阅读说明：本技术 一种从废弃三元锂离子电池的ncm111正极材料中回收碳酸锂的方法 (Method for recycling lithium carbonate from NCM111 positive electrode material of waste ternary lithium ion battery ) 是由 邵鹏辉 黄涌 罗旭彪 杨利明 石慧 喻恺 李荐 王利华 于 2020-04-07 设计创作，主要内容包括：一种从废弃三元锂离子电池的NCM111正极材料中回收碳酸锂的方法,涉及一种从废弃三元锂离子电池正极材料中回收碳酸锂的方法。本发明是要解决现有的三元锂离子电池正极材NCM111废料的再生方法中对大气环境和水环境造成了严重的二次污染、对回收设备防腐蚀性能的要求很高、再生的成本高、再生产品附加值低、再生过程能耗高的技术问题。本发明将废NCM111与氯化钠混合后进行水热反应,反应产物过滤,滤液蒸发浓缩,加入碳酸钠溶液进行加热沉锂,过滤得滤渣为碳酸锂。本发明再生成本低、易操作、对设备防腐要求低、回收的碳酸锂纯度高达95％,锂离子回收率达到80％,回收过程中不产生二次污染。本发明应用于回收碳酸锂。(A method for recovering lithium carbonate from NCM111 positive electrode materials of waste ternary lithium ion batteries relates to a method for recovering lithium carbonate from the positive electrode materials of the waste ternary lithium ion batteries. The invention aims to solve the technical problems of serious secondary pollution to the atmospheric environment and water environment, high requirement on the anti-corrosion performance of recovery equipment, high regeneration cost, low additional value of regenerated products and high energy consumption in the regeneration process in the conventional regeneration method of the ternary lithium ion battery cathode material NCM111 waste. The method comprises the steps of mixing waste NCM111 and sodium chloride, carrying out hydrothermal reaction, filtering a reaction product, evaporating and concentrating filtrate, adding a sodium carbonate solution, adding hot lithium, and filtering to obtain filter residue which is lithium carbonate. The invention has low regeneration cost, easy operation and low requirement on equipment corrosion resistance, the purity of the recovered lithium carbonate is as high as 95 percent, the recovery rate of lithium ions reaches 80 percent, and no secondary pollution is generated in the recovery process. The invention is applied to the recovery of lithium carbonate.)

1. A method for recovering lithium carbonate from an NCM111 positive electrode material of a waste ternary lithium ion battery is characterized in that the method for recovering lithium carbonate from the NCM111 positive electrode material of the waste ternary lithium ion battery is carried out according to the following steps:

firstly, placing an NCM111 positive plate in a scrapped lithium ion battery into a crucible, then placing the crucible into a tubular furnace, raising the temperature of the furnace to 550-600 ℃ from room temperature at a temperature raising rate of 5-10 ℃/min, preserving the temperature for 0.5-1 h, and then naturally cooling to room temperature; taking out the roasted positive plate, putting the positive plate into deionized water, and magnetically stirring for 5-30 min, wherein the temperature of water in the stirring process is 20-50 ℃, and the stirring speed is 10-200 r/min, so as to obtain a mixture; sieving the mixture by a sieve with 10 meshes to 20 meshes, wherein the oversize is wet aluminum foil, and the undersize is solution containing positive active substances; cleaning the oversize material with clear water for 1-3 times, and naturally drying to obtain aluminum foil; filtering the undersize product, washing the filtered product with clear water for 1-3 times, and drying to obtain the NCM111 positive active material;

the ratio of the mass of the baked positive plate to the volume of the deionized water is 1g (40 mL-70 mL);

secondly, putting the NCM111 positive electrode active material obtained in the first step and NaCl powder into an agate mortar, and grinding for 10-15 min for fully mixing to obtain co-ground powder of NCM111 and NaCl; putting the co-ground powder of NCM111 and NaCl and deionized water into a polytetrafluoroethylene reaction kettle, uniformly dispersing by ultrasonic, heating to 80-120 ℃ at a heating rate of 3-10 ℃/min, preserving heat for 360-720 min, carrying out hydrothermal reaction, and naturally cooling to room temperature;

the mass ratio of the NCM111 positive electrode active material to the NaCl powder obtained in the first step is 1 (1-2);

the ratio of the mass of the co-ground powder of NCM111 and NaCl to the volume of the deionized water is 1g (30 mL-50 mL);

thirdly, transferring the product obtained after the hydrothermal reaction in the second step into a beaker, performing first suction filtration by using a Buchner funnel, recovering filter residues which are waste residues containing nickel, cobalt and manganese elements, heating the filtrate to 95-98 ℃, slowly adding a sodium carbonate aqueous solution, and keeping the temperature of 95-98 ℃ for 30-50 min; then carrying out secondary suction filtration, washing filter residue and drying to obtain lithium carbonate;

