CN104556468B - Method for treating fluoride wastewater with fluid catalytic cracking equilibrium catalyst - Google Patents

Abstract

The invention discloses a method for treating fluoride wastewater with a fluid catalytic cracking equilibrium catalyst. The fluoride wastewater contains F＜-＞, SO4＜2-＞ and Al＜3+＞. The treatment method of the fluoride wastewater comprises the steps that a pH (potential of hydrogen) value of the fluoride wastewater is adjusted to be no less than 5; F＜-＞ is subjected to a neutralization precipitation reaction; the fluoride wastewater subjected to the neutralization precipitation reaction is contacted with a coagulant; solid-liquid separation is performed; first sludge and a first liquid phase are obtained; the obtained first liquid phase is contacted with the fluid catalytic cracking equilibrium catalyst; the solid-liquid separation is performed; and the treated wastewater is obtained. The method can effectively remove fluorine in the fluoride wastewater with higher F＜-＞, SO4＜2-＞ and Al＜3+＞ content.

Description

A method of treating fluorine-containing wastewater by using a catalytic cracking balancer

technical field

The invention relates to a treatment method for fluorine-containing wastewater, in particular to a treatment method for effectively removing fluorine from fluorine-containing wastewater produced in the production process of molecular sieves by using a catalytic cracking balancer.

Background technique

Phosphorus-containing skeleton silicon-rich ultra-stable Y molecular sieve (PSRY molecular sieve) is a new type of skeleton silicon-rich molecular sieve prepared by NaY molecular sieve through hydrothermal roasting and complex acid dealumination of silicon. It is prepared with PSRY molecular sieve as the main active component Fluid catalytic cracking (FCC) catalyst has the characteristics of good coke selectivity, high gasoline octane number, strong heavy oil cracking ability, and high diesel yield. After successful industrial trial production, FCC with PSRY molecular sieve as the main active component The catalyst has been used in many heavy oil catalytic cracking units across the country, and has achieved good economic and social benefits.

Since a certain amount of fluosilicic acid must be used in the production process, the wastewater produced by PSRY molecular sieve production process is obviously different from conventional molecular sieve production wastewater. The most prominent feature is the high content of F ^- and SO ₄ ^2- in the wastewater (F ^- content Often exceeds 2000mg/L, SO ₄ ^2- content often exceeds 20000mg/L), and PSRY molecular sieve production wastewater has the characteristics of high silicon, aluminum and ammonia nitrogen content and low pH value of conventional molecular sieve production wastewater. The main purpose of conventional molecular sieve production wastewater treatment is to remove aluminum, silicon and ammonia nitrogen contained in water. This type of wastewater treatment technology has been improved and developed for many years, and the process route is becoming more and more reasonable. The actual treatment effect can meet the requirements of molecular sieve production and environmental protection discharge. There is no corresponding method for the removal of fluorine in wastewater. At present, PSRY molecular sieves produce high-fluorine-containing and phosphorus-containing wastewater that is mixed with other types of generated wastewater and treated together. The actual treatment effect shows that this treatment method cannot make the fluorine content in wastewater reach environmental protection. Emission Standards.

Excessive fluorine will cause serious harm to the environment, not only can lead to human fluorosis (manifested as systemic chronic damage mainly invading teeth and bones), but also fluorine pollution can poison animals and plants, affecting agricultural and animal husbandry production, For this reason, the national wastewater discharge standard has strict requirements on the discharge of fluorine. Therefore, in order to ensure the normal production of PSRY molecular sieve, it is necessary to solve the problem of excessive discharge of fluorine content in PSRY molecular sieve production wastewater.

The relevant patent applications and journal literature about wastewater defluorination in the prior art are recorded as follows:

CN102070267A (a method for treating high-concentration acidic phosphorus-containing and fluorine-containing wastewater) discloses a method for treating acidic phosphorus-containing and fluorine-containing wastewater. The method comprises the following steps: 1) firstly adding calcium hydroxide to the acidic phosphorous and fluorine-containing wastewater, and controlling the pH value of the system to be between 12-14 to obtain a reaction system containing precipitation, which is recorded as reaction system 1; 2 ) remove the precipitate in the reaction system 1, and add sulfuric acid to the remaining liquid to adjust the pH value between 9-11, then add aluminum sulfate to adjust the pH value between 6-7, to obtain the reaction system 2 containing the precipitate; 3) Precipitate the reaction system 2, remove the precipitate therein, and obtain treated wastewater. The fluorine content of the waste water treated by the method of the invention is lower than 10 mg/L, the pH value is between 6 and 7, and reaches the discharge standard for water pollutants of the phosphate fertilizer industry (GB15580-95).

