Cooperative treatment method for battery black powder and nickel-cobalt sulfide concentrate

Abstract

The invention discloses a method for co-processing battery black powder and nickel-cobalt sulfide concentrate. The method mainly comprises the basic procedures of mixing and curing, blast roasting, alkaline leaching, calcium and magnesium removal through ion exchange, preparation of a lithium hydroxide solution through bipolar membrane electrolysis, preparation of lithium hydroxide through evaporation and concentration, acid leaching treatment and the like. By the adoption of the method, the nickel-cobalt sulfide concentrate is converted into the oxide under high-temperature roasting, precipitation of hydrogen sulfide gas in the conventional acid leaching process of the nickel-cobalt sulfide concentrate is avoided, and lithium in the battery black powder is converted into lithium sulfate which is soluble in water under the combined action of sulfur dioxide generated in the roasting process and supplementary auxiliaries; meanwhile, a small amount of nickel, cobalt and manganese is converted into corresponding sulfate; the roasted product obtained by roasting is leached by adopting a lithium hydroxide solution, so that introduction of other impurity ions can be avoided, and meanwhile, the purpose of inhibiting nickel, cobalt and manganese from entering a lithium-rich solution is achieved; according to the method, the use amount of the auxiliary agent can be reduced, the optimization of the process and equipment is realized, the preferential extraction of the lithium is effectively realized, the lithium is separated from nickel, cobalt and manganese, the direct recovery rate of the lithium is greater than 92%, and the leaching rate of the nickel, cobalt and manganese is greater than 99%.

Description

Technical Field

[0001] The invention belongs to the field of recycling waste battery materials and provides a method for co-processing battery black powder and nickel-cobalt sulfide concentrate. Background Art

[0002] In recent years, with the rapid development of new energy power batteries, more and more waste nickel-cobalt-manganese ternary lithium-ion batteries have been produced. In addition, waste lithium-ion batteries contain rich valuable metals and can be used as important secondary resources. After the waste batteries are discharged, disassembled, crushed, sorted and separated, the black mixture obtained is generally called black powder, which contains a large amount of valuable metals such as lithium, nickel, cobalt and manganese.

[0003] For the recycling of valuable metals in black powder, the common process is to obtain a solution rich in nickel, cobalt, manganese and lithium by wet acid leaching, and then extract and separate nickel, cobalt and manganese, and then recover lithium from the residual extract. The main disadvantage of this process is that the process is long and the direct lithium recovery rate is low. In recent years, the process of preferential lithium extraction and recovery of battery black powder has received more attention. Some processes reduce and roast the battery black powder with a reducing agent such as hydrogen, a carbonaceous reducing agent, etc. at a certain temperature, and then adopt direct water leaching or CO2 water leaching to achieve the preferential extraction of lithium; the main problem of this process is the problem of insufficient reduction, resulting in a low lithium leaching rate, which affects the economic benefits. Some processes mix waste lithium batteries with sulfuric acid, ammonium sulfate, potassium hydrogen sulfate or sodium hydrogen sulfate, and then roast them at a certain temperature, and then leaching the roasted sand to achieve the preliminary separation of lithium and nickel, cobalt and manganese. The main problem of this process is that the lithium-rich solution obtained by leaching also contains a small amount of nickel, cobalt and manganese, and secondary separation treatment is required.

[0004] At present, domestic nickel-cobalt mineral resources are mainly sulfide ores. After the ore is mined, nickel-cobalt sulfide concentrate is obtained through mineral processing, enrichment and refining. The conventional processing processes of nickel-cobalt sulfide concentrate mainly include pressure leaching and chlorine leaching processes.

[0005] If the battery black powder and nickel-cobalt sulfide concentrate can be combined for synergistic treatment, there will be certain optimization in equipment investment and process costs. Therefore, there is an urgent need for a method that can synergistically treat battery black powder and nickel-cobalt sulfide concentrate to achieve metal enrichment and recovery. Summary of the invention

[0006] The purpose of the present invention is to provide a method for the coordinated treatment of battery black powder and nickel-cobalt sulfide concentrate, and to achieve the preferential extraction of lithium, and then to achieve the enrichment and extraction of nickel, cobalt, manganese, etc. by using an acid leaching process.

