A method for full-component recovery of lithium iron phosphate battery powder

Abstract

This invention discloses a method for the complete recovery of lithium manganese iron phosphate (LFP) battery powder. The method involves mixing LFP battery powder with a graphite content of 15-30% with water to form a slurry, then adding sodium persulfate solution for oxidative leaching. The leaching is filtered to obtain a leachate and ferromanganese leaching residue. The ferromanganese leaching residue is then mixed with ferrous salt and an acid solution to form a slurry, and filtered to obtain an acid leaching solution and graphite residue. Ferric phosphate and manganese dioxide are precipitated stepwise in the acid leaching solution, and the precipitate product and phosphorus-containing filtrate are obtained by filtration. The pH of the leachate is adjusted to obtain a purified filtrate, which is then added with sodium carbonate solution to precipitate lithium, yielding a lithium carbonate product and a lithium precipitation mother liquor. The lithium precipitation mother liquor and phosphorus-containing filtrate are evaporated and concentrated separately to obtain a concentrated liquid and a byproduct. The concentrated liquid is then recycled to the slurrying step. This recovery method, by adding a small amount of ferrous sulfate, can activate the graphite in the LFP battery powder, ensuring lithium recovery while simultaneously increasing the recovery rates of manganese, iron, and phosphorus at low temperatures and in a short time.

Description

Technical Field

[0001] This invention belongs to the field of waste lithium battery recycling technology, and particularly relates to a method for the full-component recycling of lithium manganese iron phosphate battery powder. Background Technology

[0002] Lithium manganese iron phosphate battery (LiMn) x Fe 1-x Lithium manganese iron phosphate (LiFePO4) batteries are widely used in the power battery field due to their advantages such as low cost, high safety, and long cycle life. With the rapid development of the new energy vehicle industry, the amount of waste LiFePO4 batteries generated is increasing year by year. The recycling of lithium, manganese, iron and other metals and graphite in waste batteries can not only alleviate the resource shortage problem, but also reduce environmental pollution.

[0003] Used lithium iron phosphate batteries are classified into four grades according to their carbon content, as follows:

[0004] Category I: Low-carbon pure positive electrode material with C ≤ 10%

[0005] Source: Substandard materials from the material factory, and powder from the stripping of individual positive electrode sheets.

[0006] Characteristics: Very little graphite in the negative electrode, only carbon black coating on the positive electrode; copper and aluminum impurities <3%.

[0007] Advantages: No need for high-temperature deep decarbonization, direct acid leaching or direct repair and regeneration, highest purchase price.

[0008] Class II: Medium-carbon mixture with C=10%~18%

[0009] Source: Slightly mixed negative electrode sheets, disassembled coarsely sorted powder.

[0010] Advantages: With a small amount of graphite mixed in, the wet process can achieve mild oxidation and decarburization, resulting in moderate processing costs.

[0011] Category III: High-carbon black powder, C=18%~30%

[0012] Source: Unseparated positive and negative electrode mixed crushed material, whole bag of retired battery direct crushing powder

[0013] Characteristics: High amount of graphite anode + binder residual carbon; total copper and aluminum content 3%~8%.

[0014] Pain points: Calcination and decarburization are necessary, resulting in severe foaming, high processing costs, and significant price reductions.

[0015] Category IV: Ultra-high carbon waste (C>30%)

[0016] The negative electrode accounts for a very high proportion, and the separator and electrolyte are severely carbonized, so very little is collected and it is mostly used as a low-value co-processing ingredient.

[0017] Based on this, there is considerable existing research on Class I and Class II spent lithium iron phosphate batteries, where effective manganese and iron recovery can be achieved directly using acid leaching combined with an amount exceeding the theoretical limit of reducing agent. However, for Class III high-carbon black powder, the calcination decarbonization technology undoubtedly increases the cost of recycling and has significant side effects.

