Societe Francaise D'electrometallurgie Sofrem

Pechiney Electrometallurgie

Francis Dubrous

Louis Septier

Michel Demange

Dominique Dubots

Louis Boscaro

Jean-Philippe Bucher

Robert Herold

Silicon or silicon alloy exhibiting low surface oxidation as a result of a surface silica layer of less than 2 nm, and production processes by means of grinding under a minimally-reactive atmosphere in the presence of an oil or by atomization in a vacuum or in a minimally-reactive gas under reduced pressure.

Metallurgical silicon powder exhibiting low surface oxidation

The invention relates to a process for the preparation of silicon carbide whiskers by the reaction, in a non-oxidizing atmosphere, at a temperature of at least 1300.degree. C., of a charge composed of a mixture of carbon black and a source of silicon oxide, in which process the carbon black has an oxidability rate (measured by heating in air for 30 minutes at 600.degree. C.) of at least 85%, the silicon oxide source has a grain size of less than 100 .mu.m and the rate of rise in temperature between 1300.degree. and 1600.degree. C. is less than 30.degree. C.min.sup.-1 per minute if a static atmosphere prevails and at most 25.degree. C.min.sup.-1 if gas percolated. A stage of from 5 min to 5 h at 1600.degree. C. is optionally carried out. The carbon is preferably introduced into the reaction mixture in an over-stoichiometric quantity relative to the silica. The excess carbon is removed at the end of the reaction by oxidation in air at about 600.degree. C.

Process for the preparation of silicon carbide whiskers

The invention concerns a process for the recovery of combustible gases in an electrometallurgy furnace comprising an external metal casing (1) and an internal refractory lining (2), in which at least one oxidized compound is reduced by means of carbon, the various components being introduced into the furnace in the form of a divided charge (6) (A) which moves progressively downwardly towards the reaction region (C), passing through a sintering region (B). The combustible gases produced in the reaction region are collected by suction, by means of a plurality of apertures (8) provided in the external metal casing (1) and the internal refractory lining (2) and disposed at a level corresponding to the lower portion of the divided charge (A) and before it passes into the sintering region (B). Suction of the gases collected by each aperture may be controlled in dependence on at least one of the following parameters: temperature, pressure and flow rate of the gases, and concentration of carbon monoxide, nitrogen or other component in the gases. The gases collected at each aperture (8) are passed to a central collector (12) and directed as desired towards a storage means for deferred use, or towards a means for immediate use. At least 60% of the energy introduced into the furnace may be recovered.

Process and apparatus for the recovery of combustible gases in an

Process for obtaining manganese- and silicon-based alloys by

The invention relates to a pyrometallurgical process for the treatment of complex metal ores, such as oceanic nodules, containing, in particular, manganese and copper, in which the ores are subjected to reducing fusion to produce a primary slag, containing all the manganese, and a primary alloy containing copper, nickel and cobalt. The primary slag which is then decoppered, may be used for the production of ferro or silicomanganese, while the secondary alloy is recycled for the reducing fusion step.

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Sallanches, France

Francis Dubrous