[0007] To this end, the present invention provides the following technical solutions: (1) Mixing and aging: Add the battery black powder, nickel cobalt sulfide concentrate and supplementary additives into the mixer at room temperature and mix and age for 1 to 3 hours; The battery black powder contains 2.5-6% lithium, 10-30% nickel, 5-20% cobalt, 8-20% manganese, and 18-25% carbon. The nickel-cobalt sulfide concentrate is nickel sulfide concentrate, cobalt sulfide concentrate, or nickel-cobalt sulfide concentrate; the mass ratio of the battery black powder to the nickel-cobalt sulfide concentrate is 1:2-5; the supplementary additive can be one of sulfuric acid and ammonium hydrogen sulfate, and the selection standard is not to introduce other impurity ions such as sodium and potassium.

[0008] (2) Blast roasting: The matured material is placed in a roasting furnace, and air is blown in. The material is roasted at 450-600°C for 2-5 hours to obtain roasted sand. Roasting under the condition of blowing air can convert most of the nickel, cobalt, and manganese in the mixed material into oxide form, a small amount into sulfate form, and lithium into lithium sulfate form.

[0009] (3) Alkaline leaching: After the roasted sand is ground, it is leached with lithium hydroxide solution under stirring conditions, and the pH value of the leaching process is controlled to be 8-9 by the amount of lithium hydroxide solution added. After filtration, lithium-rich solution and nickel-cobalt-manganese-rich slag are obtained; the nickel-cobalt-manganese-rich slag is washed with pure water, and after filtration, a dilute lithium solution and washed nickel-cobalt-manganese-rich slag are obtained.

[0010] The lithium concentration in the lithium hydroxide solution is 3~8g / L. It can be prepared with pure water or washing water and lithium hydroxide crystals. The leaching reaction time is 30min~60min. The end point pH value after leaching is 8~9, which can achieve the purpose of inhibiting the simultaneous entry of nickel, cobalt and manganese into the lithium-rich solution. The nickel, cobalt and manganese content in the lithium-rich solution is less than 0.0001g / L. The liquid-to-solid ratio of the nickel-cobalt-manganese slag when washed with pure water is 3~5:1. The washing water obtained is a dilute lithium solution, which can be returned as a medium for preparing lithium hydroxide solution or evaporated and concentrated into a lithium-rich solution. The direct lithium recovery rate is greater than 95%. The nickel-cobalt-manganese slag after washing contains 0.03%~0.1% lithium, which effectively realizes the separation of lithium from nickel, cobalt and manganese.

[0011] (4) Ion exchange to remove calcium and magnesium: The lithium-rich solution is treated with ion exchange resin to remove impurities and calcium and magnesium, thereby obtaining a lithium-rich solution after calcium and magnesium are removed. The ion exchange resin used is a resin that removes calcium and magnesium. When the resin is saturated, it can be analyzed, regenerated, and then recycled.

[0012] (5) Preparation of lithium hydroxide solution by bipolar membrane electrolysis: The lithium-rich solution after the removal of calcium and magnesium is electrolyzed using a bipolar membrane electrolysis device. Pure water is circulated as the electrolytic medium during the process to obtain pure lithium hydroxide solution and dilute sulfuric acid.

[0013] (6) Evaporation and concentration to prepare lithium hydroxide: The pure lithium hydroxide solution is evaporated and concentrated to prepare industrial-grade or battery-grade lithium hydroxide products; part of the prepared lithium hydroxide product is recycled in step (3) as a raw material for preparing the lithium hydroxide solution.

[0014] (7) Acid leaching: The washed nickel-cobalt-manganese-rich slag obtained in step (3) is stirred with water to form a slurry, and sulfuric acid is slowly added, and the acid leaching is carried out at 60-80° C. for 2-5 hours at normal pressure, and the nickel-cobalt-manganese-rich solution and leached slag are obtained after filtration. The liquid-to-solid ratio of the washed nickel-cobalt-manganese-rich slag to water is 3-8:1, and the endpoint pH value is controlled to be 1.0-1.5 during the addition of sulfuric acid. The nickel-cobalt-manganese leaching rate during the entire acid leaching process is greater than 99%.

