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PROCESS FOR OBTAINING NANOCRYSTALLINE CORUNDUM FROM NATURAL OR SYNTHETIC ALUMS
US2013183527
The University of Valencia have developed a novel method for producing corundum of low crystallinity (nanocorundum) using natural or synthetic commodities in solid state, without pre-treatment. This procedure consist of two steps, a first one of heating treatment at adequate temperature and ordinary pressure and the second one of abrupt cooling (quenching) of the first step product. The method of the invention produces nanocorundum, avoiding the formation of alumina transition polymorphs of low temperature. As a result, the final product is porous and their disintegration is easy, avoiding the hardness and difficult grinding of the compact corundum.
Applications: The main application of the technology is in the chemical industry, for producing corundum for diverse uses (refractories, abrasives, functional fillers for polymers, production of ceramics, glasses and glazed ceramics with reactive alumina, etc) and nanocorundum for special applications (catalyst carriers, implants, aerospace applications, etc.). Advantages: The most remarkable advantages provided by this technology are: - The use of natural or synthetic commodities in solid state. - Simplicity of the procedure, allowing small-scale or in industrial-scale production of corundum. - The obtained corundum can be easily disintegrated, since it is a porous product.