CN108558239B - Magnesium oxide accurate preparation device and method - Google Patents
Magnesium oxide accurate preparation device and method Download PDFInfo
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- CN108558239B CN108558239B CN201810667115.4A CN201810667115A CN108558239B CN 108558239 B CN108558239 B CN 108558239B CN 201810667115 A CN201810667115 A CN 201810667115A CN 108558239 B CN108558239 B CN 108558239B
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- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 title claims abstract description 75
- 239000000395 magnesium oxide Substances 0.000 title claims abstract description 70
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 title claims abstract description 65
- 238000002360 preparation method Methods 0.000 title claims abstract description 19
- 238000000034 method Methods 0.000 title claims description 26
- 239000000725 suspension Substances 0.000 claims abstract description 89
- 239000000463 material Substances 0.000 claims abstract description 54
- 238000001354 calcination Methods 0.000 claims abstract description 28
- 230000000694 effects Effects 0.000 claims abstract description 25
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 35
- 229910052749 magnesium Inorganic materials 0.000 claims description 35
- 239000011777 magnesium Substances 0.000 claims description 35
- 239000000843 powder Substances 0.000 claims description 31
- 239000000446 fuel Substances 0.000 claims description 25
- 238000000354 decomposition reaction Methods 0.000 claims description 24
- 238000004519 manufacturing process Methods 0.000 claims description 17
- 239000002994 raw material Substances 0.000 claims description 14
- 238000002485 combustion reaction Methods 0.000 claims description 13
- 239000000428 dust Substances 0.000 claims description 11
- 238000001816 cooling Methods 0.000 claims description 9
- 238000000227 grinding Methods 0.000 claims description 9
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 2
- 239000007788 liquid Substances 0.000 claims description 2
- 239000004449 solid propellant Substances 0.000 claims description 2
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 14
- 239000001095 magnesium carbonate Substances 0.000 description 14
- 235000014380 magnesium carbonate Nutrition 0.000 description 14
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 14
- 230000008569 process Effects 0.000 description 13
- 239000007789 gas Substances 0.000 description 11
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 10
- 239000003546 flue gas Substances 0.000 description 10
- 230000009471 action Effects 0.000 description 7
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 6
- 235000011941 Tilia x europaea Nutrition 0.000 description 6
- 239000004571 lime Substances 0.000 description 6
- 235000012054 meals Nutrition 0.000 description 5
- 239000002893 slag Substances 0.000 description 5
- 239000002245 particle Substances 0.000 description 4
- 230000033228 biological regulation Effects 0.000 description 3
- 239000003245 coal Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000003912 environmental pollution Methods 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- JTJMJGYZQZDUJJ-UHFFFAOYSA-N phencyclidine Chemical group C1CCCCN1C1(C=2C=CC=CC=2)CCCCC1 JTJMJGYZQZDUJJ-UHFFFAOYSA-N 0.000 description 2
- 235000019738 Limestone Nutrition 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2/00—Lime, magnesia or dolomite
- C04B2/10—Preheating, burning calcining or cooling
- C04B2/102—Preheating, burning calcining or cooling of magnesia, e.g. dead burning
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2/00—Lime, magnesia or dolomite
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Muffle Furnaces And Rotary Kilns (AREA)
- Furnace Details (AREA)
Abstract
The invention discloses a magnesium oxide accurate preparation device, which comprises a mill, wherein the mill is connected with a suspension preheater through a lifter, a material outlet of a fifth-stage cyclone cylinder of the suspension preheater is communicated with a calcining chamber in a rotary kiln, a material outlet of a fourth-stage cyclone cylinder of the suspension preheater is communicated with a hollow suspension furnace, a material outlet of the hollow suspension furnace is communicated with the upper part of the fifth-stage cyclone cylinder through a first pipeline, the rotary kiln is connected with the bottom of the hollow suspension furnace through a first hot air pipeline, and a second hot air pipeline for shunting hot air is arranged on the first hot air pipeline; the first pipeline is a bent pipeline, and the second hot air flow pipeline is connected with the bent part of the first pipeline. The invention organically combines the suspension preheater, the decomposing furnace and the rotary kiln to accurately obtain the magnesium oxide, so that the activity homogeneity is within +/-20 s.
