| Abstract Scope |
The particle size distribution (PSD) control of gibbsite particles during seeded hydrate precipitation in the Bayer process is important for ensuring high-quality alumina. Various factors, including fill temperature, seed charge, and sodium oxalate precipitation etc., can influence PSD of gibbsite product. Oxalate co-crystallization with alumina trihydrate may result in poor alumina product quality, such as finer PSD, increased occluded soda, a worse attrition index, and potentially reduced productivity. To address these challenges, Syensqo has developed an aqueous crystal growth modifier (CGM) to control the PSD of gibbsite via reducing the oxalate co-precipitation. This new CGM has no downstream impacts. It can exit the Bayer process by adsorbing to oxalate and gibbsite solids, and can be destroyed during bauxite digestion. This innovation improves the PSD of precipitated hydrate crystals via reducing oxalate co-precipitation, thereby enhancing process control, product quality, and precipitation yield. |