Method for regenerating waste lithium ion battery positive electrode material resource

Abstract

The invention belongs to the technical field of lithium iron phosphate recovery, and relates to a method for regenerating a waste lithium ion battery positive electrode material resource. The invention discloses a waste lithium ion battery positive electrode material resource regeneration method, which comprises: carrying out mixing stirring reaction on roasted pretreated positive electrode black powder and a phytic acid-hydrogen peroxide system, and carrying out filtration separation to obtain solid residue and a lithium-containing leachate; mixing the solid residues with phosphoric acid, heating to react, and calcining to obtain battery-grade iron phosphate; and carrying out secondary precipitation and thermal crystallization on the lithium-containing leachate to obtain the battery-grade lithium carbonate. According to the method, the waste lithium iron phosphate battery positive electrode material is treated by adopting a phytic acid-hydrogen peroxide system, and valuable metal elements are efficiently recycled; and battery-grade iron phosphate and battery-grade lithium carbonate are obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium iron phosphate recovery and relates to a method for regenerating waste lithium-ion battery positive electrode material resources. Background Art

[0002] As the global demand for clean energy and electric vehicles continues to rise, lithium iron phosphate (LiFePO4) batteries are widely used in electric vehicles, energy storage systems and portable electronic devices due to their excellent performance and high safety. However, with the large-scale production and use of these batteries, how to effectively recycle and dispose of waste batteries has become an increasingly important issue. The recycling of lithium iron phosphate batteries is not only about the reuse of resources, but also involves environmental protection and sustainable development.

[0003] At present, the recycling of waste lithium iron phosphate batteries mainly adopts mechanical treatment, heat treatment and hydrometallurgy. Mechanical treatment methods can partially recover the materials in the battery through physical crushing and sorting, but it is difficult to effectively extract the metal ions therein; although heat treatment methods such as roasting can recover metals, they face environmental challenges due to high energy consumption and high pollution; hydrometallurgical technology can efficiently extract valuable metals in batteries at lower temperatures and is considered to be one of the most promising recycling methods. However, traditional hydrometallurgical processes usually rely on strong acids such as sulfuric acid or hydrochloric acid as leaching agents. These acidic reagents are highly corrosive, easily cause harm to the environment, and require special equipment and treatment measures to ensure safety. Summary of the invention

[0004] The purpose of the present invention is to address the above-mentioned problems existing in the prior art and to propose a method for regenerating waste lithium-ion battery positive electrode material resources based on a phytic acid-hydrogen peroxide system, which can obtain battery-grade iron phosphate and battery-grade lithium carbonate.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A method for regenerating waste lithium-ion battery positive electrode material resources comprises: mixing and stirring the roasted pretreated positive electrode black powder with a phytic acid-hydrogen peroxide system to react, filtering and separating to obtain a solid residue and a lithium-containing leaching solution; mixing the solid residue with phosphoric acid, heating and reacting, and calcining to obtain battery-grade iron phosphate; and subjecting the lithium-containing leaching solution to secondary precipitation and thermal crystallization to obtain battery-grade lithium carbonate.

[0007] Preferably, in the phytic acid-hydrogen peroxide system, the volume ratio of the phytic acid aqueous solution with a mass fraction of 0.1 to 5% and the hydrogen peroxide aqueous solution with a mass fraction of 10 to 40% is 100:(1 to 10).

[0008] Preferably, the preparation process of the battery-grade lithium carbonate comprises: mixing a lithium-containing leaching solution with a precipitant for precipitation, filtering to obtain a first filtrate, introducing carbon dioxide gas into the first filtrate for precipitation, filtering to obtain a second filtrate, and thermally crystallizing the second filtrate to obtain battery-grade lithium carbonate.

