Purification and impurity removal method for lithium chloride mixed solution

Abstract

The invention belongs to the technical field of lithium production, and particularly relates to a purification and impurity removal method for a lithium chloride mixed solution. The method includes the step that impurity removal is conducted on the high-salinity lithium chloride mixed solution through a nanometer filter to obtain a low-salinity lithium chloride solution, wherein the high-salinity lithium chloride mixed solution is a mixed solution of lithium chloride, magnesium chloride and calcium chloride; in the high-salinity lithium chloride mixed solution, the content of lithium ranges from 0 g/L to 55.0 g/L, and the content of calcium and magnesium ranges from 0 g/L to 30 g/L; in the low-salinity lithium chloride solution, the content of lithium ranges from 0 g/L to 55.0 g/L, and the content of calcium and magnesium is smaller than or equal to 5 mg/L; and a nanometer filter membrane in the nanometer filter is a monovalent ion selective nanometer filter membrane. The content of calcium and magnesium in discharged water subjected to impurity removal through the purification and impurity removal method of a salt chlorine-containing system is extremely low, the content of lithium reaches up to saturation, and possibility is provided for obtaining low-calcium and low-magnesium lithium production intermediate fine products by directly processing lithium production intermediate rough products.

Description

technical field [0001] The invention belongs to the technical field of lithium production, and in particular relates to a method for purifying and removing impurities of a lithium chloride mixed solution. Background technique [0002] Lithium is the lightest metal in the world. Due to some special properties, lithium and its compounds have extensive and special uses, and are known as "energy metals" and "metals that push the world forward". It plays an extremely important role in the energy industry, aerospace industry, metal smelting and manufacturing industry, refrigeration, ceramics, glass and other industries. At present, the global demand for lithium products is very urgent, and the demand for lithium is increasing rapidly year by year. [0003] The largest resource of lithium in the world is lithium ore, mainly including spodumene, lepidolite, lithium petalite, spodumene and eucryptite. The second major resource of lithium is salt lake brine with high lithium content...

AI Technical Summary

Problems solved by technology

Xu's method is low in cost, high in effectiveness and high in yield, but actual field tests show that although the concentration of lithium ions in brine can be increased, there is still a large amount of magnesium in brine, and the ratio of magnesium to lithium is still very high, far from The brine index for producing lithium carbonate has not been reached