Description
Technical Field
The invention belongs to the technical field of rotary kiln production of calcined clinker, and particularly relates to a device and a method for accurately preparing magnesium oxide.
Background
At present, devices adopted for producing clinker by calcining in China mainly comprise three types, namely a common shaft kiln, a mechanical shaft kiln and a rotary kiln. The common shaft kiln has the defects of poor quality, high energy consumption, serious environmental pollution and the like, and is in a phase of elimination; the mechanized shaft kilns comprise a Macez kiln, a Frakas kiln and an energy-saving shaft kiln developed at home, which are developed by adopting foreign technologies; the rotary kiln has the advantages of high utilization rate of raw materials, high product quality, high degree of mechanization, easy control of operation, high single-kiln production capacity, easy environmental protection and the like, and is widely used in China in recent years.
The invention discloses a Chinese CN106220004A patent, which relates to a rotary kiln production line and a production method for directly calcining powdered lime, and aims to provide the rotary kiln production line and the production method for directly calcining powdered lime; the technical scheme is as follows: the production line of the rotary kiln for directly calcining the powdery lime comprises a mill, wherein the mill is connected with a suspension preheater through a raw material hoister, an outlet of a fifth-stage cyclone cylinder of the suspension preheater is communicated with a calcining chamber in the rotary kiln, a material outlet of a fourth-stage cyclone cylinder is communicated with a decomposing furnace, and an outlet of the decomposing furnace is communicated with the calcining chamber in the rotary kiln; the production line also comprises a pulverized coal bin, one path of the pulverized coal bin is communicated with the combustion chamber in the rotary kiln through a pipeline, and the other path of the pulverized coal bin is communicated with the combustion chamber of the decomposing furnace; the outlet of a calcining chamber in the rotary kiln is connected with a grate cooler, and the grate cooler is connected to a lime storage through a lime hoister; the production line also comprises a liquid oxygen tank, and a conveying pipeline of the liquid oxygen tank is respectively communicated with the rotary kiln and a combustion chamber in the decomposing furnace. The rotary kiln production line has a low utilization rate of the fifth-stage cyclone, and materials in the fifth-stage cyclone directly enter the rotary kiln to be calcined under the condition that the materials are not decomposed, so that the quality of finished products is influenced.
Chinese patent No. CN102173608A relates to a process for producing cement clinker by decomposing carbide slag in a five-stage preheater with high proportion batching, which is completed by three steps of carbide slag drying, raw material grinding and clinker firing. The carbide slag drying step comprises two processes of drying and impurity removal which are carried out simultaneously, the raw material grinding step comprises two processes of grinding and waste gas emission, and the clinker firing step comprises four steps of preheating outside the kiln, decomposing outside the kiln, calcining and storing clinker. The implementation of the invention solves the problem of waste residue treatment in the chemical raw material industry of the acetylene method in China at present, so that waste residues such as carbide slag, broken limestone, lime slag and the like are utilized to the maximum extent, and the problem of environmental pollution caused by waste residue disposal is solved. The clinker process only adopts the waste heat of the four-stage cyclone cylinder, and then conveys the decomposed clinker to the fifth-stage cyclone cylinder, so that the utilization rate of the heat of the fifth-stage cyclone cylinder is low, and the energy consumption cost is high.
In the calcination process for preparing the magnesia clinker, the production is generally carried out by adopting the processes of a common vertical kiln, a reflection kiln, a fluidized bed furnace, a suspension furnace, a rotary kiln without a suspension preheater and the like.
