A kind of preparation method of potassium nitrate

Abstract

The invention discloses a preparation method of potassium nitrate. The method comprises the steps of: A, mixing nitrate with an alkali eutectic aid uniformly, and heating be not more than 300 DEG C for melting to obtain a first mixture, wherein the mass ratio of nitrate to alkali eutectic aid is not smaller than 3 to 1; B, crushing potassium rich rock, putting the crushed rock into the first mixture, continuously heating the first mixture to be not more than 600 DEG C, and preserving the heat for 6-24h to obtain a second mixture, wherein the potassium rich rock is silicate mineral which is not less than 8% by weight percent based on K2O; C, cooling the second mixture to 100-120 DEG C, introducing water to obtain a third mixture, preserving the heat of the third mixture at 50-90 DEG C for 6-36h, and performing solid-liquid separation to obtain first filter residue and first filtrate; and D, concentrating and cooling the first filtrate to separate out potassium nitrate. According to the preparation method of the potassium nitrate, the potassium rich rock is used as a raw material, and an aqueous solution of potassium nitrate can be obtained by two times of extraction, so that the method is simple, the energy consumption is low and the environment-friendly effect is achieved.

Description

technical field [0001] The invention belongs to the technical field of inorganic salt preparation, and in particular relates to a preparation method of potassium nitrate. Background technique [0002] my country is a large agricultural country, and potash fertilizer, as an important strategic agricultural resource, is related to the country's food supply security. At present, the annual demand of my country's crop potassium fertilizer market is about 4.6 million tons (in K 2 O meter), plus industrial potassium and reasonable stocks, the total annual demand for potassium salt is about 6.49 million tons. It is estimated that by 2020, my country's market demand for crop potassium fertilizer alone will reach 10 million tons. At present, my country's potash fertilizer production capacity is limited, and the annual production capacity is only about 3.2 million tons (in K 2 (2) can not meet the demand of the domestic market, and about 30% of the annual potash fertilizer demand n...

AI Technical Summary

Problems solved by technology

The method in the prior art is not only complicated in process, but also uses acid-base neutralization or other double decomposition reactions, which has the problem of high raw material cost, and produces more industrial waste residue, which greatly increases the process cost

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