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 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.

A method and device for controlling a melting and refining process in an electric arc furnace for melting a metal, wherein the electric arc furnace includes molten and solid metal and a slag layer on the surface of the molten metal, wherein an electromagnetic stirrer is arranged for stirring the molten metal. The method includes calculating/determining masses of the molten and solid metal at a point of time, wherein the calculation is based on initial values of the molten and solid metal, an arc power supplied to the electric arc furnace, and temperatures of the molten and solid metal, determining a stirring power based on the calculated/determined masses, and supplying the determined stirring power to the electromagnetic stirrer.

A slag foaming system for an electric arc furnace utilizing algae is described. The algae may be dried algae in particle form that is injected into the electric arc furnace through a solids injector and may be directed into the slag. Other slag foaming compositions may also be injected into a furnace as a function of furnace parameters to create slag foam while maintaining a high yield of slag without excess iron oxide and reduced carbon and carbon dioxide emission. The algae and slag foaming composition may be used in combination for slag formation and control.