PRODUCTION OF FINE POWDER OF ALUMINIUM OXIDE

• Main Authors: MENDES, RICARDO, CASTRO, PEDRO DE MELLO, SILVA, JOAO MANUEL CALADO DA, CAMPOS, JOSE
• Format: Patent
• Language: English
• Published: 25.08.2006
• Subjects: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM,CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THERARE-EARTH METALS; EXPLOSIVES; EXPLOSIVES OR THERMIC COMPOSITIONS; INORGANIC CHEMISTRY; MANUFACTURE THEREOF; MATCHES; METALLURGY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; THEIR RELEVANT APPARATUS; TRANSPORTING; USE OF SINGLE SUBSTANCES AS EXPLOSIVES

The novelty consists in an industrial process based on the utilisation of cyclic explosions, in a solid stage, of an oxidising component mixed with high granulometry aluminium to obtain micro- and nano-dust of aluminium oxide which purity exceeds 99.7%, essencially in the form of alpha crystalline.The process is competitive because of its capacity to transform granulated aluminum of over 150 micra into aluminium oxide with a granulometry under 5 micra.The starting system of the direct and repetitive cycle is based on a high electric current discharge over an explosive metallic bridge. This discharge creates a fast vaporisation (in hundreds of nanoseconds) and generates a partially ionised gas (metallic plasma) which iniciates the explosive compound.