓风机 将冷空气从所述冷空气进风口引入， 所述冷空气穿过位于第一冷却段的台车及其篦板， 与台 车上的热渣球进行热交换， 同时将高温渣球中残余的未反应完的碳燃烧完毕， 经过第一冷却 段的热交换后， 从第一冷却段对应的第一热风出口排出的热空气通过第一热风输送管道输送 至回转窑窑头箱再进入回转窑腔体中作为回转窑中燃烧还原反应产物的热空气来源 （具体作 为燃烧磷和 CO的助燃空气）；
( c )所述台车通过转动将高温渣球继续从第一冷却段带入所述第二冷却段， 第二冷却段 利用台车下部的鼓风机将冷空气从所述冷空气进风口引入， 所述冷空气穿过位于第二冷却段 的台车及其篦板， 与台车上的热渣球进行热交换， 经过第二冷却段的热交换后， 从第二冷却 段对应的第二热风出口排出的热空气通过第二热风输送管道输送至窑法磷酸工艺复合生球干 燥机中作为复合生球干燥的热空气来源；
( d)所述台车通过转动将高温渣球继续从第二冷却段带入后续的其余各冷却段， 其余各 冷却段利用其台车下部的鼓风机将冷空气从所述冷空气进风口引入， 所述冷空气穿过位于其 余各冷却段的台车及其篦板， 与台车上的热渣球进行热交换， 经过其余各冷却段的热交换后， 从其余各热风出口排出的热空气经除尘后可直接排放或送到窑法磷酸工艺复合生球干燥机中 作为复合生球干燥的热空气来源； 冷却后的渣球从所述卸料区排出即可。 在上述对高温渣球的综合利用过程中， 从所述第一热风出口排出的热空气的温度优选控 制在 600 °C以上，从所述第二热风出口排出的热空气的温度优选控制在 350 °C以上。一般来说， 经过最后一段冷却段的冷却， 可将渣球的温度降至 100 °C， 最后冷却段的出口热风温度则一 般小于 150 °C。 所述冷却后的渣球从卸料区排出后用作人造陶粒， 可直接作为建筑材料或花 草栽培土使用； 或者将冷却后的渣球细磨到至少过 100 目 80%以上， 然后作为制造混凝土的 活性料或作为制造水泥的混合材。
在上述对高温渣球的综合利用过程中， 所述冷却设备优选为一环冷机或者带式冷却机， 所述冷空气进风口设于台车下方， 所述热风出口设于台车上方 （当然也可采用上方进风、 下 方排出热风的方式）。所述环冷机沿周长方向被划分成所述至少两个相互连接的冷却段（优选 2〜5 个冷却段， 且每个冷却段的长度优选相等）； 各冷却段之间通过隔板分隔开。 所述带式 冷却机沿长度方向被划分成至少两个（优选 2〜5个）相互连接的冷却段； 各冷却段之间通过 隔板分隔开。 其中， 紧邻进料区的第一冷却段中设置所述第一热风出口， 紧邻第一冷却段的 第二冷却段中设置所述第二热风出口， 紧邻第二冷却段的后续其余各冷却段中设置相应的热 风出口。
上述本发明的方法， 优选的， 所述步骤（5 ) 中的水化塔中的喷淋装置包括至少两个位于 水化塔容腔不同高度处的喷淋层， 且至少两个的喷淋层中包含一稀磷酸喷淋层和浓磷酸喷淋 层， 浓磷酸喷淋层设于稀磷酸喷淋层上方； 所述循环磷酸喷淋层的进液管与所述酸液循环喷 淋系统相连通， 所述稀磷酸喷淋层的进液管与磷酸雾捕集塔中稀磷酸溶液的循环输送管道相 连通以使得磷酸雾捕集塔中的稀磷酸溶液串酸至水化塔中， 所述酸液循环喷淋系统另通过管 道连接至磷酸雾捕集塔中以使得水化塔中的循环磷酸溶液串酸至磷酸雾捕集塔中。
上述本发明的方法， 优选的， 所述步骤（5 ) 中的酸冷器为一个搅拌槽中布置有多个改性 石墨管或不锈钢管环成的换热板， 管中通入循环冷却水， 通过搅拌， 使进入酸冷器的磷酸溶 液在换热板上形成强制对流换热； 所述步骤（1 )中的出窑烟气通过与循环喷淋的循环磷酸溶 液换热以及水化塔内水冷系统的冷却， 温度降至 75 °C〜130 °C ;
上述本发明的方法， 优选的， 所述步骤（5 ) 中的水化塔内循环喷淋的磷酸溶液的质量百 分比浓度为 60%〜90%， 水化塔内浓磷酸溶液的进塔温度控制为 50 °C〜80 °C， 水化塔内喷淋液 气比控制在 lL/m3〜20L/m3。
上述本发明的方法， 优选的， 所述步骤（5 ) 中的磷酸精制工序中设有用于对粗磷酸产品 进行精制的磷酸精制槽， 磷酸精制槽内加入活性炭、 硅藻土、 脱硫剂和脱砷剂， 活性炭和硅 藻土的用量均控制为待精制粗磷酸产品质量的 0. 1%〜2%； 所述脱硫剂为可溶性钡盐， 其用量 为理论用量（根据化学反应式） 的 1〜2倍； 所述脱砷剂为硫化氢或硫化钠， 其用量为理论用 量 （根据化学反应式） 的 1〜1. 2倍； 磷酸精制槽内搅拌反应时间为 0. 5h〜2h。 搅拌反应后 的产物泵送至过滤系统过滤后， 滤液即为成品磷酸。
上述本发明的方法，优选的，所述步骤（5 )中的磷酸雾捕集塔为一流态化逆流式洗涤塔， 包括洗涤管和分离罐， 由水化塔烟气出口排出的烟气进入磷酸雾捕集塔的洗涤管中， 在洗涤 管中由下向上喷射的循环稀磷酸溶液与由上向下的烟气逆流碰撞接触后建立起泡沫区， 烟气 穿过泡沫区后与大面积不断更新的稀磷酸溶液液体表面接触， 在泡沫区发生磷酸雾粒子的捕 集、 聚合长大和热量的传递， 烟气通过绝热蒸发循环稀磷酸溶液中水分的方式被进一步降温 到 60 °C〜90 °C ; 所述洗涤管中的气体和液体进入下部的分离罐中进行气-液分离， 分离罐同 时兼作循环酸槽（稀磷酸溶液的循环槽）， 循环稀磷酸溶液落入分离罐底部后绝大部分通过循 环泵回送至洗涤管， 小部分串酸至水化塔中； 所述磷酸雾捕集塔中循环喷淋的稀磷酸溶液的 质量百分比浓度为 10%〜50%； 稀磷酸溶液的温度控制在 40 °C〜70 °C， 磷酸雾捕集塔内喷淋液 气比控制在 3L/m3〜25L/m3。出水化塔烟气中夹带的磷酸雾绝大部分转入循环的稀磷酸溶液中。
上述本发明的方法， 优选的， 所述步骤（5 ) 中的磷酸雾捕集塔中烟气出口排出的烟气再 进入到除雾分离塔中进行进一步的气-液分离，除雾分离塔下部设计成类似旋风除尘器的磷酸 液滴收捕结构， 利用离心力将已长大的磷酸液滴从烟气中捕集下来， 在除雾分离塔上部安装 有丝网除雾器， 将烟气中尚未长大的磷酸雾滴进一步捕集下来； 所述在线补水装置装设在除 雾分离塔中且位于丝网除雾器上方的烟气出口位置，其一方面作为整个工艺系统的补水设备， 另一方面通过清洗使烟气中的磷酸雾被进一步捕集， 并兼作丝网除雾器的冲洗装置。
上述本发明的方法， 优选的， 所述步骤 （5 ) 中的氟回收工序包括以下步骤：
( 1 )一级氟吸收： 先将除雾分离塔中排出的含氟烟气输送至一级氟吸收塔的氟硅酸洗涤 管， 烟气自上而下与喷嘴自下而上喷入的循环氟硅酸溶液发生充分的气液两相接触， 并进行 传质传热和化学反应， 反应生成氟硅酸， 同时烟气中的热焓通过绝热蒸发循环氟硅酸溶液中 的水分被部分转移到水蒸气中；
( 2 )一级气液分离： 所述氟硅酸洗涤管中的气体和液体全部转移至氟硅酸分离罐中进行 气液分离， 分离后的气体通过一级氟吸收塔的烟气出口进入二级氟吸收塔的二级氟硅酸洗涤 管中， 分离后的液体留存于氟硅酸分离罐中并通过带循环泵的循环输送管道回送至氟硅酸洗 涤管中进行上述一级氟吸收步骤的操作；
( 3 )二级氟吸收： 进入二级氟硅酸洗涤管中的烟气自上而下与喷嘴自下而上喷入的循环 氟硅酸溶液发生充分的气液两相接触， 并进行传质传热和化学反应， 反应生成氟硅酸， 同时 烟气中的热焓通过热量传递部分转移到循环氟硅酸溶液中；
( 4 )二级气液分离： 所述二级氟硅酸洗涤管中的气体和液体全部转移至二级氟硅酸分离 罐中进行气液分离，分离后的气体通过二级氟吸收塔的烟气出口进入后续的尾吸塔进行处理， 分离后的液体留存于二级氟硅酸分离罐中， 部分通过循环泵回送至二级氟硅酸洗涤管中进行 上述二级氟吸收步骤的操作， 部分输送到一级氟吸收塔的氟硅酸分离罐中；
( 5 )所述一级氟吸收塔中的氟硅酸溶液会不断增加， 多出的氟硅酸溶液经过滤去硅胶后 后作为副产的氟硅酸产品。
上述的一级氟吸收塔和二级氟吸收塔均为流态化逆流式洗涤塔， 一级氟吸收塔主要由氟 硅酸洗涤管和氟硅酸分离罐组成， 氟硅酸洗涤管的出口连通至氟硅酸分离罐的中部， 氟硅酸 分离罐的顶部设有烟气出口， 底部设有氟硅酸液出口， 该氟硅酸液出口通过一带循环泵的循 环输送管道与所述氟硅酸洗涤管内的喷嘴相连通；
上述的二级氟吸收塔主要由二级氟硅酸洗涤管和二级氟硅酸分离罐组成， 一级氟吸收塔 的烟气出口通过管道连接至二级氟硅酸洗涤管， 二级氟硅酸洗涤管的出口连通至二级氟硅酸 分离罐的中部， 二级氟硅酸分离罐的顶部设有除沫层 （除沫层定期用循环氟硅酸溶液喷淋冲 洗以保持除沫效果） 和烟气出口， 底部设有氟硅酸液出口， 该氟硅酸液出口通过一带循环泵 的循环输送管道与二级氟硅酸洗涤管内的喷嘴及一级氟吸收塔的氟硅酸分离罐相连通。
所述二级氟吸收塔中的循环输送管道上还可优选设有氟硅酸冷却器， 进入二级氟硅酸洗 涤管的循环氟硅酸溶液经过了所述氟硅酸冷却器的冷却处理。