[0009] Preferably, the method comprises:

[0010] (1) calcining the positive electrode black powder under an inert atmosphere to obtain pretreated positive electrode black powder;

[0011] (2) mixing a phytic acid aqueous solution with a mass fraction of 0.1 to 5% and a hydrogen peroxide aqueous solution with a mass fraction of 10 to 40% in a volume ratio of 100:(1 to 10) to obtain a phytic acid-hydrogen peroxide system;

[0012] (3) adding the pretreated positive electrode black powder to the phytic acid-hydrogen peroxide mixture in (2), and stirring the mixture at a constant temperature of 10 to 80° C. for 1 to 12 hours;

[0013] (4) After the reaction is completed, filtering and separating the solid residue and the lithium-containing leachate;

[0014] (5) mixing the solid residue with phosphoric acid, heating and reacting, and calcining to obtain battery-grade iron phosphate;

[0015] (6) After the lithium-containing leaching solution is mixed with a precipitant for precipitation, the first filtrate is obtained by filtering, carbon dioxide gas is introduced into the first filtrate for precipitation, and the second filtrate is obtained by filtering, and the second filtrate is crystallized by thermal precipitation to obtain battery-grade lithium carbonate.

[0016] Preferably, the method comprises:

[0017] (1) discharging, disassembling and crushing waste lithium iron phosphate batteries to obtain positive electrode black powder; calcining the positive electrode black powder at 100 to 280° C. under an inert atmosphere to obtain pretreated positive electrode black powder;

[0018] (2) mixing a phytic acid aqueous solution with a mass fraction of 0.1 to 5% and a hydrogen peroxide aqueous solution with a mass fraction of 10 to 40% in a volume ratio of 100:(1 to 10) to obtain a phytic acid-hydrogen peroxide system;

[0019] (3) adding the pretreated positive electrode black powder to the phytic acid-hydrogen peroxide mixture in (2) at a solid-liquid ratio of 50 to 500 g / L, stirring at a constant temperature of 10 to 50° C. for 1 to 8 hours at a stirring speed of 200 to 1000 rpm;

[0020] (4) After the reaction is completed, filtering and separating the solid residue and the lithium-containing leachate;

[0021] (5) mixing the solid residue with phosphoric acid, heating and reacting, and calcining to obtain battery-grade iron phosphate;

[0022] (6) After the lithium-containing leaching solution is mixed with a precipitant for precipitation, the first filtrate is obtained by filtering, carbon dioxide gas is introduced into the first filtrate for precipitation, and the second filtrate is obtained by filtering, and the second filtrate is crystallized by thermal precipitation to obtain battery-grade lithium carbonate.

[0023] Preferably, the mass fraction of the phytic acid aqueous solution in (1) is 0.5-2%.

[0024] Preferably, the calcination reaction temperature in (1) is 180-220° C. and the time is 1-10 h.

[0025] Preferably, the volume ratio of the phytic acid aqueous solution with a mass fraction of 0.5-2% to the hydrogen peroxide aqueous solution with a mass fraction of 30% in (2) is 100:(3-10).

[0026] Preferably, the constant temperature stirring reaction temperature in (3) is 10 to 39° C., and the time is 1 to 6 hours.

[0027] More preferably, the constant temperature stirring reaction temperature in (3) is 20 to 30° C. and the time is 2 to 3 h.

[0028] Preferably, the constant temperature stirring reaction in (3) is carried out in air at normal pressure.

[0029] Preferably, the constant temperature stirring reaction in (3) is carried out under pressure in an oxygen atmosphere.

[0030] More preferably, the pressurization pressure is 0.1 to 5 MPa.

[0031] Further preferably, in (3), the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixture in (2) with a solid-liquid ratio of 50 to 500 g / L, placed in an oxygen atmosphere and pressurized to 0.1 to 5 MPa, and stirred at a constant temperature of 10 to 38° C. for 1 to 8 hours, with a stirring speed of 200 to 1000 rpm.

[0032] Preferably, the lithium leaching rate in the lithium-containing leaching solution in (4) is ≥90%.

[0033] More preferably, the lithium leaching rate in the lithium-containing leaching solution in (4) is ≥92%.

[0034] More preferably, the lithium leaching rate in the lithium-containing leaching solution in (4) is ≥96%.

[0035] Preferably, the mass ratio of the solid residue to phosphoric acid in (5) is 1:(0.1-5).

[0036] More preferably, the mass ratio of the solid residue to the phosphoric acid in (5) is 1:(0.8-3)

[0037] Preferably, the heating reaction temperature in (5) is 70 to 94° C. and the time is 1 to 20 hours.

