阅读说明：本技术 一种锂电池正极材料的循环制备方法 (Cyclic preparation method of lithium battery positive electrode material ) 是由 任燕 邹廷军 于 2019-10-11 设计创作，主要内容包括：本发明提供了一种锂电池正极材料的循环制备方法,包括以下步骤：正极料浆液的调配、提取剂调配、提取浸出反应、液固分离、浸出液除杂净化、镍钴锰前驱体制备、氨水的回收、硫酸铵的回收、提取剂的循环制备、无钠型电池级氢氧化锂的制备、硫酸和氢氧化锂碱液的再生和新正极材料的制备工序。该方法可有效解决现有的制备方法存在的提取剂不能循环利用的问题以及制得的正极材料性能低的问题。(The invention provides a cycle preparation method of a lithium battery anode material, which comprises the following steps: preparing positive electrode slurry, preparing an extracting agent, carrying out extraction leaching reaction, carrying out liquid-solid separation, removing impurities and purifying a leaching solution, preparing a nickel-cobalt-manganese precursor, recovering ammonia water, recovering ammonium sulfate, circularly preparing the extracting agent, preparing sodium-free battery-grade lithium hydroxide, regenerating sulfuric acid and lithium hydroxide lye and preparing a new positive electrode material. The method can effectively solve the problems that the extractant can not be recycled and the prepared cathode material has low performance in the existing preparation method.)

1. A cycle preparation method of a lithium battery positive electrode material is characterized by comprising the following steps:

(1) crushing waste positive electrode materials to obtain particle materials, adding cobalt oxides, nickel oxides, manganese oxides and water into the particle materials, and uniformly mixing to obtain positive electrode material slurry, wherein the liquid-solid mass ratio in the positive electrode material slurry is 1-15: 1;

(2) taking ammonium sulfite and ammonium thiosulfate, mixing the ammonium sulfite and the ammonium thiosulfate uniformly, then adding water into the mixture, and stirring to obtain an extracting agent, wherein the molar ratio of the ammonium sulfite to the ammonium thiosulfate in the extracting agent is 0.05-1: 1;

(3) uniformly mixing the positive electrode material slurry prepared in the step (1) and the extracting agent prepared in the step (2) at the temperature of 50-70 ℃, adding sulfuric acid into the mixture, adjusting the pH value of the solution to be 0.001-3.0 and the ORP to be 150-550 mv, and reacting for 1-3 hours under the stirring condition to obtain mixed slurry;

(4) carrying out solid-liquid separation on the mixed slurry obtained in the step (3) to obtain waste residues and a leaching solution;

(5) heating the leachate prepared in the step (4) to 50-100 ℃, adding a lithium hydroxide solution into the leachate, adjusting the pH value of the solution to 3-5, stirring for 0.5-5 h, filtering to obtain first filter residue and first filtrate, adding the lithium hydroxide solution into the first filtrate, adjusting the pH value of the solution to 5-7, stirring for 0.5-5 h, filtering to obtain second filter residue and second filtrate, introducing the second filtrate into adsorption resin, standing for 0.5-5 h, and discharging to obtain a purified solution;

(6) adding a lithium hydroxide solution into the purified liquid prepared in the step (5), adjusting the pH value of the purified liquid to 10-12, simultaneously adding ammonia water into the purified liquid to enable the concentration of the ammonia water in the purified liquid to reach 0.5-1 mol/L, then heating to 40-80 ℃, stirring for reaction for 2.0-3.0 h, filtering to obtain anode precursor powder and separation liquid, washing the anode precursor powder with water, and drying to obtain an anode precursor;

(7) adding a lithium hydroxide solution into the separation liquid prepared in the step (6), adjusting the pH value of the separation liquid to 8-10, heating to 80-100 ℃, converting ammonia in the separation liquid into ammonia gas, washing the generated ammonia gas with water to obtain ammonia water, and recovering the ammonia water;

(8) evaporating and concentrating the separated liquid obtained after ammonia gas recovery in the step (7) until ammonium sulfate is saturated, cooling, crystallizing and filtering to obtain ammonium sulfate crystals and a third filtrate containing lithium sulfate and lithium hydroxide;

(9) heating the ammonium sulfate crystal prepared in the step (8) to 280-350 ℃, pyrolyzing to obtain mixed gas containing sulfur dioxide, ammonia gas and nitrogen gas, absorbing the mixed gas with water to obtain saturated ammonium sulfite solution, adding sulfur into the saturated ammonium sulfite solution, heating until the solution boils, filtering to obtain ammonium thiosulfate and a fourth filtrate, cooling and crystallizing the fourth filtrate, and filtering to obtain ammonium sulfite;

(10) evaporating and concentrating the third filtrate obtained in the step (8) until the concentration of lithium hydroxide reaches saturation, then cooling, crystallizing and filtering to obtain sodium-free lithium hydroxide and a fifth filtrate, electrolyzing the fifth filtrate, and recovering to obtain a sulfuric acid solution and a lithium hydroxide solution;

(11) and (4) mixing the positive electrode precursor prepared in the step (6) and the sodium-free lithium hydroxide prepared in the step (10) and calcining to prepare the positive electrode material.

