Abstract: The charge is moved through a rotary kiln countercurrently to the gas atmosphere. Solid carbonaceous reducing agent having a high content of volatile constituents is charged into the rotary kiln at its charging end. Solid carbonaceous reducing agent having a high content of volatile constituents is blown into the rotary kiln at its discharge end and is distributed over the charge in part of the length of the kiln. Oxygen-containing gases are supplied to the rotary kiln through its shell at a plurality of locations. In order to provide optimum operating conditions in the final zone of the kiln, solid carbonaceous material having a high content of volatile constituents is separated into a coarser fraction and a finer fraction, a part of the coarser fraction and a part of the finer fraction are mixed.

Abstract: Before iron oxide-containing materials is reduced in a rotary kiln by a treatment with solid carbonaceous reducing agents below the melting point of the charge, the iron oxide containing material and carbonaceous reducing agent are preheated in a multiple-hearth furnace, in which the reducing agent is subjected to an at least partial coking or an at least partial low-temperature carbonization. To prevent a partial reduction and sintering, the iron oxide-containing material is preheated in the upper part of the multiple-hearth furnace and the solid carbonaceous reducing agent is separately preheated in the lower part of the multiple-hearth furnace. At least part of the gases produced by the low-temperature carbonization in the lower part of the multiple-furnace is caused to flow in the upper part of said furnace in a countercurrent to the iron oxide-containing material to supply the heat required in said upper part.

Abstract: A process and apparatus for separating solid granular metallurgical products. A plurality of linearly vibrating screens are housed, one over the other, each inclining more than the one above and each having a smaller mesh opening than the one above and 1.5 to 15 times larger than the desired parting size. The solids are fed onto the uppermost screen at the upper end thereof and are deflected in the direction of inclination of the screen. The finer solids initially fall through freely and on screens having smaller mesh openings and are also deflected in the direction of inclination of the screen. The coarsest solids fraction is withdrawn as overflow from the uppermost screen, finer solids fractions are withdrawn as overflow from following screens, and solids which have passed through all screens are withdrawn as a finest fraction. A gaseous fluid is flowed through at least part of the working space required for screening approximately transversely to the direction in which the solids pass through the screens.