CN114455561A - Comprehensive utilization process of hot galvanizing pickling wastewater and method for preparing battery-grade iron phosphate - Google Patents
Comprehensive utilization process of hot galvanizing pickling wastewater and method for preparing battery-grade iron phosphate Download PDFInfo
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Abstract
Adding phosphoric acid or salt thereof into the hot galvanizing pickling wastewater after impurity removal, removing acid through oxidation and negative pressure distillation, precipitating, filtering to obtain an iron phosphate product and a zinc-containing filtrate, and concentrating and crystallizing the zinc-containing filtrate to prepare a zinc chloride product or react with carbonic acid or salt thereof to prepare a basic zinc carbonate product. The invention separates iron from the waste acid containing iron and zinc to be used as a product for preparing the ferric phosphate dihydrate and the basic zinc carbonate, can reduce the problem of treatment and discharge of the waste acid, improves the economic value of the waste acid and achieves the aim of comprehensively utilizing the waste water. Has both economic benefit and environmental benefit.
Description
Technical Field
The invention relates to a comprehensive utilization process of hot galvanizing pickling wastewater and a method for preparing battery-grade iron phosphate, in particular to a treatment process of high-concentration iron-containing zinc-containing waste hydrochloric acid solution generated during pickling in a hot galvanizing process and a method for preparing battery-grade iron phosphate by using the same, belonging to the technical field of wastewater treatment.
Background
In the hot galvanizing process, the process of cleaning iron rust and oxide film on the surface of steel by hydrochloric acid and backwashing the zinc coating on the surface of an unqualified product is widely applied, so that a large amount of waste hydrochloric acid with high zinc content and iron content is generated, the components of the waste hydrochloric acid mainly comprise hydrochloric acid, zinc ions, ferrous ions and ferric ions, the waste hydrochloric acid has extremely strong corrosivity, and if the waste hydrochloric acid is directly discharged without treatment, the environment is seriously polluted, and the waste of zinc and iron resources is also caused. The waste liquid with high concentration of zinc, iron and free acid coexisting is a difficult problem for wastewater treatment. The conventional treatment method is to neutralize the emission, and as environmental protection regulations are improved and resource shortage is increased, the method is prohibited from being adopted. Considering that the pickling waste liquid contains high-concentration iron and zinc, the comprehensive utilization of the pickling waste liquid not only avoids the waste of resources, but also is an effective way for treating pollution.
The invention patent with publication number CN110790439A discloses a method for treating hot galvanizing pickling wastewater. The method comprises the steps of adding excessive oxidant into acid pickling wastewater, oxidizing ferrous ions into ferric ions, heating, adding sodium hydroxide and sodium citrate, combining the ferric ions with the sodium hydroxide to obtain ferric hydroxide, and combining the sodium citrate with zinc ions to obtain a complex, so that metal iron ions and zinc ions are removed from the wastewater. However, in the method, excessive oxidant sodium hypochlorite is adopted, chlorine is generated when sodium hypochlorite reacts with hydrochloric acid, potential safety hazards are easy to generate, meanwhile, the pH value needs to be adjusted for many times in the production process, the process operation is too complicated, industrial production is not facilitated, and the treatment efficiency is low.
The invention patent with the publication number of CN110255778A also discloses a recycling method of hot galvanizing pickling wastewater. According to the method, the acid washing wastewater is adjusted by compounding the zinc hydroxide and the ammonia water, iron and zinc are separated under the condition of not introducing any other metal ions, and relatively pure iron hydroxide and zinc-containing recycled water which can be used as a hot galvanizing raw material are obtained, the iron hydroxide can be used as a raw material for producing iron oxide red, and the zinc-containing water can be directly recycled. The method is suitable for waste acid solution with low zinc content, has difference with high-concentration zinc-containing waste liquid generated by a hot galvanizing process, and is high in production cost because a large amount of zinc hydroxide is added in the process.
The invention patent with publication number CN112938920A discloses a method and a device for preparing industrial zinc phosphate and iron phosphate by using zinc-containing waste hydrochloric acid. According to the method, the zinc phosphate and the iron phosphate with high added values can be produced by introducing phosphate ions, other residues or residual liquid which needs to be treated additionally is not produced, but in the actual treatment process, the mixture of the zinc phosphate and the iron phosphate is obtained by adding the ammonium phosphate and the ammonia water, the mixture needs to be further separated and then reused, the separation process is complex, and the purity of the separated zinc phosphate and iron phosphate is not ideal.
