Novel process for producing high-purity lithium hydroxide by salt lake brine

Abstract

The invention discloses a novel process for producing high-purity lithium hydroxide by salt lake brine. The process comprises the following steps that A, and the process comprises the following operation mode that the process adopts continuous operation, wherein the scale of each device is optimized through the data calculated by the process, the operation mode is optimized, so that continuous operation is achieved; and B, the salt lake brine is subjected to lithium extraction (by an adsorption method or an electrodialysis method), lithium-magnesium separation, purification and reverse osmosispre-concentration to obtain a lithium chloride qualified solution, and the reverse osmosis pre-concentration qualified solution comprise the following raw materials of, 35-50 g / L of lithium chloride,lower than 10 mg / L of calcium-magnesium ions, and lower than 200 mg / L of boron ions. According to the method, (an adsorption method or a membrane method) ), the magnesium chloride solution subjectedto lithium extracting by brine, magnesium removal and reverse osmosis pre-concentration is taken as the raw material, the electrodialysis technology, a reverse osmosis technology, a resin adsorption technology, an ion membrane electrolysis technology, an evaporative crystallization technology and the like are adopted, so that the high-purity lithium hydroxide product is produced, and therefore cyclic utilization of salt lake lithium resources is guaranteed.

Description

technical field [0001] The invention relates to the technical field of high-purity lithium hydroxide production, in particular to a new process for producing high-purity lithium hydroxide from salt lake brine. Background technique [0002] At present, the main production methods of lithium hydroxide include ore sulfate solution electrolysis, causticization, etc. Among them, ore sulfate solution electrolysis is the most mature and cost-effective technology at present, but it is mainly suitable for ore resources. For brine resources Lithium chloride salt solution system, there is no mature process technology for producing lithium hydroxide. [0003] Salt lake lithium extraction refers to the extraction of lithium from lithium-containing salt lake brine and the production of lithium products. Lithium extraction from salt lake brine usually undergoes stages of solar evaporation in salt fields, different salts obtained in stages, and purification of salt solution. Finally, the li...

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Problems solved by technology

[0004] Qinghai Salt Lake Fozhao Lanke Lithium Industry Co., Ltd., a subsidiary of Qinghai Salt Lake Industry Co., Ltd., used lithium adsorbents to selectively adsorb lithium in high-magnesium and low-lithium brines, and completed the preliminary separation of magnesium and lithium (the ratio of magnesium to lithium is 500: 1 or higher), and at the same time synthesized a lithium adsorbent with excellent performance, which can eliminate the interference of a large number of coexisting alkali metal and alkaline earth metal ions in brine, and selectively adsorb lithium ions in brine. During more than three years of operation, its performance indicators can meet the target requirements. Secondly, the adsorption and desorption performance of the adsorbent is stable, which is suitable for large-scale operation. The preparation method is simple, the price is cheap, and there is no pollution to the environment. Lithium currently stays on the basis of producing raw material grade and battery grade lithium carbonate. The process of producing lithium hydroxide using lithium chloride salt solution is still in the research and development stage, and there is no successful experience to learn from. The use of salt lake brine to produce high-purity hydrogen Lithium oxide process is still in the blank

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