Abstract: A carbide former is introduced into briquettes in the production of silicon in an electric-arc low-shaft furnace to improve the trapping of silicon oxide rising in the furnace and increase the silicon yield. The carbide former can be calcium, magnesium or aluminum, preferably in the form of the silicate and most advantageous is magnesium silicate.

Abstract: Fuel briquettes are made by blending a caking coal with pitch at a temperature above 100.degree. C. but below 200.degree. C. to form a pitch/coal alloy binder which is then hot-blended with any caking coke, especially petroleum coke and optionally finely-divided limestone. The pressed briquettes are then subjected to hardening heat treatment and are found to be resistent to mechanical deterioration on long-term storage.

Abstract: Raw material bodies such as briquettes, for use in the production of silicon or silicon alloys, are formed by mixing a pitch and caking coal at a temperature above 100.degree. C. and up to 200.degree. C. to form a pitch/coal alloy. This hot binder composition is mixed with sand and a noncaking carbon carrier at a temperature in this range to form the starting composition from which preforms are pressed. The preforms are subjected to a heat treatment which involves raising the temperature to above 450.degree. C., preferably in a sand filled rotary furnace to harden the preforms into the bodies.

Abstract: A process and apparatus for the preparation of green briquettes for the production of silicon or silicon carbide or ferrosilicon in electric pit furnaces, quartz sand, a carbon carrier and a bituminous binder being mixed together, the mixture being shaped into blanks from which the green briquettes are formed by heat treatment. The process is performed with the use of blanks which are free from melted bituminous caking coal and whose specific weight is made greater than the bulk density of quartz sand by adjustment of the proportions of the mixture and by compacting. The blanks are introduced for the heat treatment into a heated rotating drum furnace whose lower part is filled with quartz sand to an extent such that the heat treatment proceeds in a dip bed of quartz sand.

Abstract: A process and apparatus for the preparation of green briquettes for the production of silicon or silicon carbide or ferrosilicon in electric pit furnaces, quartz sand, a carbon carrier and a bituminous binder being mixed together, the mixture being shaped into blanks from which the green briquettes are formed by heat treatment. The process is performed with the use of blanks which are free from melted bituminous caking coal and whose specific weight is made greater than the bulk density of quartz sand by adjustment of the proportions of the mixture and by compacting. The blanks are introduced for the heat treatment into a heated rotating drum furnace whose lower part is filled with quartz sand to an extent such that the heat treatment proceeds in a dip bed of quartz sand.

Abstract: A process for the production of silicon in a low-shaft electric furnace, in which raw-material blanks are first formed which contain fine-grain silicon dioxide, e.g. in the form of sand, and carbon in excess in respect of the reduction to silicon carbide and the raw-material blanks are introduced into the low-shaft furnance as a charge in mixture with silicon dioxide in lump form. The silicon dioxide in the raw-material moldings is reduced to silicon carbide in an upper part of the low-shaft electric furnace at a temperature of below 1600.degree. C. and coke structure agglomerates are formed from the excess carbon of the raw-material moldings. In a lower part of the low-shaft electric furnace, the silicon dioxide in lump form, is reduced to silicon with silicon carbide and carbon from the coke structure agglomerates at a temperature of above 1600.degree. C., preferably from 1800.degree. to 200.degree. C. The raw-material moldings are formed with bituminous binder containing a fine-particle silica powder.

Abstract: In the production of silicon or silicon-alloy bodies in which a shaped pre-form, blank or like member containing a silicon carrier and carbon is subjected to an electric furnace, the fine-grain silicon carrier intimately mixed with preferably a stoichiometric amount of caking coal and the mixture is molded to form the body which is subjected to hot briquetting at a temperature of 350.degree. to 550.degree. C. as is used for the hot briquetting of coal.

Abstract: A process for producing silicon in which a reaction mixture consisting, on the one hand, of hot-pressed briquettes of silicon dioxide (quartz) and carbon and, on the other hand, of granular quartz are introduced into an electric furnace and reacted so that silicon carbide is produced from the agglomerates and the silicon carbide then reacts with the quartz which fuses from the granular quartz to produce elemental silicon.

Abstract: A method of preparing an intermediate composition for the production of silicon or silicon carbide, wherein silicon dioxide particles (quartz sand) are coated with carbonaceous material in a fluidized bed from which the coated particles are extracted as they fall to the bottom of the fluidized bed by virtue of an increase in mass by the coating process. The carbon in the coating should be stoichiometrically equivalent to that required for the ultimate reaction of the silicon dioxide to form either elemental silicon or silicon carbide.