Disclosure of Invention
The invention aims to solve the problem of recycling iron and zinc in high-concentration iron-containing zinc-containing hydrochloric acid coexisting waste liquid, and provides a comprehensive utilization process of hot galvanizing pickling waste water.
The invention also aims to provide a method for preparing battery-grade iron phosphate, which takes hot galvanizing pickling wastewater as a raw material, can prepare battery-grade iron phosphate meeting the industrial standard, and can be directly used as a lithium iron phosphate raw material.
The invention is realized by the following technical scheme: a process for comprehensive utilization of the acid-washing waste water generated by hot-dip galvanizing includes such steps as adding phosphoric acid or its salt to the acid-washing waste water, oxidizing, negative-pressure distilling to remove acid, depositing, filtering to obtain iron phosphate product and zinc-contained filtrate, concentrating and crystallizing the zinc-contained filtrate to obtain zinc chloride product or reacting with carbonic acid or its salt to obtain basic zinc carbonate product,
the hot galvanizing pickling wastewater comprises the following components in percentage by weight:
zn ion: 2-8%;
fe ion: 2-8%;
HCL：4～10%；
insoluble matter: 0.1 to 0.4 percent.
And the impurity removal is to filter the hot galvanizing acidic wastewater by adopting a filter to obtain pretreated wastewater with insoluble substance content less than or equal to 0.1%.
Adding the hot galvanizing pickling wastewater after impurity removal into a reaction kettle, and then adding phosphoric acid or phosphoric acidSalt, stirring, mixing and reacting, controlling Fe in the mixed solution3+Molar ratio to phosphate radical 1: (1.0-1.20).
Wherein, Fe is contained in the mixed solution3+Reacting with phosphate radical, wherein the chemical formula is as follows:
Fe3+ + PO43-→FePO4↓
the oxidation is carried out in an oxidant oxidation or catalytic oxidation mode, the oxidation time is 0.5-2 h, and Fe is obtained2+The content of the solution is less than or equal to 0.1 percent, and the oxidant is at least one selected from hydrogen peroxide, sodium chlorate and sodium hypochlorite; sodium nitrite and oxygen are adopted in the catalytic oxidation.
The chemical equation for the oxidation process is as follows:
2Fe²⁺+H2O2+2H⁺=2Fe³⁺+2H2O
2FeSO4+H2SO4+1/2O2 =_Fe2(SO)3+ H2O
2Fe²⁺+NaClO3+2H⁺=2Fe³⁺+NaCl+H2O。
the negative pressure distillation deacidification is a process of performing negative pressure distillation by adopting heat generated by oxidation and then removing hydrochloric acid by condensation.
And the precipitation is carried out by adding a precipitator at the temperature of 50-90 ℃ and adjusting the pH of the solution to 1.0-2.0, wherein the precipitator is at least one selected from sodium hydroxide, potassium hydroxide, ammonia water and carbonate (such as potassium carbonate, sodium carbonate, ammonium carbonate and the like).
And continuously aging the solution after precipitation at the temperature of 50-90 ℃ for 1-8 h, filtering, washing and drying to obtain an iron phosphate product, wherein the iron phosphate product is used as a lithium iron phosphate raw material.
And (3) feeding the filtered zinc-containing filtrate and washing liquid into a reaction kettle, controlling the temperature of the solution to be 50-90 ℃, adding carbonate or carbon dioxide gas, adjusting the pH value of the solution to be 6-9, precipitating for 0.5-2 h, filtering and drying to obtain a basic zinc carbonate product, and crystallizing the filtrate of the basic zinc carbonate to obtain corresponding salt.
And (3) feeding the zinc-containing filtrate obtained by filtering and a washing solution into a reaction kettle, and concentrating, crystallizing, washing and drying to obtain a zinc chloride product.
A method for preparing battery-grade iron phosphate is characterized in that an iron phosphate product is prepared by any one of the methods, and meets the product index of the battery-grade iron phosphate, such as the industrial standard HG/T4701-2014.
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) the equipment used in the invention has simple structure, convenient operation, wide raw material source, simplicity, easy obtainment and low cost, and brings convenience to industrial production; the process defined by the invention has strong applicability and can be adapted to various raw materials such as phosphorus sources, oxidants and the like.
