针对我国大部分盐湖卤水高镁锂比的资源结构特点，锂的提取困难问题，本文采用纳滤技术研究镁锂分离的效果，实验考察了操作条件的影响，包括操作时间、操作压力、进水温度、溶液pH值和镁锂比对分离的影响。引入镁锂竞争系数，得出镁锂截留率之间的关系。同时也研究了Na+、K+、Ca2+的加入对镁锂分离性能的影响。结果表明，Mg/Li比、操作压力和pH值对Mg2+和Li+分离效果有较大的影响。对Mg/Li比≦45的卤水，纳滤膜对镁锂分离显示出较大的可行性。一价离子的引入对镁锂分离产生较为不利的影响。

Nowadays, lithium extraction from salt lakes was paid more attentions because of low cost and rich resource. Nevertheless Mg/Li ratio in most Chinese sake lakes is high. It is difficult to recovery of lithium from the brine due to the close property of Mg2+ and Li+. In this work, nanofiltration was used to study the separation of magnesium and lithium in brine. The operation conditions, including operation time, operation pressure, solution temperature, pH value and Mg/Li ratio were investigated. The competition coefficient was adopted to describe the relationship of Mg2+ and Li+ rejections. Moreover, the impact of Na+, K+, and Ca2+ on the separation of Mg2+ and Li+ was studied. And the conclusion was reached that, Mg/Li ratio, operation pressure, as well as pH value had a great effect on Mg/Li separation. For the brine whose Mg/Li ratio was less than 45, it shew the great feasibility of Mg/Li separation by nanofiltration. In addition, the introduction of monovalent ions had much adverse effect on Mg2+/Li+ separation.

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