Battery black powder recovery method

Abstract

The application belongs to the technical field of battery material recycling, and particularly discloses a battery black powder recycling method. The battery black powder recycling method provided by the application comprises the following steps: obtaining lithium-containing leaching liquor and leaching residue by pressurized acid leaching of battery black powder; performing acid leaching reaction on the leaching residue to obtain nickel-, cobalt- and manganese-containing leaching liquor; adding an oxidizing agent to the nickel-, cobalt- and manganese-containing leaching liquor, adjusting the pH by using alkali to remove iron and aluminum, and filtering to obtain a post-iron-and-aluminum-removal liquid; extracting Ca by using HBL120 extractant to obtain Co-, Ni- and Mn-containing raffinate; extracting Mn by using P204 extractant to obtain Mn-loaded organic phase and Co- and Ni-containing raffinate; extracting Co by using Cy272 extractant to obtain Co-loaded organic phase and Ni-containing raffinate; and removing F and P from the Ni-containing raffinate to obtain a nickel sulfate solution. The application has high lithium extraction rate and shortens the process flow of manganese recycling.

Description

Technical Field

[0001] This invention relates to the field of battery material recycling technology, and in particular to a method for recycling battery black powder. Background Technology

[0002] Waste battery black powder is a black powder containing metals such as nickel, cobalt, manganese, copper, aluminum and lithium, as well as carbon powder, obtained from waste lithium-ion batteries through processes such as dismantling, crushing, screening, pyrolysis and sorting.

[0003] Currently, lithium extraction processes are divided into two routes: front-end lithium extraction and back-end lithium extraction. Back-end lithium extraction has two main problems: first, sodium ions are introduced during the extraction of cobalt, nickel, and manganese, affecting the quality of lithium carbonate products; second, the extraction washing solution dilutes the lithium concentration, increasing concentration costs. Front-end lithium extraction (such as sodium salt, ammonium salt, or sulfation roasting) suffers from the problem that high-temperature roasting causes some cobalt, nickel, and manganese to sinter, reducing the leaching rate of subsequent metal recovery. In the manganese extraction process of battery black powder leachate, calcium ion interference is particularly prominent during P204 manganese extraction: calcium easily forms in the washing section, and hydrochloric acid back-extraction must be used in the back-extraction section (sulfuric acid back-extraction will cause calcium formation and production shutdown). This process also suffers from a lengthy process: the back-extraction product needs to undergo chemical decalcification before a second manganese extraction, which not only increases production costs but also requires the addition of large amounts of fluoride salts during the decalcification process, raising equipment requirements and creating wastewater treatment challenges.

[0004] To address the aforementioned issues, it is necessary to research and develop a novel waste battery black powder recycling process to improve Li recovery rate; effectively remove calcium from the solution and shorten the Mn recovery process; and simultaneously reduce Ni extraction processes to lower production costs. Summary of the Invention

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention provides a method for recovering battery black powder, in which lithium is extracted at the front end of the process, resulting in a high recovery rate; Ca is extracted using HBL120 extractant, and sulfuric acid back-extraction can be directly used during Mn recovery to generate manganese sulfate, shortening the process flow; at the same time, Ni is recovered through a semi-extraction process, reducing production costs.

[0006] The battery black powder recycling method provided by this invention includes the following steps:

[0007] S1. Mix battery black powder with water to form a slurry, add sulfuric acid, heat and pressurize to carry out acid leaching reaction, and filter to obtain lithium-containing leachate and leaching residue;

[0008] S2. Mix the leaching residue with water to form a slurry, add sulfuric acid and reducing agent, heat to carry out acid leaching reaction, and filter to obtain a leaching solution containing nickel, cobalt and manganese.

[0009] S3. Add an oxidant to the leaching solution containing nickel, cobalt and manganese, adjust the pH with alkali to remove iron and aluminum, and filter to obtain the iron and aluminum removed solution.

[0010] S4. Use HBL120 extractant to extract Ca from the liquid after iron and aluminum removal to obtain an organic phase loaded with Ca and a raffinate containing Co, Ni and Mn.

[0011] S5. Use P204 extractant to extract Mn from the raffinate containing Co, Ni and Mn to obtain an organic phase loaded with Mn and a raffinate containing Co and Ni. The organic phase loaded with Mn is washed with sulfuric acid and back-extracted to obtain a manganese sulfate solution.

