氢化分解法制备电池级碳酸锂过程中钙、镁除杂工艺技术

Technology of Calcium and Magnesium Removal during Preparation of Battery Grade Lithium Carbonate by Hydrogenation Decomposition

采用氢化分解法将工业级碳酸锂转变为电池级碳酸锂,除去杂质Ca、Mg的主要方法为氢化前处理+氢化分解处理联合除杂法。研究结果表明,氢化前处理用阳离子杂质总含量6倍的络合剂氨三乙酸在25℃下可有效除去工业碳酸锂中的Ca、Mg杂质,去除率达65%;氢化分解处理是向氢化浆液中加入阳离子杂质总含量6倍的EDTA,除杂效率达98%以上。经过氢化前处理+氢化分解处理除杂两阶段反应,可将Ca、Mg杂质降至电池级碳酸锂行业标准以下,得到的碳酸锂产品中Ca含量为0.000 5%,Mg含量为0.001 4%。

The industrial grade lithium carbonate was transformed into battery grade lithium carbonate by hydrogenation decomposition.The main method of Ca and Mg impurity removal is the combination of pretreatment before hydrogenation and treatment of hydrogenation decomposition.The results show that adding the complexing agent nitrilotriacetic acid with 6 times the total content of cationic impurities during the pretreatment before hydrogenation can effectively remove Ca and Mg from industrial lithium carbonate at 25℃,and the removal rate is 65%.Adding EDTA with 6 times the total content of cationic impurities to the hydrogenated slurry during hydrogenation decomposition,the impurity removal efficiency is over 98%.After the two-stage reactions of pretreatment before hydrogenation and treatment of hydrogen decomposition,Ca and Mg impurities can be reduced below the industry standard of battery grade lithium carbonate,and the Ca and Mg contents in the obtained lithium carbonate product are 0.000 5%and 0.001 4%,respectively.