A kind of method of producing potassium chloride by carnallite raw ore

Abstract

The invention provides a method for preparing potassium chloride from carnallite. The low-sodium carnallite slurry is decomposed and crystallized for the first time in the first crystallizer 8a, so that the magnesium chloride in the carnallite is transferred to the liquid phase, and the potassium chloride crystallization partly transferred to the liquid phase is separated out, and the crystallization of the first crystallizer 8a The underflow contains precipitated potassium chloride and undecomposed carnallite and sodium chloride particles. In the second crystallizer 8b, the underflow of the first crystallizer 8a is decomposed and crystallized, the sodium chloride in the carnallite is transferred to the liquid phase, and the potassium chloride crystallization partly transferred to the liquid phase is separated out, and the second crystallizer 8b The underflow contains precipitated potassium chloride and undecomposed carnallite and sodium chloride particles. The underflow of the second crystallizer 8b is sieved, and the oversize contains undecomposed carnallite and sodium chloride particles, and the undersize is used to generate potassium chloride product. The oversize is crushed, and the broken oversize is used to generate the low-sodium carnallite slurry. While ensuring the grade of potassium chloride, the recovery rate of carnallite is greatly increased.

Description

technical field [0001] The invention relates to a method for preparing potassium chloride from carnallite raw ore, in particular to a method for preparing potassium chloride from large-grain carnallite raw ore. Background technique [0002] Potassium resources in China widely exist in remote areas such as Qinghai, among which the reserves in Qinghai account for more than 50% of the national reserves, and the representative resources are salt lake resources. At present, due to the continuous expansion of potash fertilizer production scale in the Salt Lake area and the gradual release of production capacity, starting from the brine mining area, there is a trend of shortage of raw brine and a decrease in potassium content of raw brine resources year by year. Along with the use of large-grain carnallite raw ore (hereinafter referred to as raw ore) in recent years, the content of sodium chloride in the raw ore increases, causing potassium fertilizer production enterprises to prod...

AI Technical Summary

Problems solved by technology

[0007] This process can effectively reclaim undecomposed large-grain carnallite by setting recovery crystallizer 11, and improve the recovery rate of potassium chloride, but because the sodium chloride of large grain is insoluble than carnallite, the material at the bottom of reclaim crystallizer 11 There will still be incompletely dissolved large particles of sodium chloride in the slurry (underflow), reducing the grade of potassium chloride

If reclaiming crystallizer 11, add excessive water and make sodium chloride particle dissolve, can cause most of potassium chloride to transfer to liquid phase, have only a small amount of potassium chloride to separate out, the potassium chloride that transfers to liquid phase is with recovery crystallizer The overflow discharge of 11 causes the loss of potassium chloride and reduces the utilization rate of carnallite

[0008] The purpose of the present invention is to improve the above-mentioned prior art to solve the problems of low potassium chloride grade and low utilization rate of carnallite when producing potassium chloride from large-grained carnallite raw ore

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