THERMAL TRANSFORMATIONS OF BOEHMITE GEL IN CONTROLLED FURNACE ATMOSPHERES

Boehmite derived alumina gel was annealed at intermediate temperatures for three hours in five different inner furnace atmospheres. Phase development, porosity, specific surface area, morphology, and changes in bulk density were compared. An atmosphere of water vapour has specific effects on the fired product, most likely by means of intensifying surface diffusion. The product has a different microstructure from those of the other atmospheres, characterized by a higher pore volume, larger average pore size, and smaller specific surface.