Preparation method of cell-grade lithium hydroxide

Abstract

The invention belongs to the field of materials, and particularly relates to a preparation method of cell-grade lithium hydroxide. The preparation method of cell-grade lithium hydroxide has the advantages of being high in product purity, few in production process, low in production energy consumption and the like. The preparation method comprises the following steps that 1, a pre-prepared mixed solution is prepared, wherein a lithium sulfate solution and a sodium hydroxide solution are mixed according to the mole ratio 2:(1-1.2) of lithium sulfate to sodium hydroxide; 2, the pre-prepared mixed solution is frozen, wherein the pre-prepared mixed solution is frozen and crystallized for 1-2 h at the temperature of minus 15 DEG C to minus 10 DEG C, and solid-liquid separation is conducted to obtain sodium sulfafe decahydrate crystals and lithium hydroxide freezing liquid; 3, the lithium hydroxide freezing liquid obtained in the step 2 is subjected to evaporation concentration and solid-liquid separation to obtain a crude lithium hydroxide product; 4, the crude lithium hydroxide product obtained in the step 3 is redissolved to remove impurities and then subjected to evaporation concentration and solid-liquid separation to obtain lithium hydroxide with the coarse grain cell grade quality. The product is high in purity, few in impurity, coarse in grain and good in appearance, and the operation method is simple, few in production process, low in cost and low in energy consumption.

Description

technical field [0001] The invention belongs to the field of materials, in particular to a method for preparing battery-grade lithium hydroxide. Background technique [0002] After more than ten years of development, the current overall technological process for the production of lithium hydroxide by the domestic mining method is as follows: the sulfuric acid method is used to extract lithium from the ore in the previous process, and the lithium hydroxide is produced in the subsequent process. At present, there are mainly two methods for producing lithium hydroxide from spodumene at home and abroad: sulfuric acid method and lime method (ie, the previous process), and each country chooses one of them according to its own conditions. Since the 1970s abroad, basically only the sulfuric acid method has been retained. my country's limestone method has entered the world's advanced ranks in terms of yield and product quality. Therefore, there are still several limestone productio...

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Problems solved by technology

[0011] However, the aforementioned method takes a long time and consumes a lot of energy, and battery-grade lithium hydroxide can only be obtained through multiple purifications. The present

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