上述的氟回收工序中，优选的，一级氟吸收采用的循环氟硅酸溶液的质量百分浓度为 8%〜 25% (更优选 10%〜20%)， 循环氟硅酸溶液的温度为 25 °C〜65 °C (更优选 50 °C〜65 °C )， 喷淋 液气比控制在 3L/m3〜25L/m3 (更优选 3L/m3〜6L/m3 ) ; 二级氟吸收采用的循环氟硅酸溶液的质 量百分浓度为 0. 5%〜5%， 循环氟硅酸溶液的温度为 25 °C〜60 °C (更优选 45 °C〜60 °C )， 喷淋 液气比控制在 3L/m3〜25L/m3 (更优选 3L/m3〜6L/m3)。
上述的氟回收工序中， 优选的， 所述二级氟吸收塔的烟气出口还连接至一尾吸塔， 该尾 吸塔为一喷淋空塔， 尾吸塔的顶部设有烟气出口， 塔内上方设有喷淋层， 底部设有碱吸收液 箱， 该碱吸收液箱的出口通过带循环泵的循环输送管道与尾吸塔内的喷淋层相连通， 控制碱 吸收液的 11值 8。
与现有技术相比， 本发明的优点在于：
( 1 )与传统的多段破碎工艺相比， 本发明中原料预处理采用的均是经过优化改进后的高 破碎比的破碎设备， 其不仅能显著降低破碎能耗， 而且可降低破碎设备投资和工艺成本， 提 高破碎效率； 另外本发明中对每一种主要原料均配备独立的破碎设备和磨矿设备， 通过单独 破碎、 分别磨矿制粉， 可以在很大程度上保证原料配方的稳定性， 防止原料的配比出现较大 波动； 通过采用磨矿设备配备热风炉的方式， 省去了各种矿石及原料的干燥工序， 工艺流程 更为简化， 同时磨矿能耗降低达 20%以上； 磷矿石粉均化采用气流均化方法， 有利于进一步 保证工艺磷矿石化学成分的稳定， 使工业化稳定生产成为可能。
( 2 )在复合球团的成型中， 本发明中配制的粘结剂不仅成分简单、 原料来源广泛、 成本 低， 而且粘结剂的粘结效果好； 复合球团的一致性更容易得到保证， 复合球团中配料波动很 小 （复合球团中配料比的波动范围能够精确控制在 5%以内）； 本发明中对复合球团的干燥机 也作了重要改进和完善， 首先将干燥机划分成三个干燥段， 使复合生球的干燥过程由低到高 分段进行； 第一干燥段利用了第三干燥段排出的低温热气余热对干燥机初始段的湿复合生球 进行低温干燥， 这一方面利用了余热资源， 另一方面因第一干燥段的气流温度较低， 能够有 效防止湿复合生球的爆裂破坏造成球团损坏， 保证后续入窑的复合球团的质量； 第二干燥段 通入不带水汽的中温热风， 形成较高的湿度差， 这使得在保证球团不爆裂的情况下加速球团 的干燥； 最后进入第三干燥段的复合球团水分已降到 4%以下， 此时可通入较高温度的高温热 风， 在保证球团不爆裂的情况下加速球团的干燥固结过程； 本发明中出干燥机的球团水分可 控制在 1. 0%， 球团抗压强度达到 250KN/个球， 落下强度达到 20次 /1米， 可以充分保证 在还原回转窑内运转时不损坏， 从而保证后续球团还原过程的正常进行。
( 3 )本发明将回转窑窑尾烟气排出管的出口设置在与回转窑轴线的同方向上（为了布置 至水化塔管道的方便， 也可以有适当偏移）， 这样使得回转窑出窑烟气在进入出口烟道时不会 在运动方向上作较大偏移， 进而防止出窑烟气中偏磷酸在窑尾处产生离心物理沉降。 由于回 转窑内沉降的偏磷酸减少， 延长了窑尾圈的形成周期， 提高回转窑的作业效率。 优选的方案 中， 回转窑窑尾预热带的窑衬采用双层式复合材料结构， 在靠近回转窑筒体壳的部分采用黏 土材料层， 在靠近回转窑内部一侧则采用碳化硅材料层， 由于偏磷酸盐与碳化硅材料反应困 难， 使沉积在回转窑预热带的偏磷酸盐能靠重力自行掉落。 回转窑窑尾箱外还可装设一由耐 热不锈钢制成的刮刀， 一旦窑尾圈形成造成料球从窑尾返料， 则可停止加热回转窑的燃料供 给并停止向回转窑内送入料球， 同时可将刮刀逐渐伸入至回转窑内， 利用回转窑自身的旋转， 将窑尾结圈切削刮除掉。
( 4)在本发明的高温渣球综合利用工艺中， 本发明的综合利用工艺充分利用了高温渣球 的余热资源， 并将该余热用作窑法磷酸工艺中还原反应补热， 使回转窑的能耗显著降低； 同 时还用作复合生球干燥所需热源， 这充分利用了不同冷却阶段不同温度热风的热能资源， 从 而使整个窑法磷酸工艺的能源利用更加充分； 冷却后的渣球同样得到了高效、 高附加值的利 用， 而不是直接外排， 这不仅减少了固体废物对环境的污染和破坏， 而且废弃资源得到了高 效利用。
( 5 )在本发明最后的水化吸收磷和回收氟的步骤中， 本发明对现有的制磷酸设备及工艺 做了大量改进和优化， 使得整个设备的结构更加简化、 工艺流程更加合理， 具有更强的适应 性； 对现有的回收氟的设备及工艺也做了大量改进和优化， 使得整个氟回收设备的结构更加 简化、 工艺流程更加合理， 能更好地配合水化吸收磷酸的工艺路线需要； 优选的技术方案中 可以实现窑法磷酸工艺出窑烟气中 P2O5和氟的同时回收， 实现水化吸收磷和回收氟前后工序 的有效配合， 进而得到价值较高的主产品磷酸和副产品氟硅酸， 使得原料资源得到了更充分 的利用， 提高了窑法磷酸工艺的经济效益； 优选的技术方案几乎实现了工艺过程废气、废料、 废液的零排放， 使得整个工艺的环保性大大提高。
综上所述， 本发明的工艺方法不仅工艺流程合理、 优化， 而且设备投入小， 经济附加值 高， 而且解决了现有窑法磷酸工艺中存在的诸多技术难题， 整个工艺过程节能环保， 运行高 效， 产品质量优异， 完全可适用于低品位磷矿直接生产磷酸， 能够完全适应含 P205和氟的烟 气特点 （特别是窑法磷酸窑气） 及治理需要， 对于我国大量低品位磷矿的有效利用具有十分 重要的意义。
【附图说明】
图 1为本发明具体实施方式中用回转窑规模化生产磷酸的工艺流程原理图。
图 2为本发明具体实施方式中原料预处理步骤的工艺流程原理图。
图 3为本发明具体实施方式中用到的强力混合机的结构示意图。
图 4为图 3中 A-A处的剖视图及工作原理示意。
图 5为本发明具体实施方式中用到的鳞板干燥机的结构原理图。
图 6为图 5中 B-B处的剖视图及工作原理示意。
图 7为本发明具体实施方式中回转窑的结构示意图。
图 8为图 7中 A-A处的剖视图。
图 9为图 7中 B-B处的剖面图。
图 10为图 7中 C-C处的剖面图。
图 11为本发明具体实施方式中清窑机的结构示意图。
图 12为图 11中 D-D处的剖视图。
图 13为本发明具体实施方式中清窑机工作时的原理图。
图 14为图 13中 E-E处的剖视图。
图 15为本发明具体实施方式中高温渣球冷却设备的工作原理图 （俯视）。
图 16为图 15中 B-B处的局部剖视图。
图 17为本发明具体实施方式中高温渣球综合利用方法的工艺流程图。
图 18为本发明具体实施方式中水化吸磷及回收氟的工艺系统的结构原理图。 图 19为本发明具体实施方式中制磷酸设备的水化塔结构示意放大图。
图 20为本发明具体实施方式中制磷酸设备的磷酸雾捕集塔结构示意放大图。
图例说明：
1、 水化塔； 11、 烟气进口； 12、 烟气出口； 13、 喷淋装置； 14、 进液口； 15、 出液口； 16、 酸液储液槽； 17、 水冷系统； 18、 酸冷器； 2、 循环泵； 21、 压滤装置； 22、 填料过滤装 置； 23、 磷酸精制设备； 24、 浓磷酸喷淋层； 25、 稀磷酸喷淋层； 3、 磷酸雾捕集塔； 31、 洗 涤管； 32、 分离罐； 33、 酸液出口； 34、 酸液进口； 35、 喷嘴； 4、 除雾分离塔； 41、 在线水 冲洗装置； 42、 丝网除雾器； 43、 罩壳； 44、 冷空气进风口； 45、 第一热风出口； 46、 第二 热风出口； 47、 隔板； 48、 烟囱； 49、 高温渣球； 5、 一级氟吸收塔； 51、 氟硅酸洗涤管； 52、 氟硅酸分离罐； 53、 氟硅酸液出口； 54、 氟硅酸精制设备； 55、 燃料烧嘴； 56、 碳化硅材料 层； 57、 黏土材料层； 58、 高铝材料层； 6、 二级氟吸收塔； 61、 二级氟硅酸洗涤管； 62、 二 级氟硅酸分离罐； 63、 氟硅酸冷却器； 7、 尾吸塔； 71、 驱动部件； 72、 进料斗； 73、 搅拌器; 74、 壳体； 75、 翻料犁； 76、 卸料口； 77、 装料小车； 78、 干燥炉体； 79、 除尘器； 8、 风机； 80、 低温干燥段； 81、 中温干燥段； 82、 高温干燥段； 83、 进风口； 84、 保温层； 85、 出风 口； 86、 通气孔； 90、 传动大齿轮； 91、 窑头箱； 92、 托轮装置； 93、 窑体； 94、 传动小齿 轮； 95、 驱动装置； 96、 窑尾箱； 97、 出口烟道； 98、 进料管； 99、 窑尾动密封； 100、 窑头 动密封； 101、 窑衬； 102、 筒体壳； 103、 行走减速电机； 104、 机架； 105、 旋转轴； 106、 支撑桁架； 107、 回转窑门框； 108、 平台； 109、 车轮； 110、 刮刀； 111、 支撑装置； 112、 台车； 113、 热电偶； 114、 抽气泵。
【具体实施方式】
