GB1402158A - Sodium bicarbonate production - Google Patents

Abstract

1402158 Sodium bicarbonate production OLIN CORP 13 Dec 1972 [29 Dec 1971 10 Nov 1972] 57485/72 Heading C1A NaHCO 3 is produced by spraying a solution containing Na 2 CO 3 into an atmosphere containing CO 2 , removing a suspension of NaHCO 3 crystals from a crystallization zone below the spraying zone, separating the crystals, and recycling the mother liquor to the crystallization zone. In Fig. 1, Na 2 CO 3 solution is fed at 35 to sprays 12, and CO 2 is fed through lines 16 and 18. NaHCO 3 crystals collect in classifying zone 11, and some of the suspension is recycled at 21 and sprayed into the tower at 24. Liquor from zone 15, which may contain fine NaHCO 3 crystals, is used to dissolve fresh Na 2 CO 3 at 29 and fed via a filter 33 to sprays 12. Fresh Na 2 CO 3 is also fed to the crystallization from line 31. Product crystals are withdrawn at 40 to centrifuge 41, mother liquor 42 is recycled, and the NaHCO 3 is dried at 47. Some fine crystals may also be withdrawn at 44 as product. In Fig. 2 (not shown), part of stream 35 is passed in heat exchange with stream 25 and then fed to a middle zone in the classifier. In Fig. 3 (not shown), all the Na 2 CO 3 input is fed through line 31, and stream 25 is passed directly to sprays 12. In Fig. 4 (not shown) Na 2 CO 3 feed is replaced by NaOH part of which is converted into Na 2 CO 3 in dissolver 29 for feeding to sprays 12, and the remainder of which is carbonated with CO 2 from vent 17 in the presence of mother liquor from line 43a and fed to the crystallization zone.