Vacuum crystallization technique for producing potassium nitrate from potassium chloride by sodium nitrate

Abstract

A vacuum crystallization process uses the sodium nitrate to transform the potassium chloride for the production of the potassium nitrate. The process comprises the following steps: (1) a first time low temperature mother liquid is prepared according to a corresponding phase diagram; (2) the sodium nitrate and the potassium chloride are added by proportion; and the constant temperature conversion is processed at 75-90 Celsius system; (3) the slurry is precipitated at 75-90 Celsius system until the solid percentage reaches 30%-45%, the crystallized high temperature salt is separated through centrifugation and the clear liquid enters into a vacuum crystallizer after filtration; (4) the high temperature salt is washed and the washing liquid is directly sent into the vacuum crystallizer; (5) the cold separation temperature of the vacuum crystallizer is controlled at 25-40 Celsius system, and the potassium nitrate crystal is precipitated; (6) the slurry is pumped into a slurry elevated slot after vacuum crystallization, the slurry is introduced into a centrifuge for the centrifugal separation to obtain the primary product of potassium nitrate; (7) the primary product of potassium nitrate is washed, re-dried and packaged. The invention has a convenient proportion, a mild isolation and transformation condition and a short production process, which can save more than 18% water and more than 20% energy. The operation of the invention is simple, and the process is easy to realize the continuous production and automatization. The invention also has a low production cost and good economic benefits.

Description

technical field [0001] The invention relates to a production process of potassium nitrate, in particular to a production process for preparing potassium nitrate through double decomposition reaction with sodium nitrate and potassium chloride. Background technique [0002] Potassium nitrate is a colorless transparent orthorhombic crystal or powder or granule, and is an important inorganic chemical product. [0003] Used as a chemical fertilizer, its advantage is that it is completely composed of effective plant nutrients. The total content of potassium and nitrogen can reach 60%, and it is easily absorbed by plants. There is no residue after application. It is a high-quality chlorine-free potassium and nitrogen compound fertilizer. High-quality fertilizer for chlorine-avoiding crops such as tobacco, coffee, tomato, grape, citrus, gardening, flowers, potato, avocado, tea, etc., and has good physical and chemical properties. It is known as the "third-generation potassium fertil...

AI Technical Summary

Problems solved by technology

[0011] The object of the present invention is to overcome defects such as high conversion temperature in the production process of producing potassium nitrate by converting potassium chloride from sodium nitrate, large circulating water volume and high energy consumption in the solution cooling and crystallization process, and provide a solution cooling and crystallization process, Vacuum crystallization process for producing potassium nitrate by converting sodium nitrate into potassium chloride with less circulating water and lower energy consumption