Desalting and reusing method of high-salinity heavy ash mother liquor in combined-soda system

Abstract

The invention discloses a desalting and reusing method of high-salinity heavy ash mother liquor in a combined-soda system, which comprises the following steps that (1) when the sodium chloride content of heavy ash mother liquor is higher than 60 g / L, a part of high-salinity heavy ash solution is required to be discharged, and the discharged solution is conveyed to an evaporator to evaporate; (2) the discharged high-salinity heavy ash solution is evaporated to the co-saturated point of sodium carbonate and sodium chloride, so that monohydrate sodium carbonate crystals are precipitated out, and the monohydrate sodium carbonate crystals are separated from residual mother liquor after evaporating; and (3) the separated crystals are dissolved, so that a solution with a sodium chloride content of less than 20 g / L is obtained, and the solution is returned to a heavy ash system to reuse; and the residual mother liquor is applied to a salt-leaching process of a vacuum salt manufacturing device. In a solution which can be reused in the system and obtained by using the method disclosed by the invention, the sodium chloride content of is less than 20 g / L, and the sodium carbonate content is about 310 g / L, so that the solution can meet the index requirements of the heavy ash system.

Description

technical field [0001] The present invention relates to a method for desalination and reuse of high-salt heavy ash mother liquor, and in particular to a method in which sodium carbonate in high-salt heavy ash mother liquor is reused in the heavy ash system, and the remaining solution after evaporation is used in the vacuum salt washing process . Background technique [0002] The use of liquid phase hydration for heavy ash production has the advantages of high hydration rate, uniform crystal particle size, and low salt content in the product, so it is widely used. But use this method to carry out heavy ash production process, along with the heavy ash product is separated out, and chloride ion is constantly accumulated in the heavy ash mother liquor, and the sodium chloride content in the mother liquor increases gradually, and when the sodium chloride content increases to a certain degree, it will affect Due to the salt content in the heavy ash product, it is necessary to dis...

AI Technical Summary

Problems solved by technology

At present, the high-salt heavy ash mother liquor discharged from the combined alkali system is mainly used for brine refining or as a raw material for the production of baking soda, but with the recycling of the mother liquor, the system mother liquor will expand and affect the product quality

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