[0038] Preferably, the calcination in (5) is carried out in an inert gas, the calcination temperature is 550-800° C., and the calcination time is 1-8 hours.

[0039] More preferably, the purity of the battery-grade iron phosphate is ≥99.5%.

[0040] More preferably, the recovery rate of the battery-grade iron phosphate is ≥90%.

[0041] Preferably, the precipitant in (6) comprises one or both of calcium oxide and calcium hydroxide.

[0042] More preferably, 1 to 10 g of precipitant is added to every 100 ml of lithium-containing leaching solution.

[0043] More preferably, the recovery rate of lithium is ≥80%.

[0044] Preferably, in said (6), 3 to 10 g of calcium oxide is added to every 100 ml of leachate, and after complete precipitation, the first filtrate is separated by filtering, and carbon dioxide gas is continuously introduced into the first filtrate, and after complete precipitation, the second filtrate is separated by filtering, and the second filtrate is thermally crystallized at 100 to 140° C., and the solid is filtered out, washed with hot water and then dried to obtain battery-grade lithium carbonate.

[0045] More preferably, the recovery rate of lithium is ≥90%.

[0046] More preferably, the purity of the battery-grade lithium carbonate is ≥99.5%.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. The present invention uses a phytic acid-hydrogen peroxide system to treat the positive electrode material of waste lithium iron phosphate batteries, and efficiently recovers valuable metal elements in the waste lithium iron phosphate batteries.

[0049] 2. In the phytic acid-hydrogen peroxide system adopted in the present invention, phytic acid as an organic acid can effectively complex metal ions, while hydrogen peroxide as an oxidant can promote the dissolution and leaching of metals, and phytic acid can inhibit the decomposition of hydrogen peroxide, thereby reducing the amount of hydrogen peroxide used.

[0050] 3. The leaching process of the present invention is carried out at room temperature or medium to low temperature conditions, without the need for high temperature and high pressure operations. Compared with traditional heat treatment and hydrometallurgical processes, energy consumption is greatly reduced.

[0051] 4. The method for regenerating waste lithium-ion battery positive electrode material resources of the present invention realizes selective lithium extraction.

[0052] 5. The method for regenerating waste lithium-ion battery positive electrode material resources of the present invention can obtain battery-grade iron phosphate and battery-grade lithium carbonate. DETAILED DESCRIPTION

[0053] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0054] Unless otherwise specified, the materials used in the present invention are conventional commercial products, and the methods used are conventional technical means.

[0055] In this paper, the lithium leaching rate is calculated as follows:

[0056]

[0057] Where x represents the leaching rate of lithium, m1 is the mass of solid residue, m2 is the mass of raw material, ω1% is the percentage of lithium content in the solid residue detected by ICP, and ω2% is the percentage of lithium content in the raw material.

[0058] Example 1

[0059] Discharge, disassemble and crush waste lithium iron phosphate batteries to obtain positive electrode black powder; calcine the black powder at 210°C under an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder, which comprises: 4.13% lithium, 18.33% phosphorus and 32.71% iron; mix 100ml of a phytic acid aqueous solution with a mass fraction of 1% and 3ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% to obtain a phytic acid-hydrogen peroxide system; add 10g of the pretreated positive electrode black powder to the phytic acid-hydrogen peroxide mixed solution, stir and react at a constant temperature of 25°C for 2 hours, and the stirring speed is 300rpm; after the reaction is completed, filter and separate the solid residue and the lithium-containing leaching solution.

[0060] The solid residue and phosphoric acid (PH=2) in a mass ratio of 1:1 are mixed, heated at 90°C for 10 hours, then stirred and washed three times with phosphoric acid (PH=2) and water respectively, and then dried, and calcined at 650°C in an inert gas for 4 hours to obtain battery-grade iron phosphate.

[0061] Add 5g of calcium oxide to 100ml of lithium-containing leachate, filter and separate the first filtrate after complete precipitation, continuously introduce carbon dioxide gas into the first filtrate, filter and separate the second filtrate after complete precipitation, heat the second filtrate at 120°C for crystallization, filter and obtain the solid, wash with hot water at 90°C and dry to obtain battery-grade lithium carbonate.

