Method for realizing high-selectivity extraction of lithium from waste ternary battery based on reduction roasting

Abstract

The invention discloses a method for realizing high-selectivity extraction of lithium from a waste ternary battery based on reduction roasting, which comprises the following steps: firstly, carrying out wet mixing on ternary black powder, a carbon source and a foaming agent to obtain a mixture; carrying out reduction roasting on the mixed material under the protection condition of mixed gas consisting of CO and CO2 to obtain a roasted material; and finally, the roasted material is subjected to pulpifying, water leaching and stirring, then liquid-solid separation is conducted, and lithium leaching liquid and lithium extraction slag are obtained. According to the lithium extraction method, based on an existing reduction roasting lithium extraction process, the carbon source reducing agent is combined with the protective gas composed of CO and CO2, and the foaming agent is further introduced, so that the reduction effect is enhanced, the leaching rate of lithium is increased (up to 95% or above), the leaching rate of nickel, cobalt and manganese is reduced, and the loss of nickel, cobalt and manganese is reduced synchronously.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium extraction from waste ternary batteries, and in particular relates to a method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting. Background Art

[0002] Lithium batteries have become the preferred power source for modern electronic devices due to their high energy density, long life, fast charging, low self-discharge rate, and high rated voltage. Ternary lithium batteries have become the preferred power battery due to their high energy density, high battery capacity, good rate performance, and good low-temperature discharge. However, with the increase in market capacity, a large number of ternary batteries are facing retirement, and how to recycle waste ternary power batteries has become a research hotspot.

[0003] The existing ternary black powder is mainly recovered by wet acid leaching process or reduction roasting process. Among them, the wet acid leaching process for selective lithium extraction has problems such as long process, high requirements for equipment and materials, low lithium leaching rate, large amount of wastewater, and expensive additives.

[0004] The existing reduction roasting process mainly adopts a scheme of carbon-based reducing agent plus inert gas protection or directly adopts a reducing atmosphere such as hydrogen and carbon monoxide for roasting. Since the carbon-based reducing agent plus inert gas protection roasting scheme is a solid-solid reaction, the diffusion of molecules is slow, the reaction cycle is long, and the overall reaction effect is not ideal. Although the method of roasting in a reducing atmosphere overcomes the shortcomings of solid-solid reactions, the premise of gas-solid reaction is the need for gas diffusion. The reaction only begins when the gas diffuses to the solid surface. Based on the above reasons, the effects of both schemes are not ideal.

[0005] Based on this, on the basis of selective lithium extraction based on reduction roasting, the preparation process is improved to enhance the reduction effect, thereby achieving highly selective lithium extraction from waste ternary batteries. Summary of the invention

[0006] Purpose of the invention: The technical problem to be solved by the present invention is to provide a method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting, which enhances the reduction effect and improves the recovery rate of lithium.

[0007] Technical solution: The present invention provides a method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting, comprising the following steps:

[0008] (1) Wet mixing ternary black powder, a carbon source and a foaming agent to obtain a mixture; the foaming agent includes a carbon-containing low-boiling alcohol and / or a hydrocarbon organic matter;

[0009] (2) reducing and roasting the mixed material under the protection condition of a mixed gas consisting of CO and CO2 to obtain a roasted material;

[0010] (3) The roasted material is slurried, water-soaked, stirred, and then liquid-solid separated to obtain a lithium leaching solution and lithium extraction slag.

[0011] The present invention adopts a carbon source as a reducing agent and combines it with a mixed gas composed of CO and CO2. On the one hand, the carbon source reacts with the ternary black powder in a solid-solid manner after heating to initially achieve the reduction effect. On the other hand, the carbon monoxide reducing atmosphere in the mixed gas reacts with the ternary black powder in a gas-solid manner to promote the reduction effect. Furthermore, the carbon dioxide in the mixed gas can react with the carbon source to generate carbon monoxide, thereby adding a diffusion path for the reducing atmosphere to promote the reduction reaction inside the ternary black powder system, thereby enhancing the reduction effect from inside to outside the system.

