Patent ID: 8865095

Claim:
A process for producing sodium bicarbonate from a sodium carbonate bearing stream (A) comprising sodium carbonate and at least one impurity consisting of an alkaline metal water-soluble salt at a concentration C i (A), said process comprising the following steps: a) mixing the sodium carbonate bearing stream (A) with at least part of a stream (B) to produce a stream (C); b) bicarbonating the stream (C) with a gas (D) comprising CO 2 to produce an aqueous suspension (E) comprising crystals (F), said crystals (F) comprising sodium bicarbonate crystals; c) separating the aqueous suspension (E) in order to obtain crystals (F) comprising sodium bicarbonate crystals and an aqueous mother liquor (G); d) partly debicarbonating at least part of the aqueous mother liquor (G) and removing part of the water of the at least part of the mother liquor (G) to obtain the stream (B) with an at least one impurity of water-soluble salt of alkaline metal at a concentration C f (B) and an optional gas (H); e) recycling at least a part of the stream (B) to step a) so that the ratio C f (B)/C i (A) of the at least one impurity of water-soluble salt of alkaline metal is at least 1.4; and f) removing a remainder (I) of the stream (B) which is not recycled to step a) or a part (J) of the mother liquor (G) which is not partly debicarbonated in step d) to be further processed.