crystallizing the filtrate obtained by the second suction filtration in an evaporation crystallizer, and drying the crystal at 50-80 ℃ for 2-3 h to obtain sodium chloride; the crystallization conditions were: the vacuum degree is 0.012MPa to 0.015MPa, and the temperature is 60 ℃ to 80 ℃;

the concentration of the sodium carbonate aqueous solution is 1-3 mol/L;

the volume ratio of the sodium carbonate aqueous solution to the filtrate generated by the first suction filtration is 1 (10-20).

2. The method for recovering lithium carbonate from the NCM111 positive electrode material of the discarded ternary lithium ion battery according to claim 1, wherein the method for obtaining the NCM111 positive electrode sheet in the discarded lithium ion battery in the first step is as follows: placing the scrapped lithium ion battery taking the NCM111 ternary material as the anode in a saturated sodium chloride aqueous solution at room temperature, standing and soaking for 1-3 h for discharge treatment, and disassembling the scrapped lithium ion battery after the discharge treatment to obtain the anode plate.

3. The method for recovering lithium carbonate from the NCM111 positive electrode material of the discarded ternary lithium ion battery according to claim 1, wherein the method for obtaining the NCM111 positive electrode sheet in the discarded lithium ion battery in the first step is as follows: and collecting the positive leftover materials generated in the manufacturing process of the lithium ion battery using the NCM111 ternary material as the positive material to obtain the positive plate.

4. The method for recovering lithium carbonate from the NCM111 cathode material of the discarded ternary lithium ion battery according to claim 1, wherein the furnace temperature is increased to 550 ℃ at a temperature increase rate of 5 ℃/min from the room temperature in the step one, the temperature is maintained for 1h, and then the temperature is naturally cooled to the room temperature.

5. The method for recovering lithium carbonate from the NCM111 cathode material of the discarded ternary lithium ion battery according to claim 1, wherein the mass ratio of the NCM111 cathode active material to the NaCl powder obtained in the step one in the step two is 1: 2.

6. The method for recovering lithium carbonate from the NCM111 cathode material of the discarded ternary lithium ion battery according to claim 1, wherein the temperature is raised to 120 ℃ at a temperature raising rate of 5 ℃/min and kept for 720min in the second step to perform the hydrothermal reaction.

7. The method for recovering lithium carbonate from the NCM111 positive electrode material of the discarded ternary lithium ion battery according to claim 1, wherein the first suction filtration is performed by using a Buchner funnel in the third step, then the filtrate is heated to 98 ℃, the sodium carbonate aqueous solution is slowly added, and the temperature is kept constant at 98 ℃ for 30 min; and then carrying out suction filtration for the second time, washing filter residues and drying to obtain lithium carbonate.

Technical Field

The invention relates to a method for recovering lithium carbonate from a waste ternary lithium ion battery positive electrode material.

Background

Since the introduction of Lithium Ion Batteries (LIBs) into the market in 1991, Lithium Ion Batteries (LIBs) have been widely used as novel electrochemical power sources for electric vehicles such as new energy vehicles, small portable electronic and communication products such as mobile phones and notebook computers, and stationary energy storage devices for renewable energy sources such as solar energy, due to their advantages of high energy density, long life cycle, low self-discharge capacity, good safety, and the like. It is statistical that by 2018, the stock of electric cars in china will exceed 230 million, accounting for about 45% of the total world, while this ratio in the european union and the united states is about 24% and 22%, respectively. The global battery market demand is expected to reach $ 999.8 billion in 2025, and the enormous energy demand will result in the consumption of large amounts of resources at 439.32 billion kilowatts. Because the service life of the lithium ion battery is generally 3-5 years, the problems of environmental pollution and resource waste caused by scrapping the lithium ion battery are increasingly prominent, and the problem of how to reasonably dispose the discarded lithium ion battery is not negligible. The waste lithium ion batteries contain heavy metal elements such as nickel (Ni) and cobalt (Co), which are classified as carcinogenic and mutagenic substances, and toxic organic electrolytes, causing adverse effects on human health and the environment. The recycling of Co, Ni, Mn, Li, Al, Cu and other resources in the waste lithium ion batteries overcomes the pollution of the discarded method for disposing the waste lithium ion batteries to the environment, and simultaneously, the limited resources can be recycled, so that the method has great economic benefit and great significance in the aspect of environmental protection.

