Method for recovering copper in battery powder

Abstract

The invention belongs to the technical field of lithium ion batteries, and provides a method for recovering copper in battery powder, which comprises the following steps: carrying out alkaline leaching on the battery powder to obtain alkaline leaching powder; the alkaline leaching powder is subjected to low-temperature oxidation acid leaching, and leaching residues and primary acid leaching liquid are obtained; the leaching residues are subjected to oxidation acid leaching, and secondary leaching residues and secondary leaching liquid are obtained; and the primary acid leaching liquid is sequentially subjected to extraction and electro-deposition, and copper recovery is completed. Alkali leaching is used for removing aluminum in battery powder, oxidation acid leaching is carried out at low temperature, and the lithium leaching rate and the iron phosphorus precipitation rate are increased; then the leaching residues are subjected to oxidation acid leaching again so as to comprehensively improve the leaching rate of copper; the extraction is used for realizing copper and lithium separation; the electro-deposition copper extraction is used for recovering copper, and the economic value can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of lithium ion batteries, and in particular to a method for recovering copper in battery powder. Background Art

[0002] At present, in the wet recycling process of lithium-ion batteries, pole piece powder is often used as raw material, concentrated sulfuric acid is used as leaching agent, and hydrogen peroxide is used as redox agent. It is considered that battery powder will become the main raw material in the future, because it has higher content of copper, aluminum, fluorine, organic matter, etc. compared with pole piece powder. By treating battery powder through the original pole piece powder processing process, it can be clearly found that compared with pole piece powder, in the process of treating battery powder, the residual rate of aluminum, copper, fluorine, and organic matter is high, which is not conducive to the development of subsequent recycling process. Therefore, in the wet recycling process of lithium-ion batteries, it is particularly important to improve the removal rate of aluminum, fluorine, and organic matter and the effective recovery of copper when the raw materials are converted into battery powder.

[0003] Comparing the two raw materials, the obvious difference is that the aluminum, copper, fluorine and organic matter content of the battery powder is higher than that of the electrode powder. The effective treatment process is to first perform alkaline leaching, and then recover the copper in the battery powder through oxidation leaching, extraction and copper extraction by electrodeposition. The process first removes aluminum through alkaline leaching, then extracts lithium and copper through oxidation leaching, and then separates copper and lithium through extraction, and recovers copper through copper extraction by electrodeposition. Due to the high content of aluminum, copper, fluorine and organic matter in battery powder, how to improve the removal rate of aluminum, fluorine and organic matter and increase the leaching rate of copper is one of the technical problems that need to be solved urgently in this field. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems in the prior art and provide a method for recovering copper in battery powder.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for recovering copper in battery powder, comprising the following steps:

[0007] (1) alkali leaching the battery powder to obtain alkali leached powder;

[0008] (2) subjecting the alkaline leached powder to low temperature oxidative acid leaching to obtain leached residue and primary acid leaching solution;

[0009] (3) subjecting the leached residue to oxidative acid leaching to obtain secondary leaching residue and secondary leaching solution;

[0010] (4) The primary acid leaching solution is sequentially subjected to extraction and electrodeposition to complete copper recovery.

[0011] Preferably, the alkali leaching solution in step (1) is a sodium hydroxide solution; the concentration of the sodium hydroxide solution is 2-5%; the mass ratio of the sodium hydroxide solution to the battery powder is 4-6:1;

[0012] The alkali leaching time in step (1) is 40 to 60 minutes.

[0013] Preferably, the solution of low-temperature oxidation pickling in step (2) comprises pickling solution and oxidant;

[0014] The pH of the acid leaching solution is 1.5 to 2.5;

[0015] The oxidant is hydrogen peroxide, and the concentration of hydrogen peroxide is 40-60%;

[0016] The mass ratio of the low temperature oxidation acid leaching solution to the alkaline leaching powder is 3 to 4:1;

[0017] The mass ratio of the oxidant to the alkali-leached powder is 1:4-6.

[0018] Preferably, the temperature of the low-temperature oxidative acid leaching in step (2) is 10 to 70° C. and the time is 2 to 8 hours.

[0019] Preferably, the solution for oxidative pickling in step (3) comprises pickling solution and an oxidant;

[0020] The pH of the acid leaching solution is 0.5 to 1.5;

[0021] The oxidant is hydrogen peroxide, and the concentration of hydrogen peroxide is 40-60%;

[0022] The mass ratio of the oxidizing acid leaching solution to the leaching residue is 3 to 4:1;

[0023] The mass ratio of the oxidant to the leaching residue is 1:4-6.

[0024] Preferably, the oxidative acid leaching time in step (3) is 2 to 8 hours.

