System and method for preparing byproduct potassium sulfate product through hydrothermal denitration of potassium chloride brine

Abstract

The invention relates to the technical field of chemical engineering, and discloses a system and method for preparing byproduct potassium sulfate product through hydrothermal denitration of potassium chloride brine, and the method comprises the following steps: a nanofiltration membrane unit receives dechlorinated light salt brine from an external potassium alkali device and conveys the dechlorinated light salt brine to a heat exchange unit for heat exchange; secondary gas condensate generated by an evaporative crystallization unit is conveyed to the heat exchange unit, in the heat exchange unit, the dechlorinated light salt brine exchanges heat with the secondary gas condensate, the dechlorinated light salt brine after heat exchange is conveyed to the evaporative crystallization unit to be evaporated and concentrated to obtain potassium sulfate crystals, and the secondary gas condensate after heat exchange is subjected to waste heat recovery treatment; and potassium sulfate crystals are treated by a centrifugal separating unit and then enter a drying unit to be dried, qualified potassium sulfate products are obtained, and centrifugal mother liquor obtained after centrifugal separating is output to a potassium alkali device to enter a secondary brine refining procedure. According to the method, the defects of a barium-method denitration process or a calcium-method denitration process used in current industrial production are effectively overcome, and the purposes of reducing cost and improving efficiency are achieved.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a system and method for thermal denitrification of potassium chloride brine to produce potassium sulfate by-product. Background technique [0002] The removal of sulfate from solution is also known as denitrification. In the production of ion-exchange membrane potash-alkali plant, the quality of potassium chloride refined brine has a decisive effect on the life and power consumption of the ion-exchange membrane, and the content of sulfate is one of the important indicators of the quality of refined brine. In the electrolytic cell, the cations and sulfate radicals in the refined brine will form sulfate insoluble matter, which is deposited on the ion membrane, thereby causing a decrease in the current efficiency of electrolysis. Sulfate radicals in the refined brine exceed the standard for a long time, which will cause physical damage to the ionic membrane, resulting in ...

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Problems solved by technology

[0013] Therefore, it is necessary to invent a sulfate removal process that does not introduce additional impurities and does not generate solid waste, so as to effectively solve the shortcomings of the barium denitrification or calcium denitrification processes currently used in industrial production, and achieve the purpose of reducing costs and increasing efficiency

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