[0012] S6. Use Cy272 extractant to extract Co from the raffinate containing Co and Ni to obtain an organic phase loaded with Co and a raffinate containing Ni. The organic phase loaded with Co is washed with sulfuric acid and back-extracted to obtain a cobalt sulfate solution.

[0013] S7. The Ni-containing raffinate is treated to remove F and P to obtain a nickel sulfate solution.

[0014] According to some embodiments of the present invention, in step S1, the solid-liquid mass ratio of the battery black powder to water is 1:(9~11), the amount of sulfuric acid added is 1.1~1.2 times the molar amount of lithium in the battery black powder, and the conditions for the acid leaching reaction are: temperature 180~220℃, pressure 1.0~2.3MPa, and time 2~5h.

[0015] According to some embodiments of the present invention, in step S2, the solid-liquid mass ratio of the leaching residue and water is 1:(4~6), the amount of sulfuric acid added is 1.1~1.2 times the sum of the molar amounts of Co, Ni and Mn in the leaching residue, and the conditions for the acid leaching reaction are: temperature 60~70℃, time 2~5h.

[0016] According to some embodiments of the present invention, in step S2, the reducing agent includes sodium metabisulfite; the mass of the reducing agent is 15% to 20% of the mass of the leaching residue.

[0017] According to some embodiments of the present invention, in step S3, the oxidant includes hydrogen peroxide, the alkali includes sodium hydroxide, and the pH adjustment is to adjust the pH to 4.5~5.5.

[0018] According to some embodiments of the present invention, in step S4, the volume concentration of the HBL120 extractant is 20%~25%, and the saponification value is 0.1~0.15;

[0019] The extraction in step S4 also includes washing, hydrochloric acid back-extraction, and sulfuric acid back-extraction, wherein the number of extraction stages is 4 to 6, the number of washing stages is 2 to 4, the number of hydrochloric acid back-extraction stages is 2 to 4, and the number of sulfuric acid back-extraction stages is 2 to 4.

[0020] According to some embodiments of the present invention, in step S5, the volume concentration of the P204 extractant is 20%~25%, and the saponification value is 0.4~0.5;

[0021] The extraction in step S5 also includes washing and back-extraction, wherein the number of extraction stages is 9 to 11, the number of washing stages is 10 to 12, and the number of back-extraction stages is 9 to 11.

[0022] According to some embodiments of the present invention, in step S6, the volume concentration of the Cy272 extractant is 20%~25%, and the saponification value is 0.4~0.5;

[0023] The extraction in step S6 also includes washing and back-extraction, wherein the number of extraction stages is 9 to 11, the number of washing stages is 10 to 12, and the number of back-extraction stages is 9 to 11.

[0024] According to some embodiments of the present invention, in step S7, the removal of F and P is performed by adding Huasheng defluorination agent to the Ni-containing raffinate and adjusting the pH to 4-6; preferably, the pH is adjusted to 5-6.

[0025] The beneficial effects of this invention are:

[0026] 1) This invention achieves a high Li recovery rate in battery black powder: Li is extracted at the front end, with a recovery rate exceeding 90%; 2) This invention uses HBL120 for effective Ca removal, reducing the concentration to below 1 mg / L, avoiding the problem of calcium buildup in the extraction tank during Mn extraction. Simultaneously, during Mn extraction with P204, sulfuric acid is used for back-extraction to generate manganese sulfate, shortening the Mn recovery process and saving costs; 3) This invention effectively removes F: F and P can be removed to below 10 mg / L, allowing Ni to be recovered through a semi-extraction process, reducing Ni extraction and lowering production costs.

[0027] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Detailed Implementation

[0028] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0029] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0030] Example 1

[0031] This embodiment provides a method for the efficient recovery of valuable elements in battery black powder, and the specific steps are as follows:

[0032] 1) Take battery black powder, add water to make a slurry at a solid-liquid mass ratio of 1:10, add sulfuric acid at 1.1 times the molar mass of lithium, react at 180℃ for 2 hours and at a pressure of 1.0MPa, filter after the reaction is completed to obtain pressure leaching residue and pressure leaching solution.

[0033] 2) The obtained pressure leaching residue is further leached with acid. Water is added at a solid-liquid mass ratio of 1:5, sulfuric acid is added at a ratio of 1.1 times the sum of the molar masses of Co, Ni and Mn, and sodium metabisulfite at 15% of the mass of the pressure leaching residue is added. The reaction is carried out at a temperature of 60℃ and a normal pressure for 2 hours. After the reaction is completed, the mixture is filtered to obtain a normal pressure leaching solution and a normal pressure leaching residue.