The magnesium oxide clinker produced by ordinary vertical kiln is block material, and the fuel is filled in magnesite to make combustion and heat release to make magnesite decompose, and the material is discharged intermittently. The temperature field in the kiln is not uniform in the calcining process, the temperature cannot be effectively adjusted, the surface layer temperature is high, the inner layer temperature is low, and the material is easy to over-burn or under-burn in the calcining process of the blocky magnesite. The product has the defects of large activity fluctuation, unstable quality and low production efficiency.
The reflecting kiln is characterized in that lumpy magnesite ore is added from the top of the kiln and slowly moves downwards, smoke enters the kiln from the bottom of the kiln and rises to perform heat exchange with the ore in a countercurrent manner, the ore is preheated, the ore at the bottom of the kiln is heated by flame radiation below grate bricks and is decomposed at the temperature of 1000-plus 1100 ℃, the material naturally slides down on the grate to continuously produce and discharge, and the defects of inconsistent internal and external temperatures of the lumpy ore, large activity fluctuation of products, low productivity and the like still exist in the process.
The fluidized bed furnace can make magnesite particles continuously fired into magnesia clinker in a liquefied state, the magnesite particles are blown up by preheated air at the lower part in the fluidized bed furnace and suspended in a hearth, so that raw materials are fluidized and heated and decomposed by hot air sprayed from the side part of the furnace body. The process has the advantages of short retention time of materials in the fluidized bed furnace, small grain size, uncontrollable calcination time and small activity regulation space of the magnesia clinker.
The roasting principle of the suspension furnace is that in a suspension furnace system, the moving states of materials and gas are concurrent flow and countercurrent flow. The material descends and the gas ascends, the two are in a counter-current state, the gas carries the material to flow in a parallel way between two adjacent cyclones, and the material particles are suspended in the gas. After the cyclone is carried out, the materials are separated from the gas, the gas ascends and is discharged from the top of the cyclone, and the materials descend and are discharged through a chute at the bottom. After being preheated by several stages of cyclones in the preheating section, the material particles are discharged from the bottom of the last stage cyclone of the preheater, enter the roaster from the upper part of the burner at the bottom of the roaster and are immediately suspended in the airflow. The fuel is sprayed into the roaster through the burner and is combusted in the mixture of the material and the gas, the material is heated and decomposed by the heat released by combustion, the material stays in the roaster for 1-1.5s to finish roasting, the material stays in the cyclone and the roaster for a short time, the heat preservation can not be carried out for a long time, the crystal grain is not fully developed, and the activity regulation space is small.
The magnesia clinker is fired by the rotary kiln without the suspension preheater, the magnesite ore is mainly calcined and decomposed in the rotary kiln, and the decomposition process with the largest heat consumption in the calcining process is completely concentrated in the kiln, so that the heat load of the refractory lining in the rotary kiln is greatly improved, and the service life of the rotary kiln is shortened. Meanwhile, the materials are not suspended, preheated and decomposed, so that the full contact between the materials and a heat source is reduced, and the space for the growth and activity regulation of clinker grains is limited.
Therefore, in view of the above disadvantages of the magnesium oxide production processes, there is a need to design a precise magnesium oxide preparation device and method to solve the above problems.
Disclosure of Invention
The invention aims to provide a device and a method for accurately preparing magnesium oxide, which are used for organically combining a suspension preheater, a decomposing furnace and a rotary kiln, fully utilizing the decomposition function of a fifth-stage cyclone and a hollow suspension furnace, improving the decomposition efficiency of magnesium carbonate in magnesium ore, and accurately obtaining magnesium oxide clinker with different activities, so that the activity homogeneity is within +/-20 s.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
the invention provides a precise preparation device of magnesium oxide. The device comprises a mill, wherein the mill is connected with a suspension preheater through a lifter, a material outlet of a fifth-stage cyclone cylinder of the suspension preheater is communicated with a calcining chamber in a rotary kiln, a material outlet of a fourth-stage cyclone cylinder of the suspension preheater is communicated with a hollow suspension furnace, a material outlet of the hollow suspension furnace is communicated with the upper part of the fifth-stage cyclone cylinder through a first pipeline, the rotary kiln is connected with the bottom of the hollow suspension furnace through a first hot air pipeline, and a second hot air pipeline for shunting hot air is arranged on the first hot air pipeline; the first pipeline is a bent pipeline, and the second hot air flow pipeline is connected with the bent part of the first pipeline; the accurate preparation device of the magnesium oxide further comprises a fuel bin, one path of the fuel bin is communicated with a combustion chamber of the rotary kiln, the other path of the fuel bin is communicated with the hollow suspension furnace, the hollow suspension furnace is in an on-line type, and the suspension decomposition of the powder is realized through hot air flow at the bottom and fuel combustion.
