Process for preparing an aluminium oxide powder having a high alpha-al2o3 content

Abstract

Process for preparing an aluminium oxide powder which is present in the form of aggregated primary particles and comprises at least 85% by weight of alpha-aluminium oxide, in which an aluminium oxide powder which a) is present in the form of aggregated primary particles, b) is selected from the group consisting of gamma-aluminium oxide, theta-aluminium oxide, delta-aluminium oxide and/or X-ray amorphous aluminium oxide, and c) has a tamped density of at least 250 g/l, is subject to a heat treatment at 13000C or more and subsequently milled. Aluminium oxide powder which can be obtained by this process. Aluminium oxide powder in the form of aggregated primary particles having a BET surface area of from 3 to 30 m2/g, in which the proportion of alpha-aluminium oxide is at least 85% by weight and the ratio dgo/dio of the weight distribution of the primary particles is at least 2.8. Use as constituent of fluorescent tubes.

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