Abstract: A method and apparatus for processing a contaminated free-flowing material and, in particular, filter dust from industrial metallurgical waste and domestic waste incineration plants are disclosed.

Abstract: Dust like substances which are recovered from a garbage or refuse incinerator are destroyed, eliminated or disposed of by smelting in a low shaft electric furnace having at least one electrode heating a slag melt therein. The dust is introduced into the melt by a lance opening beneath the melting surface and gas produced by the smelting process is subjected to cleaning. The slag may be continuously or discontinuously withdrawn and slag formers may be compensatorily added. A metal bath consisting predominantly of iron may be provided below the slag melt to protect metallic components of the dust upon the smelting thereof.

Abstract: Sponge iron is produced by a direct reduction with solid carbonaceous reducing agents. In order to permit a melting of the sponge iron, particularly of that part thereof which is inferior in metallurgical properties, in a process which is as simple and economical as possible, the exhaust gas from the direct reduction process is used to produce electrical energy, which is supplied to the electric reducing furnace, and sponge iron at a rate corresponding to the electrical energy that is produced is charged to the electrical reducing furnace and comprises at least part of the sponge iron which is inferior in metallurgical properties.

Abstract: Methods are provided for producing in a single method low-carbon steel, while at the same time selectively obtaining a slag high in vanadium content for separate applications. Moreover, the method allows for the separate production of a slag high in titanium content if the starting materials contain titanium. The above is achieved by introducing the pre-reduced ore directly to an electro slag resistance furnace which is lined with a refractory in accordance with the slag composition being used. The resulting smelted steel is tapped and the slag is tapped separately. The slag, containing the vanadium and small quantities of iron oxides, is then introduced into a reduction furnace. Slag, high in titanium dioxide, if present originally, is then tapped separately from the smelted crude iron, which is tapped with a high vanadium content. Subsequently, the crude iron may be separated from the vanadium in a shaking pan in the presence of oxygen, if so required, depending upon the desired product.

Abstract: A method is provided for producing steel in an economically acceptable fashion from iron sponge with less than 66% Fe and with high acid slag formers. This is achieved by first determining the acid slag forming composition of the iron sponge, and, thereafter, lining an electro-slag-resistance furnace with a lining compatible with the iron sponge composition. Then, the iron sponge is charged to the furnace and the liquid metal formed is withdrawn to a conventional arc furnace, for example, for further processing.

Abstract: A method is provided for continuous smelting of ferrochrome with less than 6.5% by weight carbon content in an electric reduction furnace. In the described method, separately from the normal mixture of ores continuously fed into the melt, and consisting of lumpy ore agglomerated fine ore, part of the mixture of ores is introduced as wholly or partially unreduced oxide-rich chrome ore directly into the bath of slag. The introduction of the oxide-rich chrome ore, which is fed separately from the normal mixture of ores, may be made through a hollow electrode into the bath of slag.

Abstract: An improved method is provided for smelting steel from scrap in an electric arc furnace which reduces energy consumption, reduces operating noise, and improves the product quality in relation to the scrap charged. The method includes maintaining a continuous slag layer in the furnace vessel of a specific thickness and temperature, maintaining the furnace electrodes immersed in the slag layer, pre-heating the charge material to a specific range, and relating the charging speed to the processing speed of the furnace under prevailing operating parameters.

Abstract: A method is provided for producing steel with a very low carbon content of as low as 0.015% by continuously maintaining a foaming slag layer at a particular volume, and using as the charge a pre-reduced sponge with a specified carbon/oxygen ratio. The process includes utilizing a slag with a specific content of iron and magnesium oxide.

Abstract: A process and apparatus are provided for producing steel of more uniform grade on a continuous basis by maintaining a comparatively thick slag layer and a larger quantity of molten steel product in an electric arc resistance furnace. This is achieved partially by including in or combined with a quantity of the charge a quantity of iron sponge, or by using a pre-reduced and/or agglomerated or otherwise pelleted ore charge. By using a charge which is comprised of comparatively small-sized particles in combination with a thick slag layer, the charge is readily assimilated into the thick slag layer. This reduces the exposure of large particle size charge material surfaces to hot spots caused by arcing at the charge-slag interface. The comparatively thick slag layer and the continuously maintained large metal bath balance and assimilate additional charge quantities to produce an ultimately more uniform product.