[0015] The beneficial effects of the present invention are: Provided is a method for co-processing battery black powder and nickel-cobalt sulfide concentrate. By adopting the method, the nickel-cobalt sulfide concentrate is converted into oxides under high-temperature roasting, so that the precipitation of hydrogen sulfide gas in the conventional acid leaching process of the nickel-cobalt sulfide concentrate is avoided, and the lithium in the battery black powder is converted into lithium sulfate that is easily soluble in water by utilizing the combined effect of sulfur dioxide and supplementary auxiliary agents generated during the roasting process, and a small amount of nickel, cobalt and manganese are also converted into corresponding sulfates; the roasted sand obtained by roasting is leached with a lithium hydroxide solution, which can avoid the introduction of other impurity ions and achieve the purpose of inhibiting nickel, cobalt and manganese from entering the lithium-rich solution; the amount of auxiliary agents used can be reduced, the process and equipment can be optimized, the lithium is effectively extracted first, and is separated from nickel, cobalt and manganese, the direct recovery rate of lithium is greater than 92%, and the leaching rate of nickel, cobalt and manganese is greater than 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0017] The process and effects of the present invention are described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0018] Example 1 Reference Figure 1 This embodiment provides a method for co-processing battery black powder and nickel-cobalt sulfide concentrate, comprising the following steps: (1) Mixing and aging: 200 g of battery black powder, 300 g of nickel sulfide concentrate, and 100 g of ammonium hydrogen sulfate are added into a mixer and mixed and aged for 2 hours; the battery black powder contains 4.78% lithium, 18.3% nickel, 11.2% cobalt, and 18.44% manganese; the nickel sulfide concentrate contains 56.3% nickel, 0.23% cobalt, and 28.7% sulfur.

[0019] (2) Blast roasting: The slaking material is placed in a roasting furnace, air is blown in, and roasted at 550°C for 4 hours to obtain roasted sand. The roasted sand is weighed to be 403.4 g.

[0020] (3) Alkaline leaching: A certain amount of lithium hydroxide solution with a lithium concentration of 4g / L was prepared using pure water and monohydrate lithium hydroxide crystals. After grinding the roasted sand, the lithium hydroxide solution was added thereto. The reaction was leached at room temperature for 1h under stirring conditions. The reaction pH was controlled to 8-9 by controlling the amount of lithium hydroxide solution added. At this time, the amount of lithium hydroxide solution used was 1.2L. After filtration, 1.17L of lithium-rich solution was obtained, which contained 9.8g / L lithium, 0.32g / L calcium, and 0.18g / L magnesium. The nickel-cobalt-manganese-rich slag was washed twice with pure water at a liquid-to-solid ratio of 3:1. After filtration, 2.36L of dilute lithium solution and 365.7g of dry weight of washed nickel-cobalt-manganese-rich slag were obtained. The lithium content in the dilute lithium solution was 0.81g / L, and the lithium content in the washed nickel-cobalt-manganese-rich slag was 0.12%. During the entire leaching and washing process, the direct recovery of lithium was 97.20% calculated based on the slag.

[0021] (3) Ion exchange to remove calcium and magnesium: 1.17L of lithium-rich solution was treated with ion exchange resin to remove impurities and calcium and magnesium; 1.17L of lithium-rich solution after calcium and magnesium removal was obtained, which contained 9.6g / L lithium, less than 0.0001g / L calcium, and less than 0.0001g / L magnesium.

[0022] (5) Preparation of lithium hydroxide solution by bipolar membrane electrolysis: 1.17L of lithium-rich solution after the removal of calcium and magnesium was electrolyzed using a bipolar membrane electrolysis test device. Pure water was circulated as the electrolytic medium during the process to produce 1.76 pure lithium hydroxide solution, which contained 6.32g / L lithium. The lithium loss during the electrolysis process was less than 1%.

[0023] (6) Preparation of lithium hydroxide by evaporation and concentration: 1.76L of pure lithium hydroxide solution is concentrated by evaporation to prepare lithium hydroxide product, and the obtained product meets the index requirements of battery-grade lithium hydroxide product; (7) Acid leaching treatment: 365.7 g of washed nickel-cobalt-manganese-rich slag was stirred with 2 L of pure water to form a slurry. Sulfuric acid was slowly added at a temperature of 70°C and the reaction time was controlled to be 3 hours. The end point pH value was 1.0-1.5. After filtration, a nickel-cobalt-manganese-rich solution and leached slag were obtained. The nickel-cobalt-manganese leaching rate was greater than 99%.