2. The method for cyclically preparing the positive electrode material of the lithium battery as claimed in claim 1, wherein the particle size of the particulate material in the step (1) is 80-200 meshes, and the liquid-solid ratio of the positive electrode material slurry is 3: 1.

3. The method of cyclically preparing a positive electrode material for a lithium battery according to claim 1, wherein the amounts of the oxides of nickel, cobalt and manganese added in the step (1) are adjusted according to the type of the newly prepared positive electrode material so that the contents of the three elements of cobalt, nickel and manganese in the prepared slurry are the same as the contents of the three elements of nickel, cobalt and manganese in the newly prepared positive electrode material.

4. The method for cyclically preparing the positive electrode material of the lithium battery as claimed in claim 1, wherein the ratio of the total moles of ammonium sulfite and ammonium thiosulfate in the step (2) to the total moles of manganese, cobalt and nickel elements in the positive electrode material slurry is 0.5-2.0: 1.

5. The method for cyclically preparing a positive electrode material for a lithium battery according to claim 1, wherein the ionic valence of cobalt, nickel and manganese in the cobalt oxide, nickel oxide and manganese oxide in the step (1) is not less than + 2.

6. The method for cyclically preparing a positive electrode material for a lithium battery according to claim 1, wherein the pH of the solution adjusted in the step (3) is 1 to 2.5, and the ORP is 200 to 300 mv.

7. The cyclic production method of a positive electrode material for a lithium battery according to claim 1, wherein the adsorption resin used in the step (5) is a chelate-type ion exchange resin.

8. The method for cyclically preparing the positive electrode material of the lithium battery as claimed in claim 1, wherein the ratio of the molar amount of ammonium sulfate crystals used for pyrolysis in the step (9) to the total molar amount of ammonium sulfite and ammonium thiosulfate used in the step (2) is 0.9-1.2: 1.

9. The method for cyclically preparing the positive electrode material of the lithium battery as claimed in claim 1, wherein the ratio of the molar amount of the sulfur in the step (9) to the molar amount of the ammonium sulfite in the ammonium sulfite solution is 0.5-2.5: 1.

Technical Field

The invention relates to the technical field of lithium battery anode materials, in particular to a cycle preparation method of a lithium battery anode material.

Background

Lithium ion batteries are widely used as energy storage products in the fields of electric tools, electric automobiles, mobile phones, notebook computers and the like, and play an important role in production and life of people. In recent years, the high demand for energy storage products has led to a rise in lithium ion battery production year by year. After the lithium ion battery is repeatedly charged and discharged in the use process, the electrode material can be partially separated from the current collector through repeated expansion and contraction, so that poor contact is caused, meanwhile, the crystal form of the anode material can also be changed in the repeated charging and discharging process, and partial lithium ions can not be freely inserted and separated in the crystal structure, so that the capacity attenuation is serious and the failure is caused. Generally, the cycle life of the lithium ion battery is usually from hundreds of times to about 1000 times (3-5 years), and the service life of the lithium ion battery is limited, which means that the generation amount of the waste lithium ion battery is increased year by year, and then the recovery of the waste lithium ion battery becomes a difficult problem. The battery belongs to serious pollution type solid waste and is an important environmental pollutant, so that the recycling of lithium in the waste battery is not slow.

The lithium ion battery is prepared by tightly combining a positive plate, a negative plate and a diaphragm in a lamination type or winding type, filling the combined materials into a shell, and injecting organic electrolyte for tight packaging. Because of the four main positive electrode materials of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate and lithium nickel cobalt manganese oxide in the current industrial production, the lithium nickel cobalt manganese oxide ternary material has the advantages of high specific discharge capacity, high discharge voltage platform, high energy density and the like, and is known as a positive electrode material with the most development prospect in recent years.