Design and operation of fluorine-containing and phosphorus-containing wastewater treatment process (Industrial Water Treatment, Volume 25, No. 2, 2005) In the article, Shao Zhiguo, Wang Qichao, and Quan Yulian used lime neutralization and precipitation to treat fluorine-containing acidic wastewater and control wastewater The reaction pHs were 8.5 and 11.0, respectively, and an excess of strong electrolyte calcium chloride was added to precipitate fluoride ions. Then the precipitate is separated from the wastewater to achieve the purpose of removing fluoride ions in the acid-containing wastewater. Finally, dilute hydrochloric acid is used to neutralize, so that the fluorine-containing wastewater can be discharged up to standard after treatment. The technological process is simple, the equipment efficiency is high, the operation is simple and convenient, and it has good environmental benefits.

In addition, CN102267768A (a method of lime-fly ash joint treatment of high-concentration fluorine-containing wastewater) discloses a method of lime-fly ash joint treatment of high-concentration fluorine-containing wastewater, including the following steps: Lime primary precipitation treatment stage : The temperature is 10°C, the amount of lime added is 0.1-0.2g per 50mL of fluorine-containing wastewater, the adsorption time is 30-60min, and the pH is 5.0-8.0; the secondary adsorption treatment stage of fly ash: the temperature is 15°C-45°C, powder The amount of coal ash added is 5.0-15.0g per 50mL of fluorine-containing wastewater, the adsorption time is 60-120min, and the pH is 5.0-7.0, and the fly ash has been modified by acid solution in advance.

The above methods all use Ca ²⁺ as the main reactant for removing fluorine, and the purpose of removing most of the fluorine in wastewater is achieved through the reaction of Ca ²⁺ and F ^- to form a water-insoluble calcium salt precipitation. However, the above methods are difficult to be effectively applied to the defluorination treatment of fluorine-containing wastewater with high content of F ^- , SO ₄ ^2- and Al ³⁺ and Si ⁴⁺ in molecular sieve production enterprises.

CN1814556A (method for treating sewage with waste oil refinery catalyst) discloses a method for using waste oil refinery catalyst to adsorb and treat organic matter in various types of wastewater. The organic matter in the catalyst is adsorbed, and the waste refinery catalyst is made of molecular sieve, clay, and binder, with a specific surface area of 100-300m ² /g and a pore volume of 0.1-0.4ml/g; based on the total weight of the catalyst, Al The content of ₂ O ₃ is 45-70 wt %, the content of SiO ₂ is 25-50 wt %, the content of P ₂ O ₅ is 0.2-4 wt %, the content of Fe ₂ O ₃ is 0-0.5 wt %, Na The total content of ₂ O, MgO, K ₂ O, CaO, TiO ₂ , Re ₂ O ₃ is 3-8% by weight. After being treated by the method, the COD value of the wastewater whose COD value is 80-300 mg/L, preferably 100-250 mg/L can be reduced to below 60 mg/L. This method does not involve the adsorption of fluoride ions.

Contents of the invention

The purpose of the present invention is to overcome that the treatment of wastewater defluorination in the prior art is not suitable for the defluorination treatment of fluorine-containing wastewater with high content of F ^- , SO ₄ ^2- and Al ³⁺ , that is, the fluorine content in wastewater after treatment The defect of not meeting the emission standards, but providing an effective method for removing fluorine that is suitable for fluorine-containing wastewater with high content of F ^- , SO ₄ ^2- and Al ³⁺ , especially for catalyst manufacturers producing PSRY molecular sieves containing fluorine The method for effectively removing fluorine from waste water enables the fluorine content of the fluorine-containing waste water to be discharged up to the standard.

The inventors of the present invention found that the waste water treated by the defluoridation treatment method in the prior art does not have the characteristics of high silicon and sulfate content. For PSRY molecular sieve production wastewater, which contains a large amount of SO ₄ ^2- ions, if it is treated with conventional defluorinating agent Ca ²⁺ , CaSO ₄ will be generated, and the generation of CaSO ₄ will seriously interfere with the generation efficiency of CaF ₂ and Precipitation performance, which seriously affects the defluoridation effect of wastewater. Therefore, the above methods are difficult to be effectively applied to the defluorination treatment of fluorine-containing wastewater in molecular sieve production enterprises. Based on the above findings, the inventors of the present invention have accomplished the present invention.