以下结合说明书附图和具体优选的实施例对本发明作进一步描述， 但并不因此而限制本 发明的保护范围。
实施例：
一种如图 1所示的改进型的用回转窑规模化生产磷酸的方法， 包括以下步骤：
1. 原料预处理：
如图 2所示， 本实施例的原料预处理方法用到本实施例的原料预处理工艺系统， 该预处 理工艺系统包括相互独立的碳质还原剂预处理系统、 磷矿石预处理系统和硅石预处理系统， 碳质还原剂预处理系统、 磷矿石预处理系统和硅石预处理系统的出口通过第一输送设备均连 接至一内球料混合装置， 碳质还原剂预处理系统和硅石预处理系统的出口另通过第二输送设 备均连接至一外壳料混合装置。 本实施例中采用煤料 （焦粉或石油焦） 作为碳质还原剂， 本 实施例的碳质还原剂预处理系统主要由依次相连的单段破碎设备、煤料中间料仓、磨矿设备、 煤粉储料仓和配料装置组成； 本实施例中的磷矿石预处理系统主要由依次相连的单段破碎设 备、 磷矿石中间料仓、 磨矿设备、 均化库和和配料装置组成； 本实施例中的硅石预处理系统 主要由依次相连的两段一闭路破碎设备、 硅石中间料仓、 磨矿设备、 硅石粉储料仓和配料装 置组成。 碳质还原剂预处理系统和磷矿石预处理系统中用到的单段破碎设备均采用锤式破碎 机， 硅石预处理系统中采用的两段一闭路破碎设备则主要由依次相连的颚式破碎机、 筛分机 和圆锥破碎机组成， 且圆锥破碎机的出料口循环连接至筛分机的进料口。 碳质还原剂预处理 系统、磷矿石预处理系统的磨矿设备采用立磨， 硅石预处理系统中的磨矿设备采用球磨机和 / 或高压辊压机， 各磨矿设备分别通过各自的粉料收集输送装置连接至煤粉储料仓、 均化库和 硅石粉储料仓。 各磨矿设备配备有向粉磨过程补送热风的热风炉。 各粉料收集输送装置均包 括依次相连的旋风收粉设备、 布袋收粉设备和风机， 各风机的出风口连接至各预处理系统对 应的热风炉或直接外排。 本实施例的原料预处理方法主要是将原料煤、 磷矿石和硅石分别用 上述的碳质还原剂预处理系统、 磷矿石预处理系统和硅石预处理系统进行预处理， 预处理后 的煤粉、 磷矿石粉和硅石粉送入内球料混合装置进行混合造球， 预处理后的煤粉和硅石粉另 送入外壳料混合装置进行混合； 该原料预处理方法具体包括以下步骤。
1. 1煤料预处理： 将 -200mm的煤料 （焦粉或石油焦） 先采用单段锤式破碎方式 （也可采 用反击式或锤式 -反击式组合破碎） 破碎至粒度在 12mm以下， 然后将破碎后的碎石料送至煤 料中间料仓， 煤料中间料仓通过计量给料设备将碎石料送至立式辊磨 （即立式磨， 也可采用 风扫煤磨） 进行粉磨， 通过计量给料设备可以稳定磨机的负荷； 待立式磨将进料粉磨至 -100 目〜 -325目后， 由旋风收粉设备和布袋收粉设备组成的组合式收尘器收集粉料 （也可单独由 高浓度布袋收尘器进行收集）， 并输送至煤粉储料仓； 粉磨过程中通过配置的热风炉不断补充 热风， 以便根据原料含水量干燥粉料中夹带的水分； 整个煤料的预处理过程具有较高的破碎 比， 能够节省破碎能耗、 降低投资和工艺成本。
1. 2磷矿石预处理： 将 -200mm的磷矿石先采用单段锤式破碎方式 （也可采用反击式或锤 式 -反击式组合破碎）破碎至粒度在 12mm以下， 然后将破碎后的碎石料送至磷矿石中间料仓， 磷矿石中间料仓通过计量给料设备将碎石料送至立式磨 （也可采用风扫球磨） 进行粉磨， 通 过计量给料设备可以稳定磨机的负荷； 待立式磨将进料粉磨至 -100目〜 -200目后， 由旋风收 粉设备和布袋收粉设备组成的组合式收尘器收集粉料 （也可单独由高浓度布袋收尘器进行收 集）， 并输送至均化库； 粉磨过程中通过配置的热风炉不断补充热风， 以便根据原料含水量干 燥粉料中夹带的水分； 整个磷矿石的预处理过程具有较高的破碎比， 可以进一步节省破碎能 耗和降低投资。
1. 3硅石预处理： 将 -200mm的硅石先采用两段一闭路破碎设备 （也可采用单段反击式破 碎设备或反击式-锤式联合破碎方式） 破碎至粒度在 12mm以下， 然后将破碎后的碎石料送至 硅石中间料仓， 硅石中间料仓通过计量给料设备将碎石料送至高压辊压机 （也可采用高压辊 压联合球磨的方式） 进行粉磨， 通过计量给料设备可以稳定磨机的负荷； 待磨矿设备将进料 粉磨至 -100目〜 -200目后， 由旋风收粉设备和布袋收粉设备组成的组合式收尘器收集粉料， 并输送至硅石粉储料仓； 粉磨过程中通过配置的热风炉不断补充热风， 以便根据原料含水量 干燥粉料中夹带的水分。
1. 4 由输运设备送入煤粉储料仓中的煤粉， 同时作为后续窑法磷酸工艺内球料和外壳料 的原料； 由输运设备送入硅石粉储料仓中的硅石粉， 也同时作为后续窑法磷酸工艺内球料和 外壳料的原料； 由输送设备送入均化库的磷矿石粉， 通过采用压缩空气对库内的磷矿石粉进 行搅拌均化， 可以用间隙均化库， 也可以用连续均化库， 其均化值大于 4即可； 均化库本身 又作为磷矿石粉的储料仓。
2. 内球的制备：
将经过上述步骤 1处理后得到的碳质还原剂粉 （本实施例选用 -200目以上的煤粉， 例如 焦粉、 无烟煤粉或石油焦）、 磷矿石粉 （-150 目以上） 和硅石粉 （-150 目以上） 按复合球团 中的配比要求加入一强力混合机中， 配料时可用电子秤称量， 同时按上述添加量添加本实施 例的粘结剂。
本实施例中用到的粘结剂的制备方法具体包括以下步骤： 选用含腐植酸的风化煤 （或泥 煤、 褐煤） 和烧碱作为原料， 本实施例的风化煤中腐植酸含量在 40%以上； 将烧碱 （93%的氢 氧化钠） 与水混合、 配制得到质量百分浓度为 2%的氢氧化钠溶液； 将上述风化煤和氢氧化钠 溶液按 1 : 5的固液比进行球磨混合， 球磨时间 20min; 将混合料送入带搅拌器的反应槽， 开 启搅拌器加热到 90°C进行合成反应， 反应时间为 30min; 将反应产物进行过滤， 过滤后得到 的滤液即为粘结剂。 本实施例的粘结剂为含腐植酸钠的混合溶液， 粘结剂中腐植酸钠的质量 百分浓度为 8%。
本实施例中用到的强力混合机如图 3所示， 包括一倾斜可旋转的混合桶， 混合桶包括壳 体 74和桶内安装的可旋转式搅拌器 73， 混合桶的上方设有进料斗 72和驱动部件 71， 桶内一 侧还设有翻料犁 75， 桶底设有卸料口 76; 强力混合机的工作原理为： 混合时混合桶的旋转方 向与搅拌器的旋转方向相反 （参见图 4); 在加入上述原料后， 在倾斜、 旋转的混合桶内与逆 向旋转运动的搅拌器相对旋转运动， 使其中分散的混合料行成循环物料流进而起到强力混合 作用； 通过搅拌器与混合桶的逆向旋转， 还可使被混合的物料在其中形成紊流， 从而达到充 分搅拌混匀的效果； 该强力混合机是连续进料、 连续出料， 以保证生产过程的连续性。
充分混匀后的混合料送入料仓， 在料仓下部安装有通过电子秤计量的计量给料设备， 这 种计量给料设备可以是圆盘给料机加电子秤组合的给料设备， 通过电子秤计量与设定给料量 进行比较， 出现偏差由计算机控制系统自动调整圆盘给料机的圆盘转速， 使给料量与设定值 相等 （也可以直接使用带电子秤的其他计量给料设备）。
本实施例内球料中， CaO/Si02的摩尔比为 0. 3 (小于 0. 6或大于 6. 5均可）， 碳质还原剂 粉的配量为磷矿石粉中 P205理论量的 1. 5倍以上； 包裹料中碳质还原剂粉和硅石粉的质量比 为 2. 5： 1 ( 1. 5〜5： 1的范围均可）。充分混匀后的混合料通过计量给料设备送入一圆盘造球 机进行造球处理， 造球时以滴状和 /或雾状施加形式补加上述本实施例的粘结剂， 补加量为混 合料质量的 4%〜6%， 造球完成后得到内球。
3. 复合球团的成型：
3. 1包裹料的准备： 将上述的碳质还原剂粉和硅石粉按配比要求加入另一强力混合机中， 同时按本实施例复合球团添加量添加本实施例的粘结剂， 充分混匀后得到包裹料； 本步骤中 强力混合机的工作原理和功能结构与上述步骤 2中用到的强力混合机相同。 该强力混合机亦 可用连续进料、 连续出料的轮碾机或润磨机替代。
3. 2复合生球的成型： 将步骤 2中出球盘后得到的内球进行双层辊式筛分处理 （采用一 台双层辊式筛分机）， 筛分出符合工艺要求粒度的内球送入另一进行包裹处理的圆盘造球机 中， 同时向该圆盘造球机中通入步骤 3. 1得到的包裹料， 在包裹处理过程中以滴状和 /或雾状 施加形式补加上述粘结剂， 补加量为包裹料质量的 4%〜6%， 包裹处理完成后在内球外部形成 有作为还原带与氧化带的隔离层， 得到复合生球。 双层辊式筛分处理后， 筛除的大于和小于 设定粒径的不合格内球均送入轮碾机 （或润磨机） 中碾碎， 碾碎过程中根据轮碾机对物料湿 度的要求可选择性补入先前配料工序中的内球料， 然后返回到上述步骤 2的强力混合机中形 成闭路循环， 以充分利用工艺原料， 减少工艺过程中间废料的排放和浪费。 本实施例制得的 复合生球的抗压强度约为 10N/个球， 落下强度约为 10 次 /0. 5 米， 且本实施例复合生球中 Ca0/Si02摩尔比的波动范围能控制在 5%之内。
