Ormiston Mining and Smelting Co. Ltd.

Airborne Industrial Minerals, Inc.

Jake Halldorson

Steve Kresnyak

Mark Hantke

There is disclosed a process for recovering sodium bicarbonate and forming ammonium sulfate from a source containing sodium sulfate. The method involves contacting the sodium sulfate in solution with carbon dioxide and a compound containing ammonia. Sodium bicarbonate is precipitated in high purity form from the solution. It is important to maintain the temperature of the source solution at or above 32.degree. C. This provision eliminates contamination of hydrates or ammonium bicarbonate components. The filtrate of the sodium bicarbonate reaction can be further processed to yield an ammonium sulfate product in the concentrated liquid or precipitated form in high purity. The basic process can be expanded to be combined with a conventional Claus process for sulfur recovery as a Tail Gas Unit, or can be further employed in a wet and dry scrubbing process for FGD schemes.

Method for production of sodium bicarbonate, sodium carbonate and

A process for producing sodium bicarbonate and sodium carbonate. The process includes reacting within a reactor sodium sulfate in aqueous solution with ammonia and carbon dioxide to precipitate sodium bicarbonate and form a first mother liquor. The sodium bicarbonate is separated and dried to produce sodium bicarbonate product. Alternatively, the sodium bicarbonate may be calcined to convert it to sodium carbonate. The first mother liquor may be evaporated to precipitate unreacted sodium sulfate, with the formation of a second mother liquor. The second mother liquor may be cooled to precipitate a double salt of sodium sulfate/ammonium sulfate and water. A third mother liquor is formed from this process. The latter-mentioned liquor from the precipitation of the double salt is evaporated to precipitate a substantial pure ammonium sulfate in a purity of greater than approximately 75 wt %. A fourth mother liquor is formed. The double salt is added to the first mother liquor from the precipitation of sodium bicarbonate prior to the evaporation step and the fourth mother liquor is added to the second mother liquor from the evaporation to precipitate unreacted sodium sulfate.

There is disclosed a process for recovering sodium bicarbonate and forming ammonium sulfate from a source containing sodium sulfate. The method involves contacting the sodium sulfate in solution with carbon dioxide and a compound containing ammonia. Sodium bicarbonate is precipitated in high purity from the solution. It is important to maintain the temperature of the source solution at or above 32.degree. C. This provision eliminates contamination of hydrates or ammonium bicarbonate components. The filtrate of the sodium bicarbonate reaction can be further processed to yield an ammonium sulfate product in the concentrated liquid or precipitated form in high purity. The basic process can be expanded to be combined with a conventional Claus process for sulphur recovery as a Tail Gas Unit, combined with lime injection to result in gypsum precipitation or can be further employed in a wet scrubbing process for FGD schemes.

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Calgary, Canada

Jake Halldorson