[0034] 3) Add hydrogen peroxide to the obtained atmospheric pressure leachate and adjust the pH to 4.5 with sodium hydroxide to remove iron and aluminum. After filtration, obtain the iron and aluminum removed liquid and the iron and aluminum removed residue.

[0035] 4) The obtained liquid after removing iron and aluminum is used to extract Ca with HBL120 extractant; wherein, the volume concentration of HBL120 extractant is 20% (solvent is light white oil), the saponification value is 0.15, the number of extraction stages is 5, the number of washing stages is 3, the number of hydrochloric acid back-extraction stages is 3, and the number of sulfuric acid back-extraction stages is 3, to obtain an organic phase loaded with Ca and a raffinate containing Co, Ni and Mn (HBL120 raffinate).

[0036] 5) The raffinate containing Co, Ni, and Mn was used to extract Mn with P204 extractant; wherein, the volume concentration of P204 extractant was 20% (solvent was light white oil), the saponification value was 0.4, the number of extraction stages was 10, the number of washing stages was 11, and the number of back-extraction stages was 10, to obtain an organic phase loaded with Mn and a raffinate containing Co and Ni (P204 raffinate); the organic phase loaded with Mn was washed with sulfuric acid and back-extracted to obtain a battery-grade manganese sulfate solution, and then crystallized to obtain battery-grade manganese sulfate crystals;

[0037] 6) The Co- and Ni-containing raffinate was extracted with Cy272 extractant to extract Co; wherein the volume concentration of Cy272 extractant was 20% (solvent was light white oil), the saponification value was 0.4, the number of extraction stages was 10, the number of washing stages was 11, and the number of back-extraction stages was 10, to obtain a Co-loaded organic phase and a Ni-containing raffinate (Cy272 raffinate); the Co-loaded organic phase was washed with sulfuric acid and back-extracted to obtain a battery-grade cobalt sulfate solution, and then the battery-grade cobalt sulfate crystals were obtained by crystallization;

[0038] 7) The Ni-containing raffinate is treated with an F-removing agent to remove F and P, resulting in a battery-grade nickel sulfate solution. The solution is then evaporated and crystallized to obtain battery-grade nickel sulfate crystals. The F-removing agent is Huasheng F-removing agent with a final concentration of 4 g / L (3~5 g / L) and a solution pH of 4.

[0039] The calculations show that the overall lithium yield in this embodiment is 91.3%, the Ca in the HBL120 raffinate can be removed to 0.8 mg / L, and the F and P in the Cy272 raffinate can be removed to 8.5 mg / L and 7.3 mg / L, respectively.

[0040] Example 2

[0041] This embodiment provides a method for the efficient recovery of valuable elements in battery black powder, and the specific steps are as follows:

[0042] 1) Take battery black powder, add water to make a slurry at a solid-liquid mass ratio of 1:10, add sulfuric acid at 1.2 times the molar mass of lithium, react at 180℃ for 4 hours and at a pressure of 1.0MPa, filter after the reaction is completed to obtain pressure leaching residue and pressure leaching solution.

[0043] 2) The obtained pressure leaching residue is further leached with acid. Water is added at a solid-liquid mass ratio of 1:5, sulfuric acid is added at 1.2 times the sum of the molar masses of Co, Ni and Mn, and sodium metabisulfite at 20% of the mass of the pressure leaching residue is added. The reaction is carried out at 60℃ and atmospheric pressure for 2 hours. After the reaction is completed, the residue is filtered to obtain atmospheric pressure leachate and atmospheric pressure leaching residue.

[0044] 3) Add hydrogen peroxide to the obtained atmospheric pressure leachate, adjust the pH to 4.5 with sodium hydroxide, let it stand to precipitate, and filter to obtain the iron and aluminum removed liquid and iron and aluminum removed slag.

[0045] 4) The obtained liquid after removing iron and aluminum is used to extract Ca with HBL120 extractant; wherein, the volume concentration of HBL120 extractant is 20%, the saponification value is 0.15, the number of extraction stages is 5, the number of washing stages is 3, the number of hydrochloric acid back-extraction stages is 3, and the number of sulfuric acid back-extraction stages is 3, to obtain an organic phase loaded with Ca and a raffinate containing Co, Ni and Mn (HBL120 raffinate).

