Potassium preparation process by glauber method

Abstract

A potassium preparation process by the glauber method includes 1, conversion of a first stage, namely converting thenardite and potassium chloride with water and / or mother liquor material containing potassium sulfate, performing solid-liquor separation, and obtaining the aphthitalite and the conversion mother liquor of the first stage; 2, evaporation of a first stage, namely performing the evaporation of the first stage on the conversion mother liquor of the first stage, performing solid-liquor separation, and obtaining the sodium high temperature salt and the evaporation mother liquor of the first stage; 3, evaporation of a second stage, namely performing the evaporation of the second stage on the evaporation mother liquor of the first stage, performing solid-liquor separation, and obtaining aphthitalite / sodium high temperature mixed salt and the evaporation mother liquor of the second stage; 4, physically separating the mixed salt to obtain aphthitalite and sodium; 5, conversion of a second stage, namely converting the aphthitalite and sodium and water and / or mother liquor material containing potassium sulfate, performing solid-liquor separation, and obtaining the potassium sulfate coarse product and the conversion mother liquor of the second stage; 6, washing and drying to obtain the potassium sulfate product. By the aid of the method, the product separating purity is high, the quantity of mother liquor is small, energy consumption and cost are low, the content of K2O of the potassium sulfate product is of 51.3%, and the agricultural-use first-class potassium sulfate standard can be met.

Description

technical field [0001] The invention relates to a process for preparing potassium sulfate, in particular to a process for preparing potassium sulfate by the Glauber's salt method. Background technique [0002] Potassium sulfate is an important chlorine-free potassium fertilizer, and the agricultural demand is very strong. [0003] At present, 50% of potassium sulfate fertilizer in the world comes from minerals, and about 40% of potassium sulfate is obtained by converting potassium chloride and sulfuric acid or sulfate. Glauber's salt conversion method is also the most researched and most in-depth method of preparing potassium sulfate so far. . In my country, the proven reserves of Glauber's salt mineral resources have reached about 20 billion tons (in terms of anhydrous sodium sulfate), ranking first in the world, and are distributed in 14 provinces and regions in my country, among which Qinghai, Sichuan, Inner Mongolia, Hunan, Yunnan, The six provinces of Xinjiang are the ...

AI Technical Summary

Problems solved by technology

[0004] In the preparation of potassium sulfate by Glauber’s salt method, the second-stage transformation mother liquor is usually returned to the first-stage reactor for recycling, but there are generally technical problems such as large mother liquor treatment capacity. The traditional process is to evaporate the first-stage transformation mother liquor at high temperature to precipitate sodium chloride, and cool down Precipitate potassium mirabilite, cool the mother liquor and recirculate high temperature evaporation-cooling to recover part of the potassium. However, with the continuous circulation of the mother liquor, the amount of mother liquor will continue to accumulate, causing the expansion of the mother liquor in the system, increasing the operating pressure of the equipment, and greatly reducing the discharge of excess mother liquor. Potassium yield; if one section of the conversion mother liquor is completely evaporated, not only the evaporation amount is large, but the energy consumption is high, and the precipitated potassium-containing mixed salt composition is complex, which increases the difficulty of separation; , all of which are returned to the first-stage converter for recycling, which will increase the amount of converted materials in the first stage, resulting in low equipment capacity and low production efficiency. At the same time, a relatively large amount of circulating mother liquor runs continuously between devices, which will increase energy consumption, equipment investment and operating costs.

[0005] CN1189456A discloses a kind of production technology of potassium sulfate, is to separate sodium chloride through a high-temperature evaporation of potassium mirabilite mother liquor obtained by one stage of transformation and separation, and then participates in a stage of metathesis reaction after being evaporated into salt-making mother liquor supersaturated liquid through negative pressure, but, there is The degree of evaporation is limited, and the output of sodium chloride is small, resulting in a large amount of mother liquor returned, high operating costs of the system, and low production capacity, which will generate a large production pressure on the first-stage conversion reactor