CN113415793B - Method for preparing high-purity iron phosphate from lithium iron phosphate battery waste - Google Patents

Abstract

The invention discloses a method for preparing high-purity iron phosphate from lithium iron phosphate battery waste, and belongs to the technical field of battery waste resource recovery. The method first adopts the process of oxidative extraction of lithium to separate and enrich the valuable metal lithium in the waste of lithium iron phosphate battery, then the leaching residue is treated with high phosphoric acid dissolved iron, and after the reaction is finished, solid-liquid separation is used to obtain insoluble matter and leachate; the leachate is diluted and adjusted pH, high-purity ferric phosphate is prepared by high-temperature crystallization; the crystallization residual liquid is subjected to phosphoric acid regeneration-evaporation concentration process to realize the regeneration cycle of initial phosphoric acid. The method has a short process flow, no additional neutralizer, precipitant and acid introduction, low cost and environmental friendliness; high-purity iron phosphate can be prepared, which can be used for the preparation of lithium-ion batteries, ceramics, catalysts and other materials, and the products are additionally high value. The invention solves the problems of environmental pollution and resource waste caused by the lithium iron phosphate battery waste, and provides a new idea for efficient and economical recycling and utilization of the lithium iron phosphate battery waste.

Description

A method for preparing high-purity iron phosphate from lithium iron phosphate battery waste

technical field

The invention belongs to the technical field of recycling battery waste resources, and in particular relates to a method for preparing high-purity iron phosphate from lithium iron phosphate battery waste.

Background technique

In recent years, the new energy industry has developed rapidly, among which the development of lithium-ion batteries is the most eye-catching. At present, lithium-ion batteries are widely used in industries such as mobile phones, computers, new energy vehicles, and energy storage stations. Lithium iron phosphate lithium-ion batteries are highly regarded due to their advantages of high safety, good thermal stability, low price and low pollution. In 2019, the installed capacity of lithium iron phosphate for electric bus power batteries in my country reached 13.8GWh. While lithium iron phosphate is widely used, a large number of lithium iron phosphate batteries are scrapped and eliminated, and the amount of lithium iron phosphate battery waste is increasing rapidly.

At present, the recycling of lithium iron phosphate battery waste mainly adopts wet recycling process: one is to realize the comprehensive recovery of valuable metals through strong acid leaching, impurity removal, neutralization and precipitation; the other is to supplement lithium, iron, phosphorus To realize the repair and regeneration of lithium iron phosphate batteries. Chinese invention patent application CN 104362408A discloses a method for comprehensive recycling and reuse of lithium iron phosphate battery waste. The method first treats the pole piece of lithium iron phosphate battery waste at high temperature, then separates lithium iron phosphate and current collector aluminum foil, and then peels off the Lithium iron phosphate is baked and sieved at high temperature to obtain lithium iron phosphate powder, and finally the lithium iron phosphate cathode material is regenerated by repairing. Due to the large fluctuations in the composition of lithium iron phosphate battery waste, and the low purity and poor electrical properties of recycled materials, this method cannot realize the comprehensive recycling of bulk lithium iron phosphate battery waste. Chinese invention patent application CN 103280610A discloses a method for recycling the positive electrode of lithium iron phosphate battery. In this method, the lithium iron phosphate positive electrode is first treated with alkali solution to obtain lithium-containing solution and filter residue containing iron phosphate. The lithium-containing solution can be added with 95 ℃ saturated sodium carbonate solution, and precipitate to prepare lithium carbonate; the filter residue is first dissolved with mixed acid, so that iron exists in the form of iron phosphate precipitation and is separated from impurities such as carbon black. This method consumes a lot of acid and alkali, and cannot realize the regeneration and recycling of acid and alkali. The process cost is high, and a large amount of waste water and waste residue are produced, which is not conducive to the economical and efficient treatment of lithium iron phosphate battery waste.

Therefore, it is of great significance to develop a simple, efficient, green and environmentally friendly recycling process for lithium iron phosphate battery waste to realize the resource utilization of lithium iron phosphate battery waste.