[0046] 5) The raffinate containing Co, Ni, and Mn was used to extract Mn with P204 extractant; wherein, the volume concentration of P204 extractant was 20%, the saponification value was 0.4, the number of extraction stages was 10, the number of washing stages was 11, and the number of back-extraction stages was 10, to obtain an organic phase loaded with Mn and a raffinate containing Co and Ni (P204 raffinate); the organic phase loaded with Mn was washed with sulfuric acid and back-extracted to obtain a battery-grade manganese sulfate solution, and then crystallized to obtain battery-grade manganese sulfate crystals;

[0047] 6) The Co- and Ni-containing raffinate was used to extract Co using Cy272 extractant. The Cy272 extractant had a volume concentration of 20%, a saponification value of 0.4, 10 extraction stages, 11 washing stages, and 10 back-extraction stages, yielding a Co-loaded organic phase and a Ni-containing raffinate (Cy272 raffinate). The Co-loaded organic phase was washed with sulfuric acid and back-extracted to obtain a battery-grade cobalt sulfate solution, which was then crystallized to obtain battery-grade cobalt sulfate crystals.

[0048] 7) The Ni-containing raffinate is treated with an F-removing agent to remove F and P, resulting in a battery-grade nickel sulfate solution. The solution is then evaporated and crystallized to obtain battery-grade nickel sulfate crystals. The F-removing agent is Huasheng F-removing agent with a final concentration of 4 g / L (3~5 g / L) and a solution pH of 4.

[0049] The calculations show that the overall lithium yield in this embodiment is 92.5%, the Ca in the HBL120 raffinate can be removed to 0.6 mg / L, and the F and P in the Cy272 raffinate can be removed to 8.8 mg / L and 7.4 mg / L, respectively.

[0050] Example 3

[0051] This embodiment provides a method for the efficient recovery of valuable elements in battery black powder.

[0052] This embodiment is basically the same as Embodiment 1, except that in step 1) of this embodiment, the temperature of the pressurized acid leaching is 200℃, the pressure is 1.55MPa, and the time is 3h.

[0053] Example 4

[0054] This embodiment provides a method for the efficient recovery of valuable elements in battery black powder.

[0055] This embodiment is basically the same as Embodiment 1, except that in step 2) of this embodiment, the temperature of the acid leaching under normal pressure is 70°C and the time is 4 hours. Sulfuric acid is added at 1.2 times the sum of the molar masses of Co, Ni and Mn, and sodium metabisulfite at 20% of the mass of the pressure leaching residue is added.

[0056] Example 5

[0057] This embodiment provides a method for the efficient recovery of valuable elements in battery black powder.

[0058] This embodiment is basically the same as Embodiment 1, except that in step 4) of this embodiment, the volume concentration of HBL120 extractant is 25% and the saponification value is 0.15.

[0059] Example 6

[0060] This embodiment provides a method for the efficient recovery of valuable elements in battery black powder.

[0061] This embodiment is basically the same as embodiment 1, except that in step 7) of this embodiment, the pH of the solution during defluorination is adjusted to 5.

[0062] Comparative Example 1

[0063] This comparative example provides a method for recovering valuable elements from battery black powder.

[0064] This comparative example is basically the same as Example 1, except that in step 1) of this comparative example, the temperature of the pressurized acid leaching is 150°C and the pressure is 0.48 MPa.

[0065] Comparative Example 2

[0066] This comparative example provides a method for recovering valuable elements from battery black powder.

[0067] This comparative example is basically the same as Example 1, except that in step 1) of this comparative example, the temperature of the pressurized acid leaching is 130°C and the pressure is 0.27 MPa.

[0068] The recovery rates and content of some elements in the solution during the battery black powder recovery process of the above embodiments and comparative examples are shown in Table 1 below:

[0069] As can be seen from the test results of the above embodiments and comparative examples, the technical solution of the present invention achieves efficient recovery of lithium from battery black powder. Furthermore, increasing the reaction temperature and extending the reaction time during pressurized leaching can promote the leaching reaction and help improve the lithium recovery rate. In addition, in subsequent process steps, increasing the concentration and saponification value of the HBL120 extractant during Ca extraction can further reduce the Ca content in the raffinate. When using the F removal agent to remove F and P, appropriately increasing the pH is beneficial for the removal of F and P.

