The mechanism of Bayer process scale formation

The study focuses on sodium aluminosilicate scale formation during alumina production, particularly investigating sodalite and cancrinite. It explores the scaling mechanisms, supersaturation, and kinetics of desilication reactions that lead to precipitation. Researchers determined the equilibrium solubilities of these scales in synthetic Bayer liquor across various temperatures and measured their growth kinetics, revealing specific order dependencies and activation energies. Additionally, the transformation from sodalite to cancrinite was identified as a solution-mediated process, suggesting that adopting a seeding strategy could minimize scale accumulation in heat exchangers.