Sodium metabisulfite process

摘要

Sulfur dioxide is introduced into a solution of sodium sulfite and sodium bisulfite to form sodium bisulfite in a solution having dissolved sulfur dioxide present with a pH between 3.5 and 4.2. The solution is drawn to a cooling crystallizer where sodium hydroxide is added to produce additional sodium metabisulfite that increases the yield of sodium metabisulfite crystallizing per pass. The mother liquor is recycled./!