Contents of the invention

Aiming at the problems existing in the recycling process of lithium iron phosphate battery waste in the prior art, such as complicated procedures, large consumption of reagents, inability to recycle reagents, high cost and low purity of recovered ferric phosphate, the present invention provides a lithium iron phosphate A method for preparing high-purity iron phosphate from battery waste. This method first adopts the oxidation lithium extraction process to separate and enrich the valuable metal lithium in lithium iron phosphate battery waste, and then treats the leach residue with concentrated phosphoric acid to dissolve iron. After the reaction, the solid-liquid separation , to obtain insoluble matter and leaching solution; the leaching solution is diluted to adjust the pH, and high-purity ferric phosphate is prepared by high-temperature crystallization; the crystallization residual liquid is passed through the phosphoric acid regeneration-evaporation concentration process to realize the regeneration cycle of the initial phosphoric acid. The method has a short process flow, no additional neutralizer, precipitant and acid introduction, low cost, and is environmentally friendly; high-purity iron phosphate can be prepared, which can be used in the preparation of materials such as lithium-ion batteries, ceramics, and catalysts. high value.

The purpose of the present invention is achieved through the following technical solutions:

A method for preparing high-purity iron phosphate from lithium iron phosphate battery waste, comprising the following steps:

(1) Lithium extraction by oxidation: add oxidant and low-concentration organic acid to the lithium iron phosphate battery waste to be treated, and separate the solid and liquid after the reaction to obtain a lithium-rich leaching solution and a leaching residue whose main phase is iron phosphate;

(2) Concentrated phosphoric acid dissolves iron: add high-concentration phosphoric acid to the aforementioned leaching slag, after the reaction finishes, solid-liquid separation is obtained to obtain insoluble matter and leachate;

(3) high-temperature crystallization: add water to the leachate described in step (2) to dilute, then add ferric phosphate seed crystals and a surfactant, complete the crystallization of ferric phosphate at high temperature, and separate solid-liquid to obtain crystallization residue and crystallization product, After the crystalline product is dried, ferric phosphate is obtained;

(4) Phosphoric acid regeneration: adopt membrane separation process to treat the crystallization residual liquid described in step (3), control the temperature and pressure of phosphoric acid feed and the flow rate of phosphoric acid produced, and obtain phosphoric acid that is initially concentrated to a mass fraction of 40-60%;

(5) Concentration by evaporation: the phosphoric acid obtained in step (4) is further concentrated by an evaporation concentration process to obtain regenerated phosphoric acid, which is returned to step (2) for recycling.

Further, the lithium iron phosphate battery waste in step (1) includes one or more of waste lithium iron phosphate batteries, spent pole pieces, and lithium iron phosphate waste.

Further, the oxidant in step (1) includes hydrogen peroxide or oxygen.

Further, the organic acid described in step (1) includes one or more of citric acid, tartaric acid and malic acid.

Further, the concentration of phosphoric acid described in step (2) is 3-6mol/L.

Further, the solid-to-liquid ratio of concentrated phosphoric acid dissolved iron described in step (2) is 1:4-1:10g/mL, the reaction temperature is controlled at 70-95°C, the stirring speed is set at 300-500rpm, and the reaction time is 0.5-5h.

Further, the amount of water added in step (3) is 1-4 times the volume of the leaching solution, and the pH control range is 1.2-2.6.

Further, the added amount of the iron phosphate seed in step (3) is 10-50% of the mass fraction of the iron content in the leaching solution described in step (2).

Further, the type of surfactant described in step (3) includes one of CTAB, SDS, and SDBS, and the added amount is 0.1-0.5% of the mass fraction of the iron content in the leaching solution described in step (2).

Further, the crystallization temperature in step (3) is 85-95° C., the time is 1-12 hours, and the stirring speed is 150-400 rpm.

Further, the crystallized product in step (3) was dried in an oven at 60° C. for 8 hours to obtain iron phosphate.

Further, the membrane separation process in step (4) includes one or more combined processes of microfiltration, ultrafiltration, nanofiltration, bipolar membrane, reverse dialysis, and electrodialysis.

Further, the temperature of the phosphoric acid feed in step (4) is 25-75° C., the pressure of the phosphoric acid feed is 1.2-4.0 MPa, and the flow rate of phosphoric acid produced is controlled at 40-150 L/h.

