含锂脱附液制备碳酸锂

对锰系离子筛吸附法提锂所得脱附液除杂制备碳酸锂粉体，考察了浓缩级数对NaOH沉淀法除杂效果、碱耗、沉淀粒度及锂损失率的影响，并采用Na2CO3沉淀法用高压反渗透5倍浓缩除杂后的脱附液制备Li2CO3，研究了Na2CO3加入量对脱附液中Li+回收率、产品纯度和产品形貌的影响. 结果表明，浓缩倍数对脱附液除杂效果、沉淀粒度及Li+回收率有重要影响. 优化的除杂工艺为：采用高压反渗透将脱附液浓缩5倍，脱附液反应终点pH=12，加料速率72 mL/min，搅拌速率300 r/min. 该条件下可保证Mg2+和Mn2+完全除尽，Mg(OH)2和MnO2×H2O混合沉淀的平均粒径最大(28.05 mm)，碱耗NaOH/(Mn2++Mg2+)摩尔比]为3.48. 用Na2CO3直接沉淀脱附液中的Li+所制Li2CO3粉体纯度为99.51%，符合GB/T 11075-2013(工业级)一级标准，Li+回收率为71.26%，平均粒径为16.38 mm.

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 MnO2 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. Na2CO3 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 mL/min, and the stirring speed is 300 r/min. Mg2+ and Mn2+ in the solution can be completely removed under the optimum operation condition, the maximum mean practical size of Mg(OH)2 and MnO2×H2O blended precipitate reached 28.05 mm and the alkali consumption molar ratio of NaOH/(Mn2++Mg2+)] is reduced to 3.48. Li2CO3 with a purity of 99.51% and mean size of 16.38 mm was produced by adding Na2CO3 directly to the 5 times concentrated eluent after removal of impurity ions. The purity of Li2CO3 powder conformed to the national primary standards of GB/T 11075-2013 and the maximum Li+ recovery rate reached 71.26%.