Method for separating magnesium from old brine of saline lake and reducing magnesium lithium ratio

A method for separating magnesium from old brine of a saline lake and reducing magnesium lithium ratio relates to the field of chemical industry, and comprises the following steps in order: the old brine is concentrated by membrane distillation, and then is crystallized and separated; the method has the advantages that the magnesium lithium molar ratio of the old brine of the is reduced to less than 1, the method is as a solvent extraction method, ion exchange adsorption method and other conventional method suitable for magnesium and lithium separation of the brine of a saline lake with medium and low magnesium lithium ratio, can realize complete magnesium and lithium separation, and achieves the key technology of the development of the saline lake. 种从盐湖老卤中分离镁、降低镁锂比的方法，涉及化工领域，其由以下工序完成，老卤膜蒸馏浓缩结晶分离；本发明的有益效果为：将盐湖老卤中镁锂摩尔比降低至小于1，作为溶剂萃取法、离子交换吸附法等常规的、适用于中低镁锂比盐湖卤水中镁、锂分离方法的原料液，实现镁、锂彻底分离，实现了盐湖开发的关键技术。