Composite MVR evaporative crystallization separation method for potassium and sodium chlorate mixture wastewater

Abstract

The invention relates to a composite MVR evaporative crystallization separation method for potassium and sodium chlorate mixture wastewater, which comprises the following steps: firstly, evaporating and concentrating a wastewater stock solution containing potassium chloride and sodium chloride mixed salt into a concentrated solution in an MVR evaporative concentration continuous crystallizer; feeding concentrated supernate at the upper part of a separation chamber at the lower part of the MVR evaporation and concentration continuous crystallizer into a potassium chloride continuous crystallizer for cold crystallization to separate out potassium chloride, and feeding low-potassium supernate at the upper part of the potassium chloride continuous crystallizer into a sodium chloride evaporation continuous crystallizer for further evaporation and concentration to separate out sodium chloride; feeding the low-sodium supernate at the upper part of the separation chamber at the lower part of the sodium chloride evaporation continuous crystallizer into the MVR evaporative concentration continuous crystallizer; and evaporating the wastewater stock solution and separating potassium and sodium salts. Compared with an existing multi-effect evaporation hot and cold crystallization separation method and an MVR evaporation crystallization separation method, the method can save energy by 30-45%, and has the advantages of being low in energy consumption, good in energy-saving effect, small in equipment investment and the like.

Description

technical field [0001] The invention relates to an evaporation and separation method for inorganic salts, in particular to a compound MVR evaporation and crystallization separation method for potassium and sodium chloride salt mixture wastewater. Background technique [0002] At present, many domestic industries (such as: smelting, chemical industry, electronics, salt lake chemical industry, etc.) produce a large amount of wastewater containing mixed salts of potassium chloride and sodium chloride in the production process. If this kind of wastewater is directly discharged, it will cause serious damage and impact on the environment. Therefore, this kind of wastewater must be evaporated and crystallized, and potassium chloride and sodium chloride must be separated to make the wastewater evaporate to zero discharge and make chlorine Potassium chloride and sodium chloride are separated, and the quality meets the use requirements of some industries, so as to achieve the effect o...

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Problems solved by technology

[0008] The purpose of the present invention is to overcome the deficiencies in the prior art, and provide a kind of potassium, sodium chloride salt mixture waste water compound type MVR evaporation crystallization separation method, to solve existing multi-effect evaporation heat, cold crystallization separation method and MVR evaporation crystallization separation The problem that the energy consumption of the method is too high and the ideal energy-saving effect cannot be achieved

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