Method for preparing battery-grade lithium carbonate from lepidolite

Abstract

The invention provides a method for preparing battery-grade lithium carbonate from lepidolite, and belongs to the field of battery-grade lithium carbonate preparation. The method specifically comprises the following steps: roasting and leaching lepidolite, adding a fluorine removal agent to remove fluorine, carrying out concentrating, removing calcium and magnesium by chelating ion exchange resinto obtain a refined lithium solution, adding the refined lithium solution into a refined sodium carbonate solution of which calcium and magnesium are removed by chelating ion exchange resin, carryingout reacting, and settling to obtain crude lithium carbonate and lithium settling mother liquor; concentrating and evaporating the lithium precipitation mother liquor, freezing and salting out, addingthe product into a refined lithium solution for recycling, washing crude lithium carbonate, precipitating, centrifugally separating, drying, carrying out jet milling, mixing and packaging to obtain the battery-grade lithium carbonate. According to the method, the leachate is subjected to fluorine removal treatment, calcium and magnesium removal and then added into the refined sodium carbonate solution for reaction, the lithium precipitation mother liquor is recycled for production after being treated, and the method disclosed by the invention is simple in process step and relatively low in cost, ensures the quality of the battery-grade lithium carbonate and can be used for continuous production.

Description

technical field [0001] The invention relates to the field of preparation of battery-grade lithium carbonate, in particular to a method for preparing battery-grade lithium carbonate by using lepidolite. Background technique [0002] In the process of using salt lake brine and ore as raw materials to prepare lithium carbonate, one of the key processes is to use LiCl and Na 2 CO 3 The precipitation reaction between Li 2 CO 3 , the production process includes Na 2 CO 3 Solution preparation, conversion to lithium precipitation, filter press washing, and drying processes. As one of the raw materials for producing Li2CO3, Na 2 CO 3 , from economic considerations, industrial grade Na is mostly used 2 CO 3 , but limited by its technological characteristics, the content of Ca and Mg in industrial-grade Na2CO3 products is relatively high and fluctuates greatly, and industrial-grade Na2CO3 2 CO 3 The content of Ca and Mg in the medium is the influence of Li 2 CO 3 One of th...

AI Technical Summary

Problems solved by technology

Na as one of the raw materials for producing Li2CO3 2 CO 3 , from economic considerations, industrial grade Na is mostly used 2 CO 3 , but limited by its technological characteristics, the content of Ca and Mg in industrial-grade Na2CO3 products is relatively high and fluctuates greatly, and industrial-grade Na2CO3 2 CO 3 The content of Ca and Mg in the medium is the influence of Li 2 CO 3 One of the important sources of quality, in the process of lithium precipitation in LiCl solution, CaCO 3 , MgCO 3 Impurities introduce Li 2 CO 3 products, make Li 2 CO 3 It is difficult to control the content of Ca and Mg impurities in the product, the product quality fluctuates, and the product cannot reach the battery level Li 2 CO 3 standard; so for Li 2 CO 3 Na in production 2 CO 3 Purification of the solution to remove Ca and Mg impurity ions is of great significance

Lepidolite leachate is commonly used to prepare battery-grade lithium carbonate, but the presence of a small amount of fluorine in the leachate, directly used to produce battery-grade lithium carbonate without removing fluorine, will affect the quality of the product and does not meet the requirements for use.

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