Method for teating heavy alkali filter liquid in synthesizing alkali producing method

Abstract

The method of treating heavy alkali filtering liquid from alkali synthesizing production process includes evaporating ammonia to decompose NH4HCO3 and recover NH3 and CO2, adding MgO and evaporating ammonia to recover NH3, separating NaCl and returning to salt dissolving step, crystallizing magnesium chloride, hydrolyzing magnesium chloride to obtain MgO and HCl, reusing MgO while obtaining HCl. The present invention can raise the utilization rate of NaCl greatly, lower power consumption and cost.

Description

technical field [0001] The invention belongs to the production process of synthetic soda, in particular to a method for decomposing and separating the heavy alkali filtered mother liquor in the technological process, by which the ammonium chloride in the mother liquor can be decomposed into ammonia (NH 3 ) and hydrogen chloride (HCl), while separating out sodium chloride (NaCl). NH 3 and NaCl are returned to the previous process as raw materials, and HCl is used as a chemical raw material for other purposes. Background technique [0002] In the process of producing soda ash by synthetic soda production method (including ammonia soda method and combined soda method), no matter adopting ammonia soda method or combined soda method, it is necessary to treat the mother liquor after filtering the heavy alkali generated in the carbonation process; The mother liquor contains various substances such as ammonium chloride, ammonium bicarbonate, sodium chloride, sodium carbonate, sodi...

AI Technical Summary

Problems solved by technology

In order to decompose the ammonium chloride in the filtrate into ammonia and hydrogen chloride and separate sodium chloride, sodium chloride and ammonia are used as raw materials to return to the salt solution process and ammonia absorption process, while hydrogen chloride is used as a chemical raw material to achieve the goal of overcoming ammonia Environmental pollution by waste liquid (slag) in the alkaline process, increase the utilization rate of sodium chloride; effectively solve the problem that the by-product ammonium chloride in the combined soda process production is difficult to get out, seriously restricting the development of soda ash production; and reduce energy consumption and production costs , Improve the efficiency of soda ash production, etc.