[0018] Based on this, we now have a method for recycling high-carbon waste lithium iron phosphate batteries, which turns the high carbon content into a valuable resource, and achieves large-scale, low-cost recycling, while also enabling the recycling of all components. Summary of the Invention

[0019] Purpose of the invention: The technical problem to be solved by the present invention is to turn the high carbon content of waste manganese iron lithium batteries into a valuable resource, realize a recycling method applicable to large scale and low cost, and achieve the recycling of all components.

[0020] Technical solution: The present invention provides a method for the complete component recovery of lithium manganese iron phosphate battery powder, comprising the following steps:

[0021] (1) After mixing and slurrying lithium iron phosphate battery powder with a graphite content of 15-30% with water, sodium persulfate solution is added for oxidative leaching, and the leachate and manganese iron leaching residue are obtained by filtration.

[0022] (2) The ground manganese ferromanganese leaching residue is mixed with ferrous salt and acid solution and slurried. The mixture is then reduced and acid-leached at 150-200℃ for 1-3 hours. The resulting acid leaching solution and graphite residue are obtained by filtration. The mass of the ferrous salt added is 1.5-2% of the mass of the manganese ferromanganese leaching residue.

[0023] (3) Precipitate ferric phosphate and manganese dioxide in the acid leaching solution of step (2) in stages, and filter to obtain the precipitate product and phosphorus-containing filtrate;

[0024] (4) Add liquid alkali to the leachate from step (1) to adjust the pH value, filter to obtain purified filtrate, and add sodium carbonate solution to precipitate lithium to obtain lithium carbonate product and lithium precipitation mother liquor.

[0025] (5) The lithium precipitation mother liquor from step (3) and the phosphorus-containing filtrate from step (4) are evaporated and concentrated to obtain concentrated liquid and by-products. The concentrated liquid is then recycled to the pulping step in step (1).

[0026] Furthermore, in step (1) of the recycling method, the solid-liquid ratio of the lithium manganese iron phosphate battery powder to water is 1:(2-4)g / mL.

[0027] Furthermore, in step (1) of the recycling method, the concentration of the sodium persulfate aqueous solution is 1.5-2 mol / L, and the mass of sodium persulfate added is 1-1.5 times the mass required for the theoretical oxidation of lithium manganese iron phosphate battery powder.

[0028] Furthermore, in step (1) of the recycling method, the reaction temperature of the oxidative leaching is 60-80℃ and the reaction time is 1-2h.

[0029] Furthermore, in step (2) of the recovery method, the solid-liquid ratio of the manganese iron leaching residue to the acid solution is 1:(3-5)g / mL, the acid solution is selected from sulfuric acid or hydrochloric acid, and the concentration of the acid solution is 1-1.5mol / L.

[0030] Furthermore, in step (2) of the recovery method, the ferrous salt is selected from one or more of ferrous chloride, ferrous sulfate, or ferrous acetate.

[0031] Furthermore, in step (3) of the recovery method, the precipitated iron phosphate is prepared by adding a hydrogen peroxide solution with a concentration of 0.3-0.6 mol / L at a pH of 2-3; the precipitated manganese dioxide is prepared by adding an ammonium persulfate solution with a concentration of 0.5-1 mol / L at a pH of 4-5.

[0032] Furthermore, in step (4) of the recovery method, the liquid alkali is a sodium hydroxide solution with a concentration of 2-3.5 mol / L, and the amount of sodium hydroxide solution added is such that the pH of the leachate is 6-8.

[0033] Furthermore, in step (4) of the recovery method, the concentration of the sodium carbonate solution is 2-2.5 mol / L, the reaction temperature of adding the sodium carbonate solution is 80-90℃, and the reaction time is 1-1.5h.

[0034] Furthermore, in step (5) of the recovery method, the evaporation temperature for the evaporation concentration is 80-100℃.