[0012] In addition, based on the carbon source and the mixed gas, by further adding a foaming agent, the addition of the foaming agent can not only improve the problem of uneven local dispersion caused by mixing and grinding during the wet mixing process, but also play a certain role in cooling; on the other hand, the foaming agent will volatilize during roasting, thereby forming a certain porosity inside the mixed material system, and the porous structure can promote the diffusion of the reducing atmosphere, that is, provide a channel for the reducing atmosphere to enter the system, increase the specific surface area of ​​the solid participating in the reaction, promote the occurrence of the reaction, and strengthen the reduction effect. In addition, the decomposition and volatilization process of the carbon-based foaming agent will also produce reducing gas, further enhancing the reduction effect.

[0013] Furthermore, in step (1) of the lithium extraction method of the present invention, the amount of the foaming agent added is 5-50% of the mass of the ternary black powder. Preferably, the amount of the foaming agent added can be 20-30% of the mass of the ternary black powder.

[0014] Furthermore, in step (1) of the lithium extraction method of the present invention, the foaming agent includes at least one of water, ethanol, propanol or pentane.

[0015] Furthermore, in step (1) of the lithium extraction method of the present invention, the carbon source comprises at least one of petroleum coke, lignite, anthracite or coke, and the amount of the carbon source added is 20-150% of the mass of the ternary black powder. Preferably, the amount of the carbon source added can be 50-100% of the mass of the ternary black powder.

[0016] Furthermore, in step (2) of the lithium extraction method of the present invention, the volume fraction of CO in the mixed gas is 10-90%, and the volume fraction of CO2 is 10-90%. Preferably, the volume fraction of CO in the mixed gas can be 60-80%, and the volume fraction of CO2 can be 20-40%.

[0017] Furthermore, in step (2) of the lithium extraction method of the present invention, the calcination temperature is 500-800°C, and the calcination time is 60-300 min. Preferably, the calcination temperature can be 600-700°C, and the calcination time can be 120-150 min.

[0018] Furthermore, in step (2) of the lithium extraction method of the present invention, after the reduction roasting, the atmosphere is continued to be maintained until it is cooled to below 100° C. to obtain a roasted material.

[0019] Furthermore, in step (3) of the lithium extraction method of the present invention, the temperature of the slurry water immersion is 40-80°C, the time of the slurry water immersion is 30-120 minutes, and the solid-liquid ratio of the slurry water immersion is 1:(3-10). Preferably, the temperature of the slurry water immersion can be 60-70°C, the time of the slurry water immersion can be 90-120 minutes, and the solid-liquid ratio of the slurry water immersion can be 1:5.

[0020] Beneficial effects: Compared with the prior art, the significant advantages of the present invention are: the lithium extraction method is based on the existing reduction roasting lithium extraction process, by combining the carbon source reducing agent with the protective gas composed of CO and CO2, and further introducing a foaming agent, thereby enhancing the reduction effect, improving the lithium leaching rate (reaching more than 95%), and reducing the leaching rate of nickel, cobalt and manganese, and simultaneously reducing the loss of nickel, cobalt and manganese. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a flow chart of the lithium extraction method. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0023] It should be noted that the raw materials used in the present invention can all be purchased from commercial sources.

[0024] Example 1

[0025] This embodiment 1 is based on reduction roasting to achieve a method for highly selectively extracting lithium from waste ternary batteries, comprising the following steps, the process is as follows Figure 1 As shown:

[0026] (1) placing ternary electrode powder, coke accounting for 70% of the mass of the ternary electrode powder and 20% of ethanol in a ball mill and mixing them uniformly to obtain a mixture;

[0027] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5°C / min under a protective atmosphere consisting of 80% by volume of CO and 20% by volume of CO2, and keeping the temperature at 600°C for 120 min; then maintaining the protective atmosphere and cooling the mixture to below 100°C to obtain a calcined material;

[0028] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 60° C. for 120 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0029] Comparative Example 1

[0030] The comparative example 1 is substantially the same as the example 1, except that 20% ethanol is not added, and specifically comprises the following steps:

