硫酸锂离子膜电解法制备氢氧化锂的研究

Study on Ion Membrane Electrolysis of Lithium Hydroxide from Lithium Sulfate

设计了以硫酸锂溶液为阳极液、氢氧化锂溶液为阴极液,借助离子膜电解装置,完成氢氧化锂的电化学合成。以阴极电流效率和单位产品(氢氧化锂纯溶液)电能消耗为指标,阳极液初始浓度、阴极液初始浓度、循环转速、反应温度以及电流密度为因素,对电解条件进行了系统考察及参数优化,获得了优化的实验参数并进行了验证。结果表明,当阳极液浓度和阴极液浓度分别为200 g/L和25 g/L、循环转速为350 r/min、反应温度为70℃以及电流密度为1730 A/m2时反应体系具有较好的电解效能。优化参数下阴极电流效率为72.64%,单位产品直流电耗为5975 kWh/t,蒸发结晶产品中氢氧化锂主含量为56.7%,达到GB/T26008-2020电池级单水氢氧化锂的标准。

The cleaning process toward electrosynthesis of lithium hydroxide based on ionic membrane is designed in this paper.The electrochemical synthesis of lithium hydroxide was completed by using lithium sulfate refining solution as anolyte and lithium hydroxide solution as catholyte.The cathode current effi-ciency and unit lithium hydroxide product power consumption were used as indicators to systematically in-vestigate the electrosynthesis conditions and optimize the parameters.The effects of initial concentration of anolyte and catholyte,cycle speed,reaction temperature and current density on the electrolytic conditions were studied,and the optimized experimental parameters were obtained and verified.The experimental re-sults show that when the concentration of anolyte is 200 g/L and catholyte is 25 g/L,the cycle speed is 350 r/min,the reaction temperature is 70℃and the current density is 1730 A/m2,the electrolytic system has good per-formance.It is verified that under the optimized parameters,the current efficiency of lithium hydroxide is 72.64%,the power consumption of unit product(100%lithium hydroxide solution)is 5975 kWh/t,and the purity of evaporative crystallization product is 56.7%,which is up to the standard of GB/T26008-2020 battery grade lithium hydroxide.The preparation of lithium hydroxide by ion membrane electrolysis has the merits of high purity,controllable reaction process,high degree of automation,small by-product emis-sion,high economic value and has broad application prospect.