Abstract: A device for continuously monitoring the internal surface temperature of a refractory lining in a metallurgical furnace. The device comprises an outer sheath, a pair of dissimilar, metallic wires within the outer sheath and a powdered oxide material closely packed within the sheath and surrounding both wires. Each wire is separately insulated by a sleeving of a refractory material having a melting point higher than the normal working temperature of the furnace at the surface of the lining. The oxide material used as a packing between the outer sheath and the wires is electrically conductive at elevated temperatures and has also a melting point higher than the temperature normally encountered at the surface of the lining.

Abstract: A method of forming a porous capillary layer of a metal oxide ceramic material onto a metal oxide ceramic substrate, which comprises covering the surface of the substrate with an aqueous slurry of a powdered mixture comprising the metal oxide of the ceramic substrate, silica and an alkali metal or alkaline-earth metal oxide, the powder mixture having a maximum particle size of about 44 microns, removing excess of slurry, depositing onto the wet surface a layer of granular ceramic material having a particle size of about 250 to about 500 microns, the granular ceramic material being applied in excess relative to the powder of the aqueous slurry to insure that a porous capillary structure will be obtained and causing the slurry to be drawn up between the particles so as to absorb substantially all the slurry, and firing the coated surface at a temperature to effect bonding of the ceramic layer, the powdered constituents of the mixture being proportioned to provide liquid phases at about 200.degree.-300.degree.

Abstract: A two-stage process for converting metal-bearing ore to a metal or an alloy characterized by the steps of, first, partially reducing an ore having a relatively higher valence state to an intermediate product of a lower valence and, second, treating the intermediate product in an arc heater having a carbon-bearing reductant atmosphere in an amount in excess of that required to reduce the intermediate product to the metal form, whereby to produce a substantially pure metal or an alloy, such as ferrochromium, and an unused excess reducing gas or derivative thereof which are recirculated to the first step to assist in the partial reduction.

Abstract: A process for the production of metal powder from an ore by direct reduction in an arc heater characterized by the steps of introducing a finely divided ore into an arc heated plasma gas to effect reduction of the ore to small liquid droplets of elemental metal in a reducing atmosphere and quenching the metal droplets to form solid metal powder, the metal having a melting point of not more than the temperature of the chemical reduction reaction, such metal being iron, chromium, vanadium, manganese, cobalt or nickel.

Abstract: A process for the production of metal powder from an ore by direct reduction in an arc heater characterized by the steps of introducing a finely divided ore into a plasma arc to effect direct reduction of the ore to small solid particles of elemental metal in a reducing atmosphere and quenching the metal particles to form solid metal powder, the metal having a melting point greater than the temperature of the chemical reduction reaction, such metal being, for example, molybdenum, tungsten, tantalum, or niobium.