[0035] Beneficial effects: Compared with the prior art, the significant advantages of the present invention are as follows:

[0036] (1) By adding a small amount of reducing agent ferrous sulfate, the recovery method can fully activate the manganese and iron in lithium iron phosphate battery powder with a graphite content of 15-30%, ensuring that the lithium recovery rate is higher than 90%, while achieving a manganese recovery rate of 93.7%, an iron recovery rate of 94.5%, and a phosphorus recovery rate of 82% at low temperature and in a short time.

[0037] (2) This recycling method is low-consumption and environmentally friendly. The resulting lithium mother liquor and phosphorus-containing filtrate are reused after evaporation and concentration, achieving a process water reuse rate of 85%. The by-products anhydrous sodium sulfate and phosphoric acid can be used as industrial raw materials. The overall process is simple and does not require complex separation equipment, making it suitable for recycling applications in large-scale production lines. Detailed Implementation

[0038] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0039] In the following embodiments and comparative examples of the present invention, 100g of lithium manganese iron phosphate battery powder was weighed, and the specific composition is shown in Table 1. In the following embodiments of the present invention, the amount of sodium carbonate added was determined based on the lithium content in the lithium-rich leachate, at 1-1.2 times the amount theoretically required to generate lithium carbonate.

[0040] Table 1. Composition of Lithium Iron Manganese Phosphate Battery Powder

[0041]

[0042] Example 1

[0043] This Example 1 describes a method for the complete recovery of lithium manganese iron phosphate battery powder. The composition of the lithium manganese iron phosphate battery powder is shown in Table 1, and includes the following steps:

[0044] (1) Add 300ml of water to the lithium manganese iron phosphate battery powder according to the solid-liquid ratio of 1:3 and mix and slurry for 0.5h. Then add 150mL of Na2S2O8 aqueous solution with a concentration of 1.5 mol / L (that is, 1.5 times the mass required for theoretical oxidation of lithium manganese iron phosphate battery powder). React at 70℃ water bath temperature and stirring speed of 300rpm for 1.5h. Filter to obtain leachate and manganese iron leaching residue.

[0045] (2) After grinding the manganese ferro leaching residue, add 1.6g of ferrous sulfate and 450 mL of 1.5 mol / L H2SO4 solution and mix evenly. Then, leach at 200 rpm for 2.5 hours in a high-pressure reactor at 180℃. Filter to obtain manganese ferro acid leaching solution and graphite residue.

[0046] (3) Next, add 3 mol / L NaOH to the manganese iron acid leaching solution to adjust the pH to 2.5, and then add 350 mL of H2O2 solution with a concentration of 0.4 mol / L to obtain FePO4 precipitate.

[0047] (4) After filtration, adjust the pH to 4.5 and add 320 mL of (NH4)2S2O8 solution with a concentration of 0.8 mol / L to obtain MnO2 precipitate.

[0048] (5) After washing the graphite slag, calcine it at 550°C under a nitrogen atmosphere for 3 hours to obtain high-purity graphite.

[0049] (6) Add 3 mol / L NaOH to the leachate to adjust the pH to 7, filter to obtain purified filtrate; add 120 mL of 2.5 mol / L Na2CO3 solution (1.2 times the theoretical amount) to the filtrate, react at 85℃ for 1 hour, and filter to obtain Li2CO3.

[0050] (7) The lithium precipitation mother liquor was evaporated and concentrated at 80°C to precipitate 67.45g of anhydrous sodium sulfate, and the phosphorus-containing filtrate was evaporated and concentrated to obtain H3PO4.

[0051] Comparative Example 1

[0052] The method for recovering all components of lithium manganese iron phosphate battery powder in Comparative Example 1 is basically the same as that in Example 1, except that ferrous sulfate is not added in step (2), and the method includes the following steps:

[0053] (1) Add 300ml of water to lithium manganese iron phosphate battery powder according to the solid-liquid ratio of 1:3 and mix and slurry for 0.5h. Then add 150mL of Na2S2O8 aqueous solution with a concentration of 1.5 mol / L. React at 300rpm for 1.5h in a water bath at 70℃. Filter to obtain leachate and manganese iron leaching residue.

