Solvay Chemicals Gmbh

Solvay Sa

James C Kisielewski

David M Hansen

Alain Vandendoren

Keith O Hayes

Don Robertson

Mayra Muci-Castaneda

A process for producing crystalline sodium bicarbonate, comprising: providing an aqueous sodium-bicarbonate containing liquor originating from a reactive crystallization step in which first sodium bicarbonate crystals are produced and recovered; feeding at least a portion of said aqueous sodium-bicarbonate containing liquor to a cooling crystallization unit to form second sodium bicarbonate crystals and produce a crystals slurry comprising the second sodium bicarbonate crystals; and withdrawing a portion of the crystals slurry from the cooling crystallization unit for the withdrawn second sodium bicarbonate crystals to be further processed. A portion of the second sodium bicarbonate crystals withdrawn from the cooling crystallization unit may be fed to a sodium bicarbonate reactive crystallization unit, to a caustic unit, or may be separated and dried. The reactive crystallization, separation and/or drying units where the second sodium bicarbonate crystals are further processed may be the same units where the first sodium bicarbonate crystals are processed.

Production of crystalline sodium bicarbonate

A process for the joint production of crystalline sodium bicarbonate and another alkali compound, in which the step for producing such alkali compound generates COas a byproduct, at least a portion of which is used as a feed to the sodium bicarbonate production step. The produced alkali compound is preferably crystalline sodium sulfite. The joint production process preferably employs as feedstock one or more sodium carbonate liquors derived from trona ore. A gas feed which contains CObyproduct is subjected to a gas treatment which may include water removal and/or compression before it is used to produce sodium bicarbonate crystals from a sodium carbonate liquor. Such gas feed may comprise a reactor offgas exiting a sulfite reactor; a vent gas exiting a feed or surge tank; a decarbonation gas exiting a decarbonation unit; a vent gas vented from a crystallizer heater; or combinations of two or more thereof.

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Processes for producing sodium bisulfite from sodium sulfite purge streams are disclosed which enable recovery of additional resource material including sodium bisulfite.

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Green River, WY, United States of America

James C Kisielewski