Preparation of Battery Grade Li₂CO₃ from Defective Product by the Carbonation‐Decomposition Method

Abstract

Battery grade Li 2 CO 3 is successfully synthesized by the carbonation-decomposition method using defective crude Li 2 CO 3 with the purity of 98.56 wt% containing 5873 ppm SO 4 2− and other impurities such as Na, K, Ca, Fe, and Mg. Filter operation is found to be very important to improve quality of products. The purified Li 2 CO 3 precipitation acquired by filtering the LiHCO 3 solution possesses a higher purity of 99.65 wt% and greater whiteness with lower amounts of SO 4 2− (222.0 ppm) and Fe (6.6 ppm). For further purification, ethylenediaminetetraacetic acid disodium salt is added into the LiHCO 3 solution then Ca and Fe contents in purified Li 2 CO 3 are reduced to 2.9 and 0.7 ppm, respectively. The removal efficiencies obtained for Ca, Fe, and SO 4 2− are of 80.05%, 99.4%, and 97.5%, respectively. The research of reaction kinetics shows that the rate-determining step of the carbonation process is diffusion control and the generated HCO 3 − ions can resist the further dissolution of CO 2 . The theoretical thermal decomposition temperature is 277.10 K by the thermodynamic calculation. SO 4 2− impurity comes from absorbed Na 2 SO 4 and doped Li 2 SO 4 . This work is of great significance to economically and simply treat defective product with high impurity content in the actual Li 2 CO 3 production process.

Carbon dioxide utilization in lithium carbonate precipitation: A short review

“…Zhou et al successfully synthesized battery-grade Li 2 CO 3 via a carbonation-decomposition method using crude Li 2 CO 3 that contained various impurities [57]. The starting material was impure, defective, crude Li 2 CO 3 with a purity of 98.56 wt%, and contained 5,873 ppm of SO 4 2− , along with other impurities such as Na, K, Ca, Fe, and Mg.…”