The working principle of the device of the invention is as follows: raw meal is ground by a mill and then is conveyed into a first-stage cyclone cylinder of a suspension preheater by a lifter, an air inlet pipeline is connected with an air outlet pipe of a second-stage cyclone cylinder, hot flue gas from a rotary kiln at the tail part of the suspension preheater tangentially enters the first-stage cyclone cylinder, raw meal powder sequentially enters the first-stage cyclone cylinder tangentially along with the co-current of the hot flue gas due to high flow velocity, does spiral motion in the first-stage cyclone cylinder and performs sufficient suspension heat exchange with the hot flue gas, the raw meal powder is separated from the hot flue gas due to the centrifugal force and settles at the bottom of the first-stage cyclone cylinder, during the decomposition and aggregation process, the raw meal powder is heated to the temperature close to the hot air flow at the air outlet of the first-stage cyclone cylinder, then the raw meal enters a pipeline of an air inlet of the second-stage cyclone cylinder from the bottom of the first-stage cyclone cylinder through a pipeline, enters the second-stage cyclone cylinder along with the hot flue gas, and performs suspension heat exchange, and the raw material powder is collected by a fourth-stage cyclone cylinder and enters the hollow suspension furnace for suspension decomposition, the first pipeline is a bent pipeline, the second hot air pipeline is connected with the bent part of the first pipeline, hot air conveys the material in the hollow suspension furnace to a fifth-stage cyclone cylinder through the second hot air pipeline, the material continues to decompose under the action of hot air flow in the fifth-stage cyclone cylinder, and then the material reaches the rotary kiln from a material outlet of the fifth-stage cyclone cylinder to be calcined into active magnesium oxide.
The hot air flow in the inner cavity of the hollow suspension furnace comprises hot air flow entering the inner cavity of the rotary kiln through a first hot air flow pipeline and hot air flow formed by combustion of a fuel bin; the hot air flow in the fifth-stage cyclone cylinder comprises hot air flow in the rotary kiln entering the fifth-stage cyclone cylinder through a second hot air flow pipeline.
Preferably, the hollow suspension furnace comprises an inner cavity and an outer cavity, the top of the inner cavity is open, the bottom of the inner cavity is a conical structure, and the lowest part of the conical structure is communicated with the first hot air flow pipeline; the top of the outer cavity is higher than the inner cavity, the bottom of the outer cavity is of a wedge-shaped structure, and the lowest part of the wedge-shaped structure is communicated with the first pipeline; and a second pipeline extending into the middle part of the inner cavity is arranged at the top of the outer cavity, and the second pipeline is communicated with a material outlet of the fourth-stage cyclone.
The working principle of the hollow suspension furnace is as follows: the preheated magnesium ore enters the inner cavity of the hollow suspension furnace from the material outlet of the fourth-stage cyclone through a second pipeline; the bottom of the inner cavity is of a conical structure, materials are deposited at the bottom, the lowest part of the conical structure is communicated with the first hot air pipeline, the materials in the inner cavity are suspended and decomposed under the action of hot air and are gradually deposited at the bottom of the outer cavity, the bottom of the outer cavity is of a wedge-shaped structure, the lowest part of the wedge-shaped structure is communicated with the first pipeline, the first pipeline is connected with the second hot air pipeline, the materials at the bottom of the outer cavity are conveyed to the fifth-stage cyclone cylinder to be continuously decomposed under the action of the hot air in the second hot air pipeline, and then the materials reach the rotary kiln from the material outlet of the fifth-stage cyclone cylinder to be calcined, so that the active magnesium.
