Abstract: A high temperature reactor is fitted with a plasma gun at an anode chamber and is provided with a graphite cathode. The reactor is cooled by means of pipes in the refractory lining of the reactor, and rests on essentially horizontal bearings. The charge to be melted e.g. oxides or oxide mixtures is fed from above at an angle .alpha. at most 90.degree. to the main axis of the reactor in the direction of the plasma stream, and the molten product is tapped off at an exit port which is also close to the entry port of the plasma stream so that the plasma stream covers and therefore heats the area around the exit port.

Abstract: A high temperature reactor is fitted with a plasma gun at an anode chamber and is provided with a graphite cathode. The reactor is cooled by means of pipes in the refractory lining of the reactor, and rests on essentially horizontal bearings. The charge to be melted e.g. oxides or oxide mixtures is fed from above at an angle .alpha. at most 90.degree. to the main axis of the reactor in the direction of the plasma stream, and the molten product is tapped off at an exit port which is also close to the entry port of the plasma stream so that the plasma stream covers and therefore heats the area around the exit port.

Abstract: Submicron-sized oxide particles are produced in a process in which coarse particles are fed into a vaporizing zone of a plasma burner, where they sublimate and finer particles are produced in a cooling zone.

Abstract: A method of reshaping magnetically relatively weak ferrite particles of substantially arbitrary shape into substantially spherically-shaped globules including the steps of transporting the particles by a carrier gas stream within a conduit into the vicinity of a stream of warm gases, separating the particles from the carrier gas stream prior to contact with said warm gas stream, feeding the separated particles into the stream of warm gases, melting the particles therein, and subsequently allowing the particles to solidify into substantially spherically-shaped globules.

Abstract: A crucible, for use in heating and/or retaining melts at elevated temperatures, includes a hollow holding member composed of a heat resistant material, and a thin-walled insert composed of a substance chemically resistant to oxygen and oxidizing substances and being removably supported in the holding member.