Abstract: An electric resistance furnace for the production of silicon carbide from silicon dioxide and carbon has a U-shaped carbonaceous resistance core embedded in the burden of coke, quartz and other additives. The electrodes are disposed adjacent to each other and are connected to the resistance core at the ends of the legs of the U. The ratio of the length of the resistance core to the electrode spacing is at least 1.6.

Abstract: An electrical resistance furnace installation, especially for the production of silicon carbide, has no side walls. In the one arrangement, the installation has two end walls, each provided with an electrode, with the resistive core for heating reacting valves extending between the electrodes at the end wall. In another arrangement, the installation has only one end wall, with the resistive core extending between an electrode in the one end wall, and a connection to a further electrode arranged in the bottom of the furnace. In a still further arrangement, the furnace has neither end walls nor side walls, and the resistive core is horizontally supported above the furnace floor and electrically connected through electrodes in the bottom of the furnace. The reacting ballast, in each embodiment, is poured onto the furnace floor to surround the resistive core for heating of the ballast.

Abstract: An electrical resistance furnace, especially for the production of silicon carbide, in which the furnace has a porous bed on its floor, and a gas flow is provided for withdrawing gaseous reaction products from the furnace. Alternatively, or in addition to the porous bed, a covering sheet is provided over the burden. In addition, ducts may be provided within the furnace, beneath the cover and/or in communication with the porous bed, for the removal of gaseous products. The furnace may be of the open mound type, without side walls, in which case the cover may be a flexible cover that covers the top and sides of the burden.

Abstract: In a furnace installation for producing silicon carbide in an intermittent operation, carbon electrodes arranged in the bottom of the furnace. A horizontally arranged resistance core is electrically connected to the carbon electrodes by vertically extending elements of an electrically conductive material having a higher specific conductivity than the core material. The resistivity of the connection between the electrodes and the core and the current passing through the connection produces a temperature lower than that necessary to form silicon carbide, and thereby prevents the destruction of the connections and electrodes normally caused by the downward movement of the silicon carbide roller.