[0031] (1) placing ternary electrode powder and coke accounting for 70% of the mass of the ternary electrode powder in a ball mill and mixing them uniformly to obtain a mixed material;

[0032] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5°C / min under a protective atmosphere consisting of 80% by volume of CO and 20% by volume of CO2, and keeping the temperature at 600°C for 120 min; then maintaining the protective atmosphere and cooling the mixture to below 100°C to obtain a calcined material;

[0033] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 60° C. for 120 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0034] Comparative Example 2

[0035] This comparative example 2 is substantially the same as the example 1, except that only CO protective atmosphere is used, and specifically comprises the following steps:

[0036] (1) placing ternary electrode powder, coke accounting for 70% of the mass of the ternary electrode powder and 20% of ethanol in a ball mill and mixing them uniformly to obtain a mixture;

[0037] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5° C. / min under a protective atmosphere of CO, and maintaining the temperature at a roasting temperature of 600° C. for 120 min; then maintaining the protective atmosphere and cooling the mixture to below 100° C. to obtain a roasted material;

[0038] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 60° C. for 120 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0039] Comparative Example 3

[0040] The comparative example 3 is substantially the same as the example 1, except that only H2 protective atmosphere is used, and specifically comprises the following steps:

[0041] (1) placing ternary electrode powder, coke accounting for 70% of the mass of the ternary electrode powder and 20% of ethanol in a ball mill and mixing them uniformly to obtain a mixture;

[0042] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5°C / min under a protective atmosphere of H2, and maintaining the temperature at a roasting temperature of 600°C for 120 min; then maintaining the protective atmosphere and cooling the mixture to below 100°C to obtain a roasted material;

[0043] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 60° C. for 120 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0044] Example 2

[0045] This embodiment 2 is a method for realizing high-selective lithium extraction from waste ternary batteries based on reduction roasting, comprising the following steps:

[0046] (1) placing ternary electrode powder, lignite accounting for 50% of the mass of the ternary electrode powder and 20% of ethanol in a ball mill and mixing them uniformly to obtain a mixture;

[0047] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5°C / min under a protective atmosphere consisting of 80% by volume of CO and 20% by volume of CO2, and keeping the temperature at 600°C for 120 min; then maintaining the protective atmosphere and cooling the mixture to below 100°C to obtain a calcined material;

[0048] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 60° C. for 120 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0049] Example 3

[0050] This embodiment 3 is a method for realizing high-selective lithium extraction from waste ternary batteries based on reduction roasting, comprising the following steps:

[0051] (1) placing ternary electrode powder, anthracite accounting for 80% of the mass of the ternary electrode powder and 20% of water in a ball mill and mixing them uniformly to obtain a mixture;

[0052] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5°C / min under a protective atmosphere consisting of 80% by volume of CO and 20% by volume of CO2, and keeping the temperature at 600°C for 120 min; then maintaining the protective atmosphere and cooling the mixture to below 100°C to obtain a calcined material;

[0053] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 60° C. for 120 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0054] Example 4

[0055] This embodiment 4 is a method for realizing high-selective lithium extraction from waste ternary batteries based on reduction roasting, comprising the following steps:

[0056] (1) placing ternary electrode powder, petroleum coke accounting for 100% of the mass of the ternary electrode powder and 20% of water in a ball mill and mixing them uniformly to obtain a mixture;

[0057] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5° C. / min under a protective atmosphere consisting of 70% by volume of CO and 30% by volume of CO2, and maintaining the temperature at 600° C. for 120 min; then maintaining the protective atmosphere and cooling the mixture to below 100° C. to obtain a calcined material;

[0058] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 60° C. for 120 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0059] Example 5

[0060] This embodiment 5 is a method for realizing high-selective lithium extraction from waste ternary batteries based on reduction roasting, comprising the following steps:

[0061] (1) placing ternary electrode powder, coke accounting for 70% of the mass of the ternary electrode powder and 30% of propanol in a ball mill and mixing them uniformly to obtain a mixture;

[0062] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5° C. / min under a protective atmosphere consisting of 70% by volume of CO and 30% by volume of CO2, and maintaining the temperature at 600° C. for 120 min; then maintaining the protective atmosphere and cooling the mixture to below 100° C. to obtain a calcined material;