In order to achieve the above object, the present invention provides a method for treating fluorine-containing wastewater by using a catalytic cracking balancer, wherein the fluorine-containing wastewater contains F ^- , SO ₄ ^2- and Al ³⁺ , and the treatment method of the fluorine-containing wastewater include:

Adjusting the pH value of the fluorine ^- containing wastewater to be no less than 5, so that F- can undergo neutralization and precipitation reaction;

contacting the fluorine-containing waste water that has undergone neutralization and precipitation reaction with a coagulant, and separating the solid and liquid to obtain the first sludge and the first liquid phase;

The obtained first liquid phase is contacted with a catalytic cracking balance agent, and the solid and liquid are separated to obtain treated waste water.

The method provided by the present invention is combined with the actual situation of the catalyst production enterprise, on the basis of making full use of fluorine-containing wastewater, especially the Al ³⁺ contained in the fluoride-containing wastewater generated during the catalyst production process as a fluorine-removing reactant, combined with the ability to adsorb wastewater ^The catalytic cracking balancer in F- is used as an adsorbent for defluorination, and the large specific surface area, rich pore structure and reasonable micropore structure of the catalytic cracking balancer are used to achieve the purpose of effective defluorination of wastewater. Especially when the catalytic cracking balancer contains rare earth elements, the rare earth elements can form active center points and have chemical adsorption with fluoride ions. The combination of the two has a better adsorption effect on fluoride ions in wastewater.

Therefore, the present invention possesses following outstanding advantages:

a, the present invention does not use _Ca ²⁺ as a fluoride removal agent, but utilizes Al ³⁺ in fluorine-containing wastewater as a precipitated cation for fluorine removal, avoiding the SO ₄ ^2- contained in a large amount of molecular sieve production wastewater that is harmful to the fluoride removal process influences.

b. The present invention makes full use of the special pore size structure of the catalytic cracking balancer and the excellent chemical adsorption performance of rare earth elements contained in fluorine and other anions to adsorb and treat low-concentration fluorine-containing wastewater after flocculation and precipitation, so that the fluorine content in the wastewater can be reduced. to within 10mg/L. In addition, at the same time, the amount and cost of flocculation and defluorination agents can be greatly reduced, and the overall sewage treatment cost is less than 4.0 yuan/ton of water.

c. Catalytic cracking balancer has abundant sources. When used as a defluorinating agent, it not only achieves the purpose of resource recycling and waste treatment, but also reduces the cost of wastewater treatment for enterprises, and has good economic and environmental benefits.

Other features and advantages of the present invention will be described in detail in the following detailed description.

detailed description

Specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

According to the method for treating fluorine-containing wastewater using a catalytic cracking balancer provided by the present invention, wherein the fluorine-containing wastewater contains F ^- , SO ₄ ^2- and Al ³⁺ , the treatment method for the fluorine-containing wastewater includes:

Adjusting the pH value of the fluorine ^- containing wastewater to be no less than 5, so that F- can undergo neutralization and precipitation reaction;

contacting the fluorine-containing waste water that has undergone neutralization and precipitation reaction with a coagulant, and separating the solid and liquid to obtain the first sludge and the first liquid phase;

The obtained first liquid phase is contacted with a catalytic cracking balance agent, and the solid and liquid are separated to obtain treated waste water.

According to the present invention, the treatment steps of the fluorine-containing wastewater mainly correspond to the following four process units:

Wherein, the pH value of the fluorine-containing wastewater is adjusted to not be lower than 5, so that F ^- undergoes neutralization and precipitation reaction, that is, the neutralization unit, which can also be called the first-stage defluorination unit.

The main function of the neutralization unit is to complete the reaction between the original Al ³⁺ and F ^- in the wastewater, and convert most of the fluorine dissolved in the fluorine-containing wastewater into solid insoluble matter, that is, fluorine-containing suspended matter, to remove most of the water F ^- purpose.

Preferably, adjusting the pH value of the fluorine-containing wastewater is greater than 5.0, preferably adjusting the pH value to greater than 5.5, and optimally adjusting the pH value to 6-9, in order to further ensure the complete reaction of Al3 ⁺ and F- ^, and Ensure the precipitation of excess Al ³⁺ in water is removed.

