New Process of Mother Liquor Recovery

Abstract

The invention discloses a mother liquor recovery new process. The process adopts the traditional quadruple-effect vacuum salt production and brine mixing cooling mirabilite redissolution technologies. The brine does not need purification and can undergo steam washing. The condensate water of an I effect evaporation tank and an II effect evaporation tank undergoes flash evaporation and then returns to a boiler, and the condensate water of an III effect evaporation tank and an IV effect evaporation tank undergoes heat exchange with original brine through a plate heat exchanger, and the residual heat is recovered. Salt-leached old brine undergoes brine removal and purification. The purified refined bittern is taken as the raw material of a 300 system. The 300 system utilizes the principle that within a certain temperature range, the solubility of NaCl increases with temperature rise and the solubility of Na2SO4 decreases with temperature rise, through certain amount of feed liquid circulation, mirabilite can be precipitated under high temperature, and salt can be precipitated under low temperature, thereby realizing co-production of salt and mirabilite.

Description

technical field [0001] The invention relates to the field of mine salt production, in particular to salt production using mirabilite-type brine as raw material. Background technique [0002] The raw material brine for vacuum salt making in my country mainly has gypsum type (CaSO 4 ) and thenardite type (Na 2 SO 4 ) two types, of which Glauber's salt type brine is the majority. For gypsum brine, because CaSO 4 The solubility is low, and it is economically feasible to remove it by chemical methods. Even if it is not purified, the gypsum seed method is mature and reliable; and for Glauber's salt brine, due to its Na 2 SO 4 The content is generally high, and it cannot be removed by chemical methods economically. Even if the brine is purified, it usually only removes calcium and magnesium impurities in the brine. Therefore, in the production of Glauber's salt brine, physical methods are basically used to separate salt and nitrate. . [0003] The traditional vacuum salt pro...

AI Technical Summary

Problems solved by technology

Vacuum salt production saves investment and is easy to operate, but the salt quality is not high, which cannot meet the increasing demand for salt quality in modern society, and wastes the thenardite resources in brine and easily causes pollution

The mother liquor recovery method of co-production of salt and nitric acid has good quality and high resource utilization rate, but the investment is large and the cost of brine purification is high

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