CN-116891951-B - Method for preferentially extracting lithium from waste lithium batteries by utilizing ore pulp electrolysis technology

Abstract

The invention discloses a method for preferentially extracting lithium from waste lithium batteries by utilizing an ore pulp electrolysis technology, which comprises the following steps of sequentially discharging and disassembling the waste lithium batteries to obtain positive plates or a mixture of the positive plates and the negative plates; calcining the positive plate or the mixture of the positive plate and the negative plate, sieving to obtain positive powder or positive-negative mixed powder, adding the positive powder or the positive-negative mixed powder into dilute sulfuric acid, stirring to obtain slurry, transferring the slurry into an electrolytic tank, electrolyzing the slurry, and filtering to obtain the solution rich in lithium ions. According to the method, by pulping the waste lithium battery and adding a proper electric field, lithium ions in the positive electrode material of the waste lithium battery are promoted to migrate into the solution from the crystal structure by utilizing the electrochemical oxidation and electric field migration effects, and meanwhile, the metal lithium separated out from the negative electrode material is oxidized and dissolved, so that the selective extraction of lithium under the low-acid condition is realized, and other valuable elements except the lithium are not leached, so that the purpose of preferentially extracting lithium is achieved.

Inventors

• LIN YAN
• CUI YAN

Assignees

• 北方工业大学
• 昆明理工大学

Dates

Publication Date

20260505

Application Date

20230529

Claims (4)

1. 1. The method for preferentially extracting lithium from the waste lithium battery by utilizing the ore pulp electrolysis technology is characterized by comprising the following steps of: sequentially discharging and disassembling the waste lithium batteries to obtain a positive plate or a mixture of the positive plate and a negative plate; Calcining the positive plate or the mixture of the positive plate and the negative plate, and sieving to obtain positive plate powder or positive-negative plate mixed powder; Adding the positive electrode powder or the positive and negative electrode mixed powder into dilute sulfuric acid, and stirring to obtain slurry; transferring the slurry into an electrolytic tank, electrolyzing the slurry, and filtering to obtain a solution rich in lithium ions; The step of adding the positive electrode powder or the positive and negative electrode mixed powder into dilute sulfuric acid specifically comprises the following steps: mixing the additive with dilute sulfuric acid to obtain a mixed solution of sulfuric acid and the additive; Adding the positive electrode powder or the positive and negative electrode mixed powder into the mixed solution of the sulfuric acid and the additive; The solid-liquid mass volume ratio of the positive electrode powder or the positive and negative electrode mixed powder to the mixed solution of sulfuric acid and the additive is 1 (5-25); the concentration of the dilute sulfuric acid is 0.1 mol/L-0.5 mol/L, and the concentration of the additive in the mixed solution of the sulfuric acid and the additive is 0.05 mol/L-0.2 mol/L; the additive is one or more of hydrogen peroxide, potassium permanganate and sodium persulfate; transferring the slurry into an electrolytic tank, and filtering to obtain a solution rich in lithium ions after the slurry is electrolyzed, wherein the method specifically comprises the following steps of: Providing an electrolytic cell and an external power supply, wherein the electrolytic cell comprises a cathode, an anode and a cell body, and the cell body is directly made of graphite and directly serves as the cathode; The external power supply comprises a negative electrode and a positive electrode, wherein the negative electrode is connected with the negative electrode, the positive electrode is inserted into the tank body in a suspending way and connected with the positive electrode, and the slurry is transferred into the tank body; The external power supply is a direct current power supply, constant current electrolysis is adopted in the electrolysis mode, and the current density of the anode is 4 mA/cm 2 ~8 mA/cm 2 .
2. 2. The method for preferentially extracting lithium from waste lithium batteries by utilizing an ore pulp electrolysis technology according to claim 1, wherein the waste lithium batteries are one or more of ternary lithium ion batteries, lithium iron phosphate batteries and lithium cobalt oxide batteries.
3. 3. The method for preferentially extracting lithium from waste lithium batteries by utilizing an ore pulp electrolysis technology according to claim 1, wherein the calcining temperature is 500-600 ℃, the calcining time is 2-6 hours, and the heating rate is 5-10 ℃ per minute.
4. 4. The method for preferentially extracting lithium from waste lithium batteries by utilizing ore pulp electrolysis technology according to claim 1, wherein the electrolysis time is 3-24 hours.

