Method for preparing high-purity lithium chloride, high-purity lithium formate and high-purity lithium carbonate

Abstract

The invention discloses a method for preparing high-purity lithium chloride, high-purity lithium formate and high-purity lithium carbonate. The method for preparing high-purity lithium chloride comprises: S1, mixing crude lithium chloride and an organic solvent, heating until boiling, removing water in reflux liquid, refluxing the organic solvent until the water content in the reflux liquid and that in the mixed liquid are detected to be both lower than or equal to 0.5 percent by weight, stopping heating and cooling to room temperature to obtain turbid liquid; S2, while stirring, introducing ammonia gas into the turbid liquid, and maintaining stirring for a period of time, so that lithium chloride suspended in the organic solvent is all dissolved, and insoluble matter impurities are filtered to obtain filtrate; S3, adding pure water into the filtrate, uniformly stirring, then dropwise adding refined and decontaminated pre-prepared liquid, thoroughly stirring, filtering, adding at leastone of oxalic acid, oxalate or oxalate ester into the filtrate, stirring, lowering the temperature to -5 DEG C or below, and keep cold to filter insoluble matters in a solution to obtain an organic solution of refined lithium chloride, wherein the purity (dry basis) of lithium chloride is greater than or equal to 99.9 percent by weight.

Description

technical field [0001] The invention relates to a lithium chloride purification process and a method for preparing high-purity downstream products using high-purity lithium chloride, in particular to a method for preparing high-purity lithium chloride, high-purity lithium formate and high-purity lithium carbonate. Background technique [0002] The purity requirement of battery grade lithium carbonate is greater than 99.5wt%; the purity requirement of reagent grade lithium carbonate is greater than 99.9wt%. The existing production technology routes at home and abroad are mainly through the refining and purification of industrial grade lithium carbonate (purity is 98% ~ 99%), or lithium hydroxide is used as raw material to react with carbon dioxide to produce lithium carbonate (such as Chinese patent: ZL201010600802.8) . Because the impurities in these upstream raw materials are very complex and difficult to remove, resulting in high refining costs, this is why the supply of ...

AI Technical Summary

Problems solved by technology

The production process from crude lithium chloride to high-purity battery-grade lithium carbonate has various shortcomings such as long process, large investment in new refining equipment, and difficulty in rapidly increasing refining capacity in a short period of time.

[0004] In the carbonate-type lithium-containing salt lake represented by Zabuye Salt Lake in Tibet, the technical route of refining and producing lithium hydroxide and lithium carbonate after the solar pond was used to precipitate lithium carbonate ore in the early stage also has capacity bottlenecks and the purity of lithium carbonate products. Not advanced question

[0005] Therefore, the existing lithium carbonate preparation process generally has problems such as high requirements on raw material quality, difficulty in removing trace impurities, low refining yield, high refining cost, etc., which makes battery grade lithium carbonate and reagent grade ultrapure lithium carbonate (purity >99.99%), the market price remains high, and it is urgent to find a method that can quickly increase the volume and produce high-purity battery-grade lithium carbonate to meet the rapidly growing demand of downstream industries such as new energy electric vehicle batteries