Method for producing low-salt high-quality dense soda ash

Abstract

The invention provides an improved method for producing low-salt high-quality dense soda ash by using light soda ash produced by a hot method alkali combination process as a raw material. The method comprises the following steps: firstly, producing the light soda ash containing 0.5 to 0.9 percent of NaCl in mass fraction through hot method alkali combination; and secondly, producing the low-salt high-quality dense soda ash containing less than 0.3 percent of the NaCl in mass fraction by adopting a liquid-phase hydration method or a modified solid-phase hydration method, wherein in order to ensure the salinity in the product, a certain amount of saliferous mother liquor of 40 to 80 g / L is needed to be discharged from a hydration system continuously or discontinuously and the saliferous soda mother liquor is sent back into a brine refining system, a Na2CO3 component in the mother liquor serves as a calcium remover, and a NaCl component serves as a raw material component. The method overcomes the defects that an ammonia soda process for producing the low-salt dense soda ash has a large sewage discharge and a combination soda production method cannot normally produce the low-salt dense soda ash; the raw materials can be coarse sea salts and mine salts, or bitterns obtained through solution mining of salt mines can be used directly; and the method has the advantages of no sewage discharge, good product quality and extensive development prospect.

Description

technical field [0001] The invention relates to a method for preparing soda ash. Specifically, it relates to a method for preparing low-salt heavy soda ash with crude brine, and belongs to the industry of soda ash manufacturing, which is a basic chemical raw material. Background technique [0002] The light soda ash produced by industrial synthesis has a density of 0.45-0.79g / cm 3 , the particles are fine, the cost of packaging and storage is high, and the dust is flying when used. Therefore, most of the light soda ash should be processed into heavy soda ash. Heavy soda ash with a bulk density of 0.8g / cm 3 above. In addition, another important quality index to measure heavy soda ash is the salt content. Salt content (referring to NaCl mass fraction, the same below) is low-salt high-quality heavy soda ash if it is lower than 0.3%, and it is ordinary heavy soda ash if it is higher than this value. quality soda ash. When low-salt heavy soda ash is used to make glass, it ca...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the above-mentioned shortcoming that the waste liquid of low-salt heavy soda ash produced by the ammonia-soda method is large, and the cold method combined with soda method cannot normally produce low-salt heavy soda ash, and provides an improved method for producing low-salt heavy soda ash method

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