Method for formulating food grade sodium bicarbonate

摘要

There is disclosed a method for formulating food grade sodium bicarbonate by purification of a sodium bicarbonate liquor where an initial saturated feedstock of sodium bicarbonate which contains sodium sulfate as an impurity is filtered to remove the impurities and a first filtrate liquor formed. The filtrate liquor is then subjected to ion exchange with a cationic resin to reduce the calcium and magnesium ion concentration present in the filtrate liquor with subsequent cooling of the liquor. The cooled liquor is also treated with a source of ammonia or ammonium ions to shift the solubility of the compounds to retain sodium sulfate in solution while precipitating sodium bicarbonate with reduced sulfate occlusions. The precipitated sodium bicarbonate is then filtered to result in a food grade sodium bicarbonate product.