Thermal Properties of Hydrated Alumina Prepared by the Homogenous Precipitation Method

Abstract

The thermal properties of hydrated alumina prepared by the homogenous precipitation method was compared with ordinary hydrated alumina. The latter was a gibbsite as determined by the X-ray powder diffractometry and differential thermal analysis.
After the heat treatment at 900° for a long period, the surface area of alumina from hydrated alumina precipitated by the homogenous method did not decrease, while that from gibbsite decreased remarkably. The surface area of the former was 80 m2/g and that of the latter was 10 m2/g by the that treatment at 1000° for 24 hr.
These results show that alumina from alumina hydrate precipitated by the homogenous method is thermally more stable than that of alumina from gibbsite at heat treatment below 1000°.