[0025] Preferably, the concentration of the extractant in step (4) is 10-15%; the volume ratio of the extractant to the primary acid leaching solution is 1-2:1-2.

[0026] Preferably, the number of extractions in step (4) is ≥ 4 times, and the single extraction time is 5 to 10 minutes.

[0027] Preferably, the distance between two stages of electrodeposition in step (4) is 50 to 100 mm.

[0028] Preferably, the voltage of the electrodeposition in step (4) is 1 to 3 V, and the current density is 150 to 250 A / m 2 , time is 70 to 80 hours.

[0029] The present invention provides a method for recovering copper in battery powder, comprising the following steps: subjecting the battery powder to alkaline leaching to obtain alkaline leached powder; subjecting the alkaline leached powder to low-temperature oxidation acid leaching to obtain leached residue and primary acid leaching solution; subjecting the leached residue to oxidation acid leaching to obtain secondary leached residue and secondary leaching solution; subjecting the primary acid leaching solution to extraction and electrodeposition in sequence to complete copper recovery. In the present invention, alkaline leaching is used to remove aluminum from the battery powder, oxidation acid leaching is performed at low temperature to increase the lithium leaching rate and iron-phosphorus precipitation rate; then oxidation acid leaching is performed again on the leached residue to comprehensively increase the copper leaching rate; extraction is used to achieve separation of copper and lithium; electrodeposition copper extraction is used to recover copper, which can effectively increase the economic value.

[0030] In the present invention, the aluminum removal rate can reach more than 70% by alkali leaching. By the first step of relatively low-temperature oxidation acid leaching, when the temperature is controlled at 10-70°C, the lithium leaching rate can reach more than 90%, and the unit consumption of hydrogen peroxide is about 0.7-0.9m 3 / t (equivalent to 100% lithium sulfate). By oxidizing and acid leaching again without controlling the temperature in the second step, iron-phosphorus slag with lithium and copper contents of ≤0.1% can be obtained. After the extraction process, the copper extraction rate can reach 99%. By electroplating copper, 95% of the copper ions in the copper extraction solution can be converted into sponge copper with a purity of ≥95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The figure is a schematic diagram of the process of the method for recovering copper from battery powder in the present invention. DETAILED DESCRIPTION

[0032] The present invention provides a method for recovering copper in battery powder, comprising the following steps:

[0033] (1) alkali leaching the battery powder to obtain alkali leached powder;

[0034] (2) subjecting the alkaline leached powder to low temperature oxidative acid leaching to obtain leached residue and primary acid leaching solution;

[0035] (3) subjecting the leached residue to oxidative acid leaching to obtain secondary leaching residue and secondary leaching solution;

[0036] (4) The primary acid leaching solution is sequentially subjected to extraction and electrodeposition to complete copper recovery.

[0037] In the present invention, the alkali leaching solution in step (1) is a sodium hydroxide solution; the concentration of the sodium hydroxide solution is preferably 2-5%, more preferably 2.5-4.5%, and more preferably 3-4%; the mass ratio of the sodium hydroxide solution to the battery powder is preferably 4-6:1, more preferably 4.5-5.5:1. More preferably, it is 4.8-5.2:1.

[0038] In the present invention, the alkali leaching time in step (1) is preferably 40 to 60 min, more preferably 45 to 55 min, and even more preferably 48 to 52 min.

[0039] In the present invention, the reaction principle of alkali leaching in step (1) is as follows:

[0040] 2NaOH+Al2O3+3H2O=2Na[Al(OH)4]

[0041] 2Al+2NaOH+6H2O=2Na[Al(OH)4]+3H2↑

[0042] In the present invention, the solution of low-temperature oxidative pickling in step (2) comprises pickling solution and an oxidant.

[0043] In the present invention, the pH of the pickling solution is preferably 1.5 to 2.5, more preferably 1.6 to 2.4, and even more preferably 1.8 to 2.2.

[0044] In the present invention, the acid leaching solution is prepared by using a sulfuric acid aqueous solution, and the concentration of the sulfuric acid aqueous solution is preferably 1-4M, more preferably 2-3M, and more preferably 2.4-2.6M.

[0045] In the present invention, the oxidant is hydrogen peroxide, and the concentration of hydrogen peroxide is preferably 40 to 60%, more preferably 45 to 55%, and even more preferably 48 to 52%.

[0046] In the present invention, the mass ratio of the low-temperature oxidative acid leaching solution to the alkaline leaching powder is preferably 3-4:1, more preferably 3.2-3.8:1, and even more preferably 3.4-3.6:1.