Further, the evaporation and concentration process described in step (5) adopts MVR evaporator or multi-effect evaporator, and the mass fraction of phosphoric acid after concentration is 65-85%.

The realization principle of technical scheme of the present invention is as follows:

In the step (2) of the method of the present invention, concentrated phosphoric acid dissolved iron reacts with ferric phosphate in the leaching slag of oxidative lithium extraction to generate iron phosphate through high-concentration phosphoric acid, so as to realize the efficient separation of iron dissolution and other impurities. for:

2FePO ₄ +H ₃ PO ₄ →Fe ₂ HPO ₄ ⁴⁺ +2HPO ₄ ^2- (2)

FePO ₄ +H ₃ PO ₄ →FeHPO ₄ ⁺ +H ₂ PO ₄ ^- (3)

In step (3), crystallize in the range of 1.2≦pH≦2.6, and realize the preparation of high-purity iron phosphate by utilizing the characteristics of low solubility and easy precipitation of iron phosphate at high temperature. The mass fraction range of iron content in the prepared iron phosphate is 29.2-30%, and the mass fraction of phosphorus content is 16.5-17%. The main reactions that take place are:

In step (4), when phosphoric acid is regenerated, membrane separation technology is used to remove impurity elements by utilizing the separation properties of different membranes, which can be used for lithium extraction operations, further improving the comprehensive economic benefits of the present invention.

It can be seen from the above technical scheme that the scheme for preparing high-purity iron phosphate from lithium iron phosphate battery waste provided by the present invention effectively separates and enriches valuable metal lithium, and utilizes the characteristics of iron phosphate being soluble in high-concentration phosphoric acid and The property that the solubility of iron phosphate decreases when the temperature rises realizes the dissolution of iron in lithium iron phosphate battery waste and the preparation of high-purity iron phosphate. The crystallization residual liquid can also be regenerated and recycled as the leaching agent phosphoric acid through phosphoric acid regeneration-evaporative concentration. The method flexibly utilizes the dissolution characteristics of iron phosphate, only needs a small amount of supplementary phosphoric acid in the whole process, and no other reagents are introduced, so as to realize the efficient and economical recycling of lithium iron phosphate battery waste, the process is simple, the resource utilization rate is high, and the impact on the environment is small. The present invention flexibly utilizes the solubility characteristics of lithium iron phosphate in high-concentration phosphoric acid and the property that the solubility of iron phosphate decreases with the increase of temperature, and solves the problems of environmental pollution and resource waste caused by lithium iron phosphate battery waste, and is an excellent solution for lithium iron phosphate battery waste. Efficient and economical recycling offers new ideas.

Compared with the prior art, the technical solution of the present invention has the following technical advantages or positive effects:

(1) The method raw material adaptability of the present invention is strong, waste and old lithium iron phosphate battery, waste pole piece, lithium iron phosphate scrap etc. can all be used as the raw material in the technical scheme of the present invention;

(2) The method of the present invention consumes less reagents, does not need additional neutralizers and precipitants, and can simultaneously achieve efficient separation and enrichment of valuable metal lithium;

(3) The present invention makes full use of the iron and phosphorus resources in the lithium iron phosphate waste to produce high-purity iron phosphate, the whole process of phosphoric acid can be regenerated and recycled, the amount of phosphoric acid supplemented is very small, the process cost is low, and the degree of environmental friendliness is high;

(4) The technical process of the present invention is simple, the iron phosphate product has high added value, and is suitable for the recovery and treatment of bulk lithium iron phosphate battery waste.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings on the premise of not paying creative work.

Fig. 1 is a process flow chart of preparing high-purity iron phosphate from lithium iron phosphate battery waste according to the present invention.

Fig. 2 is a microscopic morphology diagram of iron phosphate prepared in Example 1 of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the implementation manners of the present invention will be further described in detail below.

