Abstract: A gravitational furnace for the direct reduction of mineral iron, comprising a substantially cylindrical container, a reactor arranged in a median zone of the container, between a device to feed the mineral iron and a zone to discharge the reduced metal iron. Distribution nozzles are provided in the peripheral wall of the cylinder to introduce reducing gas into the reactor. A substantially cylindrical passive element is inserted into the furnace inside the container, substantially coaxial with its longitudinal axis, to define a substantially annular reaction chamber of the reactor. Also the manufacturing of the furnace is disclosed.

Abstract: Device for the direct reduction of iron oxides of the type with a gravitational load, comprising a reactor defining, in its upper part, at least a zone inside which the reduction reaction occurs, means (14, 15) to introduce the load through a mouth (12) of the reactor, means (18, 17, 19) to introduce a current of gas into at least one section of the reactor in correspondence with the reduction zone, outlet means (13) of the reduced material from the bottom of the reactor, and means (20) to discharge the exhaust fumes, said reactor (10) including at least a first upper zone (10a) of heating, pre-reduction and final reduction, with a taper diverging downwards, and a second lower zone (10b) of carburization and cooling, with a taper converging downwards.