TOWARDS A FUNDAMENTAL RATE EQUATION FOR GIBBSITE GROWTH IN BAYER LIQUORS

Vernon, C, Parkinson, G. & Lau, D.

Equations for the growth of gibbsite from Bayer liquors have, until recently, been based on simple functions of supersaturation and temperature. Where necessary, these equations have made allowance for factors such as free caustic concentration, but none are satisfactory over a broad range of conditions. This is hardly surprising, as most approaches have been data fitting exercises and have paid little attention to the fundamental chemical processes.

The present work draws on the results of a number of techniques, ranging from the microscopic (Atomic Force Microscopy) to macroscopic (bulk batch crystallization) and recognises that a comprehensive growth model cannot be derived without knowledge of the crystal growth process, solution speciation and the effects of the liquor on the surface chemistry of gibbsite.