[0054] (2) After grinding the manganese iron leaching residue, add 450 mL of 1.5 mol / L H2SO4 solution and mix evenly. Then, leach at 200 rpm for 2.5 hours in a high-pressure reactor at 180℃. Filter to obtain manganese iron acid leaching solution and graphite residue.

[0055] (3) Next, add 3 mol / L NaOH to the manganese iron acid leaching solution to adjust the pH to 2.5, and then add 350 mL of H2O2 solution with a concentration of 0.4 mol / L to obtain FePO4 precipitate.

[0056] (4) After filtration, adjust the pH to 4.5 and add 320 mL of (NH4)2S2O8 solution with a concentration of 0.8 mol / L to obtain MnO2 precipitate.

[0057] (5) After washing the graphite slag, calcine it at 550°C under a nitrogen atmosphere for 3 hours to obtain high-purity graphite.

[0058] (6) Add 3 mol / L NaOH to the leachate to adjust the pH to 7, filter to obtain purified filtrate; add 120 mL of 2.5 mol / L Na2CO3 solution (1.2 times the theoretical amount) to the filtrate, react at 85℃ for 1 hour, and filter to obtain Li2CO3.

[0059] (7) The lithium precipitation mother liquor was evaporated and concentrated at 80°C to precipitate 66.65g of anhydrous sodium sulfate, and the phosphorus-containing filtrate was evaporated and concentrated to obtain H3PO4.

[0060] Comparative Example 2

[0061] The method for recovering all components of lithium manganese iron phosphate battery powder in Comparative Example 2 is basically the same as that in Example 1. The difference is that conventional waste lithium manganese iron phosphate battery powder is used, and the content is shown in Table 1. In step (2), the amount of ferrous sulfate added is 1.2 times the theoretical molar amount of manganese required in the manganese iron oxide leaching residue, including the following steps:

[0062] (1) Add 300ml of water to lithium manganese iron phosphate battery powder according to the solid-liquid ratio of 1:3 and mix and slurry for 0.5h. Then add 150mL of Na2S2O8 aqueous solution with a concentration of 1.5 mol / L. React at 300rpm for 1.5h in a water bath at 70℃. Filter to obtain leachate and manganese iron leaching residue.

[0063] (2) After grinding the manganese ferro leaching residue, add 103g of ferrous sulfate and 450 mL of 1.5 mol / L H2SO4 solution and mix evenly. Then, leach at 200 rpm for 2.5 hours in a high-pressure reactor at 180℃. Filter to obtain manganese ferro acid leaching solution and graphite residue.

[0064] (3) Next, add 3 mol / L NaOH to the manganese iron acid leaching solution to adjust the pH to 2.5, and then add 350 mL of H2O2 solution with a concentration of 0.4 mol / L to obtain FePO4 precipitate.

[0065] (4) After filtration, adjust the pH to 4.5 and add 320 mL of (NH4)2S2O8 solution with a concentration of 0.8 mol / L to obtain MnO2 precipitate.

[0066] (5) Add 3 mol / L NaOH to the leachate to adjust the pH to 7, filter to obtain purified filtrate; add 120 mL of 2.5 mol / L Na2CO3 solution (1.2 times the theoretical amount) to the filtrate, react at 85℃ for 1 hour, and filter to obtain Li2CO3.

[0067] (6) The lithium precipitation mother liquor was evaporated and concentrated at 80°C to precipitate 68.15 g of anhydrous sodium sulfate, and the phosphorus-containing filtrate was evaporated and concentrated to obtain H3PO4.

[0068] Example 2

[0069] Example 2 describes a method for the complete recovery of lithium manganese iron phosphate battery powder. The composition of the lithium manganese iron phosphate battery powder is shown in Table 1, and the method includes the following steps:

[0070] (1) Add 400ml of water to the lithium manganese iron phosphate battery powder according to the solid-liquid ratio of 1:4 and mix and slurry for 0.5h. Then add 150mL of Na2S2O8 solution with a concentration of 2mol / L (about 1.5 times the theoretical value), and react at 80℃ water bath temperature and 400rpm stirring speed for 1.5h. Filter to obtain leachate and manganese iron leaching residue.