Because lithium, cobalt, nickel, manganese and other precious metal resources in the waste lithium ion battery are mainly concentrated on the anode material, the recovery of lithium, manganese, cobalt and nickel from the waste ternary anode material is a core stage of resource utilization of the waste lithium ion battery. The ternary positive electrode material mainly comprises lithium manganese cobalt nickel oxygen active substances (the mass ratio is about 87-90%), acetylene black conductive agents (the mass ratio is about 5-6%), organic adhesives (the mass ratio is about 3-4%), impurities (the mass ratio is about 1-3%) such as aluminum, iron, copper and the like carried in the crushing process, and meanwhile, the battery is subjected to complex charging and discharging processes and high-low temperature conversion in the using process, so that the existing form of a phase in the waste positive electrode material is extremely complex, the existing form of cobalt nickel manganese lithium is greatly different from that of a new positive electrode material, and complex organic substances also exist, inorganic substances and organic substances are mutually wrapped and inlaid in physical forms, acid-base components and redox components coexist in chemical forms, and the regeneration and utilization process of the ternary positive electrode material is difficult, it is difficult to obtain satisfactory high-quality lithium manganese cobalt nickel products by regeneration with the existing methods.

Some patents report the reuse of the anode material, and according to the difference of the mechanism, the anode material can be roughly classified into three types: (1) a fire method and a wet method. The method reported so far can be summarized as a wet leaching process of roasting the cathode material and liquid-phase wet leaching. The technology adopts a solid-phase roasting process of the anode material, fluoride waste gas is easily generated in the roasting process to pollute the environment, the high-temperature roasting energy consumption is high, the cost of an additional reducing agent is high, and in the roasting process, the contact between an oxidation state substance and the reducing agent in the ternary anode material is insufficient, the reduction efficiency is low, and further the problem of low element leaching rate is caused. (2) A full wet process method. The method reported so far can be summarized as a wet leaching process of the acid solution of the cathode material plus a liquid-phase reducing agent. The technology has the problems of high cost and easy residue of the reducing agent, and the added reducing agent can often form new impurities and increase the cost of purifying and decontaminating the leaching solution. (3) The leaching process of acid solution and gas phase reducing agent is adopted. The reducing agent used in the technology is H₂、CO、SO₂、NH₃、H₂S, CH4, etc., having only reducing property and H₂、CO、CH₄Hydrazine hydrate and the like have extremely high use cost and are difficult to obtain in production, NH3 and H₂S is a highly toxic substance and is easy to cause serious pollution; the gas-phase reaction components of the method can only provide a reducing atmosphere to reduce the oxidizing substances in the positive electrode material, but do not contain the oxidizing substances, so that the method has little effect on substances such as organic matters which need to be oxidized and removed, and along with the reaction, the components wrapped by the organic matters in the positive electrode material at the unreacted part are difficult to be leached continuously, so that the leaching rate of nickel, cobalt, manganese and lithium is low, the reaction residue is large, and the residual organic matters pollute the cobalt, nickel and manganese products in the purification and recovery process of leachate, so that the purity and the reutilization of the products are influenced.

The traditional roasting and acid leaching process has the main problems of high energy consumption, secondary pollution and the like, and is difficult to popularize and apply, while the currently reported wet process needs to additionally consume a large amount of sulfur dioxide, sulfuric acid, alkali liquor, hydrogen peroxide, an extracting agent and other medicaments, so that the problems of high cost, difficulty in purifying and removing impurities of leachate with more impurities, difficulty in meeting the requirements of the battery anode material on the quality of the obtained lithium-manganese-cobalt-nickel product and the like are caused.

On the other hand, no matter what method is adopted for leaching the waste cathode material, most of the currently obtained lithium salt-containing leachate is added with sodium carbonate or sodium bicarbonate to prepare lithium carbonate in the subsequent utilization process, and then the lithium carbonate and the manganese-cobalt-nickel ternary precursor obtained in the previous step are mixed and fired to obtain the ternary cathode material again; because the mixed discharging effect of lithium hydroxide is better than that of lithium carbonate, the ternary cathode material with better performance can be prepared by adopting lithium hydroxide and the ternary precursor, and the sodium-free lithium hydroxide is better than the sodium-containing lithium hydroxide, so a new method is needed to solve the problem of how to prepare the cathode material with excellent performance by utilizing the waste cathode material.

In addition, the existing recycling method of the waste cathode material cannot solve the problem of recycling of an extracting agent, sulfuric acid, alkali liquor and other auxiliary agents, and the performance of the cathode material prepared by the existing method is not high.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a cycle preparation method of a lithium battery positive electrode material, which can effectively solve the problems that an extracting agent cannot be recycled and the prepared positive electrode material has low performance in the existing preparation method.