The diameter of the rotary kiln barrel is more than or equal to 2.5m, so that the temperature field stability and the product quality stability of the rotary kiln barrel can be ensured.
The outlet of the calcining chamber of the rotary kiln is connected with a cold grate dust collector; controlling the cooling speed by a grate cooler, and grading the magnesium oxide clinker in a dust removal mode to obtain powder magnesium oxide clinker with different fineness.
The fuel in the fuel bin is gas fuel, liquid fuel or solid fuel.
The temperature of the hollow suspension furnace is 700-1000 ℃; the temperature of the rotary kiln is 900-1300 ℃, and in the same production process, the temperature of the rotary kiln is higher than that of the hollow suspension furnace.
The invention also provides a method for accurately preparing the magnesium oxide by using the magnesium oxide accurate preparation device, which comprises the steps of raw material grinding, raw material lifting, suspension preheating, decomposition and calcination; the raw materials are suspended and preheated in the suspension preheater, then carbonate decomposition is carried out in the hollow suspension furnace and the fifth-stage cyclone cylinder, the decomposed materials are calcined in the rotary kiln according to the production requirement of the activity of the magnesium oxide to obtain the magnesium oxide clinker with the required activity, and finally the magnesium oxide clinker is cooled and recovered.
The invention makes the preheated raw material fully decomposed in the hollow suspension furnace and the fifth-stage cyclone, further prolongs the decomposition time, improves the decomposition efficiency and improves the utilization rate of hot air flow, the decomposition rate of the hollow suspension furnace can reach more than 95 percent, the activity of magnesium oxide is 50-70s, and then the magnesium oxide enters the rotary kiln to be calcined into the magnesium oxide with the activity of 100s, 150s, 200s, 250s, 300s and more, and the activity homogeneity of the magnesium oxide is +/-20 s.
The content of magnesium oxide in the magnesium ore is 18-47%.
Compared with the prior art, the invention has the beneficial effects that:
(1) the hollow suspension furnace comprises an inner cavity and an outer cavity which are respectively connected with the rotary kiln and the fifth-stage cyclone cylinder to realize suspension decomposition, and compared with a conventional decomposition furnace, the hollow suspension furnace can effectively improve the decomposition efficiency and improve the uniformity;
(2) the magnesium oxide decomposed in the hollow suspension furnace enters the fifth-stage cyclone to be continuously decomposed, so that the utilization rate of the fifth-stage cyclone can be effectively improved, the decomposition time is prolonged under the same condition, the magnesium carbonate is favorably and fully decomposed, and a product with stable activity can be obtained in the calcining step;
(3) the hollow suspension furnace is in an on-line type, the suspension decomposition of powder is realized through the combustion of hot air flow at the bottom and fuel, the hot air flow of the rotary kiln can be fully utilized by organically combining the fifth-stage cyclone cylinder, the decomposition furnace and the rotary kiln, the decomposition rate of magnesium carbonate reaches over 95 percent, and the activity homogeneity of magnesium oxide obtained after calcination is +/-20 s.
Drawings
FIG. 1 is a schematic structural view of an apparatus for precisely preparing magnesium oxide according to the present invention;
FIG. 2 is a schematic view of a preferred hollow suspension furnace according to the present invention;
wherein:
1. grinding; 2. a hoist; 3. a suspension preheater; 4. a hollow suspension furnace; 5. a grate cooling dust collector; 6. a fuel bunker; 7. a rotary kiln; 71. a first hot gas flow conduit; 72. a second hot gas flow conduit; 41. a first conduit; 42. an inner cavity; 43. an outer cavity; 44. a second conduit.
