Abstract: In a process for utiliting zinc-containing metallurgical dusts and sludges, the zinc-containing dusts and sludges are agglomerated, briquetted in a cold manner or pelletized and are added to the charge of a melting furnace for melting metal from metallized charges such as, scrap iron or pig iron. For this purpose, there are in particular used agglomerates or pellets having a metallizing degree of at least 30 percent by weight, preferably of at least 40 percent by weight.

Abstract: In a process for the disposal of settled sludge derived from a biological sewage-disposal plant, in which the thickened sludge is further dewatered and at least partially thermically decomposed within a centrifuge (15) by using separated steam, preferably at a pressure within the range of 1 to 15 bar and at a temperature of 100.degree. C. to 200.degree. C., the centrifugate of the centrifuge (15) subjected to the action of saturated steam is discharged via a lock (18) and is immediately subsequently subjected to a sulfidic precipitation (19) of heavy metals.

Abstract: There is disclosed a method for processing heavy-metal-containing residues from the chemical industry. For an economical and at the same time ecologically safe processing of the heavy-metal-containing residues, the heavy-metal-containing residues are introduced into a primary-gas reaction zone of a shaft gasifier containing at least one solid bed of carbon-containing material. Slag-forming substances are introduced together with the charge substances and/or together with the solid-bed formers to absorb and set the heavy metals. The lower zone of the solid bed is maintained at a temperature above the slag and ash melting temperatures. The viscosity of the slag is less than 100 poise.

Abstract: In a process for the production of calcium carbide in a shaft furnace, a plasma arc (plasma torch) is generated by the introduction of electric energy with the help of a plasma burner device penetrating the upper cover of the shaft furnace. A counter electrode is provided in the bottom part of the shaft furnace. About the plasma arc or torch, a burden mixture of calcium-oxide and carbon-containing substances is concentrically introduced so as to form a protective mound of solid burden components on the inner wall of the furnace. In order to provide an operationally safe process by using plasma burners, with which both coarse and fine-grain burden components may be employed and with which calcium carbide is obtained in higher yields with an improved utilization of the energy consumed, the burden mixture is used separately as a coarse-grain fraction and as a fine-grain fraction.

Abstract: With a method for producing metals, the raw material is melted in a metallurgical vessel by at least one plasma burner directed from top to bottom. In order to be able to protect the furnace brickwork from too strong a thermal load exerted by the plasma jet, and to make available the energy supplied by the plasma burner to melting and reducing the fine ore to as large an extent as possible as well as to prevent an agglomeration of the raw material to be used, the raw material is topcharged into the metallurgical vessel in the form of fine particles directed parallel to the plasma jet so as to peripherally surround the same. Oxygen-containing gases and carbon are bottom-blown into the vessel through the melt. A foamed slag is formed in the vessel, surrounding the plasma jet over its total height and the flow of supplied raw material particles peripherally.

Abstract: A burden of either or both CaO or CaCO.sub.3 and coal is melted and reduced by a plasma torch established between a plasma burner penetrating the upper structure of a furnace and an electrode in the bottom of the furnace to produce CaC.sub.2. The burden is supplied to the furnace from above and the CO produced by the reaction flows upwardly through the unreacted burden to pre-heat and pre-reduce it.

Abstract: There is disclosed a plasma melting furnace through the side wall of whose cylindrical furnace body a plurality of downwardly directed plasma burners are guided, whose mouths project into the furnace interior. In order to avoid several rechargings, which has been common so far, in particular with scrap of low apparent density, and to be able to charge continuously, without endangering the plasma burners by electric flashovers between parts of the charge material and the burner mouths or falling-down materials and by maintaining the inert gas atmosphere within the furnace, the cover of the furnace interior comprises a shoulder-likely re-entering part projecting upwardly. This part is closeable by a lid and delimits a central charging opening whose diameter is smaller than the diameter of the circle on which the mouths of the plasma burners are arranged.

Abstract: With a method for producing metals, the raw material is melted in a metallurgical vessel by at least one plasma burner directed from top to bottom. In order to be able to protect the furnace brickwork from too strong a thermal load exerted by the plasma jet, and to make available the energy supplied by the plasma burner to melting and reducing the fine ore to as large an extent as possible as well as to prevent an agglomeration of the raw material to be used, the raw material is topcharged into the metallurgical vessel in the form of fine particles directed parallel to the plasma jet so as to peripherally surround the same. Oxygen-containing gases and carbon are bottom-blown into the vessel through the melt. A foamed slag is formed in the vessel, surrounding the plasma jet over its total height and the flow of supplied raw material particles peripherally.

Abstract: In a method of reducing oxide-containing fine-particle ores, the ore particles are melted and reduced in a rotationally symmetric melting vessel in the presence of solid, liquid or gaseous carbon carriers by the action of a plasma jet of a plasma burner. At least part of the ore particles to be reduced are introduced through charging openings in the side wall of the vessel and are set in a cyclonic rotational movement. The plasma jet of the plasma burner is generated within the rotating particle stream. An arrangement for carrying out the method comprises a refractorily lined melting vessel having a rotationally symmetric inner space and including charging openings for the addition of oxide-containing ore particles and fluxing agents. There are openings for solid, liquid or gaseous carbon carriers and other fluxes, and at least one plasma burner.

