Method for preparing lithium carbonate by extracting lithium from waste ternary lithium battery

Abstract

The application relates to a method for preparing lithium carbonate by extracting lithium from waste ternary lithium batteries, and belongs to the technical field of battery materials. The method comprises the following steps: W1. pretreatment of the waste ternary lithium batteries, W2. acid immersion, W3. adjustment of a pH value, W4. reaction of a filtrate with a sodium carbonate solution, W5. addition of a composite additive into a lithium carbonate precursor solution, filtration of lithium carbonate precursor precipitates, and drying to obtain lithium carbonate. In the method, a composite additive composed of propanol and acetaldehyde is used, the settling speed of the lithium carbonate precursor precipitates is improved, and the impurity content is low.

Description

Technical Field

[0001] This invention belongs to the field of battery materials technology, and relates to a method for extracting lithium from waste ternary lithium batteries to prepare lithium carbonate and its application. Background Technology

[0002] Lithium-ion batteries possess numerous advantages, including high energy density and long lifespan, and have been widely used in electric vehicles, energy storage, and electronic products. Among various types of lithium-ion batteries, lithium nickel cobalt manganese oxide (NCO) batteries have significant potential advantages in material cost and cycle life, and are widely considered the future direction for lithium battery cathode materials. With the development of the lithium battery industry and the large-scale application of NCO batteries, the quantity of waste NCO batteries is becoming increasingly substantial. Recycling waste NCO batteries, especially their cathode materials, offers both economic and environmental benefits.

[0003] Invention CN117163979A discloses a method for preparing battery-grade lithium carbonate from lithium iron phosphate battery powder, belonging to the field of battery recycling technology. The method includes the following steps: retired lithium batteries are disassembled and crushed to obtain battery powder; the battery powder, after removing copper and aluminum, undergoes high-pressure conversion with a sodium carbonate solution; the conversion material and water are slurried in a reactor, and carbon dioxide is passed through for leaching to obtain sodium iron phosphate and a lithium-containing liquid; the lithium-containing liquid is purified and crystallized in a negative pressure crystallizer; the crystallized lithium carbonate is washed and dried to obtain battery-grade lithium carbonate. This invention selectively extracts lithium by completing ion exchange between sodium ions and lithium ions in the lithium iron phosphate crystal structure under high temperature and pressure.

[0004] Invention CN117125728A discloses an apparatus and method for recycling lithium carbonate from waste ternary lithium batteries. The method includes the following steps: S1, reduction roasting process: reducing and roasting the ternary electrode material to obtain roasted material; S2, grinding and water immersion process: grinding and water immersion of the roasted material to obtain a first slurry; S3, recycling reaction process: recycling the first slurry with carbon dioxide to obtain a second slurry; S4, impurity removal and filtration process: filtering the second slurry to remove impurities, obtaining filtrate and filter residue; S5, pyrolysis and lithium extraction process: pyrolyzing the filtrate to obtain solid lithium carbonate; S6, washing process: washing the solid lithium carbonate; S7, drying process: drying the washed lithium carbonate to obtain lithium carbonate product.

[0005] Invention CN116914307A discloses a method for recovering lithium carbonate and iron phosphate from waste lithium iron phosphate batteries. The method involves mixing, grinding, sieving, and drying the positive electrode material from the waste lithium iron phosphate batteries; cutting graphite sheets; weighing the positive electrode material and binder polyvinylidene fluoride, adding N,N-dimethylacetamide solvent, mixing thoroughly, and then coating the mixture onto the graphite sheets, followed by drying to obtain an iron phosphate powder electrode sheet. The iron phosphate powder electrode sheet is placed in an electrolytic cell; an electrolyte solution is added, and an oxidation reaction is carried out using the iron phosphate powder electrode sheet as the anode and a titanium electrode as the cathode; the iron phosphate powder electrode sheet is removed, cleaned, and dried to obtain a delithiated iron phosphate powder electrode sheet; the leachate is heated and concentrated to obtain lithium carbonate precipitate; and a reduction reaction is carried out using the delithiated iron phosphate powder electrode sheet as the cathode and a titanium electrode as the anode.

[0006] Invention CN116443903A discloses a method for extracting lithium from waste ternary lithium batteries to prepare lithium carbonate, belonging to the field of waste ternary lithium battery recycling technology. The method involves completely discharging and mechanically crushing waste ternary lithium batteries to obtain ternary lithium battery fragments. These fragments are then screened in two steps to obtain primary powder, secondary powder, and secondary non-powder solid waste. The secondary non-powder solid waste is washed with distilled water, and the washing wastewater is collected. The primary powder, secondary powder, and washing wastewater are mixed and subjected to chemical aluminum removal treatment to obtain wet material. The wet material, distilled water, and hydrogen peroxide are formulated into a mixed slurry, which is then leached to obtain a mixed salt solution. The mixed salt solution is desulfurized to obtain an insoluble salt mixture, which is then reduced, roasted, leached in water, and chemically converted to obtain lithium carbonate. Summary of the Invention

[0007] The purpose of this invention is to provide a method for extracting lithium from waste ternary lithium batteries to prepare lithium carbonate, which has the characteristics of low impurity content.

