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

Abstract

The invention discloses a novel process for producing high-purity lithium hydroxide from salt lake brine. The process comprises the following steps of A, an operating mode; and B, raw materials; in the step A, continuous operation is adopted by the process, the scale of each device is optimized through the data calculated by the process, the operating mode is optimized, and continuous operation isachieved; and in the step B, after salt lake brine is subject to lithium extraction (adsorption method or electrodialysis method), lithium-magnesium separation, purification and reverse osmosis pre-concentration, lithium chloride qualified solution and reverse osmosis pre-concentration qualified solution raw materials comprise 35-50 g/L of lithium chloride, 10 mg/L of calcium-magnesium ions and 200 mg/L of boron ion. According to the method, lithium chloride solution after the brine is subject to lithium extraction (the adsorption method or a membrane method), magnesium removal and reverse osmosis pre-concentration is taken as raw materials, and electrodialysis technology, reverse osmosis technology, resin adsorption technology, ion membrane electrolysis technology, evaporative crystallization technology and the like are adopted, so that high-purity lithium hydroxide products are produced, and a guarantee is provided for cyclic utilization of salt lake lithium resources.

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. Its preparation method is simple, cheap, and has 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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