Detailed Description
The technical solutions of the present invention will be described clearly and completely below, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
The embodiment provides an accurate magnesium oxide preparation device, which comprises a mill 1, wherein the mill 1 is connected with a suspension preheater 3 through a lifter 2, a material outlet of a fifth-stage cyclone of the suspension preheater 3 is communicated with a calcining chamber in a rotary kiln 7, a material outlet of a fourth-stage cyclone of the suspension preheater 3 is communicated with a hollow suspension furnace 4, a material outlet of the hollow suspension furnace 4 is communicated with the upper part of the fifth-stage cyclone through a first pipeline 41, the rotary kiln 7 is connected with the bottom of the hollow suspension furnace 4 through a first hot air flow pipeline 71, and a second hot air flow pipeline 72 for shunting hot air is arranged on the first hot air flow pipeline 71; the first pipeline 41 is a bent pipeline, and the second hot air flow pipeline 72 is connected with the bent part of the first pipeline 41; the magnesium oxide precise preparation device also comprises a fuel bin 6, one path of the fuel bin 6 is communicated with a combustion chamber of the rotary kiln 7, the other path of the fuel bin is communicated with the hollow suspension furnace 4, the hollow suspension furnace 4 is in an on-line type, and the suspension decomposition of powder is realized through hot air flow at the bottom and fuel combustion.
The method for preparing the magnesium oxide by adopting the magnesium oxide precise preparation device comprises the following steps: the magnesium ore is ground into magnesium ore powder with 70-100 meshes by a grinding machine 1, and the content of magnesium oxide in the magnesium ore is 40%. The magnesium ore powder is conveyed into a first-stage cyclone cylinder of a suspension preheater 3 by a chain type elevator 2, an air inlet pipeline is connected with a pipe for exhausting air from a second-stage cyclone cylinder, hot flue gas from a rotary kiln 7 at the tail part of the suspension preheater 3 tangentially enters the first-stage cyclone cylinder, the magnesium ore powder sequentially enters the first-stage cyclone cylinder tangentially along with the concurrent flow of the hot flue gas due to large flow velocity, does spiral motion in the first-stage cyclone cylinder and performs sufficient suspension heat exchange with the hot flue gas, the magnesium ore powder is separated from the hot flue gas and settles at the bottom of the first-stage cyclone cylinder due to the action of centrifugal force, and during the decomposition and aggregation process, the magnesium ore powder is heated to the temperature close to hot air flow at an air outlet of the first-stage cyclone cylinder, then the magnesium ore enters a pipeline for exhausting air into the second-stage cyclone cylinder from the bottom of the first-stage cyclone cylinder through a pipeline, enters the second-stage cyclone cylinder along with the hot flue gas, and performs, the magnesium ore powder is collected to enter a next-stage cyclone cylinder, the operation is repeated, finally, the magnesium ore powder is collected by a fourth-stage cyclone cylinder to enter the hollow suspension furnace 4 to be suspended and decomposed into magnesium oxide, the first pipeline 41 is a bent pipeline, the second hot air pipeline 72 is connected with the bent part of the first pipeline 41, hot air conveys the magnesium ore powder in the hollow suspension furnace 4 to a fifth-stage cyclone cylinder through the second hot air pipeline 72, the magnesium ore powder is continuously decomposed under the action of hot air flow in the fifth-stage cyclone cylinder, and then the magnesium ore powder reaches the rotary kiln 7 from a material outlet of the fifth-stage cyclone cylinder to be calcined into active magnesium oxide; the temperature of the hollow suspension furnace 4 is controlled to be 750 ℃, the temperature of the rotary kiln 7 is controlled to be 900 ℃, magnesium ore in the fifth-stage cyclone cylinder is taken for analysis, the decomposition rate of magnesium carbonate in the obtained magnesium ore reaches 95.5%, the activity of the magnesium oxide planned to be produced is 100s under the conditions, the activity detection value of the magnesium oxide actually obtained after calcination is 110s, and the homogeneity of the magnesium oxide activity can be controlled to be +/-20 s by adopting the method and the equipment.
