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.