GB876211A - Rotary ore-reducing kiln - Google Patents

Abstract

876,211. Rotary furnaces. ROUAUX, M. E. July 14, 1959 [July 24, 1958], No. 24180/59. Class 51 (2). A rotary kiln for the reduction of ore comprises throughout its length a jacket enclosing the treatment chamber and communicating with the interior of the chamber to feed a reducing gas thereto, characterized in that a large proportion of the reducing gas entering the chamber is fed into both ends of the jacket and is injected out of the medial section of the jacket into the corresponding medial section of the chamber to reintroduce the heat removed by the reducing gas off the end walls of the chamber into the medial portion of the chamber. The walls 2, Fig. 1, of the treatment chamber are surrounded by a metal casing 3 forming the annular jacket 4 through which the gas is introduced at both ends through rotary joints 6, 7 and which is injected out of the central portion of the jacket into the corresponding central portion of the chamber via radial compartments 17 and ports 20. The chamber is subdivided into transverse compartments 21, 23, 24, separated by transverse partitions to form lifters to keep the ore, which is preferably in comminuted form, in close contact with the walls of the chamber, and the central compartments 23 are subdivided into the radial compartments 17. Some reducing gas from the joint 7 enter the chamber through channels 8, Fig. 3, controlled by valves 9 and the ports 20 house nozzles 15 controlled by valves 16 to inject oxygen from a plant 10 and distributing pipes 13, 14 into the compartments 17 to burn the gas, which is exhausted through a rotary joint 43 in countercurrent to the flow of ore which is introduced into the treatment chamber from a chamber 26, Fig. 2, which forms a rotary joint 27. After exhaustion through the joint 43 the gas is fed to an arrangement 49 for regeneration and is recycled into the treatment chamber. The ore is removed from the chamber 26 by a worm conveyer 28 having a shaft 29 carried on a bearing 30 and a stuffing box 31 into a chamber 34 having transverse guiding blades 40. The ore passes through compartments 21, 23, 24, the central compartments 23 being formed by annular partitions 18 and having a tuyere fed with reducing gas and oxygen from the nozzles 15, and the metal sponge product formed in the treatment chamber enters an output port 11 to which it is guided by transverse blades 35 in a terminal chamber 36 where it is collected by a worm conveyer 37 for conveyance into a channel 38 connected with a chamber 39 forming a radial joint. The walls of the treatment chamber have helical channels 50 to collect and disperse the ore particles in a continuous manner during rotation of the kiln and the kiln may be subjected to an internal pressure by increasing the pressure of the reducing gas.