Process of reducing metal oxide to metal

摘要

1,118,077. Reducing metal oxides. FIERRO ESPONJA S.A. March 10, 1967 [March 18, 1966], No.11448/67. Heading C7D. In a process for the gaseous reduction of metal oxides in a plurality of reactors the reducing gas is passed through a body of metal-bearing material in a reactor to cool the material and is then passed through one or more reactors to reduce further bodies of the material. The cooling stage is carried out in two sequential steps in the first of which the gas feedrate to the cooler is essentially the same as that to the reducing stage and in the second of which a portion of the gas leaving the cooler is cooled and recirculated to accelerate the cooling process. The process is exemplified by the production of iron sponge from ferrous ores. In the Fig. steam and natural gas are reacted in a reformer furnace 18 to form a reducing gas containing Co and H 2 and sensible heat which is used in waste heat boiler 42. The gas is then quenched in tower 56 and led from the top thereof to the cooler reactor 10 where, in the first cooling step, it is partially cracked to deposit carbon on the iron sponge product before passing through a quench tower 66, in which water is removed therefrom, and a furnace 74 to the second reducing reactor 12. In the second cooling step a part of the gaseous product of the cooler after passing through the quench tower is led via conduit 130, compressor 128 and conduit 134 back to the feed conduit 62 to cooler 10. Some pre-heated air is introduced into the feed for reducing reactor 10 as described in Specification 2, 900, 247. After passing through reactor 12 the gas is again water quenched and heated prior to passing into the first reducing stage reactor 14 whence it is again quenched in tower 122 and then used as a furnace fuel in conduit 38.