Method for recycling sylvinite by using carnallite decomposition mother liquor

Abstract

A method for recycling sylvinite by using carnallite decomposition mother liquor comprises the following steps that 1, the carnallite decomposition mother liquor is heated to 70-80 DEG C, and the preheated carnallite decomposition mother liquor is divided into carnallite decomposition mother liquor I and carnallite decomposition mother liquor II; 2, the carnallite decomposition mother liquor II continues to be heated to be boiled and evaporated, then cooling, crystallizing and filtering are carried out, the obtained solid phase is artificial carnallite, and the liquid phase is old brine; 3, anhydrous thermal decomposition is carried out to obtain high-temperature solid-liquid mixed ore pulp; 4, dehalogenation is carried out, wherein the high-temperature solid-liquid mixed ore pulp obtainedin step 3 is subjected to heat preservation and filtration, solid-liquid separation is realized, and solid sylvinite and high-temperature mother liquor are obtained. The method is simple in technological process, easy to operate and high in heat energy utilization rate, energy waste is avoided, good economic value and appreciation space are achieved, and a new process route and idea are providedfor utilization of a large amount of carnallite decomposition mother liquid generated by producing potassium chloride from carnallite in rainy and humid regions.

Description

Technical field [0001] The invention relates to a method for recovering potash salt using carnallite decomposition mother liquor, in particular to a method for preparing potash salt by thermally decomposing artificial carnallite ore under anhydrous conditions. Background technique [0002] Potassium chloride fertilizer is one of the common fertilizers in agriculture, mainly extracted from soluble potassium salt mines by flotation. Common soluble potassium salts mainly include carnallite and sylvite; sylvite can be directly produced by flotation to produce potassium chloride; while carnallite requires a decomposition process, which is first decomposed into sylvite, and then used Flotation method produces potassium chloride. The common decomposition process in actual production is to hydrolyze carnallite to obtain potash salt, and hydrolysis will produce a large amount of carnallite decomposition mother liquor, part of which can be used for flotation and slurry adjustment, and a l...

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Problems solved by technology

[0004] CN104163440A discloses a method for the production of potassium chloride from surface carnallite ore. In step 3, it involves adding water to cool the decomposition process, but in its disclosed scheme, there is no disclosure of the method for treating the accumulated carnallite decomposition mother liquor

[0005] CN104058428A discloses a new production system and method for producing potassium chloride with carnallite. The main innovation of the method is that the carnallite decomposition equipment in the traditional process is replaced by cold decomposition crystallization equipment, but the cold decomposition crystallization equipment also needs add fresh water to decompose

[0006] CN107162019A discloses a kind of processing method of carnallite ore, and this process adopts the method for decomposition-screening to produce KCl, in this process, decomposition process also needs to constantly add fresh water, can constantly produce new carnallite decomposition mother liquor, In its disclosed process flow, although it is stated that part of the mother liquor is returned to the decomposition section, most of the decomposition mother liquor cannot be processed

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