Problems of Particle Agglomeration in making High Density Alumina Bodies from Calcined Alumina Powders

TLDR: In this article, Bayer's alumina of micron and submicron order formed agglomerates when the powder was calcined at sufficiently high temperatures and became increasingly stronger with increasing temperature of calcination.

Abstract: Wet ground and washed Bayer's alumina of micron and submicron order formed agglomerates when the powder was calcined at sufficiently high temperatures. The agglomerates became increasingly stronger with increasing temperature of calcination. Grinding, leaching with acid and finally washing with distilled water caused surface hydration which was evidenced by loss in weight on ignition and pycnometric density of alumina powders calcined at different temperatures. Pore volume reduction of agglomerates thus formed at temperatures above 1100°C caused remarkable improvement in the packing density of alumina bodies using the calcined powders. However, in order that a good alumina body may be formulated, the use of fused alumina grains seemed to be unavoidable.