Lithium chloride transformation liquid purifying method

Abstract

The invention discloses a lithium chloride transformation liquid purifying method. The lithium chloride transformation liquid purifying method comprises the following steps: (1) adding a refining agent into a lithium chloride transformation liquid, filtering and collecting a solution, obtain a primary decalcified lithium chloride solution; (2) conveying the primary decalcified lithium chloride solution obtained in the step (1) into a chelating resin tower, and obtaining a deeply decalcified lithium chloride solution; (3) conveying the deeply decalcified lithium chloride solution obtained in the step (2) into a nanofiltration device to remove SO4<2->, and conducting nanofiltration, wherein a penetrating fluid is a purified lithium chloride liquid. An anhydrous lithium chloride product is produced by evaporating and crystalizing the purified lithium chloride liquid prepared according to the method, the index of the anhydrous lithium chloride product reaches the quality index of a LiCl-1product in the GB / T 10575-2007 anhydrous lithium chloride of the national standard, the SO4<2-> is less than or equal to 0.01%, and the CaCl2 is less than or equal to 0.02%. The lithium chloride transformation liquid purifying method has the advantages of high impurity removal efficiency, high product quality, high automation degree of the process, stable operation and the like, and the productionrequirement on a battery level lithium product is met.

Description

technical field [0001] The invention belongs to the technical field of lithium salt production, and in particular relates to a method for purifying lithium chloride conversion liquid. Background technique [0002] Lithium is a very important energy metal. With the rapid development of the new energy vehicle market, the demand for power lithium batteries is increasing year by year, and the requirements for the output and quality of lithium products are getting higher and higher. Lithium products are divided into two categories: basic lithium products and high-end lithium products. Basic lithium products refer to industrial-grade lithium carbonate, lithium chloride, and industrial-grade lithium hydroxide. High-end lithium products include battery-grade lithium carbonate, high-purity lithium carbonate, Battery grade lithium metal, butyllithium, lithium fluoride, etc. Lithium chloride is a basic lithium product with a wide range of uses. Many lithium deep-processed products hav...

AI Technical Summary

Problems solved by technology

[0004] The currently disclosed lithium chloride purification technology mostly uses chemical precipitation to remove calcium ions and sulfate ions, such as the methods disclosed in patents CN201610257026.3 and CN201611093934.X. This method uses barium chloride to precipitate sulfate, which not only consumes a large amount of chemical agents , will also produce a large amount of barium sulfate solid waste, which has great environmental pollution, and the precipitation process is long, the residual amount of impurities is large, and the product quality is low, which is difficult to meet the production requirements of battery-grade lithium products