Description

Method for preferentially extracting lithium from waste lithium batteries by utilizing ore pulp electrolysis technology Technical Field The invention relates to the technical field of waste lithium ion battery material recovery, in particular to a method for preferentially extracting lithium from waste lithium batteries by utilizing an ore pulp electrolysis technology. Background Along with the increasing severity of the problems of energy exhaustion and environmental pollution, the lithium ion battery presents a rapid development situation in the field of energy application, and particularly has a wide market prospect in the fields of new energy automobiles and energy storage. Along with the popularization and application of the power lithium ion battery, the waste lithium battery is out of service in a blowout way according to the service life of the lithium ion battery of 5-8 years. If a large number of retired lithium ion batteries cannot be properly recycled and utilized, serious damage to the ecological environment can be caused. Meanwhile, the method also contains abundant valuable metal elements such as lithium, iron, phosphorus, copper, aluminum and the like, and has huge potential resource quantity and high recovery economic value. From the perspective of lithium resource reserves and demand, one electric automobile requires about 3-20 kg of lithium. According to the layout of new energy automobile industry development planning (2021-2035), the sales of new energy automobiles in China reaches about 20% of the total sales of new automobiles (258 ten thousand estimated vehicles) by 2050, and the lithium demand of electric automobiles in China reaches 5.5 ten thousand tons. Although the lithium mine resources in China are rich, the method is mainly concentrated in high-altitude and high-cold areas such as Qinghai, tibet and the like. On the one hand, the mining environment is worse, and on the other hand, the local infrastructure construction is weaker. Therefore, although the lithium reserves in China account for 22% of the world, the lithium ores are seriously dependent on import, and the external dependence is more than 85% at present. With the rapid development of new energy automobile industry, the shortage situation of lithium resources is more serious, and the rapid rise of lithium price is also caused, and the domestic battery grade lithium carbonate price is increased from about 4.2 ten thousand yuan/ton at 2015 to 36 ten thousand yuan/ton at 3 month of 2023, and the rise is over 800%. Compared with lithium ores which are more difficult to extract and refine, the method for recovering lithium from waste lithium batteries is one of important ways for guaranteeing the safety of lithium resources in China. At present, the recovery method of the waste lithium battery is mainly divided into two major types, namely a fire method and a wet method, wherein the fire method is to pretreat the waste lithium battery to remove a battery shell, then calcine or pyrolyze a mixed battery material under inert gas, release organic substances in a gas form, absorb and recover most of lithium oxide with low boiling point in a vapor form by water after release, alloy is formed by other metals (such as copper, nickel, cobalt and the like), then the alloy is separated by a hydrometallurgical technology, and fluorine, phosphorus and the like in electrolyte are solidified in slag. The disadvantage of the pyrogenic process is the low overall recovery of valuable metals, which are lost in the slag. The wet metallurgy mainly adopts inorganic acid or organic acid to leach waste battery materials, and then adopts multistage extraction or fractional precipitation to realize the separation of valuable elements. Compared with the fire process, the wet process has the advantages of high metal recovery rate, high product purity, low energy consumption, low discharge and the like. A typical wet process generally comprises two steps, wet leaching of the material and separation and recovery of metallic elements from the leaching solution. The recovery process usually adopts multistage extraction or fractional precipitation to separate valuable elements, so that the comprehensive recovery rate of lithium is low (only about 90 percent). Considering the high price of the current lithium-containing materials, the adoption of the preferential lithium extraction process is imperative to improve the lithium recovery rate. For waste lithium iron phosphate batteries, researchers have developed a Na 2S2O8 oxidation process to preferentially extract lithium and recover LiFePO 4. For waste ternary NCM lithium battery materials, xu Chengming teaches and the like, a controllable carbothermic reduction method is utilized to directionally convert the NCM materials into Ni-Co alloy, mnO, li 2 O and Li 2CO3, and then H 3PO4 solution is adopted to leach out to preferentially extract Li and Mn. However, the prior lithium extraction technology is com