阅读说明：本技术 一种废旧动力电池正极材料中锂的提取方法 (Method for extracting lithium from anode material of waste power battery ) 是由 夏永高 邓龙平 常凤真 于 2020-06-18 设计创作，主要内容包括：本发明提供一种废旧动力电池正极材料中锂的提取方法,包括以下步骤：将废旧三元动力电池的正极片在二氧化碳气氛下进行热处理,分离得到活性材料后,将所述活性材料溶解得到含有锂离子的溶液,最后将溶液中的锂离子沉淀得到锂盐。本发明采用二氧化碳对正极材料进行高温处理,在500～900℃即可生成碳酸锂及金属氧化物,比较容易对正极材料的结构进行破坏,其中的碳酸锂是一种用稀酸即可溶解的产物,便于后续处理,得到纯度较高的锂产品,这极大的提高锂的提取率；采用二氧化碳煅烧安全可控,且不易出现过渡金属在碳还原中出现的过度还原与烧结的情况,便于后续处理；二氧化碳相对于还原性气体更加安全,环保且价格便宜,具有成本优势。(The invention provides a method for extracting lithium from a waste power battery anode material, which comprises the following steps: the method comprises the steps of carrying out heat treatment on a positive plate of a waste ternary power battery in a carbon dioxide atmosphere, separating to obtain an active material, dissolving the active material to obtain a solution containing lithium ions, and finally precipitating the lithium ions in the solution to obtain the lithium salt. According to the invention, carbon dioxide is adopted to carry out high-temperature treatment on the positive electrode material, lithium carbonate and metal oxide can be generated at 500-900 ℃, the structure of the positive electrode material is easy to destroy, wherein the lithium carbonate is a product which can be dissolved by dilute acid, so that the subsequent treatment is convenient, a lithium product with higher purity is obtained, and the extraction rate of lithium is greatly improved; the calcining by adopting carbon dioxide is safe and controllable, and the excessive reduction and sintering of transition metal in the carbon reduction are not easy to occur, so that the subsequent treatment is convenient; compared with reducing gas, the carbon dioxide is safer, environment-friendly and cheap, and has cost advantage.)

1. A method for extracting lithium from a waste ternary power battery positive electrode material comprises the following steps:

the method comprises the steps of carrying out heat treatment on a positive plate of a waste ternary power battery in a carbon dioxide atmosphere, separating to obtain an active material, dissolving the active material to obtain a solution containing lithium ions, and finally precipitating the lithium ions in the solution to obtain the lithium salt.

2. The extraction method according to claim 1, characterized by comprising the steps of:

A) calcining the positive plate of the waste ternary power battery in a carbon dioxide atmosphere, and then separating a current collector from an active material by a physical separation method;

the calcining temperature is 500-700 ℃, and the calcining time is 2-12 hours;

B) mixing the separated active material with water, adding acid, adjusting the pH value of the mixed solution to 6-10, and performing solid-liquid separation after soaking;

C) and adding alkali into the filtrate obtained by the solid-liquid separation, adjusting the pH value to 8-10, and adding soluble carbonate to obtain lithium carbonate precipitate.

3. The extraction method according to claim 1, wherein the separated active material is pulverized and then subjected to a subsequent operation;

the crushed mesh number is 20-400 meshes.

4. The extraction method according to claim 2, wherein the solid-to-liquid ratio of the active material to water in the step B) is (10-100) g: 1L of the compound.

5. The extraction method according to claim 2, wherein the acid in step B) is one or more of carboxylic acid, carbonic acid, sulfuric acid, nitric acid and hydrochloric acid;

the concentration of the acid in the step B) is 0.1-1 mol/L.

6. The extraction method according to claim 2, wherein the soaking time in the step B) is 4-8 hours.

7. The extraction process according to claim 2, characterized in that the base in step C) is sodium hydroxide and/or ammonia.

8. The extraction method according to claim 2, wherein the soluble carbonate in step C) is one or more of sodium carbonate, ammonium bicarbonate, potassium carbonate and potassium bicarbonate.

9. The extraction method according to any one of claims 2 to 8, wherein the current collector separated by the physical method in the step A) is subjected to acid washing to obtain a pure current collector.

10. The extraction process according to any one of claims 2 to 8, wherein the lithium carbonate precipitate in step C) is filtered and the filtrate obtained is returned to step B) for use as a solvent for soaking.

Technical Field

The invention belongs to the technical field of lithium ion battery recovery, and particularly relates to a method for extracting lithium from a positive electrode material of a waste power battery.