[0047] In the present invention, the mass ratio of the oxidant to the alkali-leached powder is preferably 1:4-6, more preferably 1:4.5-5.5, and even more preferably 1:4.8-5.2.

[0048] In the present invention, the temperature of the low-temperature oxidative acid leaching in step (2) is preferably 10 to 70°C, more preferably 20 to 60°C, more preferably 30 to 50°C; the time is preferably 2 to 8 hours, more preferably 3 to 7 hours, more preferably 4 to 6 hours.

[0049] In the present invention, the oxidative acid leaching in step (2) is carried out in the range of 10 to 70° C., which can relatively reduce the consumption of hydrogen peroxide.

[0050] In the present invention, the solution for oxidative pickling in step (3) comprises pickling liquid and an oxidant.

[0051] In the present invention, the pH of the pickling solution is preferably 0.5 to 1.5, more preferably 0.6 to 1.4, and even more preferably 0.8 to 1.2.

[0052] In the present invention, the acid leaching solution is prepared by using a sulfuric acid aqueous solution, and the concentration of the sulfuric acid aqueous solution is preferably 1-4M, more preferably 2-3M, and more preferably 2.4-2.6M.

[0053] In the present invention, the oxidant is hydrogen peroxide, and the concentration of hydrogen peroxide is preferably 40 to 60%, more preferably 45 to 55%, and even more preferably 48 to 52%.

[0054] The mass ratio of the oxidizing acid leaching solution to the leached residue is preferably 3 to 4:1, more preferably 3.2 to 3.8:1, and even more preferably 3.4 to 3.6:1.

[0055] In the present invention, the mass ratio of the oxidant to the leached residue is preferably 1:4-6, more preferably 1:4.5-5.5, and even more preferably 1:4.8-5.2.

[0056] In the present invention, the time of oxidative acid leaching in step (3) is preferably 2 to 8 hours, more preferably 3 to 7 hours, and even more preferably 4 to 6 hours.

[0057] In the present invention, the secondary leaching solution can continue to be used as the bottom solution of the oxidative acid leaching in step (2) for the next cycle.

[0058] In the present invention, the principle of oxidative acid leaching is as follows:

[0059] 2LiFePO4+H2O2+H2SO4=2FePO4+Li2SO4+2H2O

[0060] Cu+H2SO4+H2O2=CuSO4+2H2O

[0061] In the present invention, the extractant used in step (4) is DZ984N extractant, and the concentration of the extractant is preferably 10-15%, more preferably 11-14%, and more preferably 12-13%; the volume ratio of the extractant to the primary acid leaching solution is preferably 1-2:1-2, more preferably 1.2-1.8:1.2-1.8, and more preferably 1.4-1.6:1.4-1.6.

[0062] In the present invention, the number of extractions in step (4) is preferably ≥4 times, further preferably ≥8 times, and more preferably ≥12 times, and the ratio of the number of forward extractions to the number of reverse extractions in the extraction is 1:3; the single extraction time is preferably 5 to 10 minutes, further preferably 6 to 9 minutes, and more preferably 7 to 8 minutes.

[0063] In the present invention, the principle of extraction is as follows:

[0064]

[0065] In the present invention, the copper extraction solution obtained by extraction is subjected to electrodeposition.

[0066] In the present invention, the anode of the electrodeposition in step (4) is a Pb-Sb alloy, and the cathode is stainless steel; the distance between the two stages is preferably 50 to 100 mm, more preferably 60 to 90 mm, and more preferably 70 to 80 mm.

[0067] In the present invention, the voltage of the electrodeposition in step (4) is preferably 1 to 3 V, more preferably 1.5 to 2.5 V, and more preferably 1.8 to 2.2 V; the current density is preferably 150 to 250 A / m 2 , more preferably 160 to 240 A / m 2 , more preferably 180 to 220 A / m 2 ; The time is preferably 70 to 80 hours, more preferably 72 to 88 hours, and more preferably 74 to 86 hours.

[0068] In the present invention, the principle of electrodeposition is as follows:

[0069] Cu 2+ +2e - =Cu

[0070] The schematic flow diagram of the method for recovering copper from battery powder in the present invention is as follows: Figure 1 shown.