Example 1

As shown in Figure 1, a method for preparing high-purity iron phosphate from lithium iron phosphate battery waste includes: adding hydrogen peroxide and a small amount of tartaric acid to lithium iron phosphate battery waste to complete oxidation and lithium extraction to obtain lithium-rich leachate and leaching residue ; then add 4mol/L of phosphoric acid to the leaching residue, the solid-liquid ratio is: 1:4g/mL, the reaction temperature is controlled at 85°C, the time is 2h, and the stirring speed is set at 500rpm; solid-liquid separation, to obtain insolubles and Leachate. Add 1 times the volume of water to the leaching solution for dilution, maintain the pH of the system at 1.2, add 10% ferric phosphate as a seed crystal and CTAB with an iron content of 0.1% as a surfactant, crystallization temperature is 95 ° C, and the time is 6 hours , the stirring speed was 150rpm; after the crystallization, solid-liquid separation was carried out, and the crystallized product was dried in an oven at 60°C for 8 hours to obtain ferric phosphate dihydrate. The microscopic appearance of the prepared ferric phosphate is shown in Figure 2. Phosphoric acid is regenerated by ultrafiltration-bipolar membrane-electrodialysis combined process. The regeneration conditions are as follows: the temperature of phosphoric acid feed is 75°C, the pressure of phosphoric acid feed is 4.0MPa, the flow rate of phosphoric acid produced is 150L/h, and the concentration of phosphoric acid is 45%. . The removal of large particle size impurity ions is achieved by ultrafiltration, and then the high-efficiency separation of lithium ions and the initial concentration of phosphoric acid are achieved by combining electrodialysis with bipolar membranes. The phosphoric acid prepared by membrane separation is evaporated and concentrated by a multi-effect evaporator to obtain phosphoric acid with a concentration of 65%, which can be continuously recycled.

Example 2

As shown in Figure 1, a method for preparing high-purity iron phosphate from lithium iron phosphate battery waste includes: adding a small amount of citric acid to the lithium iron phosphate battery waste and introducing oxygen to complete oxidation and extraction of lithium to obtain lithium-rich leaching solution and leaching slag; then add 5mol/L phosphoric acid to the leaching residue, the solid-liquid ratio is: 1:6g/mL, the reaction temperature is controlled at 90°C, the time is 4h, and the stirring speed is set at 500rpm; solid-liquid separation to obtain insoluble matter and leachate. Add 1 times the volume of water to the leaching solution for dilution, maintain the pH of the system at 1.8, add 20% ferric phosphate as a seed crystal and SDBS with an iron content of 0.5% as a surfactant, and crystallize at 95°C for 12 hours , the stirring speed is 150rpm; after the crystallization is completed, the solid-liquid separation is carried out, and the crystallized product is dried in an oven at 60° C. for 8 hours to obtain ferric phosphate dihydrate. The iron content in the ferric phosphate is 29.6%, and the phosphorus content is 16.5%. Phosphoric acid is regenerated by combined process of ultrafiltration and nanofiltration in the crystallization residual liquid. The regeneration conditions are as follows: the temperature of phosphoric acid feed is 30°C, the pressure of phosphoric acid feed is 1.8MPa, the flow rate of phosphoric acid produced is 120L/h, and the concentration of phosphoric acid is 40%. Ultrafiltration is used to remove large particle size impurity ions, and then nanofiltration technology is used to purify and concentrate phosphoric acid. Phosphoric acid prepared by membrane separation is evaporated and concentrated by MVR evaporator to obtain phosphoric acid with a concentration of 85%, which can be continuously recycled.

Example 3

As shown in Figure 1, a method for preparing high-purity iron phosphate from lithium iron phosphate battery waste includes: adding hydrogen peroxide and a small amount of citric acid to lithium iron phosphate battery waste to complete oxidation and extraction of lithium to obtain lithium-rich leaching solution and leaching slag; then add 6mol/L phosphoric acid to the leaching residue, the solid-liquid ratio is: 1:8g/mL, the reaction temperature is controlled at 70°C, the time is 5h, and the stirring speed is set at 400rpm; solid-liquid separation, to obtain insoluble and leachate. Add 4 times the volume of water to the leachate for dilution, maintain the pH of the system at 2.6, add 50% ferric phosphate as a seed crystal and SDBS with an iron content of 0.2% as a surfactant, and crystallize at 90°C for 1 hour , the stirring speed is 300rpm; after the crystallization is completed, the solid and liquid are separated, and the crystallized product is dried in an oven at 60° C. for 8 hours to obtain ferric phosphate dihydrate. The crystallization residual liquid adopts the nanofiltration process to remove impurity elements to realize the regeneration of phosphoric acid. The regeneration conditions are: the temperature of the input phosphoric acid is 25°C, the pressure of the input phosphoric acid is 2.5MPa, the flow rate of the produced phosphoric acid is 80L/h, and the concentration of phosphoric acid is 60%. Phosphoric acid prepared by membrane separation is evaporated and concentrated by MVR evaporator to obtain phosphoric acid with a concentration of 85%, which can be continuously recycled.