The anode material adopted by the lithium ion battery is one of the key materials for manufacturing the lithium ion battery, and the cost is highLithium ion batteries occupy a central position. LiCoO₂Is the first commercial cathode material, and currently still occupies the largest market due to its high volumetric energy density and ease of preparation. But also has some defects, such as low practical use capability and the like, and Co is a rare metal, small in amount and expensive, so that the large-scale development of the lithium ion battery is restricted. Layered ternary oxide cathode materials, e.g. LiNi_{1-x- y}Co_xMn_yO₂(NCM) and LiNi_xCo_yAl_1-x-yO₂(NCA) (three-component layered cathode material, TCM for short) has the advantages of strong reversible capacity, good thermal stability, high working voltage, low production cost and the like, is distinguished from many cathode materials and is widely considered to have great potential, wherein NCM111 (LiNi) is_1/3Co_1/3Mn_1/3O₂) The material is the most mature material for the current market industrialization because the preparation process and the use environment are easy to control.

The method for recovering valuable metals from waste lithium ion batteries using lithium cobaltate as the positive electrode material is mainly disclosed in Zhang PW et al, hydrometalurgy Vol.47 No.2-3,1998,259 and 271, wherein hydrochloric acid is used to leach the positive electrode waste of the lithium ion battery, and cobalt sulfate and lithium carbonate are obtained through extraction, precipitation and other operations. Shilihua reports that waste ternary lithium ion batteries are subjected to pretreatment methods such as overdischarge, roasting, crushing and screening to separate battery active substances, current collectors and steel shells, and then H is adopted to separate the battery active substances, the current collectors and the steel shells from non-ferrous metal (metallurgical part) polysaccharide-polysaccharide complex in doi:10.3969/j.issn.1007-7545.2018.10.018)2018₂SO₄-Na₂SO₃Leaching waste battery powder (active substance), adjusting pH of leachate to 4.5, filtering to remove iron and aluminum, adjusting pH of filtrate to about 11, separating lithium and nickel, cobalt and manganese, concentrating the obtained lithium solution, and adding Na₂CO₃Obtaining technical grade Li₂CO₃Adding ammonia water into the nickel-cobalt-manganese concentrate to separate manganese from nickel and cobalt, and finally separating nickel and cobalt by using P507, wherein the balance pH is 4.5 compared with the O/A which is 1, the organic phase composition is 25% of P507+ 75% of solvent naphtha, and the extraction rate of cobalt after secondary countercurrent extraction is 99.3%. Use of200g/L sulfuric acid is used as a stripping agent, and when the phase ratio is 5, the recovery rate of cobalt reaches 99.21%. Ammonium oxalate is used for precipitating cobalt in the strip liquor, and sodium hydroxide is used for precipitating nickel in the strip liquor, so that the recovery rate of cobalt in the whole process flow is 91.82%, and the recovery rate of nickel is 91.12%. M you J et al, Journal of Power Sources, Vol.112,2002,639-642 report dissolving the positive electrode waste obtained from spent lithium ion batteries with hot nitric acid, followed by electrodeposition and low temperature calcination to obtain Co₃O₄. Patent [ CN200910117702]Reported by the use of waste LiCoO₂Mixing the powder with alkali metal sodium and potassium salts, roasting at a higher temperature, leaching the roasted product by water, and carrying out cobalt precipitation and lithium precipitation on the leaching solution to obtain cobalt oxalate and lithium carbonate. Patent [ CN201710291806.9]The method for efficiently and cleanly recovering valuable metals in the waste ternary lithium ion battery is reported, positive electrode powder obtained by roasting and sorting the waste battery is subjected to enhanced gas reduction, reducing gas is introduced into leaching mixed liquid in the reduction process in an aeration mode and the like, generated bubbles react with the positive electrode powder, the reaction rate is greatly increased, metal ions dissolved in leachate are obtained, and extraction separation or precipitation separation is carried out after aeration reduction, so that a positive electrode material precursor and a cobalt product are obtained. Patent [ CN201610955087.7]The method comprises the steps of calcining the waste battery positive electrode material at high temperature, carrying out acid leaching, correspondingly supplementing nickel-cobalt-manganese ions into a solution, finally mixing a nickel-cobalt-manganese precursor with lithium carbonate powder, and calcining to obtain the nickel-cobalt-manganese acid lithium positive electrode material.