[0024] Embodiment 2: (1) Mixing and aging: 200 g of battery black powder, 400 g of nickel-cobalt sulfide concentrate, and 30 mL of sulfuric acid are added into a mixer for mixing and aging for 3 h; the battery black powder contains 4.78% lithium, 18.3% nickel, 11.2% cobalt, and 18.44% manganese; the nickel-cobalt sulfide concentrate contains 28.3% nickel, 11.7% cobalt, and 30.87% sulfur.

[0025] (2) Blast roasting: The aged material is placed in a roasting furnace, air is blown in, and roasted at 550°C for 4 hours to obtain roasted sand. The roasted sand weighs 487.6 g.

[0026] (3) Alkaline leaching: A certain amount of lithium hydroxide solution with a lithium concentration of 6 g / L was prepared using pure water and monohydrate lithium hydroxide crystals. After grinding the roasted sand, the lithium hydroxide solution was added thereto, and the reaction was leached for 1 hour under stirring conditions. The reaction pH value was controlled to 8-9 by controlling the amount of lithium hydroxide solution added. At this time, the amount of lithium hydroxide solution used was 0.98 L. After filtration, 0.95 L of lithium-rich solution was obtained, which contained 15.61 g / L of lithium, 0.30 g / L of calcium, and 0.17 g / L of magnesium. The nickel-cobalt-manganese-rich slag was washed twice with pure water at a liquid-solid ratio of 4:1. After filtration, 3.2 L of dilute lithium solution and 423.6 g of dry weight of washed nickel-cobalt-manganese-rich slag were obtained. The lithium content in the dilute lithium solution was 0.34 g / L, and the lithium content in the washed nickel-cobalt-manganese-rich slag was 0.088%. During the entire leaching and washing process, the direct recovery of lithium was 97.78% calculated based on the slag.

[0027] (4) Ion exchange to remove calcium and magnesium: 0.95 L of lithium-rich solution was treated with special ion exchange resin A to remove impurities and calcium and magnesium; 0.95 L of lithium-rich solution after calcium and magnesium removal was obtained, which contained 15.53 g / L lithium, less than 0.0001 g / L calcium, and less than 0.0001 g / L magnesium.

[0028] (5) Preparation of lithium hydroxide solution by bipolar membrane electrolysis: 0.95 L of lithium-rich solution after the removal of calcium and magnesium was electrolyzed using a bipolar membrane electrolysis test device. Pure water was circulated as the electrolytic medium during the process to produce 1.82 L of pure lithium hydroxide solution, which contained 8.08 g / L of lithium. The lithium loss during the electrolysis process was less than 1%.

[0029] (6) Preparation of lithium hydroxide by evaporation and concentration: 1.82 L of pure lithium hydroxide solution is concentrated by evaporation to prepare lithium hydroxide product, and the obtained product meets the product index requirements of battery-grade lithium hydroxide; (7) Acid leaching treatment: 423.6 g of washed nickel-cobalt-manganese-rich slag was stirred with 3 L of pure water to form a slurry. Sulfuric acid was slowly added at a temperature of 80°C and the reaction time was controlled to be 4 hours. The end point pH value was 1.0-1.5. After filtration, a nickel-cobalt-manganese-rich solution and leached slag were obtained. The nickel-cobalt-manganese leaching rate was greater than 99%.

[0030] In summary, the present invention relates to a method for co-processing battery black powder and nickel-cobalt sulfide concentrate, wherein the nickel-cobalt sulfide concentrate is converted into oxides under high-temperature roasting, thereby avoiding the precipitation of hydrogen sulfide gas in the conventional acid leaching process of the nickel-cobalt sulfide concentrate, and utilizing the combined effect of sulfur dioxide generated during the roasting process and supplementary additives to convert lithium in the battery black powder into lithium sulfate that is easily soluble in water, and a small amount of nickel, cobalt and manganese are also converted into corresponding sulfates; roasted sand obtained by roasting is leached with a lithium hydroxide solution, thereby avoiding the introduction of other impurity ions and achieving the purpose of inhibiting nickel, cobalt and manganese from entering a lithium-rich solution; the amount of additives used can be reduced, the process and equipment can be optimized, the preferential extraction of lithium is effectively achieved, and the lithium is separated from nickel, cobalt and manganese, the direct recovery rate of lithium is greater than 92%, and the leaching rate of nickel, cobalt and manganese is greater than 99%.

