GB838067A - Improvements in and relating to the reduction of iron oxide - Google Patents

Abstract

838,067. Reducing iron ores. HYDROCARBON RESEARCH Inc. April 12, 1956 [April 12, 1955], No. 11227/56. Class 72 A process for the reduction of iron oxides in a bed maintained in a fluidized state by a hydrogen - containing gas comprises heating the gas to a temperature above that at which the particles of the bed would agglomerate, passing it in indirect heat exchange through the bed, and passing the gas, now cooled to a temperature below that at which the particles would agglomerate, through bed to maintain the fluidized state and reduce the iron oxides. As shown, the gas, heated to a temperature above 1000‹C., may enter the reducing chamber 12 through a pipe 10 near the top of the fluidized bed and pass through pipes 11, so that some of its heat is given up to the bed, leave the pipes at the bottom of the chamber, and pass upwardly through the bed. In a modification, Fig. 2 (not shown), the gas may enter at the bottom through pipes enclosed in tubes closed at the top end, the gas passing downwardly in the annular spaces between the pipes and the tubes into a space below the bed and finally upwardly through a perforated plate supporting the bed. The process is preferably operated at a pressure of 350-450 p.s.i.g. and temperature of 700-1000 ‹C. and may be either a batch process or a continuous process. The waste gas, after removal of contaminating water, may be recycled with fresh gas which may contain methane, nitrogen, argon, carbon oxides, and water vapour but should have an average molecular weight not exceeding 10 and the water vapour content, which depends on the temperature and pressure, should be maintained at a low value, e.g. at 400 p.s.i.g. it should not exceed 0.2% by volume Specification 751,105 is referred to.