Preparation of Battery-Grade Lithium Carbonate from Calcium-Magnesium Slag in Spent Li-Ion Battery Recycling Process
With the calcium-magnesium slag generated in recycling process of spent Li-ion batteries as raw material,battery-grade lithium carbonate was prepared by adopting a process consisting of leaching for decomposition,purification,lithium precipitation and carbonization for decomposition.The results show that with the addition of MgSO4·7H2O at 1.1 times of the theory amount,initial pH of 1.5,reaction time of 2.0 h,solid-liquid ratio of 1∶6,reaction temperature of 90 ℃,and final pH of 3.5,the leaching rate of Li can reach 98.39％and the mass concentration of Li in the lixivium is 18.03 g/L.Then,the obtained lixivium is subjected to processes of defluorination with resin,impurity removal with NaOH,and Na2CO3 precipitation,and crude lithium carbonate can be obtained with purity of 95.11％.By adopting a process consisting of carbonization,removal of calcium and magnesium with resin,and pyrolysis,a battery-grade lithium carbonate with purity of 99.64％can be prepared.It is shown that by using this processing technique,the lithium recovery rate can reach 95.08％,presenting good prospect in industrial application.
spent Li-ion batteryleachingpurificationcarbonization for decompositionbattery-grade lithium carbonatebattery recyclingcalcium-magnesium slag
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