[0031] The above are preferred embodiments of the present invention. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for co-processing battery black powder and nickel-cobalt sulfide concentrate, characterized in that: The following steps are involved: (1) Mixing and maturing: Mixing and maturing the battery black powder, nickel-cobalt sulfide concentrate and supplementary additives; (2) Blast roasting: Place the matured material in a roasting furnace, blow air into it, and roast it at 450-600°C for 2-5 hours to obtain roasted sand; (3) Alkaline leaching: After grinding the roasted sand, leaching is carried out with a lithium hydroxide solution under stirring conditions, and the pH value of the leaching process is controlled to be 8-9 by the amount of lithium hydroxide solution added. After filtering, a lithium-rich solution and nickel-cobalt-manganese-rich slag are obtained; the nickel-cobalt-manganese-rich slag is washed with pure water, and after filtering, a dilute lithium solution and washed nickel-cobalt-manganese-rich slag are obtained; (4) Ion exchange to remove calcium and magnesium: The lithium-rich solution is treated with ion exchange resin to remove impurities and calcium and magnesium, thereby obtaining a lithium-rich solution after calcium and magnesium removal; (5) Preparation of lithium hydroxide solution by bipolar membrane electrolysis: The lithium-rich solution after calcium and magnesium removal is electrolyzed using a bipolar membrane electrolysis device, with pure water circulating as the electrolytic medium to obtain pure lithium hydroxide solution and dilute sulfuric acid; (6) Preparation of lithium hydroxide by evaporation and concentration: Evaporation and concentration of pure lithium hydroxide solution to prepare industrial-grade or battery-grade lithium hydroxide products; (7) Acid leaching: The washed nickel-cobalt-manganese-rich slag obtained in step (3) is stirred with water to form a slurry, and sulfuric acid is slowly added to carry out acid leaching at 60-80° C. for 2-5 hours at normal pressure, and a nickel-cobalt-manganese-rich solution and leached slag are obtained after filtration.

2. The method for co-processing battery black powder and nickel-cobalt sulfide concentrate according to claim 1, characterized in that: In step (1), the battery black powder contains 2.5-6% lithium, 10-30% nickel, 5-20% cobalt, 8-20% manganese, and 18-25% carbon.

3. The method for co-processing battery black powder and nickel-cobalt sulfide concentrate according to claim 1, characterized in that: In step (1), the nickel-cobalt sulfide concentrate is nickel sulfide concentrate, cobalt sulfide concentrate or nickel-cobalt sulfide concentrate; the mass ratio of battery black powder to nickel-cobalt sulfide concentrate is 1:2-5; and the supplementary auxiliary agent is one of sulfuric acid and ammonium hydrogen sulfate.

4. The method for co-processing battery black powder and nickel-cobalt sulfide concentrate according to claim 1, characterized in that: In step (3), the lithium concentration in the lithium hydroxide solution is 3-8 g / L; the leaching reaction time is 30 min-60 min, and the end point pH value after leaching is 8-9.

5. The method for co-processing battery black powder and nickel-cobalt sulfide concentrate according to claim 1, characterized in that: In step (3), the nickel, cobalt and manganese content in the lithium-rich solution is less than 0.0001 g / L; the liquid-to-solid ratio of the nickel-cobalt-manganese rich slag when washed with pure water is 3-5:1; and the lithium content in the nickel-cobalt-manganese rich slag after washing is 0.03%-0.1%.

6. The method for co-processing battery black powder and nickel-cobalt sulfide concentrate according to claim 1, characterized in that: In step (6), part of the prepared lithium hydroxide product is recycled in step (3) as a raw material for preparing the lithium hydroxide solution.

7. The method for co-processing battery black powder and nickel-cobalt sulfide concentrate according to claim 1, characterized in that: In step (7), the liquid-to-solid ratio of the washed nickel-cobalt-manganese rich slag to water is 3-8:1, the end point pH value is controlled to be 1.0-1.5 during the addition of sulfuric acid, and the nickel-cobalt-manganese leaching rate during the entire acid leaching process is greater than 99%.

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