[0071] (2) After grinding the manganese ferro leaching residue, add 1.57g of ferrous chloride and 350 mL of 1.0mol / L HCl solution and mix evenly. Then, leach at 200rpm for 3 hours in a high-pressure reactor at 200℃. Filter to obtain manganese ferro acid leaching solution and graphite residue.

[0072] (3) Add 3 mol / L NaOH to the manganese iron acid leaching solution to adjust the pH to 2.0, and then add 350 mL of H2O2 with a concentration of 0.4 mol / L to obtain FePO4 precipitate.

[0073] (4) After filtration, adjust the pH to 5.0 and add 250 mL of (NH4)2S2O8 solution with a concentration of 1.0 mol / L to obtain MnO2 precipitate.

[0074] (5) After washing the graphite slag, calcine it at 550°C under a nitrogen atmosphere for 2.5 hours to obtain high-purity graphite.

[0075] (6) Add 3 mol / L NaOH to the leachate to adjust the pH to 7, filter to obtain purified filtrate; add 150 mL of 2.0 mol / L Na2CO3 solution to the filtrate, react at 90℃ for 1 hour, and filter to obtain Li2CO3.

[0076] (7) The lithium precipitation mother liquor was evaporated and concentrated at 90°C to precipitate 63.13 g of anhydrous sodium sulfate, and the phosphorus-containing filtrate was evaporated and concentrated to obtain H3PO4.

[0077] Comparative Example 3

[0078] The method for recovering all components of lithium manganese iron phosphate battery powder in Comparative Example 3 is basically the same as that in Example 2, except that ferrous chloride is not added in step (2), and the method includes the following steps:

[0079] (1) Add 400ml of water to lithium manganese iron phosphate battery powder according to the solid-liquid ratio of 1:4 and mix and slurry for 0.5h. Then add 150mL of 2mol / L Na2S2O8 solution, and react at 80℃ water bath temperature and 400rpm stirring speed for 2 hours. Filter to obtain leachate and manganese iron leaching residue.

[0080] (2) After grinding the manganese ferro leaching residue, add 350 mL of 1.0 mol / L HCl solution and mix evenly. Then, leach it in a high-pressure reactor at 200℃ at 200 rpm for 3 hours. Filter to obtain manganese ferro acid leaching solution and graphite residue.

[0081] (3) Add 3 mol / L NaOH to the manganese iron acid leaching solution to adjust the pH to 2.0, and then add 350 mL of H2O2 with a concentration of 0.4 mol / L to obtain FePO4 precipitate.

[0082] (4) After filtration, adjust the pH to 5.0 and add 150 mL of (NH4)2S2O8 solution with a concentration of 1.0 mol / L to obtain MnO2 precipitate.

[0083] (5) After washing the graphite slag, calcine it at 550°C under a nitrogen atmosphere for 2.5 hours to obtain high-purity graphite.

[0084] (6) Add 3 mol / L NaOH to the leachate to adjust the pH to 7, filter to obtain purified filtrate; add 150 mL of 2.0 mol / L Na2CO3 solution to the filtrate, react at 90℃ for 1 hour, and filter to obtain Li2CO3.

[0085] (7) The lithium precipitation mother liquor was evaporated and concentrated at 90°C to precipitate 64.1 g of anhydrous sodium sulfate, and the phosphorus-containing filtrate was evaporated and concentrated to obtain H3PO4.