[0070] In Comparative Examples 1 and 2, the temperature of pressurized acid leaching was reduced, and the reaction pressure was reduced accordingly, resulting in a significant decrease in lithium recovery rate, making it difficult to achieve efficient recycling of battery black powder.

[0071] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for recycling battery black powder, characterized in that, Includes the following steps: S1. Mix battery black powder with water to form a slurry, add sulfuric acid, heat and pressurize to carry out acid leaching reaction, and filter to obtain lithium-containing leachate and leaching residue; S2. Mix the leaching residue with water to form a slurry, add sulfuric acid and reducing agent, heat to carry out acid leaching reaction, and filter to obtain a leaching solution containing nickel, cobalt and manganese. S3. Add an oxidant to the leaching solution containing nickel, cobalt and manganese, adjust the pH with alkali to remove iron and aluminum, and filter to obtain the iron and aluminum removed solution. S4. Use HBL120 extractant to extract Ca from the liquid after iron and aluminum removal to obtain an organic phase loaded with Ca and a raffinate containing Co, Ni and Mn. S5. Use P204 extractant to extract Mn from the raffinate containing Co, Ni and Mn to obtain an organic phase loaded with Mn and a raffinate containing Co and Ni. The organic phase loaded with Mn is washed with sulfuric acid and back-extracted to obtain a manganese sulfate solution. S6. Use Cy272 extractant to extract Co from the raffinate containing Co and Ni to obtain an organic phase loaded with Co and a raffinate containing Ni. The organic phase loaded with Co is washed with sulfuric acid and back-extracted to obtain a cobalt sulfate solution. S7. The Ni-containing raffinate is treated to remove F and P to obtain a nickel sulfate solution.

2. The method for recovering battery black powder according to claim 1, characterized in that, In step S1, the solid-liquid mass ratio of the battery black powder to water is 1:(9~11), the amount of sulfuric acid added is 1.1~1.2 times the molar amount of lithium in the battery black powder, and the acid leaching reaction conditions are: temperature 180~220℃, pressure 1.0~2.3MPa, time 2~5h.

3. The method for recycling battery black powder according to claim 1, characterized in that, In step S2, the solid-liquid mass ratio of the leaching residue to water is 1:(4~6), the amount of sulfuric acid added is 1.1~1.2 times the sum of the molar amounts of Co, Ni, and Mn in the leaching residue, and the conditions for the acid leaching reaction are: temperature 60~70℃, time 2~5h.

4. The method for recycling battery black powder according to claim 1, characterized in that, In step S2, the reducing agent includes sodium metabisulfite; the mass of the reducing agent is 15% to 20% of the mass of the leaching residue.

5. The method for recovering battery black powder according to claim 1, characterized in that, In step S3, the oxidant includes hydrogen peroxide, the alkali includes sodium hydroxide, and the pH adjustment is to adjust the pH to 4.5~5.

5.

6. The method for recovering battery black powder according to claim 1, characterized in that, In step S4, the volume concentration of the HBL120 extractant is 20%~25%, and the saponification value is 0.1~0.15; The extraction in step S4 also includes washing, hydrochloric acid back-extraction, and sulfuric acid back-extraction, wherein the number of extraction stages is 4 to 6, the number of washing stages is 2 to 4, the number of hydrochloric acid back-extraction stages is 2 to 4, and the number of sulfuric acid back-extraction stages is 2 to 4.

7. The method for recycling battery black powder according to claim 1, characterized in that, In step S5, the volume concentration of the P204 extractant is 20%~25%, and the saponification value is 0.4~0.5; The extraction in step S5 also includes washing and back-extraction, wherein the number of extraction stages is 9 to 11, the number of washing stages is 10 to 12, and the number of back-extraction stages is 9 to 11.

8. The method for recycling battery black powder according to claim 1, characterized in that, In step S6, the volume concentration of the Cy272 extractant is 20%~25%, and the saponification value is 0.4~0.5; The extraction in step S6 also includes washing and back-extraction, wherein the number of extraction stages is 9 to 11, the number of washing stages is 10 to 12, and the number of back-extraction stages is 9 to 11.

9. The method for recycling battery black powder according to claim 1, characterized in that, In step S7, the removal of F and P involves adding Huasheng defluorination agent to the Ni-containing raffinate and adjusting the pH to 4-6.

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