METHOD FOR REDUCING ALUMINA OR MAGNECIA BY UTILISING SUPERSONIC GAS FLOW

摘要

Provided is an alumina- or magnesia-reducing process in which a greenhouse effect gas or a substance harmful to the human body is not emitted and which can achieve an improved energy efficiency in comparison with the Hall-Héroult method or the Pidgeon method. This alumina- or magnesia-reducing process includes: introducing an alumina powder or a magnesia powder together with a carrier gas to the upstream side of a throat provided on a reducing unit; pressure-transferring the powder and the carrier gas to the throat by an operative gas introduced to the upstream side of the throat; irradiating the throat with a laser beam to convert the alumina or the magnesia into a plasma state and thus dissociate the alumina or the magnesia thermally; jetting the thermally dissociated product through a nozzle provided on the downstream side of the throat at a supersonic speed to form a frozen flow; and thus isolating aluminum or magnesium. Hydrogen may be further added to the operative gas, whereby the reduction of alumina or magnesia can be accelerated through the action of hydrogen.