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Abstract

A process and apparatus for the manufacture of high purity, ultra-fine aluminum nitride powder by the carbo-nitridization of alumina. In the method, agglomerates uniform in both size, chemical composition and porosity are formed containing a stoichiometric mixture of alumina and carbon, and a small amount of catalyst, and furnaced in a controlled manner in a well-mixed two chamber reaction vessel having optional top or bottom fluidizing gas feed to achieve a uniform and consistent level of conversion. Milling of the as-reacted agglomerates under a controlled atmosphere will produce high purity, micron sized aluminum nitride powder. The reactor is an automatically controlled fluid bed reactor for treatment of refractory materials with a hot fluidizing gas having a two chamber design in which the lower furnace chamber and reactor bed are removable from the bottom of the reactor. With unique reactor, unusually high reaction temperatures of up to 2000.degree. C. are obtainable. Further, the bottom removal feature allows for easy servicing of the reactor. Still further, the fluidizing gas may be introduced via a conduit and a bubble cap from above or below the reactor. If from below, wear on the conduit will be reduced because in such a configuration the conduit will not extend through the bed of the reactor. If the gas is introduced from above, the gas will be preheated by means of countercurrent heat flow, enabling more efficient operation of the reactor.

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First Claim