Example 2
The embodiment provides an accurate magnesium oxide preparation device, compared with embodiment 1, the difference is that the hollow suspension furnace 4 comprises an inner cavity 42 and an outer cavity 43, the top of the inner cavity 42 is open, the bottom of the inner cavity is a conical structure, and the lowest part of the conical structure is communicated with a first hot gas flow pipeline 71; the top of the outer cavity 43 is higher than the inner cavity 42, the bottom of the outer cavity is of a wedge-shaped structure, and the lowest part of the wedge-shaped structure is communicated with the first pipeline 41; the top of the outer cavity 43 is provided with a second pipeline 44 extending into the middle of the inner cavity 42, and the second pipeline 44 is communicated with the material outlet of the fourth stage cyclone.
The method for preparing the active magnesium oxide comprises the following steps: grinding magnesium ore into magnesium ore powder with the magnesium oxide content of 18 percent and the magnesium ore powder of 70 to 100 meshes, conveying the magnesium ore powder into a suspension preheater 3 by using a chain type elevator 2, and enabling the preheated magnesium ore to enter an inner cavity 42 of the hollow suspension furnace 4 from a material outlet of a fourth-stage cyclone through a second pipeline 44; the bottom of the inner cavity 42 is of a conical structure, the lowest part of the conical structure is communicated with a first hot air flow pipeline 71, materials in the inner cavity 42 are suspended and decomposed under the action of hot air flow and are gradually deposited at the bottom of the outer cavity 43, the bottom of the outer cavity 43 is of a wedge-shaped structure, the lowest part of the wedge-shaped structure is communicated with a first pipeline 41, a second hot air flow pipeline 72 is connected to the first pipeline 41, the materials at the bottom of the outer cavity 43 are conveyed to a fifth-stage cyclone cylinder to be continuously decomposed under the action of the hot air flow in the second hot air flow pipeline 72, and then the materials reach a rotary kiln 7 from a material outlet of the fifth-stage cyclone cylinder to be calcined, so that active; wherein the temperature of the hollow suspension furnace 4 is controlled to be 830 ℃, the temperature of the rotary kiln 7 is controlled to be 1000 ℃, the magnesium ore in the fifth-stage cyclone cylinder is taken for analysis, the decomposition rate of magnesium carbonate in the magnesium ore reaches 98.5 percent, the activity of the magnesium oxide planned to be produced under the conditions is 200s, and the activity detection value of the magnesium oxide obtained by calcination is 197 s.
Example 3
The embodiment provides an accurate magnesium oxide preparation device, which is different from the embodiment 2 in that an outlet of a calcining chamber of a rotary kiln 7 is connected with a grate cooling dust collector 5, the cooling speed is controlled by the grate cooling dust collector 5, and powder clinkers are classified in a dust removal mode to obtain powder clinkers with different fineness.