[0008] The objective of this invention can be achieved through the following technical solutions: A method for extracting lithium from spent ternary lithium batteries to prepare lithium carbonate includes the following steps: W1. Pre-treat the waste ternary lithium batteries by removing the packaging shell and electrolyte; W2. Immerse the pretreated waste ternary lithium batteries in an acidic solution; W3. Filter the soaked waste ternary lithium batteries out of the acidic solution to remove solid impurities, obtain the filtrate and neutralize it to adjust the pH value to 8~9; W4. Add a 30% sodium carbonate solution to the neutralized filtrate to carry out the reaction, and control the temperature and reaction time to obtain a lithium carbonate precursor solution. W5. Add a composite additive to the lithium carbonate precursor solution to rapidly form a lithium carbonate precursor precipitate, filter it out, and dry it to obtain lithium carbonate.

[0009] As a preferred embodiment of the present invention, the acidic solution in step W2 is a hydrochloric acid solution.

[0010] As a preferred embodiment of the present invention, the neutralization treatment in step W3 refers to adjusting the pH value with lithium hydroxide.

[0011] As a preferred embodiment of the present invention, the composite additive in step W5 is composed of propanol and acetaldehyde.

[0012] As a preferred embodiment of the present invention, the mass ratio of propanol to acetaldehyde is 10~15:32~36.

[0013] A lithium carbonate prepared according to the above preparation method.

[0014] The beneficial effects of this invention are: (1) In the method for preparing lithium carbonate from waste ternary lithium batteries provided by the present invention, a composite additive composed of propanol and acetaldehyde is used, which greatly improves the sedimentation rate of lithium carbonate precursor precipitation and reduces the impurity content. Detailed Implementation

[0015] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0016] Example 1 A method for extracting lithium from spent ternary lithium batteries to prepare lithium carbonate includes the following steps: W1. Pre-treat the waste ternary lithium batteries by removing the packaging shell and electrolyte; W2. By weight, 50 parts of pretreated waste ternary lithium batteries were immersed in 120 parts of hydrochloric acid solution with a mass concentration of 36% for 60 minutes. W3. After soaking, the waste ternary lithium batteries are filtered out of the acidic solution to remove solid impurities. The resulting filtrate is then neutralized with lithium hydroxide to adjust the pH value to 8. W4. By weight, add 15 parts of sodium carbonate solution with a mass concentration of 30% to every 100 parts of the neutralized filtrate and react, and control the temperature at 70℃ for 25 minutes to obtain lithium carbonate precursor solution. W5. By weight, add 10 parts of a composite additive consisting of propanol and acetaldehyde in a mass ratio of 10:32 to every 100 parts of lithium carbonate precursor solution to rapidly form lithium carbonate precursor precipitate, filter, dry, and obtain lithium carbonate.

[0017] Example 2 A method for extracting lithium from spent ternary lithium batteries to prepare lithium carbonate includes the following steps: W1. Pre-treat the waste ternary lithium batteries by removing the packaging shell and electrolyte; W2. By weight, 50 parts of pretreated waste ternary lithium batteries were immersed in 120 parts of hydrochloric acid solution with a mass concentration of 37% for 70 minutes. W3. After soaking, the waste ternary lithium batteries are filtered out of the acidic solution to remove solid impurities. The resulting filtrate is then neutralized with lithium hydroxide to adjust the pH to 8.5. W4. By weight, add 15 parts of sodium carbonate solution with a mass concentration of 30% to every 100 parts of the neutralized filtrate and react, and control the temperature at 75℃ for 30 minutes to obtain lithium carbonate precursor solution. W5. By weight, add 10 parts of a composite additive consisting of propanol and acetaldehyde in a mass ratio of 12:34 to every 100 parts of lithium carbonate precursor solution to rapidly form lithium carbonate precursor precipitate, filter, dry, and obtain lithium carbonate.

[0018] Example 3 A method for extracting lithium from spent ternary lithium batteries to prepare lithium carbonate includes the following steps: W1. Pre-treat the waste ternary lithium batteries by removing the packaging shell and electrolyte; W2. By weight, 50 parts of pretreated waste ternary lithium batteries were immersed in 120 parts of hydrochloric acid solution with a mass concentration of 38% for 90 minutes. W3. After soaking, the waste ternary lithium batteries are filtered out of the acidic solution to remove solid impurities. The resulting filtrate is then neutralized with lithium hydroxide to adjust the pH value to 9. W4. By weight, add 15 parts of sodium carbonate solution with a mass concentration of 30% to every 100 parts of the neutralized filtrate and react, and control the temperature at 80℃ for 35 minutes to obtain lithium carbonate precursor solution. W5. By weight, add 10 parts of a composite additive consisting of propanol and acetaldehyde in a mass ratio of 15:36 to every 100 parts of lithium carbonate precursor solution to rapidly form lithium carbonate precursor precipitate, filter, dry, and obtain lithium carbonate.