Example 4

As shown in Figure 1, a method for preparing high-purity iron phosphate from lithium iron phosphate battery waste includes: adding hydrogen peroxide and a small amount of malic acid to lithium iron phosphate battery waste to complete oxidation and extraction of lithium to obtain lithium-rich leaching solution and leaching slag; then add 3mol/L phosphoric acid to the leaching residue, the solid-liquid ratio is: 1:10g/mL, the reaction temperature is controlled at 95°C, the time is 0.5h, and the stirring speed is set at 350rpm; solid-liquid separation, insoluble substances and extracts. Add 3 times the volume of water to the leachate for dilution, maintain the pH of the system at 1.5, add 40% ferric phosphate as a seed crystal and SDS with an iron content of 0.4% as a surfactant, crystallization temperature is 90 ° C, and the time is 6 h , the stirring speed is 400rpm; after the crystallization is completed, the solid and liquid are separated, and the crystallized product is dried in an oven at 60° C. for 8 hours to obtain ferric phosphate dihydrate. Phosphoric acid is regenerated by bipolar membrane-electrodialysis combined process for crystallization residual liquid. The regeneration conditions are as follows: inlet phosphoric acid temperature is 60°C, inlet phosphoric acid pressure is 1.2MPa, phosphoric acid production flow rate is 40L/h, and phosphoric acid concentration is 60%. Under the action of an electric field, lithium ions and phosphate radicals are separated efficiently. The phosphoric acid prepared by membrane separation is evaporated and concentrated by a multi-effect evaporator to obtain phosphoric acid with a concentration of 85%, which can be continuously recycled.

Example 5

As shown in Figure 1, a method for preparing high-purity iron phosphate from lithium iron phosphate battery waste includes: adding a small amount of tartaric acid to the lithium iron phosphate battery waste and introducing oxygen to complete oxidation and lithium extraction to obtain lithium-rich leaching solution and leaching residue ; Then add 6mol/L phosphoric acid to the leaching residue, the solid-liquid ratio is: 1:10g/mL, the reaction temperature is controlled at 90°C, the time is 1h, and the stirring speed is set at 300rpm; solid-liquid separation, to obtain insolubles and Leachate. Add 2 times the volume of water to the leaching solution for dilution, maintain the pH of the system at 2.2, add 40% ferric phosphate as a seed crystal and CTAB with an iron content of 0.5% as a surfactant, and crystallize at 85°C for 6 hours , the stirring speed is 200rpm; after the crystallization is completed, the solid and liquid are separated, and the crystallized product is dried in an oven at 60° C. for 8 hours to obtain ferric phosphate dihydrate. The iron content in the ferric phosphate is 29.8%, and the phosphorus content is 16.6%. Phosphoric acid is regenerated by combined process of reverse dialysis and ultrafiltration in crystallization residual liquid. The regeneration conditions are as follows: the temperature of feed phosphoric acid is 30°C, the pressure of feed phosphoric acid is 3.0MPa, the flow rate of phosphoric acid produced is 130L/h, and the concentration of phosphoric acid is 54%. Phosphoric acid prepared by membrane separation is evaporated and concentrated by MVR evaporator to obtain phosphoric acid with a concentration of 85%, which can be continuously recycled.

