Antisolvent Crystallization of Anhydrous Sodium Carbonate at Atmospherical Conditions

When antisolvents are applied to crystallize sodium carbonate from aqueous solutions, the transition temperature at which the hydrates are in equilibrium is decreased. Two models proposed can predict the influence of the amount and type of antisolvent on the transition temperature. Only binary data of the water/sodium carbonate system and measured vapor pressures over ternary soda-saturated mixtures of water and antisolvent are needed. To validate the two models, continuous crystallization experiments were carried out at various temperatures using ethylene glycol (EG) and diethylene glycol (DEG) as antisolvent, in varying concentrations. Both models predict the influence of the antisolvent on the transition temperature with good accuracy. Anhydrous soda with bulk densities of up to 950 kg/m³ was crystallized at temperatures as low as 80°C.