[0019] Comparative Example 1 A method for extracting lithium from spent ternary lithium batteries to prepare lithium carbonate includes the following steps: W1. Pre-treat the waste ternary lithium batteries by removing the packaging shell and electrolyte; W2. By weight, 50 parts of pretreated waste ternary lithium batteries were immersed in 120 parts of hydrochloric acid solution with a mass concentration of 38% for 90 minutes. W3. After soaking, the waste ternary lithium batteries are filtered out of the acidic solution to remove solid impurities. The resulting filtrate is then neutralized with lithium hydroxide to adjust the pH value to 9. W4. By weight, add 15 parts of sodium carbonate solution with a mass concentration of 30% to every 100 parts of the neutralized filtrate and react, and control the temperature at 80℃ for 35 minutes to obtain lithium carbonate precursor solution. W5. The lithium carbonate precursor solution is allowed to stand, allowing the lithium carbonate precursor to precipitate and deposit in the lower layer. It is then filtered out, dried, and lithium carbonate is obtained.

[0020] Comparative Example 2 A method for extracting lithium from spent ternary lithium batteries to prepare lithium carbonate includes the following steps: W1. Pre-treat the waste ternary lithium batteries by removing the packaging shell and electrolyte; W2. By weight, 50 parts of pretreated waste ternary lithium batteries were immersed in 120 parts of hydrochloric acid solution with a mass concentration of 38% for 90 minutes. W3. After soaking, the waste ternary lithium batteries are filtered out of the acidic solution to remove solid impurities. The resulting filtrate is then neutralized with lithium hydroxide to adjust the pH value to 9. W4. By weight, add 15 parts of sodium carbonate solution with a mass concentration of 30% to every 100 parts of the neutralized filtrate and react, and control the temperature at 80℃ for 35 minutes to obtain lithium carbonate precursor solution. W5. By weight, add 10 parts propanol to every 100 parts of lithium carbonate precursor solution to form lithium carbonate precursor precipitate, filter out, dry, and obtain lithium carbonate.

[0021] Comparative Example 3 A method for extracting lithium from spent ternary lithium batteries to prepare lithium carbonate includes the following steps: W1. Pre-treat the waste ternary lithium batteries by removing the packaging shell and electrolyte; W2. By weight, 50 parts of pretreated waste ternary lithium batteries were immersed in 120 parts of hydrochloric acid solution with a mass concentration of 38% for 90 minutes. W3. After soaking, the waste ternary lithium batteries are filtered out of the acidic solution to remove solid impurities. The resulting filtrate is then neutralized with lithium hydroxide to adjust the pH value to 9. W4. By weight, add 15 parts of sodium carbonate solution with a mass concentration of 30% to every 100 parts of the neutralized filtrate and react, and control the temperature at 80℃ for 35 minutes to obtain lithium carbonate precursor solution. W5. By weight, add 10 parts of acetaldehyde to every 100 parts of lithium carbonate precursor solution to rapidly form lithium carbonate precursor precipitate, filter, dry, and obtain lithium carbonate.

[0022] Performance testing 1. The elemental content of lithium carbonate prepared in each of the above embodiments and comparative examples was analyzed, and the results are shown in Table 1.

[0023] Table 1. Elemental content analysis results of lithium carbonate

[0024] As can be seen from Table 1, the metal impurity content of Examples 1-3, which added a composite additive composed of propanol and acetaldehyde, was significantly lower than that of Comparative Example 1, which did not add the composite additive, and Comparative Examples 2 and 3, which only added propanol or acetaldehyde.

[0025] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for extracting lithium from waste ternary lithium batteries to prepare lithium carbonate, characterized in that, Includes the following steps: W1. Pre-treat the waste ternary lithium batteries by removing the packaging shell and electrolyte; W2. Immerse the pretreated waste ternary lithium batteries in an acidic solution; W3. Filter the soaked waste ternary lithium batteries out of the acidic solution to remove solid impurities, obtain the filtrate and neutralize it to adjust the pH value to 8-9; W4. Add a 30% sodium carbonate solution to the neutralized filtrate to carry out the reaction, and control the temperature and reaction time to obtain a lithium carbonate precursor solution. W5. Add a composite additive to the lithium carbonate precursor solution to rapidly form a lithium carbonate precursor precipitate, filter it out, and dry it to obtain lithium carbonate; The composite additive is composed of propanol and acetaldehyde; the mass ratio of propanol to acetaldehyde is 10-15:32-36.

2. The method for extracting lithium from waste ternary lithium batteries to prepare lithium carbonate according to claim 1, characterized in that, The acidic solution mentioned in step W2 is a hydrochloric acid solution.

3. The method for extracting lithium from waste ternary lithium batteries to prepare lithium carbonate according to claim 1, characterized in that, The neutralization treatment described in step W3 refers to adjusting the pH value with lithium hydroxide.

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