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: The present invention relates to a method and apparatus for preparing a feed mixture, made of several batch components, at one stage in order to feed it into a smelting furnace. The preparation of the batch may include the preheating and drying of the material, the removal of crystal waters and evaporable substances as well as the conduction of the batch into the smelting furnace. According to the invention, a hot inert gas is conducted through a downwards settling batch so that the gas is mixed into the batch as well as possible, but even partial fluidization is prevented. The apparatus of the invention comprises a pretreatment silo (6) which is uniform at the upper part but is divided into several sub-silos (7) at the lower part. At the lower part of the sub-silos there are connected ducts (8) wherealong the batch flows into the smelting furnace (9) located below the pretreatment silo (6).

Abstract: The present invention relates to a method and apparatus for preparing a feed mixture, made of several batch components, at one stage in order to feed it into a smelting furnace. The preparation of the batch may include the preheating and drying of the material, the removal of crystal waters and evaporable substances as well as the conduction of the batch into the smelting furnace. According to the invention, a hot inert gas is conducted through a downwards settling batch so that the gas is mixed into the batch as well as possible, but even partial fluidization is prevented. The apparatus of the invention comprises a pretreatment silo (6) which is uniform at the upper part is divided into several sub-silos (7) at the lower part. At the lower part of the sub-silos there are connected ducts (8) wherealong the batch flows into the smelting furnace (9) located below the pretreatment silo (6).

Abstract: A method for controlling and balancing the power consumption in an electric smelting or heating furnace, in which power is fed into the furnace via at least two electrodes and in which the tips of the electrodes are maintained at the same level above the melt or at the same distance from the furnace cover throughout the process sequence. Power is controlled by adjusting the voltage between the furnace electrodes, the electrotechnical quantities of the furnace varying freely throughout the process sequence. Any disequilibrium due to the electrode structure or to changes in the furnace conditions is balanced out by adjusting the moving of furnace electrodes, corresponding to the wear of the electrodes, by using the quantities measured in the furnace and the short-term and long-term variations calculated with the aid of these quantities, and the linear functions with relation to time of the variations.

Abstract: In the invention, cyanide-bearing gas scrubbing waters, which are produced in metallurgical processes, are cleaned. The same scrubbing water is circulated through all gas scrubbers (1, 3) essentially connected to the metallurgical process. The solid substance which is thus acquired in the scrubbing water is separated from the scrubbing water in a clarifier (4), wherefrom the extracted solid substance is conducted as pulp into the grinding circle of the process. The cyanide-bearing scrubbing water is further conducted into the cooling (9) of the material received from the metallurgical process smelting furnace. In the cooling (b 9), the major part of the cyanide is evaporized due to the rise in temperature.

Abstract: The invention relates to a device for poking a charge fed onto the surface of a melt in an electric arc furnace having a hood and an external cooled casing (2) articulated at one of its ends to the lower section (21) of a horizontal circumferention bend in the wall of the furnace (23) hood (24) which faces the melt, drive cylinders (5) for tilting the casing in different directions about its joint, a spindle ( 1) installed tightly in the cooled casing (2) and being axially reciprocating and rotatable, and drive cylinders (17) for making the spindle (1) to project from said one end of the casing (2) to poke the charge fed onto the melt surface and break any crust on the melt surface or inside the solid charge, when the cooled casing (2) and the spindle (1) inside it are tilted about the joint and rotated.

Abstract: A method and device for facilitating the maintenance and replacing of the contact shoes of the electrodes in an electric-arc furnace, the supporting mantle of the contact shoes consisting of two sections, the lower one of which can be lifted, together with the contact shoes, telescopically over the upper section, whereby the contact shoes rise above the furnace hood.

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.