The method for preparing the active magnesium oxide comprises the following steps: grinding magnesium ore into magnesium ore powder with the content of magnesium oxide of 70-100 meshes, conveying the magnesium ore powder to a suspension preheater 3 by using a chain elevator 2 for suspension preheating, then decomposing the magnesium ore powder into magnesium oxide powder in a hollow suspension furnace 4 and a fifth-stage cyclone cylinder, then calcining the magnesium oxide powder in a rotary kiln 7 to obtain active magnesium oxide clinker, finally controlling the cooling speed by a grate cooling dust collector 5, and grading the clinker in a dust removal mode to obtain powder clinkers with different fineness. Wherein the temperature of the hollow suspension furnace 4 is controlled to be 915 ℃, the temperature of the rotary kiln 7 is controlled to be 1300 ℃, the grate cooling dust collector 5 controls the air speed in a frequency conversion manner, the temperature is reduced to be more than 850 ℃ in 10min, and the dust collection fineness is controlled to be within 5 percent (0.08mm of screen residue), so that the magnesia powder clinker with the fineness of 3.28 percent is obtained. And (3) analyzing the magnesium ore in the fifth-stage cyclone to obtain magnesium carbonate in the magnesium ore, wherein the decomposition rate of the magnesium carbonate in the magnesium ore reaches 99%, the activity of the magnesium oxide planned to be produced under the conditions is 350s, and the activity detection value of the magnesium oxide obtained by calcining is 355 s.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (7)
1. The magnesium oxide precise preparation device is characterized by comprising a mill (1), wherein the mill (1) is connected with a suspension preheater (3) through a lifter (2), a material outlet of a fifth-stage cyclone cylinder of the suspension preheater (3) is communicated with a calcining chamber in a rotary kiln (7), a material outlet of a fourth-stage cyclone cylinder of the suspension preheater (3) is communicated with a hollow suspension furnace (4), a material outlet of the hollow suspension furnace (4) is communicated with the upper part of the fifth-stage cyclone cylinder through a first pipeline (41), the rotary kiln (7) is connected with the bottom of the hollow suspension furnace (4) through a first hot air pipeline (71), and a second hot air pipeline (72) for shunting hot air is arranged on the first hot air pipeline (71); the first pipeline (41) is a bent pipeline, and the second hot air flow pipeline (72) is connected with the bent part of the first pipeline (41); the precise magnesium oxide preparation device also comprises a fuel bin (6), one path of the fuel bin (6) is communicated with a combustion chamber of the rotary kiln (7), the other path of the fuel bin is communicated with the hollow suspension furnace (4), the hollow suspension furnace (4) is in an on-line kiln furnace type, and the suspension decomposition of powder is realized through the combustion of hot airflow at the bottom and fuel;
the hollow suspension furnace (4) comprises an inner cavity (42) and an outer cavity (43), the top of the inner cavity (42) is open, the bottom of the inner cavity is of a conical structure, and the lowest part of the conical structure is communicated with a first hot air flow pipeline (71); the top of the outer cavity (43) is higher than the inner cavity (42), the bottom of the outer cavity is of a wedge-shaped structure, and the lowest point of the wedge-shaped structure is communicated with the first pipeline (41); the top of the outer cavity (43) is provided with a second pipeline (44) extending into the middle of the inner cavity (42), and the second pipeline (44) is communicated with a material outlet of the fourth-stage cyclone cylinder.
2. The precise magnesium oxide preparation device according to claim 1, wherein the diameter of the kiln cylinder of the rotary kiln (7) is 2.5m or more.
3. The magnesium oxide precise preparation device according to claim 1, wherein the outlet of the calcination chamber of the rotary kiln (7) is connected with a grate cooling dust collector (5).
4. The precise magnesium oxide preparation device according to claim 1, wherein the fuel in the fuel bin (6) is a gas fuel, a liquid fuel or a solid fuel.
5. The precise magnesium oxide preparation device according to claim 1, wherein the temperature of the hollow suspension furnace (4) is 700-1000 ℃; the temperature of the rotary kiln (7) is 900-1300 ℃.
6. A method for accurately producing magnesium oxide of various activities by using the apparatus for accurately producing magnesium oxide according to any one of claims 1 to 5, which comprises grinding raw materials, lifting raw materials, preheating in suspension, decomposing, and calcining; the raw materials are suspended and preheated in the suspension preheater (3), then are decomposed into carbonate in the hollow suspension furnace (4) and the fifth-stage cyclone cylinder, the decomposed materials are calcined in the rotary kiln (7) according to the production requirement of the activity of the magnesium oxide to obtain the magnesium oxide clinker with the required activity, and finally, the magnesium oxide clinker is cooled and recovered.
7. The method for preparing magnesium oxide by using the magnesium oxide precise preparation device according to claim 6, wherein the raw material is magnesium ore, and the content of magnesium oxide in the magnesium ore is 18-47%.
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