[0062] In this embodiment, the lithium leaching rate is 92.3%, the lithium recovery rate is 87.3%, and the purity of battery-grade lithium carbonate is 99.5%; the recovery rate of iron phosphate is 90.3%, and the purity of battery-grade iron phosphate is 99.6%.

[0063] Example 2

[0064] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. in an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 0.5% and 3 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 10 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixed solution, and the mixture is stirred at a constant temperature of 25° C. for 2 hours, and the stirring speed is 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0065] Add 5g of calcium oxide to 100ml of lithium-containing leachate, filter and separate the first filtrate after complete precipitation, continuously introduce carbon dioxide gas into the first filtrate, filter and separate the second filtrate after complete precipitation, heat the second filtrate at 120°C for crystallization, filter and obtain the solid, wash with hot water at 90°C and dry to obtain battery-grade lithium carbonate.

[0066] In this embodiment, the lithium leaching rate is 88.6% and the lithium recovery rate is 83.5%.

[0067] Example 3

[0068] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. in an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 1% and 4 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 10 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixed solution, and the mixture is stirred at a constant temperature of 25° C. for 2 hours, and the stirring speed is 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0069] The solid residue and phosphoric acid (PH=2) in a mass ratio of 1:1.1 were mixed, heated at 90°C for 10 hours, then stirred and washed three times with phosphoric acid (PH=2) and water respectively, and then dried, and calcined at 650°C in an inert gas for 4 hours to obtain battery-grade iron phosphate.

[0070] Add 5g of calcium oxide to 100ml of lithium-containing leachate, filter and separate the first filtrate after complete precipitation, continuously introduce carbon dioxide gas into the first filtrate, filter and separate the second filtrate after complete precipitation, heat the second filtrate at 120°C for crystallization, filter and obtain solid, wash with hot water at 95°C and dry to obtain battery-grade lithium carbonate.

[0071] In this embodiment, the lithium leaching rate is 94.5%, and the lithium recovery rate is 90.2%. In this embodiment, the purity of battery-grade iron phosphate is 99.6%; the purity of battery-grade lithium carbonate is 99.6%.

[0072] Example 4

[0073] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. in an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 1% and 6 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 10 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixed solution, and the mixture is stirred at a constant temperature of 25° C. for 2 hours, and the stirring speed is 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0074] The solid residue and phosphoric acid (PH=2) in a mass ratio of 1:1 are mixed, heated at 90°C for 12 hours, then stirred and washed three times with phosphoric acid (PH=2) and water respectively, and then dried, and calcined at 650°C in an inert gas for 4 hours to obtain battery-grade iron phosphate.

[0075] Add 5g of calcium oxide to 100ml of lithium-containing leachate, filter and separate the first filtrate after complete precipitation, continuously introduce carbon dioxide gas into the first filtrate, filter and separate the second filtrate after complete precipitation, heat the second filtrate at 125°C for crystallization, filter and obtain the solid, wash with hot water at 90°C and dry to obtain battery-grade lithium carbonate.

[0076] In this embodiment, the lithium leaching rate is 96.6%, and the lithium recovery rate is 92.3%; the purity of battery-grade lithium carbonate is 99.7%; the recovery rate of battery-grade iron phosphate is 95.6%, and the purity is 99.8%.

[0077] Example 5

[0078] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. in an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 1% and 3 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 20 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixed solution, and the mixture is stirred at a constant temperature of 25° C. for 2 hours, and the stirring speed is 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0079] Add 5g of calcium oxide to 100ml of lithium-containing leachate, filter and separate the first filtrate after complete precipitation, continuously introduce carbon dioxide gas into the first filtrate, filter and separate the second filtrate after complete precipitation, heat the second filtrate at 120°C for crystallization, filter and obtain the solid, wash with hot water at 90°C and dry to obtain battery-grade lithium carbonate.

[0080] In this embodiment, the lithium leaching rate is 82.3% and the lithium recovery rate is 78.6%.

