Separating and using method for mixed sodium salt

Abstract

The invention provides a separating and using method for mixed sodium salt. The method comprises the following steps: A) adding the mixed sodium salt to ammonia water, to obtain ammoniacal brine, wherein a mass ratio of sodium sulfate and sodium chloride in the mixed sodium salt is 1:(0.5-2), and concentration of the ammonia water is 8-12%; B) feeding carbon dioxide to the ammoniacal brine, performing a gas liquid reaction, to obtain a mixed system, wherein a feeding quantity of the carbon dioxide is 10-30 L / h; C) performing evaporation and concentration on the mixed system, separating out andcrystallizing, to obtain saline mixture; and D) filtering the saline mixture, washing filter residue by using sodium sulfate saturated solution, to obtain a sodium sulfate product, cooling and crystallizing filtrate, washing a separated crystal by using ammonium chloride saturated solution, to obtain an ammonium chloride product. The method is capable of, on the basis of separating and recoveringthe sodium sulfate, converting the sodium chloride into the ammonium chloride with the wider application range, and providing a new technology for separation of the sodium sulfate and the sodium chloride.

Description

technical field [0001] The invention belongs to the technical field of solid waste resource treatment, and in particular relates to a method for separating and utilizing mixed sodium salts. Background technique [0002] The mixed sodium salt of sodium sulfate and sodium chloride is mainly produced in the coal chemical industry and zero-discharge wastewater treatment. According to statistics, the mixed sodium salt produced in these two industries is about 5 to 6 million tons per year. At present, the main way to dispose of this mixed salt is the combined production of salt and nitrate. [0003] Salt and nitrate co-production is to separate and recover the sodium chloride salt and sodium sulfate salt in the raw brine. At present, the main methods are: three production technologies and process modes: freezing salt salt cogeneration, thermal salting out salt salt coproduction and evaporation salt salt coproduction. The principles of the three methods are based on the NaCl-Na ...

AI Technical Summary

Problems solved by technology

[0007] At present, the treatment technology and process of mixed salt are to separate and recover sodium sulfate and sodium chloride. On the one hand, there are defects and deficiencies in the recovery process and technology, and on the other hand, the recovered industrial grade sodium chloride and sodium sulfate products have an application market small, low resource value

Images