Abstract: The process feeds a mixture of scrap metal, chromite, flux materials, carbonaceous material and wood chips to a submerged arc furnace to make a base iron suitable for iron and steel purposes. The mixture contains about 1-60% chromite, about 1 to 20% flux materials, about 5 to 35% carbonaceous material, about 0-10% wood chips, all based on the weight of scrap in the mixture. By maintaining the charge in the furnace, good energy efficiencies are obtained.

Abstract: Continuously cast metal billets are continuously passed by a symmetric light source comprising a plurality of single light sources arranged in a circle or in another way such that the light falls substantially symmetrically on the part of the surface of the metal billet which is to be detected in such a way that the surface of the metal billet which faces the light source is illuminated except for pinholes. Reflected light from the surface of the billet is detected by a linescan camera arranged centrally in relation to the light source, which camera has a scanning direction normal to the direction of movement of the metal billet, whereby pinholes are detected by registration of reflected light intensity below a preset threshold value.

Abstract: This is a method for treatment of spent potlining from aluminium reduction cells including the refractory material in order to transfer the spent potlining to a form in which it can be used as a filler or as a raw material. The spent potlining is crushed and supplied to a closed electrothermic smelting furnace optionally together with a SiO.sub.2 source, wherein the spent potlining is melted at a temperature between 1300.degree. and 1750.degree. C. An oxidation agent is supplied to the furnace in order to oxidize carbon and other oxidizable components contained in the spent potlining such as metals, carbides and nitrides. Further, a source of calcium oxide is supplied to the smelting furnace in an amount necessary to react with all fluoride present to form CaF.sub.2 and to form a calcium aluminate or calcium aluminate silicate slag containing CaF.sub.

Abstract: The present invention relates to a method for treatment of zinc-containing by-products and waste materials from primary and secondary production of nonferrous metals and especially zinc- and leadcontaining slags from the production of lead. The by-products and the waste materials are supplied to a gastight closed electric smelting furnace in which the materials are melted and subjected to a selective metallothermic reduction in order to reduce and volatilize zinc and other volatile metals. Elemental sulphur and/or sulphur compounds are added to the smelting furnace in an amount sufficient to form a sulphide phase containing one or more of the elements Cu, Ni, Pb, As, Bi, Sb and Ag. An inert slag phase and the sulphide phase are tapped from the furnace, and zinc and other volatile metals are recovered from the off-gas from the furnace by condensation.

Abstract: The present invention relates to a method for recovering zinc from zinc-containing materials, especially from zinc-containing materials recovered from waste gases in metallurgical smelting processes. Particulate zinc-containing materials are agglomerated together with a carbonaceous reduction material and optionally slag forming materials, and are supplied to a gas tight closed electrothermic smelting furnace containing a molten bath kept at a temperature between 1200.degree. and 1700.degree. C. in which the agglomerates are smelted and subjected to selective reduction and volatilization of zinc and other volatile metals. An inert slag phase and optionally a liquid metal phase are tapped from the smelting furnace, and zinc and other volatile metals are recovered from the waste gas from the smelting furnace by condensation. In order to prevent reoxidation of metallic zinc the particulate zinc-containing materials are agglomerated together with a carbonaceous binder which cracks at a temperature below 700.

Abstract: The present invention relates to a method and a means for continuous production of elongated carbon bodies having a constant or substantially constant cross-section where a casing filled with unbaked paste consisting of carbon and a carbon containing binder is continuously baked to a solid carbon body by heating by means of direct electric current. The first terminal of the direct current source is being slidably connected to the casing through a plurality of vertical ribs extending radially outwards from the casing, said ribs being made from a current conducting material, and the second terminal of the direct current source being connected to the baked part of the carbon body or to a bottom contact in a smelting furnace in which the carbon body is consumed. The casing containing the carbon containing paste is continuously or substantially continuously moved in axial direction by means of slipping- and holding means.

Abstract: The present invention relates to a plasma torch intended for being submerged into a bath of molten metal, such as for example a steel melt. The torch comprises an outer electrode made from a non-consumable material and an inner electrode, where at least the outer electrode is made from a copper pipe having internal channels for circulation of a cooling medium, said copper pipe at least on the outside having a layer of refractory material.The layer of refractory material has a thickness between 1 and 5 mm and is made from Al.sub.2 O.sub.3 or from ZrO.sub.2 stabilized with 5-25% by weight of MgO and/or Y.sub.2 O.sub.3 or oxides of other rare earth elements.

Abstract: The present invention relates to a method for production of metals and/or ferro alloys by prereduction of particulate metal oxide co-current with a reducing gas. Reducing gas having a temperature between 650.degree. and 1100.degree. C. and metal oxide particles are supplied at the lower end of a substantially vertical prereduction column which comprises at least two chambers having a substantially circular cross-section, said chambers in their upper and lower ends having a decreasing cross-section and where a ringshaped member for decreasing the cross-section is arranged in the intermediate zone between the chambers. The mixture of reducing gas and prereduced metal oxide particles is collected at the top of the prereduction column, whereafter the prereduced metal oxide particles are transported to a smelting furnace for smelting and final reduction to metallix state by addition of a reduction material.The present invention also relates to a column for treatment of particulate solid materials with a gas.

Abstract: The present invention relates to a method for detecting flaws and surface defects in metallic workpieces, particularly in non-magnetic steel workpieces. The surface of the workpiece is heated by passing the workpiece in its longitudinal direction through an induction coil, scanning the surface of the workpiece with an infrared camera transversely across the surface of the moving workpiece immediately after induction heating and recording a streaked pattern temperature profile in which the streaked pattern repeats itself where there are flaws in the surface. It is used an induction coil with a current frequency which gives a penetration depth of the induced current in the workpiece which is greater than the depth of the flaws which are to be detected. The flaws and surface defects are detected by recording a lower surface temperature than the rest of the surface of the workpiece by scanning the temperature profile immediately after induction heating.

Abstract: The present invention relates to a method for production of metals and/or ferro alloys by prereduction of particulate metal oxide co-current with a reducing gas. Reducing gas having a temperature between 650.degree. and 1100.degree. C. and metal oxide particles are supplied at the lower end of a substantially vertical prereduction column which comprises at least two chamber having a substantially circular cross-section, said chambers in their upper and lower ends having a decreasing cross-section and where a ringshaped member for decreasing the cross-section is arranged in the intermediate zone between the chambers. The mixture of reducing gas and prereduced metal oxide particles is collected at the top of the prereduction column, whereafter the prereduced metal oxide particles are transported to a smelting furnace for smelting and final reduction to metallic state by addition of a reduction material.The present invention also relates to a column for treatment of particulate solid materials with a gas.

Abstract: A method of treating ash and dust from incineration plants. The ash and dush are coprocessed by mixing one or more hazardous wastes and/or metallic scraps therewith. The mixture is supplied to a smelting furnace together with a reducing agent.