In order to achieve the purpose, the technical scheme adopted by the invention for solving the technical problems is as follows:

a cycle preparation method of a lithium battery positive electrode material comprises the following steps:

(1) crushing waste positive electrode materials to obtain particle materials, adding cobalt oxides, nickel oxides, manganese oxides and water into the particle materials, and uniformly mixing to obtain positive electrode material slurry, wherein the liquid-solid mass ratio in the positive electrode material slurry is 1-15: 1;

(2) taking ammonium sulfite and ammonium thiosulfate, mixing the ammonium sulfite and the ammonium thiosulfate uniformly, then adding water into the mixture, and stirring to obtain an extracting agent, wherein the molar ratio of the ammonium sulfite to the ammonium thiosulfate in the extracting agent is 0.05-1: 1;

(3) uniformly mixing the positive electrode material slurry prepared in the step (1) and the extracting agent prepared in the step (2) at the temperature of 50-70 ℃, adding sulfuric acid into the mixture, adjusting the pH value of the solution to be 0.001-3.0 and the ORP to be 150-550 mv, and reacting for 1-3 hours under the stirring condition to obtain mixed slurry, wherein the mixed slurry contains cobalt sulfate, nickel sulfate, manganese sulfate, lithium sulfate and ammonium sulfate as main components, and also contains iron, aluminum, fluoride, a conductive agent and a binder with extremely low contents;

(4) carrying out solid-liquid separation on the mixed slurry obtained in the step (3) to obtain waste residues and a leaching solution; the waste residues contain a conductive agent, a binder and a small amount of aluminum scraps, and are treated as industrial raw materials;

(5) heating the leachate prepared in the step (4) to 50-100 ℃, adding a lithium hydroxide solution into the leachate, adjusting the pH value of the solution to 3-5, stirring for 0.5-5 h, filtering to obtain a first filter residue and a first filtrate containing ferric hydroxide and aluminum hydroxide, adding the lithium hydroxide solution into the first filtrate, adjusting the pH value of the solution to 5-7, stirring for 0.5-5 h, filtering to obtain a second filter residue and a second filtrate containing copper hydroxide, introducing the second filtrate into adsorption resin, standing for 0.5-5 h, removing fluoride in the second filtrate, and discharging to obtain a purified solution;

(6) adding a lithium hydroxide solution into the purified liquid prepared in the step (5), adjusting the pH value of the purified liquid to 10-12, simultaneously adding ammonia water into the purified liquid to enable the concentration of the ammonia water in the purified liquid to reach 0.5-1 mol/L, then heating to 40-80 ℃, stirring for reaction for 2.0-3.0 h, filtering to obtain positive electrode precursor powder containing manganese hydroxide, cobalt hydroxide and nickel hydroxide and a separation liquid containing lithium sulfate, ammonium sulfate and lithium hydroxide, washing the positive electrode precursor powder with water, and drying to obtain a sodium-free nickel cobalt manganese positive electrode precursor; returning the washing water to be reused in the step (1) and the step (2) or using the washing water in the subsequent step;

(7) adding a lithium hydroxide solution into the separation liquid prepared in the step (6), adjusting the pH value of the separation liquid to 8-10, heating to 80-100 ℃ to convert ammonia in the separation liquid into ammonia gas, washing the generated ammonia gas with the washing water generated in the step (6) to obtain ammonia water, and recovering the ammonia water;

(8) evaporating and concentrating the separated liquid obtained after ammonia gas recovery in the step (7) until ammonium sulfate is saturated, then cooling, crystallizing and filtering to obtain ammonium sulfate crystals and a third filtrate containing lithium sulfate and lithium hydroxide, condensing water vapor generated in the evaporation process to obtain condensed water, and returning the condensed water to the step (1), the step (2), the step (6) or subsequent steps for recycling;

(9) heating the ammonium sulfate crystal prepared in the step (8) to 280-350 ℃, pyrolyzing to obtain mixed gas containing sulfur dioxide, ammonia gas and nitrogen gas, absorbing the mixed gas with water to obtain saturated ammonium sulfite solution, adding sulfur into the saturated ammonium sulfite solution, heating until the solution boils, filtering to obtain ammonium thiosulfate and fourth filtrate, cooling and crystallizing the fourth filtrate, filtering to obtain ammonium sulfite, and returning the obtained ammonium thiosulfate and ammonium sulfite to the step (2) for reuse;

