A method for recovering waste lithium titanate battery

Abstract

A method for recovering waste lithium titanate battery comprises the following steps: a, discharging; b, crushing and screening; c adding water to prepare slurry; d. adding hydrochloric acid to maintain the pH of the slurry at 0.5 to 1.5, temporarily stopping the addition of hydrochloric acid if the pH value of the slurry drops below 0.5 during the addition of hydrochloric acid, restarting the addition of hydrochloric acid after the pH value of the slurry rises above 1.5 during the reaction, and stopping the addition of hydrochloric acid when the pH value of the slurry rises less than 0.3 within 20 minutes; e filtering the slurry obtained in the step (d) to obtain filter residue containing titanium and carbon black; f, adding coke into the slag containing titanium and carbon black, introducing chlorine gas, returning the remaining solid slag to the step g, adding hydrogen peroxide to the solution containing the positive electrode active material powder obtained in the step e, filteringand removing iron, aluminum and titanium impurities, extracting and removing calcium and magnesium impurities, adding sodium carbonate to the remaining solution, and evaporating and concentrating after the reaction is complete. The method can separate high purity battery grade lithium titanate from waste lithium titanate battery.

Description

technical field [0001] The invention relates to the field of recycling waste batteries, in particular to a method for recycling waste lithium titanate batteries. Background technique [0002] Lithium titanate batteries have good safety. The most important point of electric vehicle batteries is the need for high safety. Lithium titanate has good safety because of its high equilibrium potential and will not form lithium dendrites on the negative electrode. In addition, lithium titanate batteries have the following advantages: good cycle performance, because it is a "zero strain" material, no structural changes will occur during charging and discharging, and has very superior cycle performance; it can be charged and discharged quickly, and lithium The diffusion coefficient of ions in lithium titanate crystal is 2×10 -8 cm -2 / s, an order of magnitude more than the graphite negative electrode, can be charged and discharged quickly; the operating temperature range is wide -30°C...

AI Technical Summary

Problems solved by technology

Although this method recovers lithium titanate to a certain extent and obtains three kinds of reclaimed products, it has at least two obvious problems: the leaching rate of lithium is low, which reduces the total weight of lithium carbonate obtained in the end. There are impurities such as calcium, aluminium, titanium, iron and magnesium in the finally obtained lithium carbonate, and the impurity content such as iron and magnesium is higher, causes the purity of the lithium carbonate finally obtained to be lower, does not reach the purity requirement of battery grade lithium carbonate