Wherein, the method for adjusting the pH value of fluorine-containing wastewater can be carried out by methods known to those skilled in the art, such as adjusting with alkali, usually inorganic alkalis such as sodium hydroxide and potassium hydroxide can be used to adjust the pH value of the neutralization system . Wherein, the form of the base may be solid or liquid, and most preferably, an aqueous sodium hydroxide solution is used.

According to the present invention, the waste water is preferably stirred while or after adjusting the pH value to ensure sufficient reaction.

According to the present invention, in order to ensure the complete reaction of Al ³⁺ and F ^- , the reaction time of the neutralization unit is not less than 4 minutes, the preferred reaction time is 5-25 minutes, and the optimum reaction time is 10-20 minutes. The present invention has no special requirements on the reaction temperature of this step, usually the actual temperature of incoming water.

In addition, the reaction in the neutralization unit can be carried out in a conventional reactor in the art, for example, it can be carried out in a neutralization reactor.

According to the present invention, the fluorine-containing waste water that has undergone neutralization and precipitation reaction is contacted with a coagulant, and the solid and liquid are separated to obtain the first sludge and the first liquid phase, that is, the coagulation and sedimentation unit.

The purpose of the coagulation and sedimentation unit is to increase the degree of aggregation of suspended solids in water, so as to ensure that suspended solids are effectively separated from water, and most of the fluoride ions in wastewater are removed here.

According to the present invention, contacting the fluorine-containing wastewater after neutralization and precipitation with a coagulant can increase the settling performance of the fluorine-containing suspended matter in water, and then perform solid-liquid separation to achieve the purpose of separating the fluorine-containing suspended matter.

According to the present invention, the coagulant is a substance that can increase the degree of aggregation of suspended solids in wastewater. Compound product of flocculant. Preferably, the coagulant includes an aluminum-containing coagulant, and the aluminum-containing coagulant is preferably one or more of aluminum chloride, aluminum sulfate, polyaluminum chloride and polyaluminum ferric chloride; Based on the aluminum-containing coagulant, the dosage of the filter blending agent is 20-400 mg/L waste water, preferably 50-200 mg/L waste water. Further, the coagulant is an aluminum-containing coagulant and polyacrylamide (PAM, the number average molecular weight is usually 1 million to 9 million), and the amount of the aluminum-containing filter mixture is 20-400mg/L Wastewater, preferably 50-200 mg/L waste water, the amount of polyacrylamide is 2-20 mg/L waste water, preferably 2-10 mg/L waste water. Wherein, the waste water mentioned in the definition of coagulant dosage refers to the waste water to be treated.

According to the present invention, the method of contacting the fluorine-containing wastewater after the neutralization and precipitation reaction with the coagulant is preferably mixed, more preferably under stirring. The mixing time only needs to ensure that the two are fully mixed. It can be 0.5-4h, preferably 0.5-2h.

According to the present invention, the first sludge obtained after solid-liquid separation usually needs to be dehydrated and concentrated, and the obtained solid waste residue is treated as solid waste. Since the filtrate after dehydrating the first sludge still contains F ^- ions , Therefore, it is preferred that the filtrate obtained after dehydration and concentration of the first sludge enters the next treatment unit together with the first liquid phase, that is, the filtrate obtained together with the first liquid phase and the catalytic cracking balance agent capable of adsorbing F ⁱⁿ the waste water touch.

The inventors of the present invention found that most of the fluoride ions in the fluorine-containing wastewater containing F ^- , SO ₄ ^2- and Al ³⁺ in the present invention, especially the PSRY molecular sieve wastewater pass through the pH in the neutralization unit and the coagulation and sedimentation unit. Adjustment and flocculation precipitation can be removed, the fluorine concentration in the first liquid phase after two-stage treatment can be reduced to about 50mg/L, and it is relatively easy to reduce the fluorine content from a high concentration to about 50mg/L. At this time, the sewage treatment cost of adding coagulation and defluoridation agent is about 3.5 yuan/ton of water, and the comprehensive discharge standard required by the enterprise is that the fluorine concentration is less than 10mg/L. To meet this standard, if you continue to use coagulation The method of defluoridation agent treatment will greatly increase the dosage and increase the difficulty of treatment. Just as it is easier to adjust the pH value of tap water from 7.0 to 2.5, if you continue to adjust it to 1.0, the amount of acid consumed is much more than the first. In order to meet the standard of fluorine concentration less than 10mg/L, the amount of acid consumed will be as high as 30.0 yuan per ton of water, and the difficulty of fluoride removal will also become difficult.

