Producing sodium bicarbonate from sodium carbonate-containing first stream, comprises e.g. mixing first stream with second stream portion, bicarbonizing flow, separating aqueous suspension and partially decarbonizing aqueous mother liquor

摘要

Producing sodium bicarbonate from a sodium carbonate-containing first stream, comprises: (a) mixing the sodium carbonate-containing first stream with at least second stream portion for producing a flow; (b) bicarbonizing the flow with gas comprising carbon dioxide for preparing an aqueous suspension containing crystals; (c) separating aqueous suspension to obtain crystals; (d) partially decarbonizing the aqueous mother liquor and removing a portion of water; (e) recycling at least second stream portion from the step (a); and (f) removing the remaining flow or a part of aqueous mother liquor. Producing sodium bicarbonate from a sodium carbonate-containing first stream, where a sodium carbonate-containing first stream portion is generated from a sodium crystallizer, and the sodium carbonate-containing first stream comprises at least 2 wt.%, preferably at least 4 wt.% of sodium chloride and/or sodium sulfate, comprises: (a) mixing the sodium carbonate-containing stream with at least second stream portion for producing a flow; (b) bicarbonizing the flow with a gas comprising carbon dioxide for preparing an aqueous suspension containing crystals, where the crystals include sodium bicarbonate crystals; (c) separating the aqueous suspension to obtain crystals, at least one part comprising sodium bicarbonate crystals and an aqueous mother liquor; (d) partially debicarbonizing the aqueous mother liquor and removing a portion of the water to obtain the flow and an optionally gas; (e) recycling at least second stream portion from the step (a); and (f) removing the remaining flow or a part of the aqueous mother liquor for further processing. An independent claim is also included for joint production of sodium carbonate and sodium bicarbonate crystals, comprising introducing sodium carbonate solution comprising sodium carbonate and at least one impurity of sodium chloride and/or sodium sulfate in a sodium carbonate-crystallizer, forming a first aqueous suspension comprising sodium carbonate-crystals, subjecting the aqueous suspension to a first separation to obtain crystals including sodium carbonate and mother liquor. A portion of the mother liquor is withdrawn from the sodium carbonate-crystallizer to form the sodium carbonate-containing first stream, which is further processed for producing sodium bicarbonate.