The extraction of potassium or lithium from saline lake generates the discharge of waste liquid and residue containing magnesium, which occupies many land and even covers the mineral deposit. Long-term accumulation of residuals with high magnesium content may also pollute groundwater. Therefore, the comprehensive utilization of saline lake resources must be realized, especially magnesium. In this work, a novel cation exchange membrane (CEM) electrolysis method of separating cations from brine and utilization of magnesium was raised. What’s more, the concentrations of electrolyte were optimized in electrolysis of magnesium chloride process. It also provides data for cations separation of simulating saline lake brine by electrolysis. In this paper, the effects of electrolyte concentrations on cell voltage, catholyte pH and current efficiency in the electrolysis process were investigated. The phase, morphology and particle size distribution of magnesium hydroxide were also characterized. Magnesium extraction rate can reach 90.62% in the process of simulating brine electrolysis. The separation rate of metal cations reached 90.59% and the consumption rate of chlorine in anodic brine reached 97.59%. The electrolytic catholyte containing almost no Mg²⁺ can be directly used to prepare lithium carbonate. The anolyte desalted magnesium and chloride can be used to extract boron.

从盐湖中提取钾或锂会产生废液和含镁残渣的排放，这些废液和残渣占据了许多土地，甚至覆盖了矿床。镁含量高的残留物的长期积累也可能污染地下水。因此，必须实现盐湖资源特别是镁资源的综合利用。在这项工作中，提出了一种从盐水中分离阳离子并利用镁的新型阳离子交换膜（CEM）电解方法。此外，在氯化镁电解过程中优化了电解质的浓度。它还提供了通过电解模拟盐湖盐水的阳离子分离数据。在本文中，电解质浓度对电池电压的影响 研究了电解过程中阴极电解液的pH值和电流效率。还表征了氢氧化镁的相，形态和粒度分布。模拟盐水电解过程中镁的提取率可达到90.62％。金属阳离子的分离率达到90.59％，阳极盐水中氯的消耗率达到97.59％。几乎不含镁的电解阴极液²⁺可直接用于制备碳酸锂。阳极电解液脱盐的镁和氯化物可用于提取硼。