Method of preparing battery grade lithium hydroxide by directly electrolyzing lithium chloride

Abstract

The invention relates to a method of preparing battery grade lithium hydroxide by directly electrolyzing lithium chloride. The method comprises the steps of refining a lithium chloride solution, adding the refined lithium chloride solution into an anode chamber of a bipolar natural circulation ion-exchange membrane electrolyzer, adding a lithium hydroxide solution with a mass percent concentrationof 5.5-7.5% into a cathode chamber of the bipolar natural circulation ion-exchange membrane electrolyzer, adding pure water into the cathode chamber, and preparing the mass percent concentration of the lithium hydroxide solution to be 4.9-6.5%, wherein an ion exchange membrane of the bipolar natural circulation ion-exchange membrane electrolyzer is a cation exchange membrane. The invention aims at providing the method of preparing battery grade lithium hydroxide by directly electrolyzing lithium chloride; produced battery grade lithium hydroxide is high in purity and few in impurity; a utilization ratio of a lithium element resource is high; the waste of the lithium element resource is low; circular economic utilization of all raw materials and products in a whole lithium hydroxide preparation process is achieved; the method is environment-friendly and efficient; and almost no pollutant is discharged.

Description

technical field [0001] The invention relates to the field of lithium hydroxide preparation, in particular to a method for directly electrolytically preparing lithium hydroxide from a lithium chloride solution by using an electrolysis method. Background technique [0002] Lithium hydroxide is an important chemical raw material, which is widely used in machinery, pharmaceuticals, lithium batteries and many other fields. At the same time, lithium hydroxide is one of the core raw materials for the preparation of ternary lithium battery cathode materials. [0003] In recent years, as ternary lithium batteries have gradually replaced binary lithium batteries as the main category of lithium-ion batteries, the price of lithium hydroxide in its upstream has been rising with the increasing demand for cathode materials for ternary lithium batteries, while the secondary The price of lithium carbonate, the main raw material for lithium battery cathode materials, has been falling all the...

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Problems solved by technology

For example, the limestone roasting method and pressure leaching method using spodumene as raw material, etc., but the above methods have high energy consumption, low efficiency, serious pollution, and the purity of lithium hydroxide obtained is not high; while the causticization method using lithium carbonate as raw material The method is the current mainstream chemical method to prepare lithium hydroxide, but the prepared lithium hydroxide contains high impurity content, the process is complicated, and the price of lithium carbonate used is high, leaving little profit space for enterprises. many

[0005] To sum up, the currently existing chemical methods for preparing lithium hydroxide have more or less problems of one kind or another, and are no longer suitable for national policies on lithium resource utilization and environmental protection.

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