The present invention provides an electric furnace including: a cylindrical furnace wall; a furnace cover that is provided at an upper end of the furnace wall; and a furnace bottom that is provided at a lower end of the furnace wall and includes a deep bottom portion and a shallow bottom portion as a region having a height of 150 mm to 500 mm from a deepest point of the deep bottom portion, in which a slag pouring port into which molten slag or a solidified slag lump is capable of being poured from a slag transport container directly or through a tilting trough is provided, the slag pouring port overlaps the shallow bottom portion in a plan view, and the area ratio of the shallow bottom portion to the furnace bottom in a plan view is 5% to 40%.

A direct reduction method/system, including: adding variable amounts of natural gas, hydrogen, and a carbon-free oxidizing gas to a feed gas stream upstream of a reformer; reforming the feed gas stream in the reformer to form a reformed gas stream, and delivering the reformed gas stream to a shaft furnace, where the reformed gas stream is used to reduce a metallic ore material to a direct reduced metallic material. The feed gas stream includes a top gas stream recycled from the shaft furnace. Optionally, the carbon-free oxidizing gas includes steam and the method further includes controlling a steam flow rate of the steam to maintain a maximum k-factor value of the feed gas stream of 0.74 or lower. Optionally, the variable amount of hydrogen is selected to replace 20-90% of the natural gas by fuel value. The variable amount of hydrogen is selected based upon an available supply of hydrogen.

The invention is directed to a method for processing asbestos-containing steel scrap into useful products, which products can be handled in a safe manner. In accordance with the present invention the asbestos-containing steel scrap is melted in a furnace, which results in destruction of the asbestos fibers. It has been found possible to carry out such a process in an economically feasible manner. In accordance with the invention asbestos-containing steel is heated to high temperature so that the steel melts. As a result the asbestos will be converted into harmless material, which allows for safe handling and processing of the resulting products.

[Object] To provide a method for processing steelmaking dust, a method for producing zinc, and a method for producing an iron- and steelmaking raw material, which are more advantageous than the Waelz method in terms of energy and economy.

[Solving Means] A method for processing steelmaking dust according to an embodiment of the present invention includes: adding a calcium compound containing Ca to steelmaking dust containing zinc, the number of moles of Ca being equivalent to or more than the number of moles of Fe in the steelmaking dust; and heating and reducing, in a furnace, the steelmaking dust to which the calcium compound has been added. A ratio of the number of moles of Ca in the calcium compound to the number of moles of Fe in the steelmaking dust is adjusted to be not less than 1.3 and not more than 1.5.

A method of charging a pre-packaged charge in a metallurgical or refining furnace includes providing a disposable metal container having at least one attachment member and forming a pre-packaged charge by loading scrap material into the metal container. The method also includes releasably coupling the at least one attachment member of the container to a lifting device, and then de-coupling the pre-packaged charge from the lifting device so that the combination of the scrap material and the disposable metal container are charged in the furnace.

A method for forming a foamy slag in an electric arc melting furnace during the production of a ferrous alloy may include: (a) melting a metal charge in the electric arc furnace to obtain a molten metal bath including a layer of a floating slag; (b) introducing a foamy slag forming agent into the furnace to foam the floating slag. The agent may be a composite material in granular form which includes at least one thermoplastic polymeric material and at least one biogenic carbonaceous material.

A method for recycling processing of dust generated in a converter furnace, includes: crushing and drying a cake formed by adding a binder to a slurry containing iron powder-containing dust that is generated at the time of converter blowing and wet-collected to produce a mixed slurry and subjecting the produced mixed slurry to a dehydration treatment in a filter press; accumulating the cake in an accumulation tank; and charging the cake into a converter furnace 10, the crushed product in the accumulation tank 25 is kept at a temperature of less than 90 C. by forcibly passing air into the accumulation tank 25 and charged into a converter furnace according to the converter operation.

The present invention provides a method of simultaneously recycling plastics and detoxifying chromite ore processing residue with residual heat from a steel slag. By heating and gasifying plastics with steel slag, followed by catalytically split-decomposing the plastics with catalysts such as chromite ore processing residue, the plastics are thoroughly converted into a energy gas under water vapor gasification. The surface coking of Chromite Ore Processing Residue is avoided. Meanwhile, the energy gas reduces Cr.sup.6+ in Chromite Ore Processing Residue into Cr.sup.3+, and the energy gas is cooled, and CO.sub.2 and Cl in the energy gas are adsorbed by alkaline substances in Chromite Ore Processing Residue. With this method, chromite ore processing residue is detoxified, and steel slag is cooled, furthermore, energy is saved and a energy gas is obtained.

The invention relates to the field of metallurgy, and specifically to a method for producing steel in an electric arc furnace. A known method for making steel in an electric arc furnace includes, at least, loading, into the working space of a furnace, a solid metal charge and, at least, solid carbon-containing materials, melting the charge using electric arcs, carburizing the metal using the solid carbon-containing materials during melting, and outputting metal and slag from the furnace. It is proposed to conduct the melting process with the addition, to the working space of the furnace, of a high-carbon carburizer in the form of a liquid phase of iron recovered from the arc combustion zone for the additional carburization of the metal, wherein the high-carbon carburizer is obtained from iron oxides and carbonaceous material. The iron oxides and carbonaceous material are fed into the arc combustion zone, the dimensions of which are limited by D=d.sub.p+6d.sub.el, where d.sub.p is the electrode pitch circle diameter and d.sub.el is the diameter of an electrode. The total carbon content, in free and dissolved forms in the liquid iron phase, does not exceed 30%. The total amount of carburizer used in melting does not exceed 20% of the mass of the metal charge. The carburizer is fed continuously or periodically into the working space of the furnace during the charge melting process. The feeding of carburizer begins as charge melting begins. The use of the invention results in increased liquid metal output by means of regulating carbon content in the course of melting, increasing the carburization level of metal from the very beginning of melting, and reducing the loss of iron to slag and smoke.

A process is disclosed for the combined manufacture of steel and cement clinker. Steel scrap is loaded in an electric arc furnace for forming molten steel. Cement paste derived from construction and demolition waste is loaded in the electric arc furnace to act as a flux for the steel to assist in the removal of impurities from the molten steel and forming an electric are furnace slag. The heat of the molten steel promotes clinkering of the electric are furnace slag to form clinkered electric arc furnace slag. The clinkered electric arc furnace slag is removed from the electric arc furnace.