Salt lake brine treatment method for separating lithium from high-magnesium-lithium-ratio salt lake brine

Abstract

The invention discloses a salt lake brine treatment method for separating lithium from high-magnesium-lithium-ratio salt lake brine. The treatment method comprises the steps that S1, the salt lake brine is subjected to multistage salt pan evaporation to form first old brine; S2, sulphur removal is conducted: lime milk is added to the first old brine for separating out gypsum, and second old brine is obtained; S3, the second old brine is subjected to salt pan evaporation, bischofite is separated out, and third old brine is obtained; S4, the third old brine is diluted, and sent to a nanofiltration membrane device for nanofiltration treatment, and contributing water rich in lithium and thick water poor in lithium are obtained; and S5, the contributing water in Step S4 is sent to a reverse osmosis membrane device for reverse osmosis treatment, and reverse osmosis thick water and fresh water are obtained. The method combines a salt pan technology with a membrane system, makes full use of solar energy, and reduces energy consumption; a technological process is simple; equipment is easy to configure, mount and transfer; popularization and an application are very easy.

Description

【Technical field】 [0001] The invention relates to a salt lake brine treatment method, in particular to a salt lake brine treatment method for separating lithium from salt lake brine with a high magnesium-lithium ratio. 【Background technique】 [0002] Lithium is the lightest metal in the world. Due to some special properties, lithium and its compounds have extensive and special uses, and are known as "energy metals" and "metals that push the world forward". It plays an extremely important role in the energy industry, aerospace industry, metal smelting and manufacturing industry, refrigeration, ceramics, glass and other industries. At present, the global demand for lithium products is very urgent, and the demand for lithium is increasing rapidly year by year. [0003] The largest resource of lithium in the world is lithium ore, mainly including spodumene, lepidolite, lithium petalite, spodumene and eucryptite. The traditional lithium mining industry mainly extracts lithium p...

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Problems solved by technology

[0016] Chinese patents 03108088.X and 201010295933.X have pointed out that the use of nanofiltration membranes can achieve the separation of magnesium and lithium, but the brine conditions given in patent 03108088.X are too broad, without considering the applicability of the equipment, and have little practical significance; patent 201010295933 .X has been partially improved, but recycling the concentrated water obtained by nanofiltration in the nanofiltration membrane system will greatly increase the ratio of magnesium to lithium in the nanofiltration water, increasing the number of stages of the nanofiltration membrane system; the experiment is to use A simple verification experiment was carried out on the self-prepared solution, without considering the influence of other ions in the actual multi-component brine on the separation of magnesium and lithium in the process of nanofiltration membrane separation, and without considering the influence of membrane performance on the separation effect of magnesium and lithium

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