Therefore, according to the present invention, the obtained first liquid phase is contacted with the catalytic cracking balance agent, and the solid and liquid are separated to obtain the treated wastewater; that is, the adsorption unit, which can also be called the second-stage defluorination unit.

The purpose of the adsorption unit is mainly to further defluorinate the wastewater through the adsorption and exchange of the catalytic cracking balancer capable of adsorbing F- ⁱⁿ the wastewater to the residual F- ⁱⁿ the water.

According to the present invention, in the effluent of the previous unit, that is, the first liquid phase (or the mixture of the first liquid phase and the filtrate obtained after dehydrating and concentrating the first sludge) and the catalytic cracking balance agent capable of adsorbing F ⁱⁿ wastewater The way of contacting is preferably mixing, more preferably under stirring. In order to ensure effective adsorption exchange removal of F ^- , the stirring reaction time of the adsorption exchange unit should not be less than 5 minutes, and preferably, the contact time is 30-150 minutes. There is no particular limitation on the contact temperature, in order to further ensure the effective removal of residual F ^- in the wastewater, the contact temperature is 10-50°C, preferably 20-45°C. After treatment, the fluoride in the effluent can be reduced to below 10mg/L.

In the refining process of petrochemical industry, the activity of the catalytic cracking catalyst used in the catalytic cracking unit will gradually decrease during use. In order to maintain its activity, it is necessary to frequently replenish fresh catalyst and discharge the spent catalyst. The spent catalyst is also called catalytic cracking balancer (hereinafter referred to as FCC balancer), an oil refinery with an annual refining capacity of 1 million tons will produce 800-1200 tons of FCC balancer each year, and these balancers are currently mainly used as waste residues for sanitary landfill disposal.

The inventors of the present invention found that the catalytic cracking balancer has a better adsorption effect on wastewater containing phosphorus and fluorine. Especially for the fluorine-containing wastewater containing F ^- , SO ₄ ^2- and Al ³⁺ described in the present invention, the following catalytic cracking balancer with large specific surface area, rich pore structure and reasonable micropore structure is used as the adsorbent, The defluoridation effect is more significant. The catalytic cracking balancer has a specific surface area of 100-300m ² /g, preferably 150-250m ² /g, and a pore volume of 0.1-0.4ml/g, preferably 0.15-0.35ml/g. The composition of the catalytic cracking balancer is well known to those skilled in the art, and its main components are alumina, clay and molecular sieve, which may or may not contain rare earth elements. In the present invention, the catalytic cracking balancer containing rare earth elements is preferred. Based on the quality of the catalytic cracking balancer and in terms of oxides, the content of rare earth elements is preferably 1-20% by weight, more preferably 2-10% by weight. The rare earth element is preferably Ce and/or La.

In addition, the FCC balancer is used for adsorption treatment to remove the remaining low-concentration fluoride ions in the wastewater. The treatment cost is less than 4.0 yuan/ton of water. Moreover, catalyst manufacturers are often adjacent to oil refineries, and there are sufficient waste materials. Using FCC balancer for advanced treatment of phosphorus- and fluorine-containing wastewater can not only make waste utilization, achieve the purpose of treating waste with waste, but also allow sewage to be treated, saving waste filling. Burial and sewage treatment are two parts of the cost.

According to the present invention, the addition amount of the catalytic cracking balance agent only needs to ensure that the F- ⁱⁿ the waste water can be fully absorbed to meet the discharge standard of fluorine content in the waste water. On the basis of the foregoing steps of the present invention, the consumption of the catalytic cracking balance agent is 10-50g/L waste water and can obtain satisfactory effect, considering the construction and operation cost of adsorption efficiency and adsorption device comprehensively, the consumption of catalytic cracking balance agent is more preferred It is 15g-30g/L waste water. Wherein, the waste water mentioned in the definition of the dosage of the catalytic cracking balancer refers to the waste water to be treated.

According to the present invention, the adsorption unit can adopt a conventional adsorption-sedimentation device or a column-type fixed-bed device for adsorption operation.

According to the present invention, the method of dehydration and concentration involved in the above-mentioned treatment unit can be carried out by methods known to those skilled in the art, for example, filtration, such as press filtration (specifically, plate and frame filter press), centrifugal separation, etc., dehydration and concentration The water content of the obtained solid sludge is generally about 80% by weight. Specifically, in the present invention, it is preferable to transport the sludge to a sludge dewatering device for sludge concentration treatment.