(2) The method provided by the invention can be used for recycling the waste hydrochloric acid containing zinc without generating other residues or residual liquid which need to be treated, so that the treatment cost of enterprises is reduced, and the reduction is realized from the source.
(3) The wastewater and the like generated by the production process can be recycled after conventional treatment, so that the water resource recycling is realized, and the emission pollution is reduced.
(4) According to the invention, negative pressure distillation is carried out to remove acid by using the reaction heat in the waste acid oxidation process, the reaction heat in the oxidation process is fully utilized in the technical process, the hydrochloric acid content in the solution is removed, the addition of the iron phosphate precipitator is reduced, the concentration of the impurity content in the iron phosphate is reduced, the water consumption for later washing is reduced, and the energy-saving and consumption-reducing green and environment-friendly production is achieved.
(5) According to the invention, through the matching of the processes of negative pressure distillation, precipitation and aging, the product purity of the iron phosphate product obtained by converting Fe in the hot galvanizing pickling wastewater can be improved, and the battery-grade iron phosphate product (meeting the industrial standard HG/T4701-.
(6) According to the invention, the iron phosphate product can be obtained by recovering Fe in the hot galvanizing pickling wastewater, and the economic benefit is obviously higher than that of the existing oxidation recovery product ferric hydroxide. In the practical application process, about 221 kg of iron phosphate product can be recovered from each ton of hot galvanizing pickling wastewater, the benefit is about 2000 yuan/ton, and the benefit is higher than about 500 yuan/ton according to the recovery of ferric hydroxide.
(7) According to the invention, zinc chloride or basic zinc carbonate products can be obtained by recovering Zn in the galvanizing pickling wastewater, and compared with the existing method of reusing the high-zinc-containing waste liquid as a hot galvanizing raw material, the method can realize diversification of zinc-containing products, and the prepared basic zinc carbonate has low cost and high yield.
In conclusion, through the introduction of phosphate radicals, under the coordination of the processes of oxidation, negative pressure distillation, precipitation, aging and the like, the high-efficiency recovery and utilization of zinc ions and iron ions in the hot galvanizing pickling wastewater can be realized, the recovery rate of Zn is more than or equal to 95%, the recovery rate of Fe is more than or equal to 95%, meanwhile, a battery-grade iron phosphate product can be prepared, and a zinc chloride product or a basic zinc carbonate product can be obtained.
Drawings
FIG. 1 is a schematic process flow diagram of the present invention.
Detailed Description
The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.
The following examples all relate to a comprehensive utilization process of hot galvanizing pickling wastewater, and further include a method for preparing a battery-grade iron phosphate product from the hot galvanizing pickling wastewater, referring to a process flow shown in fig. 1. The hot galvanizing pickling waste water is from waste hydrochloric acid containing high zinc and iron generated by a hot galvanizing process, and the percentage content of the main components is as follows: zn ion: 2-8%, Fe ion: 2-8% of HCL: 4-10% and insoluble matter: 0.1 to 0.4 percent.
Example 1: and (4) comprehensively treating hot galvanizing pickling wastewater.
Removing insoluble particles in hot galvanizing pickling wastewater by using a filter to obtain pretreated wastewater with the content of the insoluble particles being less than or equal to 0.1%, adding the pretreated wastewater into a reaction kettle, adding ammonium phosphate, stirring, mixing and reacting, and controlling Fe in the mixed solution3+The molar ratio of the phosphate radical to the phosphate radical is 1: 1. adding sodium chlorate into the reaction kettle for oxidation reaction, and measuring Fe in the solution after the oxidation reaction is completed2+Less than or equal to 0.1 percent. Vacuumizing the reaction kettle by using a vacuum pump, and opening hydrochloric acidAnd recovering the condenser, performing negative pressure deacidification on the wastewater, and performing negative pressure suction filtration for 30 min. After the deacidification is completed, the electric heating is started to raise the temperature in the reaction kettle to 90 ℃, and the sodium carbonate solution is slowly added for precipitation under the condition of continuous stirring. The pH value of the solution is controlled to be 2.0 during the precipitation process. And after the pH value of the iron phosphate slurry reaches the precipitation pH value, keeping the reaction temperature at 90 ℃ for aging for 8h, and after the iron phosphate slurry is completely aged, filtering and washing the iron phosphate slurry until no chloride ions exist in the filtrate. And transferring the iron phosphate filter cake into a drying oven for drying, and obtaining a battery-grade iron phosphate product after complete drying, wherein the battery-grade iron phosphate product can be directly used as a lithium iron phosphate raw material.