In the regeneration method of the NCM111 waste material of the ternary lithium ion battery anode material reported at present, the waste NCM111 is dissolved by hydrochloric acid, sulfuric acid, nitric acid, citric acid, malic acid and the like, and acid-containing gas and NO are inevitably generated in the recovery process_xWaste gas and waste water with high inorganic acid content and high organic acid content cause serious secondary pollution to atmospheric environment and water environment; the dissolving process adopts higher acid concentration and adds reducing agents such as hydrogen peroxide or ammonium persulfate and the like, which has high requirements on the corrosion resistance of the recovery equipment; the post-treatment process after dissolution is long, and the cost for regenerating the spent NCM111 is high. By pyrogenic processThe method for manufacturing the ferromanganese alloy by using the NCM111 waste lithium ion battery as the raw material in the metallurgical technology has the defects of low added value of the regenerated product and high energy consumption in the regeneration process.

Disclosure of Invention

The invention provides a method for recycling lithium carbonate from an NCM111 positive material of a waste ternary lithium ion battery, aiming at solving the technical problems that the existing regeneration method of the NCM111 waste material of the ternary lithium ion battery causes serious secondary pollution to the atmospheric environment and the water environment, has high requirement on the corrosion resistance of recycling equipment, high regeneration cost, low additional value of regenerated products and high energy consumption in the regeneration process.

The method for recovering lithium carbonate from the NCM111 positive electrode material of the waste ternary lithium ion battery is carried out according to the following steps:

firstly, placing an NCM111 positive plate in a scrapped lithium ion battery into a crucible, then placing the crucible into a tubular furnace, raising the temperature of the furnace to 550-600 ℃ from room temperature at a temperature raising rate of 5-10 ℃/min, preserving the temperature for 0.5-1 h, and then naturally cooling to room temperature; taking out the roasted positive plate, putting the positive plate into deionized water, and magnetically stirring for 5-30 min, wherein the temperature of water in the stirring process is 20-50 ℃, and the stirring speed is 10-200 r/min, so as to obtain a mixture; sieving the mixture by a sieve with 10 meshes to 20 meshes, wherein the oversize is wet aluminum foil, and the undersize is solution containing positive active substances; washing the oversize material with clear water for 1-3 times, and naturally drying to obtain aluminum foil (aluminum element is from impurities in the NCM111 positive plate); filtering the undersize product, washing the filtered product with clear water for 1-3 times, and drying to obtain the NCM111 positive active material;

the ratio of the mass of the baked positive plate to the volume of the deionized water is 1g (40 mL-70 mL);

secondly, putting the NCM111 positive electrode active material obtained in the first step and NaCl powder into an agate mortar, and grinding for 10-15 min for fully mixing to obtain co-ground powder of NCM111 and NaCl; putting the co-ground powder of NCM111 and NaCl and deionized water into a polytetrafluoroethylene reaction kettle, uniformly dispersing by ultrasonic, heating to 80-120 ℃ at a heating rate of 3-10 ℃/min, preserving heat for 360-720 min, carrying out hydrothermal reaction, and naturally cooling to room temperature;

the mass ratio of the NCM111 positive electrode active material to the NaCl powder obtained in the first step is 1 (1-2);

the ratio of the mass of the co-ground powder of NCM111 and NaCl to the volume of the deionized water is 1g (30 mL-50 mL);

thirdly, transferring the product obtained after the hydrothermal reaction in the second step into a beaker, performing first suction filtration by using a Buchner funnel, recovering filter residues which are waste residues containing nickel, cobalt and manganese elements, heating the filtrate to 95-98 ℃, slowly adding a sodium carbonate aqueous solution, and keeping the temperature of 95-98 ℃ for 30-50 min; then carrying out secondary suction filtration, washing filter residue and drying to obtain lithium carbonate;

crystallizing the filtrate obtained by the second suction filtration in an evaporation crystallizer, and drying the crystal at 50-80 ℃ for 2-3 h to obtain sodium chloride; the crystallization conditions were: the vacuum degree is 0.012MPa to 0.015MPa, and the temperature is 60 ℃ to 80 ℃;

the concentration of the sodium carbonate aqueous solution is 1-3 mol/L;

the volume ratio of the sodium carbonate aqueous solution to the filtrate generated by the first suction filtration is 1 (10-20).

The sodium chloride finally recovered by the invention can be recycled in the second step.

Compared with the prior art, the method has the advantages of simple flow, low operation cost, low regeneration cost, easy operation, low requirement on equipment corrosion resistance, high purity of the recovered lithium carbonate up to 95 percent, high recovery rate of lithium ions up to 80 percent, high recovery rate of sodium chloride up to 80 percent and high economic value; the whole process of the invention does not add acid, alkali and reducing agent, does not generate harmful gas, the nickel, cobalt and manganese in the filter residue of the first suction filtration in the step three can be prepared into a precursor or directionally recovered, no waste water and gas is discharged into the environment, and no secondary pollution is generated in the recovery process.

Detailed Description