Method for preparing potassium chloride from carnallite containing magnesium sulfate

Abstract

The invention relates to a method for preparing potassium chloride from carnallite containing magnesium sulfate. The method comprises the following steps of: (1) dividing raw brine into two parts, naturally evaporating one part to obtain old brine, and naturally evaporating the other part to a sodium salt section to obtain a separating liquid; (2) mixing the old brine with the separating liquid to obtain a mixed liquid phase; (3) naturally evaporating the mixed liquid phase and separating to obtain a solid phase A and a separated liquid phase A; (4) naturally evaporating the separated liquid phase A and separating to obtain a solid phase B and a separated liquid phase B; (5) uniformly mixing the solid phase B with water which is mixed with a floating agent and an inhibiting agent to obtain decomposed slurry; (6) roughing the decomposed slurry; (7) scavenging roughing tail washings; (8) performing primary cleaning on roughed foam and performing secondary cleaning on the primarily-cleaned foam; (9) filtering secondarily-cleaned foam to obtain a filtrate and a solid phase C; and (10) washing the solid phase, separating to obtain a solid phase D, and drying the solid phase to constant weight to obtain a potassium chloride product. The method has a simple separating process and high yield of brine pan potassium.

Description

technical field [0001] The invention relates to the technical field of inorganic chemical industry, in particular to a method for preparing potassium chloride from magnesium sulfate-containing carnallite ore. Background technique [0002] The Qinghai-Tibet Plateau has a unique natural geographical environment and salt-forming geochemical background, forming a dotted modern inland salt lake and rich natural resources of salt lakes. The salt lakes on the Qinghai-Tibet Plateau are mainly sulfate-type water and no carbonate-type water. Among them, the Qaidam Basin is a distribution area of ​​sulfate-chloride type water, and only Xiaochaidan Lake exists in the sodium sulfate subtype water, while the chloride-type water It is only distributed in the area of ​​Kuntyi Lake and Chaerhan Lake in the center of the basin, because these two lake areas are both subsidence centers and concentration centers, the lake water has a long history of evolution, and the degree of water quality det...

AI Technical Summary

Problems solved by technology

At present, although some production enterprises have produced potassium chloride products in some sulfate-type salt lake areas, the salt field process, decomposition process, flotation reagents and processes are not reasonable enough, and the quality and yield of potassium chloride products have not reached a reasonable state.

The grade of potassium chloride produced is low, and the general grade is lower than 90%. The product impurities mainly contain magnesium sulfate impurities except sodium chloride. This is mainly because the agents used in potassium chloride flotation cannot well suppress Sulfate, it is not suitable for salt field mines containing a large amount of magnesium sulfate produced by sulfate-type salt lake brine

At the same time, the tailings produced in the potassium chloride production process contain a large amount of magnesium sulfate, which has not been effectively utilized at present

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