And (3) feeding zinc-containing filtrate obtained by filtering the iron phosphate slurry and washing liquid into a reaction kettle, heating to 90 ℃, and continuously stirring for 10 min. Adding 20% carbon dioxide gas for precipitation, controlling the pH value of the precipitate to be 9, filtering the filtrate containing the basic zinc carbonate precipitate after the precipitation is completed, washing the filtrate until no chloride ions exist in the filtrate. And (3) transferring the basic zinc carbonate filter cake obtained by filtering into a drying oven for drying, controlling the drying temperature at 120 ℃, and completely drying to obtain a basic zinc carbonate product. Can be used for light astringent and emulsion products, skin protectant, rayon production and desulfurizing agent, analytical reagent, pharmaceutical industry, feed additive, etc.
Example 2: and (4) comprehensively treating hot galvanizing pickling wastewater.
Removing insoluble substance particles from hot galvanizing pickling wastewater by using a filter to obtain pretreated wastewater with the content of the insoluble substance being less than or equal to 0.1%, adding the pretreated wastewater into a reaction kettle, adding phosphoric acid, stirring, mixing and reacting, and controlling Fe in the mixed solution3+The molar ratio of the phosphate radical to the phosphate radical is 1: 1.2. adding sodium nitrite and oxygen into the reaction kettle for catalytic oxidation reaction, and measuring Fe in the solution after the oxidation is completed2+Less than or equal to 0.02 percent. And vacuumizing the reaction kettle by using a vacuum pump, opening a hydrochloric acid recovery condenser, performing negative pressure deacidification on the wastewater, and performing negative pressure suction filtration for 30 min. After the deacidification is completed, starting electric heating to raise the temperature in the reaction kettle to 50 ℃, and slowly adding sodium hydroxide solution for precipitation under the condition of continuous stirring. The pH value of the solution is controlled at 1.0 during the precipitation process. And after the pH value of the iron phosphate slurry reaches the precipitation pH value, keeping the reaction temperature at 50 ℃ for aging for 60min, and after the iron phosphate slurry is completely aged, filtering and washing the iron phosphate slurry until no chloride ions exist in the filtrate. And transferring the iron phosphate filter cake into a drying oven for drying, and obtaining a battery-grade iron phosphate product after complete drying, wherein the battery-grade iron phosphate product can be directly used as a lithium iron phosphate raw material.
Zinc-containing filtrate and washing liquid obtained by filtering the iron phosphate slurry are sent into a reaction kettle, a multi-effect evaporation concentration process is adopted, and a pure zinc chloride product is finally obtained after concentration, crystallization, washing and drying, can be used as an activating agent for producing activated carbon in the inorganic industry, so that the activated carbon becomes a porous substance and the surface area of the activated carbon is increased; also used as raw materials for manufacturing the anti-dissolving foam fire extinguishing fluid and producing zinc cyanide. Also can be used in organic industry as solvent of polyacrylonitrile, contact agent, dehydrating agent, condensing agent, deodorant, special surfactant for organic synthesis, and catalyst for vanillin, cyclamen aldehyde, anti-inflammatory drug, and cation exchange resin production; can also be used as a purifying agent in the petroleum industry; the dye industry is used as a stabilizer for ice dyeing dye color development salt; the pigment industry is used as a white pigment raw material; the metallurgical industry is used for producing aluminum alloys and treating metal surfaces; the rust remover is used during welding; the coal preparation plant is used for carrying out a floating and sinking experiment and the like, and has wide application.
Example 3:
and (4) comprehensively treating hot galvanizing pickling wastewater.