3. 3干燥固结： 将步骤 3. 2后得到的复合生球送入一鳞板干燥机进行干燥固结。 如图 5 和图 6所示， 本实施例中的鳞板干燥机包括干燥炉体 78， 干燥炉体 78由低温干燥段 80、 中 温干燥段 81和高温干燥段 82组成， 干燥炉体 78的顶部设有热风的进风口 83， 底部设有出 风口 85， 外围包覆有保温层 84， 干燥炉体 78的腔室中设有装料小车 77， 若干装料小车 77 前后连接、 形成环形， 装料小车 77上开设有通气孔 86， 其采用链传动， 通过带座链条拖动 装料小车 77循环转动， 达到连续输送干燥的目的。干燥炉体 78的底部设有除尘器 79以回收 处理干燥过程中产生的烟尘。 在复合生球物料的输送过程中， 在物料运动的垂直方向由上往 下通入干燥热风以达到干燥的目的。 本实施例中的鳞板干燥机的具体工作原理为：沿复合生球装料小车 77的运动输送方向共 分为低温、 中温和高温三个干燥段。 复合生球先进入低温干燥段 80， 低温干燥段 80 通入 130°C〜200°C的低温热风由上至下进行抽风（或由下至上进行鼓风）， 使低温热风垂直穿过复 合生球料层， 并对复合生球进行穿流干燥； 低温热风是源自高温干燥段 82的高温热风出口处 排出的废气， 并经风机引至低温干燥段 80; 低温干燥段 80—方面利用了高温干燥段 82排出 的低温热气余热， 另一方面因低温干燥段 80的气流温度较低， 能够有效防止湿复合生球的爆 裂破坏造成球团损坏， 保证后续入窑的复合球团的质量。经过低温干燥段 80干燥后的复合生 球再进入中温干燥段 81干燥， 中温干燥段 81通入 200°C〜250°C的中温热风并由上至下进行 抽风（或由下至上进行鼓风）， 使中温热风垂直穿过料层， 并对复合生球进行穿流干燥； 中温 干燥段通入的是不带水汽的中温热风， 形成较高的湿度差， 这使得在保证球团不爆裂的情况 下加速球团的干燥。 经过中温干燥段 81干燥后的复合生球再进入高温干燥段 82干燥， 最后 进入高温干燥段 82的复合球团水分已降到 4%以下，高温干燥段 82通入 250°C〜350°C的高温 热风并由上至下进行抽风（或由下至上进行鼓风）， 使高温热风垂直穿过料层， 并对复合生球 进行最后的干燥。高温干燥段 82的高温热风优选来自后续回转窑出料冷却阶段的废气余热利 用， 也可另行设置热风炉送风。 低温干燥段 80和中温干燥段 81排出的废气可用风机进行收 集， 经除尘器 79除尘达到环保要求后通过烟道排入大气。
经干燥固结后得到的复合球团为外壳包覆内球的核壳形结构， 内球主要由内球料和粘结 剂组成， 外壳主要由包裹料和粘结剂组成； 内球料由碳质还原剂粉、磷矿石粉和硅石粉组成， 内球中粘结剂的添加量为内球料质量的 6% (可以是 1%〜10%); 包裹料由碳质还原剂粉和硅石 粉组成， 外壳中粘结剂的添加量为包裹料质量的 6% (可以是 1%〜10%)； 内球与外壳通过粘结 剂复合成核壳形结构。 该复合球团的水分控制在 1. 0%， 球团平均抗压强度达到 2501^/个 球， 落下强度达到 20次 /1米， 可以有效保证复合球团在后续的还原回转窑内运转时不被破 坏， 从而保证复合球团还原过程的顺利进行。
本实施例中出干燥机后的复合球团通过一台振动筛 （也可不设） 筛除在干燥过程中损坏 的复合球团（小于 5mm的部分）， 以减少后续进入回转窑的粉料量， 从而进一步延缓物料在回 转窑高温段的结圈周期。 出振动筛后的复合球团通过锁风阀由下料管从回转窑窑尾箱送入回 转窑进行后续的高温还原处理。
4. 窑法还原：
本实施例的工艺方法中用到的回转窑如图 7〜图 10所示， 包括窑体 93、 窑头箱 91、 窑 尾箱 96和驱动窑体 93转动的驱动装置 95， 驱动装置 95包括电机、 与电机相连的传动小齿 轮 94以及与传动小齿轮 94咬合的传动大齿轮 90， 另设有支撑窑体 93的托轮装置 92。 窑头 箱 91与窑体 93之间采用窑头动密封 100， 窑尾箱 96与窑体 93之间采用窑尾动密封 99。 在 窑体 93的窑头处设有燃料烧嘴 55和高温渣球出口， 在窑体 93的窑尾箱 96处设有进料管 98 和一连接至外部水化塔的出口烟道 97， 进料管 98连通至回转窑的内腔。 窑体 93的上部不设 置风管， 出口烟道 97设于回转窑轴线上， 且出口烟道 97中的烟气输送方向与回转窑的轴线 方向基本平行。 窑体 93包括外部的筒体壳 102和设于筒体壳 102内侧的窑衬 101， 所述窑体 93沿回转窑长度方向被划分包括还原带和预热带， 还原带靠近窑头箱 91， 预热带靠近窑尾箱 96， 还原带长度可占窑体 93长度的 1/3〜3/5 (本实施例中为 1/2)， 预热带长度可占窑体 93 长度的 2/5〜2/3 (本实施例中为 1/2)。 窑衬 101主要由复合耐火浇注料 （或者复合耐火砖） 构成， 如图 9所示， 位于还原带的窑衬 101包括靠近筒体壳 102的黏土材料层 57和靠近回转 窑内腔的高铝材料层 58 (氧化铝 65%)； 如图 10所示， 位于预热带的窑衬 101则包括靠近 筒体壳 102的黏土材料层 57和靠近回转窑内腔的碳化硅材料层 56。 窑尾箱 96外配套设有一 清窑机， 如图 11和图 12所示， 清窑机安放于平台 108上， 清窑机底部设有可在平台 108上 滚动的车轮 109， 车轮 109通过行走减速电机 103驱动， 清窑机的主体为一机架 104， 机架 104上方安装有一电机驱动的旋转轴 105， 旋转轴 105沿大致水平方向延伸出机架 104外， 伸 出部外围套设一支撑桁架 106， 旋转轴 105伸出部分的自由端设有一可渐进式伸入回转窑窑 尾箱 96内 （刮刀旋转可方便进刀） 并可与其腔体内壁保持相对刮蹭的刮刀 110 (耐热不锈钢 制）。一旦窑尾圈形成造成料球从窑尾返料， 则可停止加热回转窑的燃料供给并停止向回转窑 内送入料球， 同时可将刮刀 110逐渐伸入至回转窑内， 利用回转窑自身的旋转， 将窑尾结圈 切削刮除掉。
采用本实施例的上述回转窑进行窑法还原的具体操作包括： 采用上述的回转窑进行窑法 磷酸工艺，使上述步骤 3后的复合球团原料从回转窑窑尾处的进料管 98处进入回转窑的腔体 内， 点燃燃料烧嘴 55， 使回转窑内还原带温度加热到 1300°C〜1450°C， 回转窑中的磷矿石原 料在高温条件下经还原剂还原后生成出窑烟气，通过将回转窑窑尾出口烟道 97的出口设置在 与回转窑轴线的同方向上（即平行于回转窑轴线设置）， 使回转窑窑尾的出窑烟气在进入出口 烟道 97时不在运动方向上发生较大偏移，进而阻止出窑烟气中的偏磷酸在回转窑窑尾处产生 离心物理沉降， 使窑气中偏磷酸直接随出窑烟气进入到后续的水化塔中， 遇水转变成正磷酸。 更进一步的，本实施例中将回转窑位于预热带的窑衬 101制作成双层式的复合耐火浇注料（或 复合耐火砖）， 在靠近回转窑的筒体壳 102的窑衬部分采用黏土材料制作成黏土材料层 57， 在靠近回转窑内腔的窑衬部分则采用碳化硅材料制作成碳化硅材料层 56， 由于偏磷酸盐与碳 化硅材料反应困难，这使得反应沉积在回转窑预热带窑衬 101上的偏磷酸盐与回转窑窑衬 101 的附着力降低， 这样的窑衬结构可以进一步阻止偏磷酸盐与窑衬 101的反应结圈， 使其自行 掉落， 进一步缓解窑尾结圈的发生。 再有， 通过在本实施例回转窑的窑尾箱 96外配套的清窑 机内装设一耐热不锈钢制刮刀 110， 该刮刀 110为一可渐进式伸入回转窑窑尾箱 96内并可与 腔体内壁保持相对刮蹭的刮刀； 当回转窑窑尾结圈造成工艺原料的料球从窑尾处往回转窑外 返料时， 先停止加热回转窑的燃料供给， 同时停止向回转窑内送入料球， 并排空回转窑内料 球， 然后将清窑机中的刮刀 110从回转窑门框 107逐渐伸入至回转窑内， 再利用回转窑自身 的旋转， 将窑尾结圈切削刮除 （清窑机的工作原理参见图 13和图 14)。 由上可见， 本实施例 的回转窑通过多重保障措施和技术手段有效缓解了窑法磷酸工艺中回转窑窑尾结圈的难题。
另外， 本实施例回转窑沿窑体 93的长度方向上安装有多个监控窑内温度的热电偶 113， 热电偶 113通过导电环或无线发送接收装置与回转窑外的温度控制装置及温度显示器相连。 通过设置热电偶 113， 能够有效保证对内球料 Ca0/Si02摩尔比小于 0. 6的复合球团最高温度 不超过 1370°C的反应设定温度要求；对内球料 Ca0/Si02摩尔比大于 6. 5的复合球团最高温度 不超过 1450°C的反应设定温度要求。在回转窑的窑头则安装有监控回转窑内炉况的工业电视。 本实施例回转窑的窑尾箱 96出口的出口烟道 97上安装有抽取气样的抽气泵 114。 通过抽气 泵 114取样， 对气样水洗除去粉尘后送入 CO和 02气体分析仪监测回转窑出口烟气的 CO和 02 含量， 以便更好地控制出窑烟气 CO和 的含量范围 （一般为 0〜5%)。