[0086] Example 3

[0087] Example 3 describes a method for the complete recovery of lithium manganese iron phosphate battery powder. The composition of the lithium manganese iron phosphate battery powder is shown in Table 1, and the method includes the following steps:

[0088] (1) Add 250ml of water to lithium manganese iron phosphate battery powder at a solid-liquid ratio of 1:2.5 and mix and slurry for 0.5h. Then add 120mL of Na2S2O8 aqueous solution with a concentration of 1.5 mol / L (about 1.2 times the theoretical value). The oxidative leaching temperature is 60℃ and the time is 1 hour to obtain leaching solution and manganese iron leaching residue.

[0089] (2) After grinding the manganese ferro leaching residue, add 1.46g of ferrous sulfate and 300 mL of 1mol / L H2SO4 solution and mix evenly. Then, leach at 200rpm for 2.5 hours in a high-pressure reactor at 150℃. Filter to obtain manganese ferro acid leaching solution and graphite residue.

[0090] (3) Add 3 mol / L NaOH to the manganese iron acid leaching solution to adjust the pH to 3.0, and then add 350 mL of 0.4 mol / L H2O2 to obtain FePO4 precipitate.

[0091] (4) After filtration, adjust the pH to 5.0 and add 320 mL of 0.8 mol / L (NH4)2S2O8 solution to obtain MnO2 precipitate.

[0092] (5) After washing the graphite slag clean, calcine it in air at 500°C for 2 hours to obtain high-purity graphite.

[0093] (6) Add 3 mol / L NaOH to the leachate to adjust the pH to 7, filter to obtain purified filtrate; add 120 mL of 2.5 mol / L Na2CO3 solution to the filtrate and react at 80℃ for 1 hour, filter to obtain Li2CO3.

[0094] (7) The lithium precipitation mother liquor was evaporated and concentrated at 100°C to precipitate 60.7 g of anhydrous sodium sulfate, and the phosphorus-containing filtrate was evaporated and concentrated to obtain H3PO4.

[0095] Performance testing

[0096] The quality and composition of major elements of the manganese-iron leaching residues of Examples 1-4 and Comparative Examples 1-3 are shown in Table 2, and the recovery rate and purity of phosphorus, lithium, manganese and iron elements are shown in Table 3.

[0097] Table 2. Quality and percentage of major elements in ferromanganese leaching residue.

[0098]

[0099] Table 3 Recovery rate and purity of phosphorus, lithium, manganese and iron elements

[0100]

[0101] Based on the experimental results, Examples 1 to 3 of this invention, using waste lithium manganese iron phosphate battery powder with high carbon content, achieved a several-fold increase in iron and manganese leaching rates compared to Comparative Examples 1, 2, and 3 under the same reduction leaching time by adding only a small amount of reducing agent during the acid leaching process. Analysis of these experimental results shows that in Examples 1-3, the ultrafinely ground and activated graphite (possessing a high specific surface area, abundant edge defects, and oxygen-containing functional groups), when a small amount of ferrous solution is introduced, rapidly reduces the ferric manganese in the leaching residue to ferrous iron while simultaneously reducing the ferric manganese in the acid solution. Furthermore, the ground and activated graphite has shorter electron shuttle channels (more uniform and finer particle size), allowing for faster electron transfer between the redox pairs of ferrous and ferrous iron, thereby stimulating the reduction activity of graphite under these reaction conditions.

[0102] In Comparative Examples 1 and 3, although there was ultrafine ground and activated graphite in the acid solution, there was no small amount of ferrous solution as an excitation source, so it was difficult to activate the reduction activity of graphite, resulting in a low manganese-iron extraction rate.

[0103] In Comparative Example 2, when only ferrous sulfate (1.2 times the theoretical amount of manganese and iron in the slag) was added to the acid solution, the ferric iron content in the solution continuously increased while leaching and reducing tetravalent manganese. 3+It readily hydrolyzes to form Fe(OH)3 colloid or flavonoid iron alum, which instead covers the surface of unreacted phosphorus-iron-manganese slag, forming a dense passivation layer that results in poor leaching performance and requires more time for reduction acid leaching.

