Abstract: An alumina- or magnesia-reducing process in which a greenhouse gas or substance harmful to the human body is not emitted, which can achieve improved energy efficiency in comparison with the Hall-Heroult or Pidgeon methods. The process includes: introducing an alumina or magnesia powder with a carrier gas to the upstream side of a throat provided on a reducing unit; pressure-transferring the powder and 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 magnesia into a plasma state and dissociate the alumina or 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 isolating aluminum or magnesium. Hydrogen may be added to the operative gas to accelerate the reduction of alumina or magnesia.

Abstract: A method to provide renewable energy by utilizing aluminum, which is easy to store and stably suppliable, as a fuel without harming the environment or human body. Aluminum powder and oxygen are introduced into a combustion chamber and subjected to stationary combustion. The stationary combustion of aluminum is conducted by controlling either or both amounts of aluminum powder and oxygen introduced into the chamber. The amount of the aluminum powder is controlled by the amount of aluminum powder sucked into a jet stream of a carrier gas that introduces the powder into the combustion chamber, or by the amount of an impurity to be mixed with the powder. The amount of oxygen is controlled by the mixing ratio of oxygen to a diluent gas introduced simultaneously. The alumina from the combustion is recovered, reduced to aluminum, and recycled as a fuel.

Abstract: An alumina- or magnesia-reducing process in which a greenhouse gas or substance harmful to the human body is not emitted, which can achieve improved energy efficiency in comparison with the Hall-Heroult or Pidgeon methods. The process includes: introducing an alumina or magnesia powder with a carrier gas to the upstream side of a throat provided on a reducing unit; pressure-transferring the powder and 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 magnesia into a plasma state and dissociate the alumina or 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 isolating aluminum or magnesium. Hydrogen may be added to the operative gas to accelerate the reduction of alumina or magnesia.