According to the present invention, the solid-liquid separation method involved in the coagulation sedimentation unit and the adsorption unit can adopt various methods known to those skilled in the art, as long as the sufficient separation of the suspended solids and the liquid phase can be guaranteed. Yes, for example, it can be left standing to carry out conventional solid-liquid separation methods such as gravity settling, centrifugal separation, and pressure filtration (such as plate and frame filtration). According to the present invention, preferably, the solid-liquid separation method preferably adopts the method of gravity settling, and there is no special limitation on the time of gravity settling, usually the settling time is 0.5-4 hours. In addition, the gravitational sedimentation device of the gravity sedimentation separation method preferably adopted by the coagulation sedimentation unit and the adsorption unit can adopt a conventional wastewater treatment solid-liquid separation device, for example, it can be an advection sedimentation tank, a radial flow sedimentation tank and a settling tank Wait.

According to the present invention, the F- content in the fluorine ^- containing wastewater is greater than 100 mg/L, generally greater than 500 mg/L, the SO ₄ ^2- content is greater than 500 mg/L, generally greater than 2000 mg/L, and the Al ³⁺ content is greater than 100 mg/L. L is generally greater than 1000 mg/L, and the pH value of the fluorine-containing wastewater is generally greater than or equal to 1 to less than 5. The wastewater treatment method of the present invention is suitable for various fluorine-containing wastewater satisfying the above-mentioned ion content, and is particularly suitable for the treatment of fluorine-containing wastewater produced by a catalyst for producing PSRY molecular sieves.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way if there is no contradiction. The combination method will not be described separately.

In addition, various combinations of different embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the idea of the present invention, they should also be regarded as the disclosed content of the present invention.

The present invention will be described in detail below by way of examples.

In the following examples, the fluorine-containing wastewater produced by the molecular sieve is the fluorine-containing wastewater produced by the catalyst of the PSRY molecular sieve. The test methods for the F ^- content, SO ₄ ^2- content, and Al ³⁺ content in the fluorine-containing wastewater are fluorine reagent spectrophotometry (GB/T57505-2006), EDTA titration, inductively coupled plasma emission spectrometry (ICP ). The determination method of phosphorus content in fluorine-containing wastewater is the ammonium molybdate spectrophotometric method in Sinopec's "Cooling Water Analysis and Test Methods".

The coagulant polyacrylamide (PAM) with a number average molecular weight of 8 million was purchased from Beijing Xitao Technology Development Co., Ltd.; the coagulant aluminum sulfate was purchased from Gongyi Hongyuan Water Purification Material Factory.

FCC balancer comes from Sinopec Yanshan Branch.

Example 1

The composition of the FCC balance agent is: the content of Al ₂ O ₃ is 59% by weight, the content of SiO ₂ is 32.6% by weight, and the total content of other components such as P ₂ O ₅ , Na ₂ O, MgO, K ₂ O, etc. is 8.4% by weight , the specific surface area is 210m ² /g, and the pore volume is 0.35ml/g.

Weigh 3g of FCC balancer and add it to 200mL of fluorine-containing wastewater with different concentrations, at a rotation speed of 150r·min ^-1 , stir at room temperature (25°C) for 90min, let it stand for 20min, take a sample to measure the fluoride ion in the water, and calculate the static adsorption of F ^- Capacity (adsorbed fluorine concentration × water sample volume / balancer mass) and F ^- adsorption rate, the treatment effect of FCC balancer on different concentrations of fluorine-containing solutions is shown in Table 1.

Table 1

F ^- content (mg·L ^-1 ) 49.8 99.5 135.3 305.2 F ^- Static adsorption capacity (mg·g ^-1 ) 3.3 3.7 4.3 4.4 F ^- adsorption rate (%) 99.4 55.8 47.8 21.6

From the results in Table 1 above, it can be seen that when the fluoride ion content is around 50mg/L, the adsorption rate can reach 99%. With the increase of the fluoride ion content, the adsorption rate decreases gradually due to the limitation of the saturated adsorption capacity. When the fluoride ion content is close to 100mg /L, the adsorption rate is greatly reduced.

Example 2

This example is used to illustrate the method provided by the present invention for treating fluorine-containing wastewater by using a catalytic cracking balancer.

Production workshop effluent: F ^- content: 1853.2mg/L; SO ₄ ^2- content: 21638mg/L; phosphorus content: 109.7mg/L; aluminum content: 2750mg/L; pH: 4.1.

The FCC balancer is the same as in Example 1.