Removing insoluble substance particles from hot galvanizing pickling wastewater by using a filter to obtain pretreated wastewater with the content of the insoluble substance being less than or equal to 0.1%, adding the pretreated wastewater into a reaction kettle, adding sodium phosphate, stirring, mixing and reacting, and controlling Fe in the mixed solution3+The molar ratio of the phosphate radical to the phosphate radical is 1: 1.2. adding hydrogen peroxide into the reaction kettle for oxidation reaction, and measuring Fe in the solution after the oxidation reaction is completed2+Less than or equal to 0.05 percent. And vacuumizing the reaction kettle by using a vacuum pump, opening a hydrochloric acid recovery condenser, performing negative pressure deacidification on the wastewater, and performing negative pressure suction filtration for 30 min. After the deacidification is completed, the electric heating is started to perform the reactionThe temperature in the kettle is raised to 80 ℃, and sodium hydroxide solution is slowly added under the condition of continuous stirring for precipitation. The pH value of the solution is controlled to be 1.2 during the precipitation process. And after the pH value of the iron phosphate slurry reaches the precipitation pH value, keeping the reaction temperature at 80 ℃ for aging for 3h, filtering and washing the iron phosphate slurry after the iron phosphate slurry is completely aged until no chloride ions exist in the filtrate. And transferring the iron phosphate filter cake into a drying oven for drying, and obtaining a battery-grade iron phosphate product after complete drying, wherein the battery-grade iron phosphate product can be directly used as a lithium iron phosphate raw material.
And (3) feeding zinc-containing filtrate obtained by filtering the iron phosphate slurry and washing liquid into a reaction kettle, heating to 60 ℃, and continuously stirring for 10 min. Adding 20% potassium carbonate solution to precipitate, controlling the pH value of the precipitate at 7.5, filtering the filtrate containing basic zinc carbonate precipitate after the precipitation is completed, washing, and washing until no chloride ion exists in the filtrate. And (3) transferring the basic zinc carbonate filter cake obtained by filtering into a drying oven for drying, controlling the drying temperature at 120 ℃, and completely drying to obtain a basic zinc carbonate product.
Example 4: and (4) comprehensively treating hot galvanizing pickling wastewater.
Removing insoluble substance particles from hot galvanizing pickling wastewater by using a filter to obtain pretreated wastewater with the content of the insoluble substance being less than or equal to 0.1%, adding the pretreated wastewater into a reaction kettle, adding phosphoric acid, stirring, mixing and reacting, and controlling Fe in the mixed solution3+The molar ratio of the phosphate radical to the phosphate radical is 1: 1.1. adding hydrogen peroxide into the reaction kettle for oxidation reaction, and measuring Fe in the solution after the oxidation reaction is completed2+Less than or equal to 0.04 percent. And vacuumizing the reaction kettle by using a vacuum pump, opening a hydrochloric acid recovery condenser, performing negative pressure deacidification on the wastewater, and performing negative pressure suction filtration for 30 min. After the deacidification is completed, the electric heating is started to raise the temperature in the reaction kettle to 85 ℃, and ammonia water is slowly added under the condition of continuous stirring for precipitation. The pH value of the solution is controlled to be 1.0 during the precipitation process. And after the pH value of the iron phosphate slurry reaches the precipitation pH value, keeping the reaction temperature at 80 ℃ for aging for 2h, filtering and washing the iron phosphate slurry after the iron phosphate slurry is completely aged until no chloride ions exist in the filtrate. Iron phosphate filter cakeAnd (4) drying in a drying oven, and obtaining a battery-grade iron phosphate product after complete drying, wherein the battery-grade iron phosphate product can be directly used as a lithium iron phosphate raw material.
And (3) feeding zinc-containing filtrate obtained by filtering the iron phosphate slurry and washing liquid into a reaction kettle, and finally obtaining a pure zinc chloride product by adopting a multi-effect evaporation concentration process and carrying out concentration, crystallization, washing and drying.
Example 5:
filtering hot galvanizing pickling wastewater by a filter with filter cloth under negative pressure to remove insoluble particles in the hot galvanizing pickling wastewater, so that the content of the insoluble particles is less than or equal to 0.1 percent, and transferring 15kg of the filtered wastewater into a reaction kettle for stirring. 2.3kg of 85% phosphoric acid was added to the reaction kettle and stirring was continued for 10 min. Slowly adding 1.2kg of 30% hydrogen peroxide into the reaction kettle for oxidation reaction, and measuring Fe in the solution after the oxidation reaction is completed2+Less than or equal to 0.02 percent. And vacuumizing the reaction kettle by using a vacuum pump, opening a hydrochloric acid recovery condenser, performing negative pressure deacidification on the wastewater, and performing negative pressure suction filtration for 30 min. After the deacidification is completed, starting electric heating to raise the temperature in the reaction kettle to 85 ℃, and slowly adding 4mol/L sodium hydroxide solution for precipitation under the condition of continuous stirring. The pH value of the solution is controlled at 1.6 during the precipitation process. And after the pH value of the iron phosphate slurry reaches the precipitation pH value, keeping the reaction temperature at 85 ℃ for aging for 90min, and after the iron phosphate slurry is completely aged, filtering and washing the iron phosphate slurry until no chloride ions exist in the filtrate. And (3) transferring the iron phosphate filter cake into a drying oven for drying, controlling the drying temperature at 95 ℃, crushing after complete drying, and carrying out analytical test, wherein the results are shown in the following table 1.