[0071] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0072] Example 1

[0073] The battery powder and 3% sodium hydroxide solution were mixed in a ratio of 1:5, and alkali-leached for 50 minutes to obtain alkali-leached powder;

[0074] A 3M sulfuric acid aqueous solution is used to prepare an acid leaching solution with a pH of 2, the acid leaching solution is mixed with 50% hydrogen peroxide (the mass ratio of hydrogen peroxide to alkaline leaching powder is 1:5) to obtain a low-temperature oxidation acid leaching solution, the low-temperature oxidation acid leaching solution and the alkaline leaching powder are mixed in a mass ratio of 3:1, and soaked at 50°C for 6 hours to obtain leached residue and a primary acid leaching solution;

[0075] A 3M sulfuric acid aqueous solution is used to prepare an acid leaching solution with a pH of 1.5, the acid leaching solution is mixed with 50% hydrogen peroxide (the mass ratio of hydrogen peroxide to leached residue is 1:5) to obtain an oxidative acid leaching solution, the oxidative acid leaching solution is mixed with the leached residue in a mass ratio of 3:1, and the mixture is immersed for 6 hours to obtain secondary leaching residue and secondary leaching solution;

[0076] The primary acid leaching solution was extracted with DZ984N extractant with a concentration of 12%, the volume ratio of the extractant to the primary acid leaching solution was 1:1, one extraction, three back extractions, and a single extraction time of 10 minutes to obtain a copper extraction solution.

[0077] Pb-Sb alloy is the anode, stainless steel is the cathode, the plate spacing is 80mm, the voltage is 2V, and the current density is 200A / m 2 , electroplating was carried out for 72 hours to obtain sponge copper.

[0078] The components of the products obtained in this example were analyzed, and the results are shown in Table 1.

[0079] Table 1 Chemical composition of products

[0080] project Li Fe P Cu Al Battery powder 3.23％ 28.08％ 16.19％ 2.74％ 1.70％ Primary acid leaching solution 6.80g / L 11.10g / L 5.01g / L 7.41g / L 1.96g / L Secondary leaching residue 0.096％ 0.027％ copper extraction liquid 48.47g / L Sponge Copper 98.97％

[0081] Example 2

[0082] The battery powder and 2.5% sodium hydroxide solution were mixed in a ratio of 1:6, and alkali-leached for 45 minutes to obtain an alkali-leached powder;

[0083] A 2M sulfuric acid aqueous solution is used to prepare an acid leaching solution with a pH of 1.5, the acid leaching solution is mixed with 45% hydrogen peroxide (the mass ratio of hydrogen peroxide to alkaline leaching powder is 1:5) to obtain a low-temperature oxidation acid leaching solution, the low-temperature oxidation acid leaching solution and the alkaline leaching powder are mixed in a mass ratio of 3.5:1, and soaked at 60°C for 4 hours to obtain leached residue and a primary acid leaching solution;

[0084] A 2M sulfuric acid aqueous solution is used to prepare an acid leaching solution with a pH of 1, the acid leaching solution is mixed with 50% hydrogen peroxide (the mass ratio of hydrogen peroxide to leached residue is 1:5) to obtain an oxidative acid leaching solution, the oxidative acid leaching solution is mixed with the leached residue in a mass ratio of 3.5:1, and the mixture is immersed for 6 hours to obtain secondary leaching residue and secondary leaching solution;

[0085] The primary acid leaching solution was extracted with DZ984N extractant at a concentration of 11%, the volume ratio of the extractant to the primary acid leaching solution was 1:1, one extraction, three back extractions, and a single extraction time of 5 minutes to obtain a copper extraction solution.

[0086] Pb-Sb alloy is the anode, stainless steel is the cathode, the plate spacing is 70mm, the voltage is 1.5V, and the current density is 180A / m 2 , electroplating was carried out for 74 hours to obtain sponge copper.

[0087] The components of the products obtained in this example were analyzed, and the results are shown in Table 2.

[0088] Table 2 Chemical composition of products

[0089] project Li Fe P Cu Al Battery powder 3.23％ 28.08％ 16.19％ 2.74％ 1.70％ Primary acid leaching solution 7.24g / L 10.97g / L 5.07g / L 7.44g / L 1.87g / L Secondary leaching residue 0.078％ 0.018％ copper extraction liquid 49.52g / L Sponge Copper 99.23％

[0090] Example 3

[0091] The battery powder and 4.2% sodium hydroxide solution were mixed in a ratio of 1:4.5, and alkali-leached for 55 minutes to obtain an alkali-leached powder;

[0092] A 3M sulfuric acid aqueous solution is used to prepare an acid leaching solution with a pH of 2.3, the acid leaching solution is mixed with 57% hydrogen peroxide (the mass ratio of hydrogen peroxide to alkaline leaching powder is 1:5.2) to obtain a low-temperature oxidation acid leaching solution, the low-temperature oxidation acid leaching solution and the alkaline leaching powder are mixed in a mass ratio of 4:1, and soaked at 15°C for 7 hours to obtain leached residue and a primary acid leaching solution;

