Sodium metabisulfite process
AssigneeSolvay Minerals, Inc.
InventorsVladimir M. Zolotoochin, Jim P. Metziner, David M. Hansen
Life of this patent
Estimating the term…
Abstract
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 an alkali such as soda ash, caustic soda, sodium sulfite, and mixtures thereof is added to produce additional sodium metabisulfite that increases the yield of sodium metabisulfite crystallizing per pass. The mother liquor is recycled.
Claims20
A process for manufacturing sodium metabisulfite comprising:
- introducing soda ash into an aqueous solution of sodium bisulfite to form a feed liquor of sodium bisulfite and sodium sulfite;
- introducing sulfur dioxide into the feed liquor and converting sodium sulfite to sodium bisulfite to form a reaction liquor having dissolved sulfur dioxide;
- introducing an alkali selected from the group consisting of soda ash, caustic soda, sodium sulfite, and mixtures thereof into the reaction liquor to react with dissolved sulfur dioxide to form sodium bisulfite;
- cooling the reaction liquor to precipitate sodium metabisulfite and form a mother liquor;
- and
- separating sodium metabisulfite from the mother liquor and recycling the liquor.
A process for the manufacture of sodium metabisulfite comprising:
- in a contacting tower, producing a solution comprising sodium bisulfite close to saturation and dissolved sulfur dioxide, said solution having a pH from about 3.5 to about 4.2 and a temperature between about 100 and about 160.degree. F.;
- in a separate vessel, introducing said solution and adding alkali to react with the sulfur dioxide in the solution, and crystallizing sodium metabisulfite from the solution at a temperature between about 50 and about 115.degree. F. to produce a mother liquor.
Dependencies are inferred from the claim text.