[0081] Example 6

[0082] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. in an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 1% and 8 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 20 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixed solution, and the mixture is stirred at a constant temperature of 25° C. for 2 hours, and the stirring speed is 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0083] Add 5g of calcium oxide to 100ml of lithium-containing leachate, filter and separate the first filtrate after complete precipitation, continuously introduce carbon dioxide gas into the first filtrate, filter and separate the second filtrate after complete precipitation, heat the second filtrate at 120°C for crystallization, filter and obtain the solid, wash with hot water at 90°C and dry to obtain battery-grade lithium carbonate.

[0084] In this embodiment, the lithium leaching rate is 85.6% and the lithium recovery rate is 81.3%.

[0085] Example 7

[0086] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. in an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 1% and 10 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 10 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixture, and the mixture is stirred at a constant temperature of 25° C. for 2 hours, and the stirring speed is 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0087] Add 5g of calcium oxide to 100ml of lithium-containing leachate, filter and separate the first filtrate after complete precipitation, continuously introduce carbon dioxide gas into the first filtrate, filter and separate the second filtrate after complete precipitation, heat the second filtrate at 120°C for crystallization, filter and obtain the solid, wash with hot water at 90°C and dry to obtain battery-grade lithium carbonate.

[0088] In this embodiment, the lithium leaching rate is 96.7% and the lithium recovery rate is 92.5%.

[0089] Example 8

[0090] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. in an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 2% and 3 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 10 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixed solution, and the mixture is stirred at a constant temperature of 25° C. for 2 hours, and the stirring speed is 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0091] Add 5g of calcium oxide to 100ml of lithium-containing leachate, filter and separate the first filtrate after complete precipitation, continuously introduce carbon dioxide gas into the first filtrate, filter and separate the second filtrate after complete precipitation, heat the second filtrate at 120°C for crystallization, filter and obtain the solid, wash with hot water at 90°C and dry to obtain battery-grade lithium carbonate.

[0092] In this embodiment, the lithium leaching rate is 96.5% and the lithium recovery rate is 92.3%.

[0093] Example 9

[0094] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. under an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 1% and 3 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 10 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixed solution, and the mixture is stirred at a constant temperature of 25° C. for 1 hour, and the stirring speed is 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0095] Add 5g of calcium oxide to 100ml of lithium-containing leachate, filter and separate the first filtrate after complete precipitation, continuously introduce carbon dioxide gas into the first filtrate, filter and separate the second filtrate after complete precipitation, heat the second filtrate at 120°C for crystallization, filter and obtain the solid, wash with hot water at 90°C and dry to obtain battery-grade lithium carbonate.

[0096] In this embodiment, the lithium leaching rate is 91.2% and the lithium recovery rate is 86.5%.

[0097] Example 10

[0098] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. in an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 1% and 3 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 10 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixed solution, and the mixture is stirred at a constant temperature of 25° C. for 3 hours, and the stirring speed is 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0099] Add 5g of calcium oxide to 100ml of lithium-containing leachate, filter and separate the first filtrate after complete precipitation, continuously introduce carbon dioxide gas into the first filtrate, filter and separate the second filtrate after complete precipitation, heat the second filtrate at 120°C for crystallization, filter and obtain the solid, wash with hot water at 90°C and dry to obtain battery-grade lithium carbonate.

[0100] In this embodiment, the lithium leaching rate is 91.4% and the lithium recovery rate is 86.6%.

[0101] Embodiment 11

[0102] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 190° C. under an inert atmosphere for 4 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 1% and 3 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 10 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixture, and the mixture is stirred at a constant temperature of 30° C. for 2 hours, and the stirring speed is 400 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0103] The solid residue and phosphoric acid (PH=2) in a mass ratio of 1:1.2 were mixed, heated at 90°C for 10 hours, then stirred and washed three times with phosphoric acid (PH=2) and water respectively, and then dried, and calcined at 650°C in an inert gas for 4 hours to obtain battery-grade iron phosphate.

[0104] Add 7g of calcium oxide to 100ml of lithium-containing leachate, filter and separate the first filtrate after complete precipitation, continuously introduce carbon dioxide gas into the first filtrate, filter and separate the second filtrate after complete precipitation, heat the second filtrate at 120°C for crystallization, filter and obtain the solid, wash with hot water at 90°C and dry to obtain battery-grade lithium carbonate.