本实施例中回转窑的轴线与水平面呈 1. 2 ° 〜2. 9 ° 的夹角 α (本实施例为 2. 3 ° )， 且 窑体 3的长径比为 10〜25： 1 (本实施例为 15： 1 )， 回转窑的填充率为 7%〜25% (本实施例 为 13%)， 回转窑的转速控制为 0. 6 r/min〜3r/min (本实施例为 lr/min)。 回转窑耐火材料 厚度优选为 200讓〜280讓 （本实施例为 220讓）。
5. 高温渣球的综合利用：
如图 17所示， 将上述步骤 4后出回转窑的高温渣球进行综合利用， 具体包括以下步骤。
5. 1将窑法磷酸工艺中出回转窑高温渣球 49输送至一环冷机 （也可采用带式冷却机） 的 进料区。 如图 15和图 16所示， 本实施例的环冷机包括支撑装置 111、 台车 112和罩壳 43， 台车 112位于支撑装置 111上， 罩壳 43架设于台车 112上方， 冷却设备的进料区、 卸料区均 与台车 112相通， 高温渣球 49被送进冷却设备的台车 112上； 该环冷机沿周长方向被划分成 3个相互连接的冷却段； 各冷却段之间通过隔板 47分隔开。 各冷却段分别设置有冷空气进风 口 44和与之对应的热风出口； 冷空气进风口 44设于台车 112下方， 热风出口设于台车 112 上方； 冷空气进风口 44与热风出口之间的气流通道穿过台车 112; 台车 112的运动轨迹依次 经过进料区、多个冷空气进风口 44和卸料区； 各冷却段包括紧邻进料区的第一冷却段以及依 次相接的第二冷却段和第三冷却段，第一冷却段中对应设置的第一热风出口 45通过第一热风 输送管道连接至回转窑的腔体中；第二冷却段中对应设置的第二热风出口 46通过第二热风输 送管道连接至干燥机的腔体中。 第三冷却段中对应设置有第三热风出口。
5. 2环冷机的台车 112通过绕旋转中心转动 （台车由电机和减速器驱动） 将高温渣球 49 带入第一冷却段， 第一冷却段利用台车 112下部的鼓风机将冷空气从冷空气进风口 44引入， 冷空气穿过位于第一冷却段的台车 112， 与台车 112上的热渣球进行热交换， 同时将高温渣 球 49中残余的未反应完的碳燃烧完毕， 经过第一冷却段的热交换后， 从第一冷却段对应的第 一热风出口 45排出的热空气 （从第一热风出口 45排出的热空气的温度控制在 600°C以上） 通过第一热风输送管道输送至回转窑腔体中， 作为回转窑中燃烧还原反应的热空气来源；
5. 3台车 112通过绕其旋转中心转动将高温渣球 49继续从第一冷却段带入第二冷却段， 第二冷却段利用台车 112下部的鼓风机将冷空气从冷空气进风口 44引入，冷空气穿过位于第 二冷却段的台车 112， 与台车 112上的热渣球进行热交换， 经过第二冷却段的热交换后， 从 第二冷却段对应的第二热风出口 46排出的热空气 （从第二热风出口 46排出的热空气的温度 控制在 350°C以上） 通过第二热风输送管道输送至窑法磷酸工艺复合生球干燥机中， 作为复 合生球干燥的热空气来源；
5. 4台车 112通过转动将高温渣球 49继续从第二冷却段带入后续的第三冷却段， 第三冷 却段利用其台车 112下部的鼓风机将冷空气从冷空气进风口 44引入，冷空气穿过位于第三冷 却段的台车 112， 与台车 112上的热渣球进行热交换， 经过热交换后， 从第三热风出口排出 的热空气经除尘后可由烟囱 48直接排放 （或者也可送入干燥机中）； 冷却后的渣球从卸料区 排出即可。 冷却后的渣球从卸料区排出后用作人造陶粒， 并直接作为建筑材料或花草栽培土 使用； 或者将冷却后的渣球细磨到至少过 100 目 80%以上， 然后作为制造混凝土的活性料或 作为制造水泥的混合添加料。
6.水化吸磷和回收氟：
本实施例的水化吸磷步骤需要用到图 18所示的以下工艺系统，该工艺系统包括制磷酸系 统和回收氟的设备。 本实施例中用到的制磷酸系统包括水化塔 1、 酸液循环喷淋系统、 磷酸 雾捕集塔 3和除雾分离塔 4。水化塔 1的本体为一喷淋空塔（参见图 19)， 水化塔 1的下部设 有出窑烟气的烟气进口 11， 顶部设有经水化吸收后的烟气出口 12， 烟气进口 11上方的水化 塔 1容腔中设有喷淋装置 13， 酸液循环喷淋系统的进液口 14设于水化塔 1的底部， 酸液循 环喷淋系统的出液口 15连接至喷淋装置 13的进液管， 酸液循环喷淋系统中还设有酸液储液 槽 16和循环泵 2。 本实施例水化塔 1的容腔外壁包覆设有水冷系统 17， 且水冷系统 17中的 冷却水采用下进上出的方式。另外， 在酸液循环喷淋系统中靠近其进液口 14的位置设有酸冷 器 18; 酸冷器 18的出口与酸液储液槽 16的进口相连， 酸液储液槽 16的出口通过循环泵 2 与喷淋装置 13的进液管相连， 进而形成一个酸液循环喷淋系统。磷酸雾捕集塔 3为一个流态 化逆流式洗涤塔， 其主要由洗涤管 31和分离罐 32组成， 水化塔 1的烟气出口 12通过管道与 洗涤管 31的进口相连通， 洗涤管 31的出口连通至分离罐 32的中部， 分离罐 32的顶部设有 烟气出口 12， 底部设有酸液出口 33， 该酸液出口 33通过一带循环泵 2的循环输送管道与洗 涤管 31内的喷嘴 35相连通 （参见图 20)， 分离罐 32同时作为磷酸雾捕集塔 3中循环输送管 道的酸循环槽。
为了实现水化塔 1与磷酸雾捕集塔 3相互串酸，本实施例中水化塔 1的喷淋装置 13设有 三个位于水化塔 1容腔不同高度处的喷淋层，且三个喷淋层中包含一个稀磷酸喷淋层 25和两 个浓磷酸喷淋层 24 (参见图 19)， 两个浓磷酸喷淋层 24设于稀磷酸喷淋层 25上方； 浓磷酸 喷淋层 24的进液管与上述水化塔 1的酸液循环喷淋系统相连通， 稀磷酸喷淋层 25的进液管 则与磷酸雾捕集塔 3的循环输送管道相连通， 这样首先实现了磷酸雾捕集塔 3中的酸液串至 水化塔 1。 另外， 在上述酸液循环喷淋系统中循环泵 2后的输送管道上通过一支管连接至磷 酸雾捕集塔 3的酸液进口 34处。但考虑与后续磷酸的过滤、精制工序相衔接， 该支管上设有 一填料过滤装置 22， 填料过滤装置 22的进酸口通过支管连通至酸液循环喷淋系统， 填料过 滤装置 22的滤液出口则分成三路， 一路连通至磷酸雾捕集塔 3的酸液进口 34， 一路连通至 外部的磷酸精制设备 23， 另一路则连通至酸液储液槽 16; 填料过滤装置 22的底流出口则通 过管道连接至压滤装置 21的进料口， 压滤装置 21的溢流口通过管道与酸液循环喷淋系统中 的酸液储液槽 16连通， 以充分实现磷酸的回收利用， 保证磷酸的高收率。 填料过滤装置 22 的底流定期用泵送至压滤装置 21过滤， 以排除酸液循环喷淋系统中存在的固体物质。
磷酸雾捕集塔 3的烟气出口 12通过管道与除雾分离塔 4的下部相连通，除雾分离塔 4的 顶部设有烟气出口 12以排出水化吸磷后的烟气， 底部设有酸液出口 33， 该酸液出口 33通过 管道与磷酸雾捕集塔 3的酸液进口 34相连通。 除雾分离塔 4中设在线水冲洗装置 41， 在线 水冲洗装置 41加入的水同时可作为整个水化吸收制磷酸工序的补水，并通过管道逐级返补至 上游的磷酸雾捕集塔 3及水化塔 1中。 除雾分离塔 4的上部安装有丝网除雾器 42， 下部设计 成类似旋风除尘器的磷酸液滴收捕结构， 在线水冲洗装置 41安装在丝网除雾器 42上方。
本实施例中用到的回收氟的设备包括一级氟吸收塔 5和二级氟吸收塔 6。一级氟吸收塔 5 和二级氟吸收塔 6均采用流态化逆流式洗涤塔。一级氟吸收塔 5主要由氟硅酸洗涤管 51和氟 硅酸分离罐 52组成， 氟硅酸洗涤管 51的进口连通至水化吸磷后的烟气的输送管道， 氟硅酸 洗涤管 51的出口连通至氟硅酸分离罐 52的中部， 氟硅酸分离罐 52的顶部设有烟气出口 12， 底部设有氟硅酸液出口 53， 该氟硅酸液出口 53通过一带循环泵 2的循环输送管道与氟硅酸 洗涤管 51内的喷嘴 35相连通， 氟硅酸分离罐 52则兼做循环输送管道的酸循环槽。二级氟吸 收塔 6的结构与一级氟吸收塔 5相似，二级氟吸收塔 6主要由二级氟硅酸洗涤管 61和二级氟 硅酸分离罐 62组成，一级氟吸收塔 5的烟气出口 12通过管道与二级氟硅酸洗涤管 61的进口 连通， 二级氟硅酸洗涤管 61的出口连通至二级氟硅酸分离罐 62的中部， 二级氟硅酸分离罐 62的顶部设有烟气出口 12， 底部设有氟硅酸液出口 53， 该氟硅酸液出口 53通过一带循环泵 2的循环输送管道与二级氟硅酸洗涤管 61内的喷嘴 35相连通。 二级氟吸收塔 6的循环输送 管道上还设有氟硅酸冷却器 63， 氟硅酸冷却器 63的进口与循环泵 2相连， 出口则分成两路， 一路与二级氟硅酸洗涤管 61内的喷嘴 35相连通，另一路与二级氟硅酸分离罐 62顶部的喷淋 层连通， 二级氟硅酸分离罐 62同样兼做循环输送管道的酸循环槽。二级氟吸收塔 6的循环泵 2出口还通过支管与一级氟吸收塔 5的氟硅酸分离罐 52的进液口相连， 借此可将二级氟吸收 塔 6多余的氟硅酸溶液串至一级氟吸收塔 5内。 为实现全部污染物的达标排放， 在本实施例 回收氟的设备最后还连接有尾吸塔 7， 该尾吸塔 7为一喷淋空塔， 二级氟吸收塔 6的烟气出 口 12通过管道与尾吸塔 7的烟气进口 1 1相连通。 尾吸塔 7的顶部设有烟气出口 12， 塔内上 方设有喷淋层， 底部设有氢氧化钠吸收液箱， 该氢氧化钠吸收液箱出口通过带循环泵 2的循 环输送管道与尾吸塔 7内各喷淋层相连， 进而形成一个尾气吸收循环喷淋系统。 上述的氟硅 酸液出口 53另外通过带给料泵的管道与外部的氟硅酸精制设备 54 (或氟盐加工设备）连接， 在进入氟硅酸精制设备 54之前可通过压滤装置 21先进行压滤处理，压滤装置 21的溢流口再 通过管道连接至氟硅酸精制设备 54。
