Patent ID: 6447713
Filing Date: 2002-09-10
Classification: C21B,Y02P

Abstract:
Rotating-hearth furnace for the reduction of metallic oxides comprising:a ring-shaped rotating hearth subdivided into: a charging zone, a first zone adjacent to the charging zone, a second zone adjacent to the first zone and a discharge zone adjacent to the second zone, the charging zone comprising a device for depositing a charge with one or more layer of a mixture of metallic oxides and coal and equipment for forming on a surface of the deposited layer furrows having a substantially triangular section so as to obtain a substantially sawtooth-shaped surface, the first zone of the furnace and the second zone comprising blade equipment for leveling off the peaks of the sawteeth, a levelled-off part of the peaks being pushed into the hollows of the furrows and, by a second action, to level off one face of each saw tooth, the levelled-off part being pushed on to a face of the adjacent sawtooth so as to cover the material pushed by the first action, and displacing the mixture radially as the hearth rotates, said equipment of the first zone and second zone comprising respectively, first and second dual action blades such that upon each passage through the charge, a part of the charge is turned over, such that an upper layer of the charge initially comprises metallic oxides, then a mixture of metallic oxides and coal, and finally comprises reduced metallic oxides wherein the successive mixing of the parts of the charge limit the maximum surface temperature thereof to a temperature less than or equal to 1200Â° C.