[0105] In this embodiment, the lithium leaching rate is 92.7%, the lithium recovery rate is 87.1%, the purity of battery-grade lithium carbonate is 99.5%, the recovery rate of iron phosphate is 96.6%, and the purity of battery-grade iron phosphate is 99.5%.

[0106] Example 12

[0107] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 190° C. in an inert atmosphere for 4 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 1% and 3 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 10 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixed solution, placed in an oxygen environment at 25° C. and pressurized to 1 MPa, stirred for reaction for 2 hours at a stirring speed of 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0108] Battery-grade lithium carbonate was recovered according to the method in Example 1.

[0109] In this embodiment, the lithium leaching rate is 96.6% and the lithium recovery rate is 92.4%.

[0110] Embodiment 13

[0111] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 300°C in an inert atmosphere for 2 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 1% and 3 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 10 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixed solution, and the mixture is stirred at a constant temperature of 25°C for 2 hours, and the stirring speed is 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0112] Lithium carbonate was recovered according to the method in Example 1.

[0113] In this embodiment, the lithium leaching rate is 93.5% and the lithium recovery rate is 87.4%.

[0114] Comparative Example 1

[0115] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. in an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 10 g of the pretreated positive electrode black powder is added to 100 ml of a 1% phytic acid aqueous solution, and the reaction is carried out at a constant temperature of 25° C. and a stirring speed of 300 rpm. After the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0116] Lithium carbonate was recovered according to the method in Example 1.

[0117] In this comparative example, the lithium leaching rate is 32.3% and the lithium recovery rate is 19.6%.

[0118] Comparative Example 2

[0119] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. in an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 10 g of the pretreated positive electrode black powder is added to 100 ml of a 0.9% by mass hydrogen peroxide solution, and the reaction is carried out at a constant temperature of 25° C. and stirred for 2 hours at a stirring speed of 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0120] Lithium carbonate was recovered according to the method in Example 1.

[0121] In this comparative example, the lithium leaching rate is 36.2% and the lithium recovery rate is 26.4%.

[0122] Comparative Example 3

[0123] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. under an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 100 ml of a phytic acid aqueous solution with a mass fraction of 1% and 3 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a phytic acid-hydrogen peroxide system; 10 g of the pretreated positive electrode black powder is added to the phytic acid-hydrogen peroxide mixed solution, and the mixture is stirred at a constant temperature of 50° C. for 2 hours, and the stirring speed is 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0124] Lithium carbonate was recovered according to the method in Example 1.

[0125] In this comparative example, the lithium leaching rate is 84.7% and the lithium recovery rate is 80.1%.

[0126] Comparative Example 4

[0127] The waste lithium iron phosphate battery is discharged, disassembled and crushed to obtain positive electrode black powder; the black powder is calcined at 210° C. in an inert atmosphere for 3 hours to obtain pretreated positive electrode black powder; 100 ml of a citric acid aqueous solution with a mass fraction of 1% and 3 ml of a hydrogen peroxide aqueous solution with a mass fraction of 30% are mixed to obtain a citric acid-hydrogen peroxide system; 10 g of the pretreated positive electrode black powder is added to the citric acid-hydrogen peroxide mixture, and the mixture is stirred at a constant temperature of 25° C. for 2 hours, and the stirring speed is 300 rpm; after the reaction is completed, the solid residue and the lithium-containing leaching solution are filtered and separated.

[0128] Lithium carbonate was recovered according to the method in Example 1.

[0129] In this comparative example, the lithium leaching rate is 89.3% and the lithium recovery rate is 79.5%.

[0130] Comparative Example 5

[0131] The solid residue of Example 1 and phosphoric acid (PH=2) in a mass ratio of 1:1 were mixed, heated at 70°C for 10 hours, then stirred and washed three times with phosphoric acid (PH=2) and water respectively, and then dried, and calcined at 650°C in an inert gas for 4 hours to obtain iron phosphate.

[0132] Add 1g of calcium oxide to 100ml of lithium-containing leaching solution, filter and separate the first filtrate after complete precipitation, continuously introduce carbon dioxide gas into the first filtrate, filter and separate the second filtrate after complete precipitation, heat the second filtrate at 120°C for crystallization, filter and obtain solid, wash with hot water at 90°C and dry to obtain lithium carbonate.