在本实施例提供的上述图 18所示工艺系统的基础上，本实施例的从窑法磷酸工艺的出窑 烟气中水化吸磷及回收氟的方法具体包括以下步骤：
6. 1水化塔中 P205的水化吸收：
将上述步骤 4后含 P205和氟的、 温度在 500 °C以上的出窑烟气 （P205含量 80g/Nm3 ) 由水 化塔 1下部的烟气进口 1 1通入塔内， 此前开启酸液循环喷淋系统的循环泵 2， 使水化塔 1中 的浓磷酸溶液通过上、 中两层浓磷酸喷淋层 24喷出， 最上层浓磷酸喷淋层 24的部分喷嘴从 斜下方喷向塔内壁， 其余喷嘴垂直向下喷出， 中、 下两层喷淋层的喷嘴垂直向下喷淋， 喷淋 的浓磷酸溶液与进入塔内的含 P205和氟的烟气逆流充分接触， 进行传质传热， 烟气中的 P205 与喷淋的浓磷酸溶液中的水发生化学反应生成磷酸， 生成的磷酸一半以上被吸收进喷淋液， 其余部分形成磷酸雾保持在气相中， 而烟气中的氟（例如 SiF^P HF等）在浓磷酸和较高温度 条件下， 很难被吸收进喷淋液中； 烟气通过与循环喷淋的较低温浓磷酸溶液换热以及水化塔 1内水冷系统 17的冷却， 温度降至 75 °C〜130°C， 出水化塔 1的循环浓磷酸溶液温度则被提 高到 70 °C〜95 °C。 根据烟气中水分的含量大小， 循环喷淋的浓磷酸溶液的质量百分比浓度可 选择在 60%〜90%的范围内 （本实施例采用 70%〜85%浓度的磷酸溶液）， 水化塔内浓磷酸溶液 的进塔温度控制为 50 °C〜80 °C， 喷淋液气比控制在 3L/m3〜20L/m3。在出塔烟气中夹带有较多 以雾状形态存在磷酸雾， 不能在水化塔 1 中沉降下来， 随烟气一起被带出水化塔 1。 该水化 塔 1具有冷却烟气和水化吸收 P205的双重功能， 其中主要发生的化学反应如下：
P205 + 3H20 = 2¾P04
水化塔 1中喷淋落下的浓磷酸溶液最后通过进液口 14进入酸液循环喷淋系统，然后流入 酸冷器 18中， 酸冷器 18的结构为一个搅拌槽中布置有若干不锈钢管环成的换热板， 管中通 入循环冷却水， 通过搅拌， 使进入酸冷器 18的磷酸溶液在换热板上形成强制对流换热， 提高 传热效率， 将浓磷酸中的热焓部分转移到酸冷器 18的循环冷却水中， 通过冷却水将循环浓磷 酸溶液的热量不断转移。 从酸冷器 18出口流出的循环酸液进入酸液储液槽 16， 并通过循环 泵 2再次回送到上、 中两层浓磷酸喷淋层 24的各个喷嘴进行循环喷淋。
6. 2磷酸雾捕集塔中磷酸雾的捕集：
由水化塔 1顶部烟气出口 12排出的气相物质 （即烟气） 进入磷酸雾捕集塔 3的洗涤管 31 中， 该塔为一台流态化逆流洗涤塔， 在洗涤管 31 中由下向上喷射循环稀磷酸溶液， 稀磷 酸溶液与由上向下的高速烟气流碰撞接触后在气 -液界面区域形成强烈的湍动区域，流体动量 达到平衡后建立起一定高度的稳定的泡沫区（泡沫柱）， 烟气穿过泡沫区， 与大面积不断更新 的磷酸溶液液体表面接触， 在泡沫区发生粒子的捕集、 聚合长大和热量的传递， 烟气中夹带 的磷酸雾绝大部分转入循环稀磷酸溶液， 吸收区内烟气表观流速为 10m/S〜30m/s， 液气比为 3L/m3〜25L/m3。烟气通过绝热蒸发循环稀磷酸溶液中水分的方式被进一步降温到 60°C〜75°C。 与传统热法磷酸文丘里除雾器相比， 在同样的除雾效果情况下， 本发明的磷酸雾捕集塔可大 大减少设备的动力压头损失， 降低收酸装置能耗。
磷酸雾捕集塔 3中循环喷淋的酸液采用 10%〜50%质量百分浓度的稀磷酸溶液，洗涤管 31 中的气体和液体进入塔下部的分离罐 32中进行气-液分离， 循环酸液落入分离罐 32底部， 该 塔的分离罐 32同时兼作循环酸槽， 底部的稀磷酸溶液再通过循环泵 2回送至洗涤管 31或者 根据需要串酸至水化塔 1的稀磷酸喷淋层 25中。
6. 3除雾分离塔中磷酸雾的捕集：
从磷酸雾捕集塔 3中烟气出口 12排出的烟气再进入到除雾分离塔 4中进行进一步的气- 液分离， 以进一步除去烟气中的磷酸雾， 除雾分离塔下部设计成类似旋风除尘器的磷酸液滴 收捕结构， 利用离心力将已长大的磷酸液滴从烟气中捕集下来， 在除雾分离塔上部安装有丝 网除雾器 42， 将烟气中尚未长大的磷酸雾滴进一步捕集下来以保证设备对 P205的直收率； 除 雾分离塔 4排出的水化吸磷后的烟气则送入氟回收设备中进行回收氟的处理。
由于磷酸的水化吸收过程化合烟气中 P205需要消耗水， 另外烟气降温过程中从喷淋酸液 中蒸发了部分水分， 因此水化吸收过程需要不断补充水， 本实施例工艺系统中需要补充的水 量全部从除雾分离塔 4烟气出口 12处补入， 此时在线水冲洗装置 41不仅充当补水装置， 同 时兼做除雾分离塔 4上部丝网除雾器的冲洗装置。 由于全部的补水都加入到了除雾分离塔 4 中， 而除雾分离塔 4的底液又通过磷酸雾捕集塔 3的酸液进口 34回流至磷酸雾捕集塔 3中， 因此磷酸雾捕集塔 3中循环酸液浓度会逐步降低， 而另一方面， 水化塔 1中由于不断吸收烟 气中的 P205， 其中循环酸液浓度会逐渐增加， 因此， 水化塔 1和磷酸雾捕集塔 3的循环酸液 系统需要进行串酸， 以保持各自循环酸液浓度的稳定， 水化塔 1串至磷酸雾捕集塔 3的酸在 填料过滤装置 22中澄清、 过滤后引至磷酸雾捕集塔 3， 磷酸雾捕集塔 3串至水化塔 1的酸则 直接从磷酸雾捕集塔 3的循环泵 2出口处引出即可。 由于水化塔 1中的循环酸液吸收了烟气 中的粉尘等杂质， 为了不让这些杂质累积， 需要从水化塔 1的酸液循环喷淋系统中引出多余 的酸液 （对应物料平衡的产酸量） 先到填料过滤装置 22进行澄清过滤 （一级过滤）， 澄清液 一部分串酸至磷酸雾捕集塔 3， 另一部分则作为粗成品磷酸进入精制工序， 加入活性碳、 硅 藻土及钡盐， 脱去粗磷酸的颜色和 S04 2—， 然后用板框压滤装置 21 (二级过滤） 除杂、 提纯后 得到浓磷酸成品。
6. 4—级氟吸收：
先将水化吸磷后的烟气输送至一级氟吸收塔 5的氟硅酸洗涤管 51，烟气中大部分的氟 (主 要是四氟化硅） 自上而下与喷嘴 35自下而上喷入的循环氟硅酸溶液 （质量百分浓度为 10%〜 20%)发生充分的气液两相接触， 并进行传质传热和化学反应， 烟气中的大部分氟与水反应后 生成氟硅酸， 同时烟气中的热焓通过热量传递大部分转移到循环氟硅酸溶液中； 烟气通过绝 热蒸发循环氟硅酸溶液中的水分和传热给循环氟硅酸溶液的方式被进一步降温到 50°C〜 70 °C ; 此步骤中主要发生的化学反应如下：
3SiF4 +3¾0 = 2H2SiF6 + Si02* ¾0。
6. 5—级气液分离：
在氟硅酸洗涤管 51中最后得到的产物全部转移至氟硅酸分离罐 52中进行气液分离， 分 离后的气体通过一级氟吸收塔 5的烟气出口进入二级氟吸收塔 6的二级氟硅酸洗涤管 61中， 分离后的液体留存于氟硅酸分离罐 52中并通过带循环泵 2的循环输送管道回送至氟硅酸洗涤 管 51中进行上述步骤 4的操作。
6. 6二级氟吸收：
进入二级氟硅酸洗涤管 61中的烟气（剩余的绝大部分的含氟物质， 主要是四氟化硅） 自 上而下与喷嘴 35 自下而上喷入的循环氟硅酸溶液 （质量百分浓度为 0. 5%〜1. 5%) 发生充分 的气液两相接触， 并进行传质传热和化学反应， 反应生成氟硅酸， 同时烟气中的热焓通过热 量传递再次转移到循环氟硅酸溶液中； 经步骤 （3 ) 处理后的产物的温度进一步降至 60 °C以 下； 本步骤中主要发生的化学反应与步骤 4相同。
6. 7二级气液分离：
在二级氟硅酸洗涤管 61中最后得到的产物全部转移至二级氟硅酸分离罐 62中进行气液 分离， 二级氟硅酸分离罐 62顶部设除雾单元， 以除去烟气中夹带的雾沫， 提高氟的吸收率， 除雾单元通过顶部喷入循环氟硅酸溶液进行清洗。 分离后的气体通过二级氟吸收塔 6的烟气 出口进入后续的尾吸塔 7进行处理，分离后的液体留存于二级氟硅酸分离罐 62中通过带循环 泵 2的循环输送管道回送至二级氟硅酸洗涤管 61中进行上述步骤 6的操作，该循环输送管道 安装有氟硅酸冷却器 63， 以便移除循环氟硅酸溶液中的部分热量， 使氟吸收反应能在较适宜 的温度下进行。 进入二级氟硅酸洗涤管 61 的循环氟硅酸溶液经过了氟硅酸冷却器 63 (常规 冷却设备） 的冷却处理； 部分多余的循环氟硅酸溶液则可直接排放到一级氟吸收塔 5的氟硅 酸分离罐 52中。
