METHOD FOR PRODUCING ENRICHED CARNALLITE Russian patent published in 2023 - IPC C01F5/30 C01D3/08 C22B3/00 

FIELD: chemical industry.

SUBSTANCE: invention can be used in production of edible salt, artificial sylvinite and raw materials for production of metallic magnesium. First, underground dissolution of carnallite or mixed potassium-magnesium ore is carried out with a hot solution with a mass fraction of magnesium chloride not exceeding 25%. The resulting solution is evaporated in a multi-vessel vacuum evaporator in counterflow to the heating steam. The sodium chloride suspension is separated, removed from the first tanks of the vacuum evaporator and sent for processing to produce edible salt. In the last building of the vacuum evaporator, a solution saturated with magnesium chloride is obtained, and the solid phase, which is a mixture of potassium and sodium chlorides, is separated using thickening to obtain a suspension, which is sent for processing to obtain artificial sylvinite for production of potassium chloride using flotation or hot leaching crystallization method. The hot solution saturated with magnesium chloride, obtained in the last tank of the vacuum evaporator, is cooled under vacuum, as a result of which carnallite crystallizes into a solid phase. Then a suspension of carnallite is obtained, which is separated to obtain the target product - enriched carnallite, and the circulating solution is directed to the condensation of the solution vapor formed by cooling the hot solution saturated with magnesium chloride under vacuum, while recuperating the heat of the solution vapor with the circulating solution. The circulating solution heated in this way is combined with the remaining part of the secondary steam condensate of the multi-vessel vacuum evaporator, the filtrate and washing water from the stage of obtaining food salt, as well as with the filtrate and washing water from the stage of obtaining artificial sylvinite and returned to the stage of underground ore dissolution.

EFFECT: waste-free technology for obtaining enriched carnallite with the most complete extraction of components for production of edible salt and artificial sylvinite is provided.

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