Weigh 300mL of the above-mentioned fluorine-containing wastewater, use NaOH aqueous solution to adjust the pH of the wastewater to 7.0, and stir for 15 minutes;

Then, add the PAM of 2mg/L waste water and the aluminum sulfate coagulant of 150mg/L waste water in the waste water that described pH value is adjusted, mix and carry out coagulation reaction, settle down 90min, get the first supernatant, this upper F ^- content in serum: 51.2mg/L;

Under stirring, add FCC balancing agent to the separated 200mL of the first supernatant, the dosage is 3g (equivalent to 15g/L wastewater), mix and stir for 120min at 25°C, settle for 20min, and the final F ^- content of the effluent is 7.4mg/L, phosphorus content is less than 0.5mg/L.

Comparative example 1-2

This comparative example is used to illustrate the reference method for the treatment of fluorine-containing wastewater.

The fluorine-containing wastewater was treated according to the method of Example 2, except that activated carbon and fly ash were used to replace the FCC balancer, and the F ^- contents of the final effluent were 25.2mg/L and 41.5mg/L respectively.

Example 3

This example is used to illustrate the method provided by the present invention for treating fluorine-containing wastewater by using a catalytic cracking balancer.

Fluorine-containing wastewater produced by molecular sieve: F ^- content: 520mg/L; SO ₄ ^2- content: 5657mg/L; phosphorus content: 35.4mg/L, aluminum content: 1650mg/L; pH: 3.95.

The FCC balancer is the same as in Example 1.

Weigh 1L of fluorine-containing wastewater, use NaOH solution to adjust the pH of the wastewater to 7.0, and stir for 15 minutes;

Then, add PAM of 5 mg/L waste water and 100 mg/L aluminum sulfate coagulant in the waste water of described pH value adjustment, mix uniformly and carry out coagulation aiding reaction, settle for 90min, obtain the first supernatant, this supernatant Medium F ^- content 48.3mg/L;

Under stirring, add FCC balancing agent to the separated 200mL of the first supernatant, the dosage is 5g (equivalent to 25g/L wastewater), mix and stir at 30°C for 60min, let it stand for 30min, and finally the F ^- content of the effluent It is 8.1mg/L, and the phosphorus content is less than 0.5mg/L.

Example 4

This example is used to illustrate the method provided by the present invention for treating fluorine-containing wastewater by using a catalytic cracking balancer.

The production of fluorine-containing wastewater by molecular sieves and the test methods and conditions are the same as in Example 3, except that the composition of the FCC balancer is: the content of Al ₂ O ₃ is 57.4% by weight, the content of SiO ₂ is 33.7% by weight, La ₂ The content of O ₃ is 2.0% by weight, the content of CeO ₂ is 3.0% by weight, the total content of other components such as P ₂ O ₅ , Na ₂ O, MgO, K ₂ O is 3.9% by weight, and the specific surface area is 220m ² /g , the pore volume is 0.33ml/g.

The final effluent F ^- content is 2.1mg/L, and the phosphorus content is less than 0.5mg/L.

Example 5

This example is used to illustrate the method provided by the present invention for treating fluorine-containing wastewater by using a catalytic cracking balancer.

The production of fluorine-containing wastewater by molecular sieves and the test methods and conditions are the same as in Example 3, except that 1L of fluorine-containing wastewater was weighed, the pH of the wastewater was adjusted to 9.0 with NaOH solution, and the reaction was stirred for 25 minutes;

Then add PAM of 10mg/L waste water and 200mg/L aluminum sulfate coagulant in the waste water that described pH value is adjusted, mix homogeneously and carry out coagulation aiding reaction, settling for 60min, get the first supernatant, this supernatant Medium F ^- content 54.2mg/L;

Under stirring, add FCC balancing agent to the separated 200mL of the first supernatant, the dosage is 6g (equivalent to 30g/L wastewater), mix and stir at room temperature (25°C) for 40min, let stand for 20min, and finally effluent F ^- The content is 8.3mg/L, and the phosphorus content is less than 0.5mg/L.

Example 6

This example is used to illustrate the method provided by the present invention for treating fluorine-containing wastewater by using a catalytic cracking balancer.

The production of fluorine-containing wastewater by molecular sieves and the test methods and conditions are the same as in Example 3, except that 1L of fluorine-containing wastewater is weighed, and the pH of the wastewater is adjusted to 5.5 with NaOH solution. The F ^- content of the final effluent is 10.6mg/L, and the phosphorus content Less than 0.5mg/L.