(10) evaporating and concentrating the third filtrate obtained in the step (8) until the concentration of lithium hydroxide reaches saturation, condensing water vapor generated in the evaporation process to obtain condensed water, and returning the condensed water to the step (1), the step (2), the step (6) or subsequent steps for recycling; then cooling the solution for crystallization, filtering to obtain sodium-free lithium hydroxide and a fifth filtrate, electrolyzing the fifth filtrate to obtain a sulfuric acid solution at the anode and a lithium hydroxide solution at the cathode, recovering the sulfuric acid solution and the lithium hydroxide solution, and respectively returning the sulfuric acid solution and the lithium hydroxide solution to the previous step for reuse;

(11) and (4) mixing the positive electrode precursor prepared in the step (6) and the sodium-free lithium hydroxide prepared in the step (10) according to a certain proportion, and calcining to prepare the positive electrode material.

Further, in the step (1), the particle size of the particle material is 80-200 meshes, and the liquid-solid ratio of the anode material slurry is 3: 1.

Further, in the step (1), the adding amount of the nickel oxide, the cobalt oxide and the manganese oxide is adjusted according to the type of the newly prepared cathode material, so that the contents of the three elements of cobalt, nickel and manganese in the prepared slurry are consistent with the contents of the three elements of nickel, cobalt and manganese in the newly prepared cathode material.

Further, the ratio of the total mole number of the ammonium sulfite and the ammonium thiosulfate in the step (2) to the total mole number of the manganese, cobalt and nickel elements in the slurry is 0.5-2.0.

Further, the ionic valence of cobalt, nickel and manganese in the cobalt oxide, nickel oxide and manganese oxide in the step (1) is not less than + 2.

Further, the pH value of the solution is adjusted to be 1-2.5 in the step (3), and the ORP is 200-300 mv.

Further, the adsorption resin used in the step (5) is a chelate type ion exchange resin.

Further, the ratio of the molar amount of the ammonium sulfate crystals used for pyrolysis in the step (9) to the total molar amount of the ammonium sulfite and the ammonium thiosulfate used in the step (2) is 0.9-1.2.

Further, the ratio of the molar weight of the sulfur in the step (9) to the molar weight of the ammonium sulfite solution is 0.5 to 2.5.

The beneficial effect produced by the scheme is as follows:

1. the preparation method realizes the recycling of condensed water after condensing extracting agents of ammonium sulfite, ammonium thiosulfate, sulfuric acid, lithium hydroxide alkali liquor and water vapor, can reduce the usage amount of additional chemical agents, greatly reduces the production cost, can realize the recycling of waste water, reduces the harm of sewage discharge to the environment, and realizes water balance in the whole preparation process; in addition, the preparation method does not introduce new impurities, adopts the lithium hydroxide alkali liquor produced by the system to precipitate and remove impurities such as iron, aluminum, copper and the like, is easy to remove impurities and purify, and is beneficial to the efficient recovery of the subsequent lithium, manganese, cobalt and nickel resources.

2. According to the method, a one-step multiple reaction system in which an acid-base neutralization reaction and an oxidation-reduction reaction are performed in a mutually crossed manner is constructed by constructing an oxidation-reduction and liquid-solid complementary system, so that the purpose that the inorganic component and the organic component are wrapped and embedded to be dissociated only by anode materials with different components in the leaching process in different oxidation-reduction reaction atmospheres is achieved, and the leaching efficiency of the one-step reaction of cobalt, nickel, manganese and lithium can be improved by leaching the anode material with complex components by the method.

3. The method does not produce process wastewater, waste residues and waste gases in the process, and realizes the complete utilization of the waste anode material.

4. According to the method, a unique three-phase one-step leaching reaction system is constructed, the reaction is a unique reaction system in which acid-base neutralization reaction and redox reaction are carried out in a mutually crossed manner, the pH value and the ORP value are used as key indexes in the reaction process according to the characteristics of the acid-base neutralization reaction and the redox reaction, and the optimal proportion and leaching conditions are achieved by adjusting the components in the mixed slurry and the gas components according to the key indexes, so that the aim of saving the medicament cost is fulfilled. And the two parameters of pH and ORP are easy to detect on line and realize automatic control, so that the method is easier to realize automatic and intelligent large-scale industrial production.

Drawings

FIG. 1 is a schematic diagram of the reaction of the present invention;

FIG. 2 is a graph showing the cycle of discharge characteristics of the positive electrode material in example 1;

fig. 3 is a discharge performance cycle graph of the positive electrode material in example 2;

fig. 4 is a discharge performance cycle chart of the positive electrode material in example 3.

Detailed Description