A new industrial process of NaHCO3 and its crystallization kinetics by using the common ion effect of Na2CO3

Sodium bicarbonate (NaHCO 3 ) has been conventionally manufactured by a carbonation synthesis from the reaction of sodium carbonate (Na 2 CO 3 ) and CO 2 in a carbonation column. To enhance the quality and the production yield of NaHCO 3 , it is imperative to carefully control supersaturation in the carbonation crystallization process and make NaHCO 3 concentration of filtrate obtained from column bottom possibly least. A new method of NaHCO 3 production was proposed with help of common ion effect by adding Na 2 CO 3 as feed in filtering liquor. A cooling crystallizer was incorporated in the system after the carbonation tower to generate more NaHCO 3 . The crystallization kinetics of NaHCO 3 including nucleation and crystal growth was experimentally and theoretically investigated in a continuous mixed-suspension-mixed-product removal (MSMPR) crystallizer cooled from 353 to 308 K. The effect of Na 2 CO 3 concentration and additives on the crystallization of NaHCO 3 was studied. The growth and nucleation rate G V = 6.618 × 10 - 15 σ 0.290 , B 0 = 2.560 × 10 - 32 G V - 3.82 M T 1.11 were determined by moments analysis based on the experimental crystal size distribution (CSD) data. The kinetic parameters in two empirical equations were estimated by linear regression with the 0.290 of the relative supersaturation rate order, indicating that the meant surface integration and diffusion play an equally importance to the growth of NaHCO 3 crystal. The growth rate order of −3.82 suggested that nucleation of NaHCO 3 from the Na 2 CO 3 -rich solution in the MSMPR crystallizer was particle size-limiting.