Control method for granularity of potassium nitrate product produced through double decomposition

Abstract

The invention relates to a control method for the granularity of a potassium nitrate product produced through double decomposition. The control method comprises the following steps: (1) adding potassium chloride, ammonium nitrate and mother liquor into a double decomposition tank for double decomposition so as to obtain reaction slurry; (2) delivering the reaction slurry into a potassium nitrate cooling crystallization reaction vessel and carrying out cooling crystallization in two steps so as to obtain potassium nitrate crystallizer underflow slurry; (3) introducing the potassium nitrate crystallizer underflow slurry into a cyclone so as to separately obtain coarse-grain potassium nitrate crystal underflow and a feed liquid containing fine potassium nitrate crystal and allowing the feed liquid containing fine potassium nitrate crystal to return to the potassium nitrate cooling crystallization reaction vessel in the step (2); (4) separating the coarse-grain potassium nitrate crystal underflow from a lower outlet of the cyclone and carrying out centrifugation, washing and drying so as to separately obtain crystallization mother liquor and a large-granule potassium nitrate product with crystal granularity stabilized in a range of 1.0 to 1.5 mm and uniform particle sizes; and (5) evaporating the crystallization mother liquor according to a conventional method so as to separately obtain a byproduct--ammonium chloride and circulating mother liquor. The method provided by the invention is simple and reliable, is convenient to operate and has obvious effect.

Description

technical field [0001] The invention relates to a production method of a large particle potassium nitrate product, in particular to a method for controlling the granularity of a potassium nitrate product by a double decomposition method. Background technique [0002] Potassium nitrate is a high-quality nitrogen-potassium binary compound fertilizer, all of which are instant nutrients. Potassium ions and nitrate ions can be quickly absorbed by crops. It is a chemical nitrogen-potassium compound fertilizer with a promising market prospect. [0003] The domestic production of potassium nitrate by metathesis mainly adopts the ammonium nitrate-potassium chloride process, and is mainly based on the four-step circulation method: add water, mother liquor, potassium chloride and ammonium nitrate to the circulating mother liquor, and when the temperature drops, potassium nitrate crystallizes out. Ammonium nitrate is added to the mother liquor, and after evaporation and concentration, c...

AI Technical Summary

Problems solved by technology

[0004] In the current potassium nitrate production process, there are problems such as large energy consumption, uneven crystal size, difficult separation, high operation requirements and unstable product purity.