Background

At present, lithium ion batteries have been widely used in the fields of electric vehicles, mobile phones, and the like because of their advantages of high specific capacity, long cycle life, small self-discharge, and the like. Considering that the general service life of the battery is 5-8 years, it is expected that a large amount of batteries enter a scrapping stage in the coming years even if a part of batteries with good states are utilized in a gradient manner and continue to play a value in the fields of energy storage and the like. The batteries contain a large amount of organic chemicals and heavy metals, which, if left untreated, pose a great threat to the environment. Because lithium, cobalt and nickel contained in the waste batteries have high economic value, and part of metals (such as cobalt and nickel) are strategic national resources, the effective treatment of the waste batteries and the recovery of valuable metals not only can generate great economic benefit, but also have important significance in the aspects of environmental protection and national strategy.

The high-efficiency recovery of different metals of waste lithium ion batteries is attracting more and more attention, and the current recovery technology mainly comprises pyrometallurgy and hydrometallurgy (including bioleaching). In pyrometallurgical processes, only the recovery of valuable metals is usually of interest, not considering electrolytes and plastics (about 40% to 50% by weight of the cell) or other components (e.g. lithium salts). Compared with the pyrogenic recovery, the wet recovery can explore more values of the waste batteries. But the front-end disassembly process still depends on a large amount of manpower, and the requirement of large-scale production cannot be met; meanwhile, in the process of extracting metal ions (such as nickel, cobalt, manganese and the like) for multiple times, the lithium solution is continuously diluted, the finally obtained lithium diluted solution (0.5-3 g/L) is very difficult to treat, and the lithium diluted solution is generally treated as waste water after being precipitated by saturated sodium carbonate, so that the recovery of lithium is obviously unreasonable. Therefore, there remains a need to explore a simplified hydrometallurgical process to simultaneously separate and recover different metals from existing complex spent lithium ion batteries.

At present, the anode material is mainly subjected to heat treatment by using reducing gases such as ammonia gas and/or sulfur dioxide in the industry. However, the use of ammonia gas and/or sulfur dioxide gas has high requirements for equipment, has certain toxicity, is easy to cause excessive reduction and sintering of transition metals, and is not beneficial to separation of subsequent metals.

Disclosure of Invention

The invention aims to provide an extraction method of lithium in a waste power battery anode material, which is safer and more controllable and has high extraction rate.

The invention provides a method for extracting lithium from a waste ternary power battery positive electrode material, which comprises the following steps:

the method comprises the steps of carrying out heat treatment on a positive plate of a waste ternary power battery in a carbon dioxide atmosphere, separating to obtain an active material, dissolving the active material to obtain a solution containing lithium ions, and finally precipitating the lithium ions in the solution to obtain the lithium salt.

Preferably, the method comprises the following steps:

A) calcining the positive plate of the waste ternary power battery in a carbon dioxide atmosphere, and then separating a current collector from an active material by a physical separation method;

the calcining temperature is 500-700 ℃, and the calcining time is 2-12 hours;

B) mixing the separated active material with water, adding acid, adjusting the pH value of the mixed solution to 6-10, and performing solid-liquid separation after soaking;

C) and adding alkali into the filtrate obtained by the solid-liquid separation, adjusting the pH value to 8-10, and adding soluble carbonate to obtain lithium carbonate precipitate.

Preferably, the separated active material is crushed and then subjected to subsequent operation;

the crushed mesh number is 20-400 meshes.

Preferably, the solid-to-liquid ratio of the active material to water in the step B) is (10-100) g: 1L of the compound.

Preferably, the acid in step B) is one or more of carboxylic acid, carbonic acid, sulfuric acid, nitric acid and hydrochloric acid;

the concentration of the acid in the step B) is 0.1-1 mol/L.

Preferably, the soaking time in the step B) is 4-8 hours.

Preferably, the base in step C) is sodium hydroxide and/or aqueous ammonia.

Preferably, the soluble carbonate in step C) is one or more of sodium carbonate, ammonium bicarbonate, potassium carbonate and potassium bicarbonate.

Preferably, the current collector separated by the physical method in the step a) is subjected to acid washing to obtain a pure current collector.

Preferably, the lithium carbonate precipitate in step C) is filtered, and the filtrate obtained is returned to step B) for use as a solvent for soaking.