一级氟吸收塔 5和二级氟吸收塔 6中的循环氟硅酸溶液因吸收烟气中的氟 （主要是四氟 化硅）有累积， 一级氟吸收塔 5中的氟硅酸浓度因吸收烟气中的 SiF^P HF而增加， 二级氟吸 收塔 6中多余的循环氟硅酸溶液则排放至一级氟吸收塔 5中使其浓度维持恒定， 最终一级氟 吸收塔 5中多余的循环氟硅酸溶液经给料泵送至压滤装置 21进行压滤除去其中的硅胶等固体 物， 滤液去氟硅酸精制工序精制成氟硅酸成品 （浓度为 12%左右） 或加工成氟盐产品； 滤渣 为硅胶， 洗净除杂后作为副产品。
6. 8尾吸净化处理：
进入后续尾吸塔 7进行处理的烟气在尾吸塔 7的向上运动过程中与向下喷淋的 NaOH溶液 进行逆流接触， 尾吸塔 7底部吸收液箱通过循环泵 2与塔内各喷淋层相连， 形成一个循环喷 淋系统； 为了保持吸收液的吸收能力， 吸收液的 PH值保持在 8以上， 需要不断加入稀 NaOH 溶液， 而吸收液因稀 NaOH溶液的加入和烟气中 P205、 氟等杂质的吸收会有累积， 需要不断排 出进行污水处理， 处理回收的水可回用到窑法磷酸的原料工序； 烟气中剩余的污染物 （P205、 SiF4、 粉尘等） 被喷淋液吸收， 烟气得到进一步的洗涤净化， 达到国家排放标准 （气体氟含 量降低到 9mg/m3以下）， 然后通过引风机排至烟囱排放。 本步骤中主要发生的化学反应如下：
3SiF4 + 6Na0H = 2N¾SiF6 + N¾Si03 + 3¾0
P205 + 6Na0H = 2N¾P04+ 3H20。
以上仅为本发明的优选实施例， 在上述技术方案的基础上所作的等同修改、变换及润色， 均在本发明的保护范围内。

Claims

权 利 要 求
1、 一种改进型的用回转窑规模化生产磷酸的方法， 包括以下步骤：
( 1 ) 原料预处理： 将原料碳质还原剂、 磷矿石和硅石分别用碳质还原剂预处理系统、 磷矿石预处理系统和硅石预处理系统进行预处理， 预处理后的碳质还原剂、 磷矿石和硅石 送入内球料混合装置进行混合造球， 预处理后的碳质还原剂和硅石另送入外壳料混合装置 进行混合；
(2) 内球的制备： 将经过步骤 （1 ) 处理后得到的碳质还原剂粉、 磷矿石粉和硅石粉 按配比要求加入一强力混合机或润磨机中， 同时添加粘结剂， 充分混匀后的混合料通过计 量给料设备送入造球机进行造球处理， 造球时以滴状和 /或雾状施加形式补加所述粘结剂， 补加量为所述混合料质量的 1%〜10%， 造球完成后得到内球；
(3 ) 复合球团的成型： 将经过步骤 （1 ) 处理后得到的碳质还原剂粉和硅石粉按配比 要求加入另一强力混合机或润磨机中， 同时添加粘结剂， 充分混匀后得到包裹料； 将步骤
(2) 中得到的内球进行双层辊式筛分处理， 筛分出符合工艺要求粒度的内球送入另一进 行包裹处理的造球机中， 向该造球机中通入所述包裹料， 在包裹处理过程中以滴状和 /或雾 状施加形式补加所述粘结剂，补加量为所述包裹料质量的 1%〜12%，包裹处理完成后得到 复合生球； 复合生球送入干燥机进行干燥固结， 最终成型得到复合球团；
(4) 窑法还原： 将步骤 （3 ) 中得到的复合球团从回转窑窑尾箱的进料管处进入回转 窑的腔体内， 点燃燃料烧嘴， 使回转窑内还原带温度加热到 1300°C〜1450°C， 回转窑中的 复合球团在高温条件下经还原剂还原后生成出窑烟气， 通过所述出口烟道的设置使回转窑 窑尾的出窑烟气在进入出口烟道时不在运动方向上发生较大偏移， 进而阻止出窑烟气中的 偏磷酸在回转窑窑尾处产生离心物理沉降， 使窑气中偏磷酸直接随出窑烟气进入到后续的 水化塔中； 出回转窑的高温渣球则输送至一冷却设备进行综合利用；
( 5 ) 水化吸磷： 将含 P205和氟的出窑烟气通入一水化塔内， 此前开启与水化塔相连 接的酸液循环喷淋系统， 酸液循环喷淋系统将浓磷酸溶液不断输送到水化塔内的喷淋装置 中， 向下喷淋的浓磷酸溶液与进入塔内的含 P205和氟的出窑烟气逆流充分接触，进行传质 传热，烟气中的 P205与喷淋的浓磷酸溶液中的水发生化学反应生成磷酸并被吸收进喷淋液 中， 其余部分形成磷酸雾保持在气相中， 水化塔中剩余烟气通过其烟气出口排出； 水化塔 中喷淋落下的磷酸溶液进入酸液循环喷淋系统中， 先流入酸冷器， 从酸冷器出口流出的循 环磷酸溶液再通过循环泵回送到所述水化塔的喷淋装置继续进行循环喷淋； 从所述烟气出 口排出的烟气再依次通过磷酸雾捕集塔和除雾分离塔， 使出水化塔烟气中夹带的磷酸雾被 进一步捕集， 所述磷酸雾捕集塔和除雾分离塔捕集磷酸雾后形成的稀磷酸溶液通过管道布 置与所述水化塔中的浓磷酸溶液保持串酸； 在水化吸磷的操作过程中， 酸液循环喷淋系统 中的浓磷酸溶液会不断增加， 多出的部分经过滤后作为粗磷酸产品， 粗磷酸产品进入后续 的磷酸精制工序； 另一方面， 配套的在线补水装置对整个工艺过程实施在线补水， 除雾分 离塔排出的含氟烟气则进入后续的氟回收工序。
2、 根据权利要求 1所述的方法， 其特征在于， 所述步骤 （1 ) 中，
所述碳质还原剂预处理系统的工艺过程包括： 将碳质还原剂先采用单段破碎设备破碎 至粒度在 30mm以下， 然后将破碎后的碎石料送至碳质还原剂中间料仓， 碳质还原剂中间 料仓通过计量给料设备将碎石料送至磨矿设备进行粉磨， 待磨矿设备将进料粉磨至工艺要 求的粒度后， 由旋风收粉设备和布袋收粉设备组成的组合式收尘器收集粉料， 并输送至碳 质还原剂粉储料仓； 所述粉磨过程中通过配置的热风炉不断补充热风以干燥粉料中夹带的 水分；
所述磷矿石预处理系统的工艺过程包括： 将磷矿石先采用单段破碎设备破碎至粒度在 30mm 以下， 然后将破碎后的碎石料送至磷矿石中间料仓， 磷矿石中间料仓通过计量给料 设备将碎石料送至磨矿设备进行粉磨， 待磨矿设备将进料粉磨至工艺要求的粒度后， 由旋 风收粉设备和布袋收粉设备组成的组合式收尘器收集粉料， 并输送至均化库； 所述粉磨过 程中通过配置的热风炉不断补充热风以干燥粉料中夹带的水分；
所述硅石预处理系统的工艺过程包括： 将硅石先采用单段破碎设备或两段一闭路破碎 设备破碎至粒度在 30mm以下， 然后将破碎后的碎石料送至硅石中间料仓， 硅石中间料仓 通过计量给料设备将碎石料送至磨矿设备进行粉磨， 待磨矿设备将进料粉磨至工艺要求的 粒度后， 由旋风收粉设备和布袋收粉设备组成的组合式收尘器收集粉料， 并输送至硅石粉 储料仓； 所述粉磨过程中通过配置的热风炉不断补充热风以干燥粉料中夹带的水分。
3、 根据权利要求 2所述的方法， 其特征在于， 所述步骤 （1 ) 中，
所述单段破碎设备采用锤式破碎机或反击式破碎机， 或者采用锤式破碎机和反击式破 碎机组合成的联合式破碎机； 所述两段一闭路破碎设备主要由依次相连的颚式破碎机、 筛 分机和圆锥破碎机组成， 且圆锥破碎机的出料口循环连接至筛分机的进料口；
所述碳质还原剂预处理系统中的磨矿设备采用立式磨或风扫煤磨； 所述磷矿石预处理 系统中的磨矿设备采用立式磨或风扫球磨； 所述硅石预处理系统中的磨矿设备采用球磨机 和 /或高压辊压机； 所述均化库为间隙均化库或连续均化库， 所述均化库采用压缩空气对库内粉料进行搅 拌均化， 且均化值大于或等于 4。
4、 根据权利要求 1 所述的方法， 其特征在于， 所述步骤 （2) 和步骤 （3 ) 中， 所述 粘结剂为含腐植酸钠的混合溶液，所述粘结剂中腐植酸钠的质量百分浓度为 4%〜20%，所 述粘结剂的制备包括以下步骤： 选用含腐植酸的煤料和烧碱作为原料， 将烧碱与水混合按 比例配制成 NaOH溶液； 将所述煤料和 NaOH溶液按 1 : 3〜10的固液比进行球磨混合； 将混合料搅拌加热到 40°C〜95 °C进行合成反应， 反应时间不小于 30min; 将反应产物进行 过滤， 过滤后得到的滤液即为粘结剂。
5、 根据权利要求 1所述的方法， 其特征在于， 所述步骤 （3 ) 中用到的干燥机为鳞板 干燥机， 该鳞板干燥机沿复合生球的输送方向共分为低温、 中温和高温三个干燥段； 所述低温干燥段通入 100°C〜200°C的低温热风由上至下进行抽风或由下至上进行鼓 风， 使低温热风垂直穿过料层， 并对复合生球进行穿流干燥； 所述低温热风是源自所述高 温干燥段的高温热风出口处排出的废气；
所述中温干燥段通入 150°C〜250°C的中温热风由上至下进行抽风或由下至上进行鼓 风， 使中温热风垂直穿过料层， 并对复合生球进行穿流干燥；
所述高温干燥段通入 200°C〜350°C的高温热风由上至下进行抽风或由下至上进行鼓 风， 使高温热风垂直穿过料层， 并对复合生球进行穿流干燥。