Claims (23)

1. A method for utilizing a catalytic cracking balancer to treat fluorine-containing wastewater, characterized in that, the fluoride-containing wastewater contains F ^- , SO ₄ ^2- and Al ³⁺ , and the treatment method of the fluoride-containing wastewater comprises: Adjusting the pH value of the fluorine ^- containing wastewater to be no less than 5, so that F- can undergo neutralization and precipitation reaction; contacting the fluorine-containing waste water that has undergone neutralization and precipitation reaction with a coagulant, and separating the solid and liquid to obtain the first sludge and the first liquid phase; The obtained first liquid phase is contacted with a catalytic cracking balance agent, and the solid and liquid are separated to obtain treated waste water. 2. The method according to claim 1, wherein the pH value of the fluorine-containing wastewater is adjusted to be greater than 5. 3. The method according to claim 2, wherein the pH value of the fluorine-containing wastewater is adjusted to be greater than 5.5. 4. The method according to claim 2 or 3, wherein the pH value of the fluorine-containing wastewater is adjusted to 6-9. 5. The method according to claim 1, wherein the neutralization and precipitation reaction is carried out under stirring, and the reaction time is not less than 4 minutes. 6. The method according to claim 5, wherein the reaction time is 5-25 minutes. 7. The method according to claim 1, wherein the coagulant comprises an aluminum-containing coagulant, and the amount of the coagulant is 20-400 mg/L waste water based on the aluminum-containing coagulant. 8. The method according to claim 7, wherein, based on the aluminum-containing coagulant, the amount of the coagulant is 50-200 mg/L waste water. 9. The method according to claim 7 or 8, wherein the aluminum-containing coagulant is one or more of aluminum chloride, aluminum sulfate, polyaluminum chloride and polyaluminum ferric chloride. 10. The method according to any one of claims 1, 7 and 8, wherein the coagulant is an aluminum-containing coagulant and polyacrylamide, and the amount of the aluminum-containing filter mixture is 20-400mg /L waste water, the consumption of described polyacrylamide is 2-20mg/L waste water. 11. The method according to claim 10, wherein the dosage of the aluminum-containing filter mixture is 50-200 mg/L wastewater, and the dosage of the polyacrylamide is 5-10 mg/L wastewater. 12. The method according to claim 10, wherein the aluminum-containing coagulant is one or more of aluminum chloride, aluminum sulfate, polyaluminum chloride and polyaluminum ferric chloride. 13. The method according to claim 1, wherein the specific surface area of the catalytic cracking balancer is 100-300m ² /g, and the pore volume is 0.1-0.4ml/g. 14. The method according to claim 13, wherein the specific surface area of the catalytic cracking balancer is ^150-250m2 /g, and the pore volume is 0.15-0.35ml/g. 15. The method according to claim 13, wherein the catalytic cracking balancer contains rare earth elements, taking the quality of the catalytic cracking balancer as a benchmark and in terms of oxides, the content of the rare earth elements is 1-20% by weight, and the rare earth The elements are Ce and/or La. 16. The method according to claim 15, based on the mass of the catalytic cracking balancer and in terms of oxides, the content of rare earth elements is 2-10% by weight. 17. The method according to any one of claims 1 and 13-16, wherein the amount of the catalytic cracking balancer is 10g-50g/L waste water. 18. The method according to claim 17, wherein the consumption of the catalytic cracking balancer is 15g-30g/L waste water. 19. according to the method described in any one in claim 1 and 13-16, wherein, the contact of the first liquid phase that obtains and catalytic cracking equalizer carries out under stirring, and the time of contact is not less than 5 minutes, and the contact time The temperature is 10-50°C. 20. The method according to claim 19, wherein the contacting time is 30-150 minutes and the contacting temperature is 20-45°C. 21. The method according to claim 1, wherein the method further comprises contacting the filtrate obtained after dehydrating and concentrating the first sludge together with the first liquid phase with a catalytic cracking balance agent. 22. The method according to claim 1, wherein, in the fluorine ^- containing wastewater, the content of F- is greater than 100 mg/L, the content of SO ₄ ^2- is greater than 500 mg/L, and the content of Al ³⁺ is greater than 100 mg/L, containing The pH value of fluorine wastewater is greater than or equal to 1 to less than 5. 23. The method according to claim 1, wherein the fluorine-containing wastewater is fluorine-containing wastewater produced by a catalyst for producing PSRY molecular sieves.