Abstract: In a method of carrying out metallurgical or chemical processes in a shaft furnace having an upper cover, electric energy is supplied by a plasma burner penetrating the upper cover. A plasma torch is formed between the plasma burner and a counter-electrode penetrating the bottom of the shaft furnace. Charging stock is introduced concentrically about the plasma torch and forms a protective wall at the inner wall of the furnace. There is also provided an arrangement for carrying out this method.

Abstract: There is disclosed a method for carrying out melting, melt-metallurgical and/or reduction-metallurgical processes in a plasma melting furnace. In its interior, freely burning plasma torches are produced between plasma burners guided through the lid or through the side walls of the furnace body and a bottom electrode. Fluxes and reactive substances to be melted and reacted, respectively, are charged into the region of the plasma torches. In order to increase the energy supply to the charges to be melted or reacted and thus improving the thermal efficiency or kinetics of the process, additional gas flows, which differ from the original plasma gas, are injected into the plasma torches. An arrangement for carrying out the method includes a furnace through whose lid or side walls plasma burners are guided and in whose bottom a counter electrode is arranged. Supply means for introducing additional gas flows into the region of the plasma torches are additionally provided.

Abstract: A plasma melting furnace includes one or more plasma burners penetrating the furnace lining, in particular a plasma burner projecting vertically into the interior of the furnace. In order to ensure a most uniform stress on the lining by the heat radiation, the inner surface of the lining is designed to be inclined, converging upwardly.

Abstract: A plasma melting furnace includes a cover and a melt container. Through its side wall plasma burners arranged so as to be inclined towards the furnace axis are guided. A main flue gas conduit equipped with a draft regulating damper is connected to the cover and a separate discharge means for flue gases from other furnace openings is additionally provided. In order to provide an efficient discharge of flue gases and reaction gases forming as well as dusts and fumes without straining the furnace hall and the environment, and to maintain a protective gas atmosphere in the furnace interior safely during all the necessary working cycles, the separate discharge means is designed as a downwardly open channel. The channel is peripherally attached to the outer side of the container in the region of the upper rim of the melt container.

Abstract: In an arrangement for the production of steel from solid and/or liquid charging materials, such as pig iron, heavy scrap and light scrap, a liftable and lowerable heating-refining arrangement and, if desired an arrangement for supplying further additions are positioned in a refactorily lined refining vessel. In order to be able to use as high a scrap portion of the materials charged as possible without substantially increasing the time required until the end of the refining operation per charge, the heating-refining arrangement consists of a plasma burner, a jacket surrounding the plasma burner for supplying oxygen, and a cooling jacket surrounding that jacket, a counter-electrode being arranged in the bottom of the refining vessel.

Abstract: A plasma melting furnace includes a water-cooled bottom electrode of copper and a temperature probe connected with the bottom electrode. A wearing part of steel is provided in the bottom of the furnace, covering the bottom electrode. At least one counter electrode is arranged at a distance above the wearing part for the formation of the plasma jet. In order to prevent the risk of a melting through of the bottom electrode as far as to its water-cooled section on account of a secondary arc, a metal layer is provided between the bottom electrode and the wearing part. The metal layer is formed by a metal having a low thermal conductivty and a low melting point, as compared to copper, as well as a high melting enthalpy. Preferably, a metal layer of lead or its alloys with tin and/or zinc is provided.

Abstract: A plasma melting furnace includes a furnace body, a covering cap, one or more electrodes penetrating the bottom of the furnace body, and at least three plasma burners penetrating the furnace wall or the covering cap and arranged so as to be inclined towards the bottom. In order to achieve a high melting performance with a simultaneously low energy consumption, charging openings are provided in the covering cap for the continuous melting of small-sized material, such as light scrap and iron sponge. Their vertical axes are located in a plane extending through the angular symmetry of the normal projection of the axes of two neighboring plasma burners as well as between two vertical planes each extending perpendicular to the normal projections of the individual burner axes.

Abstract: In a method of, and arrangement for, producing molten pig iron or steel pre-material iron-oxide-containing raw-material particles are top-charged into a fluidized bed formed of carbon particles and an oxygen-containing carrier gas. When passing the fluidized bed, the raw-material particles are heated, reduced and smolten. In order to achieve a better utilization of energy with such a method, i.e. to considerably lower the total energy input, additional energy is supplied to the fluidized bed by plasma heating.

Abstract: An austenitic steel surface is cleaned of ferritic contaminations and other impurities by blasting it with a wet abrasive mixture containing 40-90% by volume, of corundum having an average grain size of 0.2 to 0.6 mm and of triangular faces. This wet abrasive mixture is accelerated and applied to the surface under a gas pressure of 2.5 to 5.5 atmospheres, 0.8 to 3 kg of corundum being applied per 100 cm.sup.2 of the surface to be cleaned. Before the surface has dried, a rinsing liquid is applied thereto.