纳滤法提锂氢氧化镁废渣制取碳酸锂的研究  

Study on Preparation of Carbonate Lithium from Magnesium Hydroxide Waste of Lithium Extraction Process by Nanofiltration

作　　者：廖浩然[1] 徐徽[1] 李贵[1] 程俊峰[1] 刘卫平[1] 

机构地区：[1]中南大学冶金与环境学院,长沙410083

出　　处：《材料导报》2015年第4期90-94,共5页Materials Reports

基　　金：中央专项中南大学前沿研究计划重点项目(2010QZZD003)

摘　　要：以含锂氢氧化镁废渣为原料,采用碳酸氢铵碳化法提取锂,恒温热分解法制备高纯碳酸锂。最优碳化条件为：反应温度40 ℃、反应时间120 min、NH4HCO3/Mg（OH）2物质的量比1∶0.8、液固比20,锂提取率高达97.5%。母液循环10次后,锂质量浓度由0.7 mg/L富集至5.5 g/L。80 ℃恒温分解母液60 min,制得产率为81.7%,纯度为99.3%的工业级碳酸锂。同时,推导出碳酸锂结晶符合准二级反应动力学,0-30 min和40-125 min两个阶段的活化能分别为140.67 kJ/mol和107.56 kJ/mol。表明碳酸锂的结晶决定步骤是由化学反应控制的。Waste product of magnesium hydroxide contains a large amount of lithium. A simple method based on ammonium bicarbonate carbonation was developed to extract lithium from the waste, followed by decomposition of LiHCO3 to produce Li2CO3. The optimum carbonation process involved the reaction temperature of 40 ℃, reaction time of 2 h, NH4HCO3/Mg（OH）2 molar ratio of 1∶0.8, and the ratio of liquid to solid of 20.With the conditions above,the extraction yield of lithium is up to 97.5%. The concentration of lithium rose from 0.7 mg/L to 5.5 g/L after ten cycles. Li2CO3 produced by the method using decomposition had a high purity of 99.3% and a yield of 81.7%. Additionally, the crystallization of Li2CO3 appeared to be described by pseudo-second-order reactions, with activation energies of 140.67 kJ/mol and 107.56 kJ/mol in time ranges of 0-30 min and 40-125 min,respectively,indicating that chemical reaction is the dominant step for Li2CO3 growth.

关 键 词：含锂氢氧化镁 碳酸氢铵 碳酸锂 

分 类 号：TQ132.2[化学工程—无机化工]