Process for producing high-purity magnesium oxide and lithium salt by using salt lake old brine

Abstract

The invention discloses a process for producing a high purity magnesium chloride, which is as follows: the crystal magnesium chloride separated from the salt lake old brine which is evaporated and concentrated or the residual liquid after the crystallization is processed by primary pyrolysis, counter moisture absorption and secondary pyrolysis. The invention also discloses a process for jointly producing the high purity magnesium chloride and the lithium salt, which is as follows: after the salt lake old brine is evaporated, concentrated and crystallized, the obtained residual liquid is processed by dehydration, primary pyrolysis, counter moisture absorption, secondary pyrolysis, gasification and calcination. The invention is widely adapted to the different salt lake brine, the extraction ratio of magnesium chloride and lithium salt is high. The invention is applied to magnesium chloride production alone, and is also applied to lithium salt joint production, thus the presently difficult technology problem of magnesium-lithium separation is completely resolved at home and abroad. The invention has the advantages of low requirement process, simple equipment, simple principle and easy mastery, short process for single product, low cost for comprehensive productions, .The invention is adapted to the production requirement of different size, and provides the new approach for comprehensive development of the salt lake in Chinese western region.

Description

technical field

[0001] The invention belongs to the field of inorganic salt chemical industry, and in particular relates to a production process for preparing high-purity magnesium oxide and lithium salt by using old brine from salt lakes as raw materials. Background technique

[0002] At present, the methods of producing magnesium oxide from brine at home and abroad mainly include:

[0003] 1 brine-soda ash method;

[0004] 2 brine-ammonium bicarbonate method;

[0005] 3 brine-ammonia method;

[0006] 4 brine-lime method;

[0007] 5 Brine-spray pyrolysis method; (see "Magnesium Compound Production and Application", pp. 57-61, pp. 128-129), "Sea Lake Salt and Chemical Industry", Vol. 20, No. 2, pp. 26-29, Volume 20, Issue 3, Pages 37-38).

[0008] There are many methods used at home and abroad to prepare lithium salt from brine, mainly including:

[0009] 1. Brine-aluminate precipitation method;

[0010] 2. Organic solvent extraction;

[0011] 3. Ion sieve method (io...

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