[0063] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 60° C. for 120 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0064] Example 6

[0065] This embodiment 6 is a method for realizing high-selective lithium extraction from waste ternary batteries based on reduction roasting, comprising the following steps:

[0066] (1) placing ternary electrode powder, coke accounting for 70% of the mass of the ternary electrode powder and 20% of pentane in a ball mill and mixing them uniformly to obtain a mixture;

[0067] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5° C. / min under a protective atmosphere consisting of 70% by volume of CO and 30% by volume of CO2, and maintaining the temperature at 600° C. for 120 min; then maintaining the protective atmosphere and cooling the mixture to below 100° C. to obtain a calcined material;

[0068] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 60° C. for 120 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0069] Example 7

[0070] This embodiment 7 is a method for realizing high-selective lithium extraction from waste ternary batteries based on reduction roasting, comprising the following steps:

[0071] (1) placing ternary electrode powder, coke accounting for 70% of the mass of the ternary electrode powder and 20% of ethanol in a ball mill and mixing them uniformly to obtain a mixture;

[0072] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5° C. / min under a protective atmosphere consisting of 70% by volume of CO and 30% by volume of CO2, and maintaining the temperature at 600° C. for 120 min; then maintaining the protective atmosphere and cooling the mixture to below 100° C. to obtain a calcined material;

[0073] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 60° C. for 120 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0074] Example 8

[0075] This embodiment 8 is a method for realizing high-selective lithium extraction from waste ternary batteries based on reduction roasting, comprising the following steps:

[0076] (1) placing ternary electrode powder, coke accounting for 70% of the mass of the ternary electrode powder and 20% of water in a ball mill and mixing them uniformly to obtain a mixture;

[0077] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5° C. / min under a protective atmosphere consisting of 70% by volume of CO and 30% by volume of CO2, and maintaining the temperature at 600° C. for 120 min; then maintaining the protective atmosphere and cooling the mixture to below 100° C. to obtain a calcined material;

[0078] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 60° C. for 120 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0079] Example 9

[0080] This embodiment 8 is a method for realizing high-selective lithium extraction from waste ternary batteries based on reduction roasting, comprising the following steps:

[0081] (1) placing ternary electrode powder, coke accounting for 70% of the mass of the ternary electrode powder and 30% of ethanol in a ball mill and mixing them uniformly to obtain a mixture;

[0082] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5° C. / min under a protective atmosphere consisting of 60% by volume of CO and 40% by volume of CO2, and maintaining the temperature at 700° C. for 150 min; then maintaining the protective atmosphere and cooling the mixture to below 100° C. to obtain a calcined material;

[0083] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 70° C. for 90 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0084] Comparative Example 4

[0085] This comparative example 4 is substantially the same as Example 9, except that 30% ethanol is not added, and specifically comprises the following steps:

[0086] (1) placing ternary electrode powder and coke accounting for 70% of the mass of the ternary electrode powder in a ball mill and mixing them uniformly to obtain a mixed material;

[0087] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5° C. / min under a protective atmosphere consisting of 60% by volume of CO and 40% by volume of CO2, and maintaining the temperature at 700° C. for 150 min; then maintaining the protective atmosphere and cooling the mixture to below 100° C. to obtain a calcined material;

[0088] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 70° C. for 90 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0089] Comparative Example 5

[0090] This comparative example 5 is substantially the same as Example 9, except that only CO protective atmosphere is used, and specifically comprises the following steps:

[0091] (1) placing ternary electrode powder and coke accounting for 70% of the mass of the ternary electrode powder in a ball mill and mixing them uniformly to obtain a mixed material;

[0092] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5° C. / min under a CO protective atmosphere, and maintaining the temperature at a roasting temperature of 700° C. for 150 min; then maintaining the protective atmosphere and cooling the mixture to below 100° C. to obtain a roasted material;

[0093] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 70° C. for 90 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0094] Comparative Example 6

[0095] This comparative example 6 is substantially the same as the example 9, except that only H2 protective atmosphere is used, and specifically comprises the following steps:

