The preparation of boehmite and amp;-alumina powders by hydrothermal synthesis from aluminium metal

摘要

Hydrothermal oxidation of aluminium metal has been effected in the temperature and pressure ranges of 30O-55O0C and 10-120 MPa respectively. While boehmite and 13; a-alumina form at the extremities of these temperatures and13; pressures respectively,at intermediate temperatures their mixtures are obtained. The products which had average particle sizes in the range of 4-15 pm were further characterised by XRD, IR spectroscopy, and by SEM observations.The quantity of metal reacting with unit volume of water shows three regions having distinctly different slopes in the temperature ranges of 300- 35OoC, 350-45OoC and 450-550xB0;C corresponding to the formation of fully crystalline forms of boehmite, boehmite + a-alumina and a-alumina respectively.