[0093] A 3M sulfuric acid aqueous solution is used to prepare an acid leaching solution with a pH of 0.8, the acid leaching solution is mixed with 57% hydrogen peroxide (the mass ratio of hydrogen peroxide to leached residue is 1:6) to obtain an oxidative acid leaching solution, the oxidative acid leaching solution is mixed with the leached residue in a mass ratio of 4:1, and the mixture is immersed for 2 hours to obtain secondary leaching residue and secondary leaching solution;

[0094] The primary acid leaching solution was extracted with DZ984N extractant at a concentration of 15%, the volume ratio of the extractant to the primary acid leaching solution was 1:1, one extraction, three back extractions, and the process of one extraction and back extraction was repeated, and the single extraction time was 10 minutes to obtain a copper extraction solution.

[0095] Pb-Sb alloy is the anode, stainless steel is the cathode, the plate spacing is 90mm, the voltage is 2.5V, and the current density is 230A / m 2 , electroplating was carried out for 76 hours to obtain sponge copper.

[0096] The components of the products obtained in this example were analyzed, and the results are shown in Table 3.

[0097] Table 3 Chemical composition of products

[0098]

[0099]

[0100] It can be seen from the above embodiments that the present invention provides a method for recovering copper in battery powder. After the first step of low-temperature oxidation acid leaching, a copper- and lithium-containing solution of ≥5 g / L can be obtained. In the second step, the temperature is not controlled and the acid leaching is performed again to obtain a leached residue with a copper and lithium content of ≤0.1%. After extraction and stripping, a copper-rich solution of ≥45 g / L can be obtained; after copper extraction by electrodeposition, a sponge copper with a purity of ≥95% can be obtained.

[0101] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for recovering copper from battery powder, characterized in that: It includes the following steps: (1) alkali leaching the battery powder to obtain alkali leached powder; (2) subjecting the alkaline leached powder to low temperature oxidative acid leaching to obtain leached residue and primary acid leaching solution; (3) subjecting the leached residue to oxidative acid leaching to obtain secondary leaching residue and secondary leaching solution; (4) The primary acid leaching solution is sequentially subjected to extraction and electrodeposition to complete copper recovery.

2. The method for recovering copper in battery powder according to claim 1, characterized in that: The alkali leaching solution in step (1) is a sodium hydroxide solution; the concentration of the sodium hydroxide solution is 2-5%; the mass ratio of the sodium hydroxide solution to the battery powder is 4-6:1; The alkali leaching time in step (1) is 40 to 60 minutes.

3. The method for recovering copper in battery powder according to claim 1 or 2, characterized in that: In step (2), the low-temperature oxidation acid leaching solution comprises an acid leaching solution and an oxidant; The pH of the acid leaching solution is 1.5 to 2.5; The oxidant is hydrogen peroxide, and the concentration of hydrogen peroxide is 40-60%; The mass ratio of the low temperature oxidation acid leaching solution to the alkaline leaching powder is 3 to 4:1; The mass ratio of the oxidant to the alkali-leached powder is 1:4-6.

4. The method for recovering copper in battery powder according to claim 3, characterized in that: In step (2), the temperature of low-temperature oxidation acid leaching is 10 to 70° C. and the time is 2 to 8 hours.

5. The method for recovering copper in battery powder according to claim 1 or 4, characterized in that: The oxidative acid leaching solution in step (3) comprises an acid leaching solution and an oxidant; The pH of the acid leaching solution is 0.5 to 1.5; The oxidant is hydrogen peroxide, and the concentration of hydrogen peroxide is 40-60%; The mass ratio of the oxidizing acid leaching solution to the leaching residue is 3 to 4:1; The mass ratio of the oxidant to the leaching residue is 1:4-6.

6. The method for recovering copper in battery powder according to claim 5, characterized in that: The time of oxidative acid leaching in step (3) is 2 to 8 hours.

7. The method for recovering copper in battery powder according to claim 6, characterized in that: The concentration of the extractant in step (4) is 10-15%; the volume ratio of the extractant to the primary acid leaching solution is 1-2:1-2.

8. The method for recovering copper in battery powder according to claim 7, characterized in that: The number of extractions in step (4) is ≥ 4 times, and the single extraction time is 5 to 10 minutes.

9. The method for recovering copper in battery powder according to claim 8, characterized in that: The distance between the two stages of electrodeposition in step (4) is 50 to 100 mm.

10. The method for recovering copper in battery powder according to claim 9, characterized in that: The voltage of the electrodeposition in step (4) is 1 to 3 V, and the current density is 150 to 250 A / m 2 , time is 70 to 80 hours.

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