Preparation of Lithium Carbonate from a Li-bearing Desorption Solution

The process of removing impurity ions from the eluent and preparation industrial grade lithium carbonate powder was investigated in this study. The eluent was obtained by eluting MnO 2 ion-sieve precursor after adsorption process with HCl solution. The effects of enrichment on impurities removal efficient, NaOH consumption, size of the precipitate, and lithium loss rate of the precipitation process were systematically investigated. Na 2 CO 3 was used to precipitate Li + in the 5 times concentrate eluent via HPRO after removal impurity ions. The results indicate that the concentrate rate had an essential effect on impurities removal efficient, size of the precipitate, and lithium recovery rate. The optimal purification process was determined as follows: HPRO permeate of an enrichment of 5, the ending pH=12, the feed rate of NaOH was 72 μL/min, and the stirring speed is 300 r/min. Mg 2+ and Mn 2+ in the solution can be completely removed under the optimum operation condition, the maximum mean practical size of Mg（OH） 2 and MnO 2 ·H 2 O blended precipitate reached 28.05 μm and the alkali consumption [molar ratio of Na OH/(Mn 2+ +Mg 2+ )] is reduced to 3.48. Li 2 CO 3 with a purity of 99.51% and mean size of 16.38 μm was produced by adding Na 2 CO 3 directly to the 5 times concentrated eluent after removal of impurity ions. The purity of Li 2 CO 3 powder conformed to the national primary standards of GB/T 11075-2013 and the maximum Li + recovery rate reached 71.26%.