Deacon, A.J. and Wainwright, M.S.

Particle characterisation methods are assuming greater importance for quality control and optimization in the process industries. The alumina companies have recognised the importance of measurements such as particle size distribution, surface area, porosity, density, strength, flowability and phase composition since these and other properties affect marketability of alumina. This paper addresses the importance of instrument selection, maintenance and laboratory practice when using modern analytical instrumentation for measuring such properties. Results obtained on different instruments using the same alumina samples will be used to illustrate the importance of standardised instrumentation and inter-laboratory trials.

Methods for measurement of alumina and hydrate properties that are not currently in general use are discussed. These include image analysis since many producers have expressed interest in the measurement of shape factors and shape distribution.

The measurement of the surface area of hydrate is considered both through the difficulties of using available techniques and the possibility of alternative approaches. The importance of making meaningful measurements of hydrate surface areas for modelling and optimization of precipitation are discussed.