中国科学院过程工程研究所机构知识库

An energy-saving, modified Solvay process for dense soda ash production was proposed to replace the high-temperature, calcination step of NaHCO3. We found NaHCO3 completely decomposed into anhydrous, Na2CO3 at 353 K in a mixed-solvent containing at least 65 wt% of monoethanolamine (MEA), which is an amine-absorbent prevalently used for CO2 capture. A chemical model was built after the determination of solubilities and through data regression for the solid-liquid system: Na-Cl-NH4-CO3-HCO3-MEA-H2O. Reparameterization for paired-ion interactions were performed via the mixed-solvent electrolyte model. Thermodynamic analysis elucidated the shift in ion dominance from HCO3- to CO32+, thereby providing the phase transition mechanisms. An exploratory, fed-batch experiment was implemented to verify the accuracy of the model, for which the obtained solids were in the form of saleable, dense soda ash products; bulk densities up to 1.01 g/cm(3) were achieved in the laboratory.