In summary, the embodiment of the present invention uses high-concentration phosphoric acid to treat lithium iron phosphate battery waste to realize the dissolution of iron in lithium iron phosphate battery waste, high-temperature crystallization of the leaching solution to prepare high-purity iron phosphate, and the crystallization residual liquid to realize phosphoric acid through the phosphoric acid regeneration-evaporation concentration process. The regeneration and recycling utilization of the whole process does not require the introduction of neutralizers and precipitants. At the same time, the valuable metal lithium is efficiently separated and enriched, which provides a new idea for the efficient utilization and industrial application of lithium iron phosphate battery waste.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (8)

1. The method for preparing high-purity iron phosphate from the lithium iron phosphate battery waste is characterized by comprising the following steps of:

(1) And (3) oxidizing to extract lithium: adding an oxidant and low-concentration organic acid into the lithium iron phosphate battery waste to be treated, and performing solid-liquid separation after the reaction is finished to obtain a lithium-rich leaching solution and leaching residues of which the main phase is iron phosphate;

(2) Concentrated phosphoric acid dissolved iron: adding high-concentration phosphoric acid into the leaching residue, and after the reaction is finished, carrying out solid-liquid separation to obtain insoluble substances and a leaching solution;

the concentration of the phosphoric acid in the step (2) is 3-6mol/L; the solid-liquid ratio of the concentrated phosphoric acid soluble iron is 1:4-1, 10g/mL, the reaction temperature is controlled to be 70-95 ℃, the stirring speed is set to be 300-500rpm, and the reaction time is 0.5-5h;

(3) High-temperature crystallization: adding water into the leachate obtained in the step (2) for dilution, then adding iron phosphate seed crystals and a surfactant, completing crystallization of iron phosphate at high temperature, carrying out solid-liquid separation to obtain a crystallization residual liquid and a crystallization product, and drying the crystallization product to obtain iron phosphate;

the adding amount of water in the step (3) is 1-4 times of the volume of the leachate, and the pH control range is 1.2-2.6; the addition amount of the iron phosphate seed crystal is 10-50% of the mass fraction of the iron content in the leachate obtained in the step (2); the type of the surfactant comprises one of CTAB, SDS and SDBS, and the addition amount of the surfactant is 0.1-0.5% of the mass fraction of the iron content in the leachate obtained in the step (2);

(4) Regeneration of phosphoric acid: treating the crystallized residual liquid in the step (3) by adopting a membrane separation process, and controlling the temperature and pressure of phosphoric acid feeding and the flow rate of phosphoric acid production to obtain phosphoric acid which is preliminarily concentrated to 40-60% in mass fraction;

(5) And (3) evaporation and concentration: and (3) further concentrating the phosphoric acid obtained in the step (4) by adopting an evaporation concentration process to obtain regenerated phosphoric acid, and returning to the step (2) for recycling.

2. The method for preparing high-purity iron phosphate from the waste lithium iron phosphate batteries according to claim 1, wherein the waste lithium iron phosphate batteries in the step (1) comprise one or more of waste lithium iron phosphate batteries, waste pole pieces and waste lithium iron phosphate.

3. The method for preparing high-purity iron phosphate from lithium iron phosphate battery waste according to claim 1, wherein the oxidizing agent in step (1) comprises hydrogen peroxide or oxygen; the organic acid comprises one or more of citric acid, tartaric acid and malic acid.

4. The method for preparing high-purity iron phosphate from the lithium iron phosphate battery waste according to claim 1, wherein the crystallization temperature in the step (3) is 85-95 ℃, the crystallization time is 1-12 hours, and the stirring speed is 150-400rpm.

5. The method for preparing high-purity iron phosphate from the lithium iron phosphate battery waste material as claimed in claim 1, wherein the crystalline product obtained in the step (3) is dried in an oven at 60 ℃ for 8 hours to obtain the iron phosphate.

6. The method for preparing high-purity iron phosphate from the lithium iron phosphate battery waste material as claimed in claim 1, wherein the membrane separation process in the step (4) comprises one or more combined processes of microfiltration, ultrafiltration, nanofiltration, bipolar membrane, reverse dialysis and electrodialysis.

7. The method for preparing high-purity iron phosphate from the lithium iron phosphate battery waste material as claimed in claim 1, wherein the phosphoric acid feeding temperature in the step (4) is 25-75 ℃, the phosphoric acid feeding pressure is 1.2-4.0MPa, and the flow rate of the generated phosphoric acid is controlled to be 40-150L/h.

8. The method for preparing high-purity iron phosphate from the lithium iron phosphate battery wastes as claimed in claim 1, wherein the evaporation concentration process in the step (5) adopts an MVR evaporator or a multi-effect evaporator, and the mass fraction of the concentrated phosphoric acid is 65-85%.

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