A Cost-effective Process for Recovery of Low Sodium Salt from Bittern

A new process for recovery of Low Sodium Salt from bittern has been described consisting comprising desulphatation, evaporation  processing.

Realizing the demand of low sodium salt which is commonly prepared by homogeneous mixing of NaCl and KCl, CSIR-CSMCRI has developed a cost effective process for the production of low sodium salt using the bittern, the mother liquor left out after production of salt in solar salt works. The process involves the desulphatation of bittern using cheap agents like distiller waste liquor of soda ash plants and processing the desulphated bittern for the recovery of low sodium salt via the intermediate product carnallite.

• The homogeneous mixture of sodium chloride and potassium chloride, which constitutes low sodium salt, can be produced directly from 29-30° Be′ bittern instead of producing such salt through artificial mixing of the two solids as presently undertaken.
• The ratio of potassium chloride and sodium chloride can be adjusted in the range from 20% KCl to 70% KCl according to customer requirements by varying the baume density at which the carnallite crystallizer pan is charged.
• The process involves no heating or cooling except final drying of product in an oven and the production of crude carnallite is carried out under ambient conditions with the help of solar energy while subsequent processing of the carnallite for recovery of low sodium salt is also carried out under ambient conditions.
• Other nutrients like calcium and magnesium which are beneficial in small amounts are drawn from bittern itself and need not be added from outside.
• The supernatant liquor remaining after formation of low sodium salt can be recycled in the carnallite pan to boost yield of the process.
• A variety of calcium ion-containing raw material can be used for the desulphatation of bittern required for carnallite production when the bittern contains high levels of sulphate.