METHOD OF PRODUCING ULTRAPURE LITHIUM CARBONATE FROM TECHNICAL-GRADE LITHIUM CARBONATE AND APPARATUS THEREFOR Russian patent published in 2015 - IPC C01D15/08 C01D7/10 C01D7/12 

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry. A method of producing ultrapure lithium carbonate from technical-grade Li₂CO₃ includes conducting a carbonisation process with fourfold excess lithium carbonate to obtain a lithium bicarbonate solution. The residual solid Li₂CO₃ after the carbonisation process is separated from the lithium bicarbonate solution and returned in the form of a thickened pulp to the process of preparing the initial Li₂CO₃ pulp. Insoluble impurities are filtered off from the lithium bicarbonate solution, followed by ion-exchange purification of the filtrate from impurity cations and decarbonisation of the lithium bicarbonate solution while heating to release carbon dioxide gas. Lithium carbonate pulp is obtained. Lithium carbonate is separated from the carbonate mother solution, washed with hot water and dried.

EFFECT: invention enables to avoid mechanochemical grinding, reduces the power consumption of the carbonisation process 1,6-fold, increases efficiency of carbonisation 1,8-fold and output of ultrapure Li₂CO₃ to 98,6%, and enables to conduct the process of producing ultrapure Li₂CO₃ in a continuous mode.

7 cl, 2 dwg, 5 tbl, 4 ex