[0096] (1) placing ternary electrode powder, coke accounting for 70% of the mass of the ternary electrode powder and 30% of ethanol in a ball mill and mixing them uniformly to obtain a mixture;

[0097] (2) transferring the mixed material into a crucible and placing it in a tube furnace, setting a heating rate of 5°C / min under a H2 protective atmosphere, and maintaining the temperature at a roasting temperature of 700°C for 150 min; then maintaining the protective atmosphere and cooling the mixture to below 100°C to obtain a roasted material;

[0098] (3) The roasted material was slurried in water at a solid-liquid ratio of 1:5 at 70° C. for 90 min, and then liquid-solid separation was performed to obtain lithium leaching solution and lithium extraction slag.

[0099] The lithium leaching rates of Examples 1 to 9 and Comparative Examples 1 to 6 were tested, and the results obtained are shown in Table 1 below.

[0100] Table 1 Lithium leaching rate of the embodiments and comparative examples

[0101]

[0102]

[0103] Wherein, lithium leaching rate % = {1-(leached slag weight g×lithium content %) / (black powder weight g×lithium content %)}*100%.

[0104] It can be seen from Table 1 that the lithium extraction method of the present invention can enhance the reduction effect, thereby not only improving the lithium leaching rate to more than 95%, but also the enhanced reduction effect can further inhibit the leaching rate of nickel, cobalt and manganese, reducing the loss of nickel, cobalt and manganese.

[0105] In addition to the above embodiments, the lithium extraction steps and process parameters of the present invention can achieve the technical effect of enhancing the reduction effect and improving the lithium leaching rate as claimed in the present invention. Therefore, for the process parameter ranges involved, for example, the amount of the foaming agent added is in the range of 5 to 50% of the mass of the ternary black powder, the amount of the carbon source added is in the range of 20 to 150% of the mass of the ternary black powder, the volume fraction of CO in the mixed gas is 10 to 90%, the volume fraction of CO2 is 10 to 90%, and other parameter ranges, no longer need to be tested and verified one by one.

Claims

1. A method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting, characterized in that: The steps include: (1) Wet mixing ternary black powder, a carbon source and a foaming agent to obtain a mixture; the foaming agent includes a carbon-containing low-boiling alcohol and / or a hydrocarbon organic matter; (2) reducing and roasting the mixed material under the protection condition of a mixed gas consisting of CO and CO2 to obtain a roasted material; (3) The roasted material is slurried, water-soaked, stirred, and then liquid-solid separated to obtain a lithium leaching solution and lithium extraction slag.

2. The method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting according to claim 1, characterized in that: In step (1), the amount of the foaming agent added is 5 to 50% of the mass of the ternary black powder.

3. The method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting according to claim 2, characterized in that: The added amount of the foaming agent is 20-30% of the mass of the ternary black powder.

4. The method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting according to claim 1, characterized in that: In step (1), the foaming agent includes at least one of water, ethanol, propanol or pentane.

5. The method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting according to claim 1, characterized in that: In step (1), the carbon source includes at least one of petroleum coke, lignite, anthracite or coke, and the added amount thereof is 20 to 150% of the mass of the ternary black powder.

6. The method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting according to claim 5, characterized in that: The added amount of the carbon source is 50-100% of the mass of the ternary black powder.

7. The method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting according to claim 1, characterized in that: In step (2), the volume fraction of CO in the mixed gas is 10 to 90%, and the volume fraction of CO2 is 10 to 90%.

8. The method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting according to claim 7, characterized in that: The volume fraction of CO in the mixed gas is 60-80%, and the volume fraction of CO2 is 20-40%.

9. The method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting according to claim 1, characterized in that: In step (2), the calcination temperature is 500-800° C. and the calcination time is 60-300 min.

10. The method for highly selectively extracting lithium from waste ternary batteries based on reduction roasting according to claim 1, characterized in that: In step (3), the temperature of the slurry water immersion is 40-80° C., the time of the slurry water immersion is 30-120 min, and the solid-liquid ratio of the slurry water immersion is 1:(3-10).

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