[0104] In addition to the above embodiments, it should be noted that the process and process parameters set by the present invention can achieve the technical effects claimed by the present invention, and therefore no further testing and verification are required.

Claims

1. A method for the complete component recovery of lithium iron phosphate battery powder, characterized in that, Includes the following steps: (1) After mixing and slurrying lithium iron phosphate battery powder with a graphite content of 15-30% with water, sodium persulfate solution is added for oxidative leaching, and the leachate and manganese iron leaching residue are obtained by filtration. (2) The ground manganese ferromanganese leaching residue is mixed with ferrous salt and acid solution and slurried. The mixture is then reduced and acid-leached at 150-200℃ for 1-3 hours. The resulting acid leaching solution and graphite residue are obtained by filtration. The mass of the ferrous salt added is 1.5-2% of the mass of the manganese ferromanganese leaching residue. (3) Precipitate ferric phosphate and manganese dioxide in the acid leaching solution of step (2) in stages, and filter to obtain the precipitate product and phosphorus-containing filtrate; (4) Add liquid alkali to the leachate from step (1) to adjust the pH value, filter to obtain purified filtrate, and add sodium carbonate solution to precipitate lithium to obtain lithium carbonate product and lithium precipitation mother liquor. (5) The lithium precipitation mother liquor from step (3) and the phosphorus-containing filtrate from step (4) are evaporated and concentrated to obtain concentrated liquid and by-products. The concentrated liquid is then recycled to the pulping step in step (1).

2. The method for full-component recovery of lithium manganese iron phosphate battery powder according to claim 1, characterized in that, In step (1), the solid-liquid ratio of the lithium manganese iron phosphate battery powder to water is 1:(2-4)g / mL.

3. The method for full-component recovery of lithium manganese iron phosphate battery powder according to claim 1, characterized in that, In step (1), the concentration of the sodium persulfate aqueous solution is 1.5-2 mol / L, and the mass of sodium persulfate added is 1-1.5 times the mass required for the theoretical oxidation of lithium manganese iron phosphate battery powder.

4. The method for full-component recovery of lithium manganese iron phosphate battery powder according to claim 1, characterized in that, In step (1), the reaction temperature of the oxidative leaching is 60-80℃ and the reaction time is 1-2h.

5. The method for full-component recovery of lithium manganese iron phosphate battery powder according to claim 1, characterized in that, In step (2), the solid-liquid ratio of the manganese iron leaching residue to the acid solution is 1:(3-5)g / mL, the acid solution is selected from sulfuric acid or hydrochloric acid, and the concentration of the acid solution is 1-1.5mol / L.

6. The method for full-component recovery of lithium manganese iron phosphate battery powder according to claim 1, characterized in that, In step (2), the ferrous salt is selected from one or more of ferrous chloride, ferrous sulfate or ferrous acetate.

7. The method for full-component recovery of lithium manganese iron phosphate battery powder according to claim 1, characterized in that, In step (3), the precipitated iron phosphate is prepared by adding a hydrogen peroxide solution with a concentration of 0.3-0.6 mol / L at a pH of 2-3; the precipitated manganese dioxide is prepared by adding an ammonium persulfate solution with a concentration of 0.5-1 mol / L at a pH of 4-5.

8. The method for full-component recovery of lithium manganese iron phosphate battery powder according to claim 1, characterized in that, In step (4), the liquid alkali is a sodium hydroxide solution with a concentration of 2-3.5 mol / L, and the amount of sodium hydroxide solution added is such that the pH of the leachate is 6-8.

9. The method for full-component recovery of lithium manganese iron phosphate battery powder according to claim 1, characterized in that, In step (4), the concentration of the sodium carbonate solution is 2-2.5 mol / L, the reaction temperature of adding the sodium carbonate solution is 80-90℃, and the reaction time is 1-1.5h.

10. The method for full-component recovery of lithium manganese iron phosphate battery powder according to claim 1, characterized in that, In step (5), the evaporation temperature for the evaporation concentration is 80-100℃.

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