The invention provides a method for extracting lithium from a waste power battery anode material, which comprises the following steps: the method comprises the steps of carrying out heat treatment on a positive plate of a waste ternary power battery in a carbon dioxide atmosphere, separating to obtain an active material, dissolving the active material to obtain a solution containing lithium ions, and finally precipitating the lithium ions in the solution to obtain the lithium salt. According to the invention, carbon dioxide is adopted to carry out high-temperature treatment on the positive electrode material, lithium carbonate and metal oxide can be generated at 500-900 ℃, the structure of the positive electrode material is easy to destroy, wherein the lithium carbonate is a product which can be dissolved by dilute acid, so that the subsequent treatment is convenient, a lithium product with higher purity is obtained, and the extraction rate of lithium is greatly improved; the method of calcining in carbon dioxide is adopted, so that the structure of the anode material can be damaged at a lower temperature, the calcining temperature is effectively reduced, and the energy consumption is reduced; the calcining by adopting carbon dioxide is safe and controllable, and the excessive reduction and sintering of transition metal in the carbon reduction are not easy to occur, so that the subsequent treatment is convenient; compared with reducing gas, the carbon dioxide is safer, environment-friendly and cheap, and has cost advantage.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a process flow diagram of the present invention;

FIG. 2 is an XRD spectrum of the positive electrode material treated with argon, air and carbon dioxide atmosphere only for 4 hours in example 2 and comparative example of the present invention at 600 ℃;

the blank is an untreated positive electrode material, and it can be seen from the comparison of the standard PDF cards in the figure (4 standard PDF cards from bottom to top in fig. 2 are lithium carbonate and LiCoMn in sequence₃O₈、Li_1.15(Mn_xNi_1-x)_0.85O₂And standard PDF card of cobalt oxide), the positive electrode material baked in the air atmosphere has no structural change, while the positive electrode material baked in the argon-hydrogen atmosphere has a structural change, the structure of the positive electrode material is completely destroyed, MnO, CoO, lithium carbonate and nickel metal phases are generated, obviously, the positive electrode material is excessively reduced in the atmosphere to generate a large amount of nickel metal, which will seriously affect the subsequent treatment. The structure of the anode material roasted in the carbon dioxide atmosphere is completely destroyed to generate MnO₂CoO, NiO, lithium carbonate and a trace of nickel metal phase. The conditions of excessive reduction and sintering of transition metal in carbon reduction are proved to be difficult to occur during the roasting in the mild reducing atmosphere of carbon dioxide;

fig. 3 is an XRD pattern of the lithium carbonate product obtained in example 2 of the present invention. As can be seen from comparison of the standard PDF card (bottom of fig. 3) in the figure, the spectrum peak (upper part of fig. 3) of the standard PDF card is consistent with that of the standard PDF card of lithium carbonate, and no other miscellaneous peak is found, which indicates that according to the scheme for extracting lithium from the waste power battery provided by the present invention, a lithium carbonate product with higher purity can be obtained.

Detailed description of the preferred embodiments

The invention provides a method for extracting lithium from a waste power battery anode material, which comprises the following steps:

the method comprises the steps of carrying out heat treatment on a positive plate of a waste ternary power battery in a carbon dioxide atmosphere, separating to obtain an active material, dissolving the active material to obtain a solution containing lithium ions, and finally precipitating the lithium ions in the solution to obtain the lithium salt.

The method comprises the following specific steps:

A) calcining the positive plate of the waste power battery in a carbon dioxide atmosphere, and then separating the current collector from the active material by a physical separation method;

the calcining temperature is 500-900 ℃, and the calcining time is 1-12 hours;

B) mixing the separated active material with water, adding acid, adjusting the pH value of the mixed solution to 5-10, and performing solid-liquid separation after soaking;

C) and adding alkali into the filtrate obtained by the solid-liquid separation, adjusting the pH value to 8-12, heating the solution to 40-95 ℃, and adding a saturated soluble carbonate solution to obtain a lithium carbonate precipitate.

The mass percentage of each element contained in the untreated positive electrode material in the technical scheme is shown in figure 3), after the treatment of the step A), an aluminum current collector is recovered after simple acid washing, after the positive electrode material is treated by the step B), nickel, cobalt and manganese are remained in filter residues, lithium ions are separated out along with filtrate, and the obtained lithium-containing filtrate is subjected to the step C) to obtain a lithium carbonate product with the purity of 99.5%.

The invention takes out a positive plate from a waste power battery, and then places the positive plate in a carbon dioxide atmosphere for calcination, wherein the waste power battery is preferably a waste lithium-cobalt oxide, a lithium-nickel oxide, a lithium-manganese oxide, a lithium-nickel manganese composite oxide, a lithium-manganese nickel cobalt composite oxide, a lithium-nickel cobalt aluminum composite oxide, a lithium-titanium oxide, a lithium-vanadium oxide battery, more preferably a lithium-cobalt oxide, a lithium-nickel oxide, a lithium-manganese oxide, a lithium-nickel manganese composite oxide, a lithium-manganese nickel cobalt composite oxide, a lithium-nickel cobalt aluminum composite oxide battery, and in the embodiment of the invention, the lithium-manganese nickel cobalt composite oxide can be used.

In the present invention, the positive electrode sheet is placed in a furnace through which carbon dioxide is introduced and calcined.