TABLE 1
And (3) feeding zinc-containing filtrate obtained by filtering the iron phosphate slurry and washing liquid into a reaction kettle, heating to 75 ℃, and continuously stirring for 10 min. Adding 20% sodium carbonate solution to precipitate, controlling pH value of precipitate at 7.5, filtering filtrate containing basic zinc carbonate precipitate, washing, and washing until there is no chloride ion in the filtrate. And (3) transferring the basic zinc carbonate filter cake obtained by filtering into a drying oven for drying, controlling the drying temperature at 120 ℃, and completely drying to obtain a basic zinc carbonate product. Sampling tests were performed on the basic zinc carbonate product as shown in table 2 below.
TABLE 2
Example 6: preparation of battery grade iron phosphate.
Filtering hot galvanizing pickling wastewater by a filter with filter cloth under negative pressure to remove insoluble particles in the hot galvanizing pickling wastewater, so that the content of the insoluble particles is less than or equal to 0.1 percent, and transferring 15kg of the filtered wastewater into a reaction kettle for stirring. Adding 85% phosphoric acid into the reaction kettle2.5kg, and stirring is continued for 10 min. Then adding 30 percent hydrogen peroxide into the reaction kettle slowly1.4kg, carrying out oxidation reaction, and measuring Fe in the solution after the oxidation is completed2+Less than or equal to 0.02 percent. And vacuumizing the reaction kettle by using a vacuum pump, opening a hydrochloric acid recovery condenser, performing negative pressure deacidification on the wastewater, and performing negative pressure suction filtration for 30 min. After the deacidification is completed, starting electric heating to raise the temperature in the reaction kettle to 80 ℃, and slowly adding 4mol/L potassium hydroxide solution for precipitation under the condition of continuous stirring. The pH value of the solution is controlled to be 1.5 during the precipitation process. And after the pH value of the iron phosphate slurry reaches the precipitation pH value, keeping the reaction temperature at 80 ℃ for aging for 3h, filtering and washing the iron phosphate slurry after the iron phosphate slurry is completely aged until no chloride ions exist in the filtrate. And (3) transferring the iron phosphate filter cake into a drying oven for drying, controlling the drying temperature to be 90 ℃, crushing after complete drying, and carrying out analytical test, wherein the table 3 is shown below.
TABLE 3
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.
Claims (10)
1. A comprehensive utilization process of hot galvanizing pickling wastewater is characterized in that: adding phosphoric acid or its salt into the hot galvanizing pickling waste water after impurity removal, removing acid through oxidation and negative pressure distillation, precipitating, filtering to obtain an iron phosphate product and a zinc-containing filtrate, concentrating and crystallizing the zinc-containing filtrate to prepare a zinc chloride product, or reacting with carbonic acid or its salt to prepare a basic zinc carbonate product,
the hot galvanizing pickling wastewater comprises the following components in percentage by weight:
zn ion: 2-8%;
fe ion: 2-8%;
HCL：4～10%；
insoluble matter: 0.1 to 0.4 percent.
2. The comprehensive utilization process of hot galvanizing pickling wastewater according to claim 1, characterized in that: and the impurity removal is to filter the hot galvanizing acidic wastewater by adopting a filter to obtain pretreated wastewater with insoluble substance content less than or equal to 0.1%.
3. The comprehensive utilization process of hot galvanizing pickling wastewater according to claim 1, characterized in that: adding the hot galvanizing pickling wastewater after impurity removal into a reaction kettle, adding phosphoric acid or salt thereof, stirring, mixing and reacting, and controlling Fe in the mixed solution3+Molar ratio to phosphate radical 1: (1.0-1.20).