[0133] In this comparative example, the recovery rate of iron phosphate is 80.6%, and the purity is 99.5%; the recovery rate of lithium carbonate is 79.6%, and the purity is 99.5%.

[0134] In summary, the method for regenerating waste lithium-ion battery positive electrode material resources of the present invention has low energy consumption, mild reaction conditions, and a lithium leaching rate of more than 96%, and can obtain battery-grade iron phosphate and battery-grade lithium carbonate.

[0135] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A method for regenerating waste lithium-ion battery positive electrode material resources, characterized in that: The method comprises: mixing and stirring the calcined pretreated positive electrode black powder with a phytic acid-hydrogen peroxide system for reaction, filtering and separating to obtain a solid residue and a lithium-containing leaching solution; mixing the solid residue with phosphoric acid, heating for reaction, and calcining to obtain battery-grade iron phosphate; and subjecting the lithium-containing leaching solution to secondary precipitation and thermal crystallization to obtain battery-grade lithium carbonate.

2. The method for regenerating positive electrode materials of waste lithium-ion batteries according to claim 1, characterized in that: In the phytic acid-hydrogen peroxide system, the volume ratio of the phytic acid aqueous solution with a mass fraction of 0.1-5% and the hydrogen peroxide aqueous solution with a mass fraction of 10-40% is 100:(1-10).

3. The method for regenerating positive electrode materials of waste lithium-ion batteries according to claim 1, characterized in that: The method comprises: (1) calcining the positive electrode black powder under an inert atmosphere to obtain pretreated positive electrode black powder; (2) mixing a phytic acid aqueous solution with a mass fraction of 0.1 to 5% and a hydrogen peroxide aqueous solution with a mass fraction of 10 to 40% in a volume ratio of 100:(1 to 10) to obtain a phytic acid-hydrogen peroxide system; (3) adding the pretreated positive electrode black powder to the phytic acid-hydrogen peroxide mixture in (2), and reacting at a constant temperature of 10 to 80° C. with stirring for 1 to 12 hours; (4) After the reaction is completed, filtering and separating the solid residue and the lithium-containing leachate; (5) mixing the solid residue with phosphoric acid, heating and reacting, and calcining to obtain battery-grade iron phosphate; (6) After the lithium-containing leaching solution is mixed with a precipitant for precipitation, the first filtrate is obtained by filtering, carbon dioxide gas is introduced into the first filtrate for precipitation, and the second filtrate is obtained by filtering, and the second filtrate is crystallized by thermal precipitation to obtain battery-grade lithium carbonate.

4. The method for regenerating positive electrode material resources of waste lithium-ion batteries according to claim 3, characterized in that: The constant temperature stirring reaction in (3) is carried out in air under normal pressure.

5. The method for regenerating positive electrode materials of waste lithium-ion batteries according to claim 3, characterized in that: The constant temperature stirring reaction in the step (3) is carried out under pressure in an oxygen atmosphere, and the pressure is 0.1 to 5 MPa.

6. The method for regenerating positive electrode material resources of waste lithium-ion batteries according to claim 3, characterized in that: The constant temperature stirring reaction temperature in (3) is 10 to 39° C. and the time is 1 to 6 hours.

7. The method for regenerating positive electrode materials of waste lithium-ion batteries according to claim 3, characterized in that: The mass ratio of the solid residue to the phosphoric acid in (5) is 1:(0.1-5).

8. The method for regenerating waste lithium-ion battery positive electrode material resources according to claim 3, characterized in that: The heating reaction temperature in (5) is 70-94° C. and the reaction time is 1-20 h.

9. The method for regenerating positive electrode materials of waste lithium-ion batteries according to claim 3, characterized in that: The calcination in (5) is carried out in an inert gas, the calcination temperature is 550-800° C., and the calcination time is 1-8 hours.

10. The method for recycling waste lithium-ion battery positive electrode material resources according to claim 3, characterized in that: In the step (6), 1 to 10 g of a precipitant is added to every 100 ml of the lithium-containing leaching solution.

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