In the invention, the calcination temperature is preferably 500-700 ℃, more preferably 550-600 ℃, and specifically, in the embodiment of the invention, the calcination temperature can be 500 ℃, 550 ℃, 600 ℃ or 700 ℃; the calcination time is preferably 1 to 12 hours, more preferably 4 to 10 hours, and specifically, in the embodiment of the present invention, the calcination time may be 4 hours, 6 hours, 8 hours, or 10 hours.

In the present invention, the pressure of carbon dioxide in the furnace is preferably 100KPa to 1 MPa.

After calcining and sintering, the invention separates the current collector from the active material of the calcined positive plate by physical separation methods such as manual shaking or vibration screening.

In the invention, the current collector can be an aluminum current collector, and the separated aluminum current collector is subjected to acid washing to obtain pure aluminum foil, in the invention, the acid solution for acid washing is preferably one or more of sulfuric acid, nitric acid and hydrochloric acid, and the concentration of the acid solution is preferably 1-3 mol/L, more preferably 1.5-2.5 mol/L, and most preferably 2 mol/L.

And placing the separated active material in a stirring device, adding deionized water to adjust to a certain solid-to-liquid ratio, slowly adding an acid solution, adjusting the pH of the mixed solution to 5-10, and filtering and separating after soaking.

In the invention, the solid-to-liquid ratio of the active material to the deionized water is preferably (10-100) g: 1L, more preferably (20 to 80) g: 1L, most preferably (30-60) g: 1L, specifically, in the embodiment of the present invention, may be 40 g: 1L, 50 g: 1L, 60 g: 1L; the acid solution is preferably one or more of formic acid, acetic acid, propionic acid, butyric acid, caprylic acid, adipic acid, oxalic acid, malonic acid, succinic acid, maleic acid, tartaric acid, carbonic acid, sulfuric acid, nitric acid and hydrochloric acid; the concentration of the acid solution is preferably 0.1-5 mol/L, more preferably 0.3-2 mol/L, and specifically, in the embodiment of the present invention, it may be 1 mol/L. The addition amount of the acid solution is not particularly limited, and the pH value of a mixture of the active material and water can be adjusted to 5-10, preferably 6-8.

After the acid solution is added, the active material is soaked in the acid solution environment for 1 to 8 hours, preferably 3 to 7 hours, and more preferably 5 to 6 hours.

And (3) filtering and separating after soaking, taking filtered filtrate, firstly adjusting the pH value to 8-12 by using an alkali liquor, heating the solution to 40-95 ℃, then adding soluble carbonate to precipitate lithium carbonate, and carrying out isothermal hot water washing on the lithium carbonate to realize the recovery of the lithium element in the positive plate.

In the present invention, the alkali solution is preferably sodium hydroxide and/or ammonia water; the concentration and the dosage of the alkali liquor are not particularly limited, and the pH value of the filtrate can be adjusted to 8-12. The soluble carbonate is preferably one or more of sodium carbonate, ammonium bicarbonate, potassium carbonate and potassium bicarbonate, and more preferably one or more of a saturated sodium carbonate solution, a saturated ammonium bicarbonate solution and a saturated ammonium carbonate solution.

The invention provides a method for extracting lithium from a waste power battery anode material, which comprises the following steps: A) calcining the positive plate of the waste power battery in a carbon dioxide atmosphere, and then separating the current collector from the active material by a physical separation method; the calcining temperature is 500-900 ℃, and the calcining time is 1-12 hours; B) mixing the separated active material with water, adding acid, adjusting the pH value of the mixed solution to 5-10, and performing solid-liquid separation after soaking; C) and adding alkali into the filtrate obtained by the solid-liquid separation, adjusting the pH value to 8-12, heating the solution to 40-95 ℃, and adding soluble carbonate to obtain lithium carbonate precipitate. According to the invention, carbon dioxide is adopted to carry out high-temperature treatment on the positive electrode material, lithium carbonate and metal oxide can be generated at 500-900 ℃, the structure of the material is easy to destroy, wherein the lithium carbonate is a product which can be dissolved by dilute acid, so that the subsequent treatment is convenient, a lithium product with higher purity is obtained, and the extraction rate of lithium is greatly improved; the method of calcining in carbon dioxide is adopted, so that the material structure can be damaged at a lower temperature, the calcining temperature is effectively reduced, and the energy consumption is reduced; the calcining by adopting carbon dioxide is safe and controllable, and the excessive reduction and sintering of transition metal in the carbon reduction are not easy to occur, so that the subsequent treatment is convenient; compared with reducing gas, the carbon dioxide is safer, environment-friendly and cheap, and has cost advantage.

In order to further illustrate the present invention, the following will describe the method for extracting lithium from the positive electrode material of waste power battery in detail with reference to the examples, but it should not be construed as limiting the scope of the present invention.