Abstract: A direct reduction process is disclosed for iron oxide-containing materials. Synthesis gas is mixed with top gas produced during direct reduction of the iron oxide-containing materials and is used as reduction gas for directly reducing and heating the iron oxide-containing materials up to reduction temperature. In order to set the H.sub.2 S content at a predetermined value by a relatively simple technique and with a relatively simple equipment, at least part of the sulphur contained in the iron oxide-containing materials as H.sub.2 S produced during heating or direct reduction is added to the reduction gas together with the top gas.

Abstract: An extruder has a nozzle from which it extrudes a strand formed of a mixture of wood chips and a synthetic-resin binder into a passage formed by a plurality of transversely and longitudinally movable walls. Opposite walls are urged transversely inwardly by respective hydraulic cylinders to compact and densify the strand as it cures, and other cylinders urge the walls upstream toward the nozzle with a force slightly smaller than the extrusion force. Thus as the extrusion force exceeds the opposite longitudinal biasing force the walls will move downstream with the strand, to return upstream between advance steps of the strand.