Abstract: An apparatus for thermally treating mineral solids includes a preheater, a separating apparatus arranged at an outlet of an entrained flow reactor, and a thermal treatment zone at an outlet of a gas stream of the separating apparatus, with an outlet of the treatment zone being connected to an inlet of the preheater for the gas stream.

Abstract: An apparatus for thermal treatment of mineral materials may include a first combustion chamber, a second combustion chamber, and a reactor for the thermal treatment of mineral materials. The first combustion chamber is configured for burning a first fuel fed by a first fuel feed device, and the first combustion chamber and the second combustion chamber are connected via a first conduit for transferring hot gases from the first combustion chamber into the second combustion chamber. The second combustion chamber is configured for burning a second fuel that is different than the first fuel and is fed by a second fuel feed device. The second combustion chamber and the reactor are connected via a second conduit for transferring hot gases from the second combustion chamber into the reactor. The reactor has a third feed conduit for introducing a third fuel.

Abstract: A feeding device for closed shaft furnaces connected to a gas-extracting device, in particular for low shaft furnaces for melting steel scrap, having a transporting device, which leads to the head of the upper furnace vessel and is integrated at least partially in the furnace atmosphere, and a distributing device for distributing the charge. In this case, a carousel which can be charged by a conveying device is provided in the furnace head. The carousel, in the furnace head, is guided rotatably on a path, fastened on the casing of the upper furnace vessel, above the gas-extracting device and has shutter elements connected to actuators.

Abstract: The invention pertains to a process and to a device for supplying current to an electric-arc melting unit for melting and heating metal, especially steel, with a three-phase a.c. source, which sends the current via devices for producing direct current or alternating current to at least one electrode projecting into the vessel of the melting unit. The three-phase a.c. source (91) is followed by at least two power supply modules (41, 4n), connected in parallel, where each power supply module (41; 4n) has an uncontrolled three-phase bridge (51, 5n), a direct-current intermediate circuit (61, 6n), and a transistor unit (71, 7n) connected in series, and where, downline from the power supply modules (41, 4n) in the current flow direction, a common current-carrying line (31) leads to at least one electrode (21) of the melting unit (11) and away from at least one other electrode (22, 24).