6、 根据权利要求 1所述的方法， 其特征在于， 所述步骤 （4) 中， 所述回转窑包括窑 体、 窑头箱、 窑尾箱和驱动窑体转动的驱动装置， 在窑体的窑头处设有燃料烧嘴， 在窑尾 箱处设有进料管和一连接至外部水化塔的出口烟道， 所述窑体的上部不设置风管， 所述出 口烟道设于以回转窑轴线为中心的窑体半径范围内， 且出口烟道中的烟气输送方向与回转 窑的轴线方向基本平行或呈小于 45 ° 的夹角；
所述窑体包括外部的筒体壳和设于筒体壳内侧的窑衬， 所述窑体沿回转窑长度方向被 划分包括还原带和预热带， 还原带靠近窑头箱， 预热带靠近窑尾箱， 还原带长度占窑体长 度的 1/3〜3/5， 预热带长度占窑体长度的 2/5〜2/3； 所述窑衬主要由复合耐火砖或复合耐 火浇注料构成， 位于还原带的窑衬包括靠近筒体壳的黏土材料层和靠近回转窑内腔的高铝 材料层； 位于预热带的窑衬则包括靠近筒体壳的黏土材料层和靠近回转窑内腔的碳化硅材 料层。
7、 根据权利要求 6所述的方法， 其特征在于， 所述步骤 （4) 中， 所述窑尾箱外配套 设有一清窑机， 清窑机中设有一可渐进式伸入回转窑窑尾箱内并可与其腔体内壁保持相对 刮蹭的刮刀； 所述回转窑的轴线与水平面呈 1.7° 〜2.9° 的夹角， 且窑体（3 ) 的长径比为 10〜25 : 1范围； 回转窑的填充率为 7%〜25%， 回转窑的转速控制为 0.6 r/min〜3r/min。
8、 根据权利要求 1或 5所述的方法， 其特征在于， 所述步骤 （4) 中， 所述综合利用 的方法， 包括以下步骤：
( a)将窑法磷酸工艺中出回转窑高温渣球输送至一冷却设备的进料区，所述冷却设备 包括支撑装置、 台车和罩壳， 所述台车位于支撑装置上， 所述罩壳架设于台车上方， 所述 冷却设备的进料区、 卸料区均与所述台车相通， 所述高温渣球被送进冷却设备的台车上； 所述冷却设备被划分成至少两个相互连接的冷却段， 各冷却段分别设置有冷空气进风口和 与之对应的热风出口； 所述冷空气进风口与热风出口之间的气流通道穿过所述台车； 所述 台车的运动轨迹依次经过所述进料区、 多个冷空气进风口和卸料区；
(b ) 所述台车通过转动将高温渣球带入第一冷却段， 第一冷却段利用台车下部的鼓 风机将冷空气从所述冷空气进风口引入， 所述冷空气穿过位于第一冷却段的台车， 与台车 上的热渣球进行热交换， 同时将高温渣球中残余的未反应完的碳燃烧完毕， 经过第一冷却 段的热交换后， 从第一冷却段对应的第一热风出口排出的热空气通过第一热风输送管道输 送至回转窑腔体中， 作为回转窑中燃烧还原反应产物的热空气来源；
( c)所述台车通过转动将高温渣球继续从第一冷却段带入第二冷却段，第二冷却段利 用台车下部的鼓风机将冷空气从所述冷空气进风口引入， 所述冷空气穿过位于第二冷却段 的台车， 与台车上的热渣球进行热交换， 经过第二冷却段的热交换后， 从第二冷却段对应 的第二热风出口排出的热空气通过第二热风输送管道输送至窑法磷酸工艺复合生球干燥 机中， 作为复合生球干燥的热空气来源；
( d) 所述台车通过转动将高温渣球继续从第二冷却段带入后续的其余各冷却段， 其 余各冷却段利用其台车下部的鼓风机将冷空气从所述冷空气进风口引入， 所述冷空气穿过 位于其余各冷却段的台车，与台车上的热渣球进行热交换，经过其余各冷却段的热交换后， 从其余各热风出口排出的热空气经除尘后可直接排放或送到上述复合生球干燥机中作为 干燥的热空气来源； 冷却后的渣球从所述卸料区排出即可。
9、 根据权利要求 1所述的方法， 其特征在于， 所述步骤 （5 ) 中， 所述水化塔中的喷 淋装置包括至少两个位于水化塔容腔不同高度处的喷淋层， 且至少两个的喷淋层中包含一 稀磷酸喷淋层和浓磷酸喷淋层， 浓磷酸喷淋层设于稀磷酸喷淋层上方； 所述浓磷酸喷淋层 的进液管与所述酸液循环喷淋系统相连通， 所述稀磷酸喷淋层的进液管与磷酸雾捕集塔中 稀磷酸溶液的循环输送管道相连通以使得磷酸雾捕集塔中的稀磷酸溶液串酸至水化塔中， 所述酸液循环喷淋系统另通过管道连接至磷酸雾捕集塔中以使得水化塔中的浓磷酸溶液 串酸至磷酸雾捕集塔中。
10、 根据权利要求 1或 9所述的方法， 其特征在于， 所述步骤 （5 ) 中， 所述酸冷器 为一个搅拌槽中布置有多个改性石墨管或不锈钢管环成的换热板， 管中通入循环冷却水， 通过搅拌， 使进入酸冷器的磷酸溶液在换热板上形成强制对流换热； 所述步骤 （1 ) 中的 出窑烟气通过与循环喷淋的浓磷酸溶液换热以及水化塔内水冷系统的冷却， 温度降至 75°C〜130°C ;所述水化塔内循环喷淋的浓磷酸溶液的质量百分比浓度为 60%〜90%，水化 塔内浓磷酸溶液的进塔温度控制为 50°C〜80°C， 水化塔内喷淋液气比控制在 lL/m3〜 20L/m3。
11、 根据权利要求 10所述的方法， 其特征在于， 所述步骤 （5 ) 中， 所述磷酸雾捕集 塔为一流态化逆流式洗涤塔， 包括洗涤管和分离罐， 由水化塔烟气出口排出的烟气进入磷 酸雾捕集塔的洗涤管中， 在洗涤管中由下向上喷射的循环稀磷酸溶液与由上向下的烟气逆 流碰撞接触后建立起泡沫区， 烟气穿过泡沫区后与大面积不断更新的稀磷酸溶液液体表面 接触， 在泡沫区发生粒子的捕集、 聚合长大和热量的传递， 烟气通过绝热蒸发循环稀磷酸 溶液中水分的方式被进一步降温到 60°C〜90°C ;所述洗涤管中的气体和液体进入下部的分 离罐中进行气-液分离，循环稀磷酸溶液落入分离罐底部后再通过循环泵回送至洗涤管且部 分串酸至水化塔中； 所述磷酸雾捕集塔中循环喷淋的稀磷酸溶液的质量百分浓度为 10%〜 50%； 稀磷酸溶液的温度控制在 40°C〜70°C， 磷酸雾捕集塔内喷淋液气比控制在 3L/m3〜 25L/m3 ;
从所述磷酸雾捕集塔中烟气出口排出的烟气再进入到除雾分离塔中进行进一步的气- 液分离， 除雾分离塔下部设计成类似旋风除尘器的磷酸液滴收捕结构， 利用离心力将已长 大的磷酸液滴从烟气中捕集下来， 在除雾分离塔上部安装有丝网除雾器， 将烟气中尚未长 大的磷酸雾滴进一步捕集下来； 所述在线补水装置装设在除雾分离塔中且位于丝网除雾器 的上方， 并兼作丝网除雾器的冲洗装置。
12、 根据权利要求 11所述的方法， 其特征在于， 所述步骤 （5 ) 中， 氟回收工序包括 以下步骤：
( 1 ) 一级氟吸收： 先将除雾分离塔中排出的含氟烟气输送至一级氟吸收塔的氟硅酸 洗涤管， 烟气自上而下与喷嘴自下而上喷入的循环氟硅酸溶液发生充分的气液两相接触， 并进行传质传热和化学反应， 反应生成氟硅酸， 同时烟气中的热焓通过绝热蒸发循环氟硅 酸溶液中的水分被部分转移到水蒸气中； ( 2 ) 一级气液分离： 所述氟硅酸洗涤管中的气体和液体全部转移至氟硅酸分离罐中 进行气液分离， 分离后的气体通过一级氟吸收塔的烟气出口进入二级氟吸收塔的二级氟硅 酸洗涤管中， 分离后的液体留存于氟硅酸分离罐中并通过带循环泵的循环输送管道回送至 氟硅酸洗涤管中进行上述一级氟吸收步骤的操作；
( 3 ) 二级氟吸收： 进入二级氟硅酸洗涤管中的烟气自上而下与喷嘴自下而上喷入的 循环氟硅酸溶液发生充分的气液两相接触，并进行传质传热和化学反应，反应生成氟硅酸， 同时烟气中的热焓通过热量传递部分转移到循环氟硅酸溶液中；
( 4 ) 二级气液分离： 所述二级氟硅酸洗涤管中的气体和液体全部转移至二级氟硅酸 分离罐中进行气液分离， 分离后的气体通过二级氟吸收塔的烟气出口进入后续的尾吸塔进 行处理， 分离后的液体留存于二级氟硅酸分离罐中， 部分通过循环泵回送至二级氟硅酸洗 涤管中进行上述二级氟吸收步骤的操作， 部分输送到一级氟吸收塔的氟硅酸分离罐中；
( 5 ) 所述一级氟吸收塔中的氟硅酸溶液会不断增加， 多出的氟硅酸溶液经过滤去硅 胶后后作为副产的氟硅酸产品。
13、 根据权利要求 12所述的方法， 其特征在于， 所述一级氟吸收塔和二级氟吸收塔 均为流态化逆流式洗涤塔， 一级氟吸收塔主要由氟硅酸洗涤管和氟硅酸分离罐组成， 氟硅 酸洗涤管的出口连通至氟硅酸分离罐的中部， 氟硅酸分离罐的顶部设有烟气出口， 底部设 有氟硅酸液出口， 该氟硅酸液出口通过一带循环泵的循环输送管道与所述氟硅酸洗涤管内 的喷嘴相连通；
所述二级氟吸收塔主要由二级氟硅酸洗涤管和二级氟硅酸分离罐组成， 一级氟吸收塔 的烟气出口通过管道连接至二级氟硅酸洗涤管， 二级氟硅酸洗涤管的出口连通至二级氟硅 酸分离罐的中部， 二级氟硅酸分离罐的顶部设有除沫层和烟气出口， 底部设有氟硅酸液出 口， 该氟硅酸液出口通过一带循环泵的循环输送管道与二级氟硅酸洗涤管内的喷嘴及一级 氟吸收塔的氟硅酸分离罐相连通；
一级氟吸收采用的循环氟硅酸溶液的质量百分浓度为 8%〜25%，循环氟硅酸溶液的温 度为 25 °C〜65 °C， 喷淋液气比控制在 3L/m3〜25L/m3; 二级氟吸收采用的循环氟硅酸溶液 的质量百分浓度为 0.5%〜5%， 循环氟硅酸溶液的温度为 25 °C〜60°C， 喷淋液气比控制在 3L/m3〜25L/m3。
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