Abstract: The invention relates to a smelting furnace, particularly a D.C. arc furnace, suited for the treatment of finely-divided material, which comprises at least three electrodes suspended through the roof in order to create the electric arc. The process material is fed in through at least one feed gate (30) arranged inside the circle orbit formed by the electrodes (4, 16, 26) suspended through the furnace roof, which feed gate (30) is provided with auxiliary members in order to create an even supply of the material into the furnace. In order to discharge the gases created in the process, there is provided at least one outlet (20) outside the circle orbit formed by the electrodes (4, 16, 26).The invention also relates to a method for feeding finely divided material into the smelting furnace. According to this method, the material is fed through the feed gate (30) in suspension, either vertically or tangentially.

Abstract: A process for the exploitation of low-grade oxidic and iron-bearing complex ores or concentrates, whereby the initial materials are reduced in a rotary kiln at a temperature of 1000.degree.-1500.degree. C. in such a manner that the products are a magnetic fraction primarily consisting of iron, and a non-magnetic oxide fraction, the materials present in this fraction being further exploitable by conventional methods.

Abstract: A device for blowing gas and a finely-divided solid into a metallurgical melt is disclosed, the device having a blast pipe which has at one end an inlet connected to a gas source and at the opposite end an outlet immersed below the melt surface in order to blow the gas into the melt. A cooling device surrounds the blast pipe, the cooling device having, at that end which is near the blast-pipe inlet, inlets and outlets for the cooling medium, and a mantle of ceramic material which surrounds at least the lower part of the cooling device. In the outlet of the blast pipe there is a Laval nozzle which is at an angle to the blast pipe and extends through the thermally insulating mantle.

Abstract: A ferrochromium slag for use as a refractory material having good resistance to mechanical compression and wear is disclosed to contain less than 25% by weight of MgO.

Abstract: A method and an apparatus for refining a melt by means of a pulverous solid material and a carrier gas, in which the pulverous solid material and gas are injected into a reactor while melt is poured into the reactor, the kinetic energy of the melt created by falling being utilized for mixing the pulverous reagent and the gas with the melt, and the agitation of the melt surface being attenuated by causing the flow of the injected pulverous reagent and gas and the flow of the melt being poured to impinge against each other from opposite directions in the reactor.