4. The comprehensive utilization process of hot galvanizing pickling wastewater according to claim 1, characterized in that: the oxidation is carried out in an oxidant oxidation or catalytic oxidation mode, the oxidation time is 0.5-2 h, and Fe is obtained2+The content of the solution is less than or equal to 0.1 percent, and the oxidant is at least one selected from hydrogen peroxide, sodium chlorate and sodium hypochlorite; sodium nitrite and oxygen are adopted in the catalytic oxidation.
5. The comprehensive utilization process of hot galvanizing pickling wastewater according to claim 1, characterized in that: the negative pressure distillation deacidification is a process of performing negative pressure distillation by adopting heat generated by oxidation and then removing hydrochloric acid by condensation.
6. The comprehensive utilization process of hot galvanizing pickling wastewater according to claim 1, characterized in that: and the precipitation is carried out by adding a precipitator at the temperature of 50-90 ℃ and adjusting the pH of the solution to 1.0-2.0, wherein the precipitator is at least one of sodium hydroxide, potassium hydroxide, ammonia water and carbonate.
7. The comprehensive utilization process of hot galvanizing pickling wastewater according to claim 1, characterized in that: and continuously aging the solution after precipitation at the temperature of 50-90 ℃ for 1-8 h, filtering, washing and drying to obtain an iron phosphate product, wherein the iron phosphate product is used as a lithium iron phosphate raw material.
8. The comprehensive utilization process of hot galvanizing pickling wastewater according to claim 7, characterized in that: and (3) feeding the zinc-containing filtrate obtained by filtering and a washing solution into a reaction kettle, controlling the temperature of the solution to be 50-90 ℃, adding carbonate or carbon dioxide gas, adjusting the pH value of the solution to be 6-9, precipitating for 0.5-2 h, filtering and drying to obtain a basic zinc carbonate product.
9. The comprehensive utilization process of hot galvanizing pickling wastewater according to claim 7, characterized in that: and (3) feeding the zinc-containing filtrate obtained by filtering and a washing solution into a reaction kettle, and concentrating, crystallizing, washing and drying to obtain a zinc chloride product.
10. A method of preparing battery grade iron phosphate, characterized by: the iron phosphate product prepared by the method according to any one of claims 1 to 7 meets the product index of battery-grade iron phosphate.
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| CN107954479A (en) * | 2017-12-18 | 2018-04-24 | 东北大学 | A kind of waste water extraction iron of iron content containing zinc and the method for preparing iron hydroxide |
| CN110255778A (en) * | 2019-07-18 | 2019-09-20 | 上海电力大学 | A kind of hot galvanizing pickling waste waters reuse method |
| CN110498402A (en) * | 2019-09-25 | 2019-11-26 | 龚典局 | A kind of phosphorous spent acid method of comprehensive utilization |
| CN110790439A (en) * | 2019-11-29 | 2020-02-14 | 镇江市和云工业废水处置有限公司 | Treatment method of hot galvanizing pickling wastewater |
| CN111453711A (en) * | 2020-04-18 | 2020-07-28 | 蒋央芳 | Resource treatment method of phosphating waste liquid |
| CN112938920A (en) * | 2021-03-30 | 2021-06-11 | 生态环境部南京环境科学研究所 | Method and device for preparing industrial zinc phosphate and iron phosphate by using zinc-containing waste hydrochloric acid |
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2021
- 2021-10-11 CN CN202111183057.6A patent/CN114455561A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107954479A (en) * | 2017-12-18 | 2018-04-24 | 东北大学 | A kind of waste water extraction iron of iron content containing zinc and the method for preparing iron hydroxide |
| CN110255778A (en) * | 2019-07-18 | 2019-09-20 | 上海电力大学 | A kind of hot galvanizing pickling waste waters reuse method |
| CN110498402A (en) * | 2019-09-25 | 2019-11-26 | 龚典局 | A kind of phosphorous spent acid method of comprehensive utilization |
| CN110790439A (en) * | 2019-11-29 | 2020-02-14 | 镇江市和云工业废水处置有限公司 | Treatment method of hot galvanizing pickling wastewater |
| CN111453711A (en) * | 2020-04-18 | 2020-07-28 | 蒋央芳 | Resource treatment method of phosphating waste liquid |
| CN112938920A (en) * | 2021-03-30 | 2021-06-11 | 生态环境部南京环境科学研究所 | Method and device for preparing industrial zinc phosphate and iron phosphate by using zinc-containing waste hydrochloric acid |
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