Reduction of Fine Iron Ores in Gas Conveyed Systems

Abstract

High reaction rate of finely powdered iron ores was expected because of their large reaction surface. In order to take advantage of this property, gas conveyed system was applied to the reduction of finely powdered iron ores, and feasibility of the process was studied. Hydrogen reduction of very fine powder of pyrite cinder, which had been very difficult by fluidized bed, proceded successfully in this way, and the capacity of processing seemed to be larger than that of fluidized bed process for similar effective volume. Hydrogen reduction of fine iron ores by the gas conveyed system was largely affected by water vapor formed during the reduction process. Reduction of fine hematite are by very dilute phase was studied and relations between the rate constant and the vapor pressure were determined. From these relations, a rate equation for high solid/gas ratio was derived. It was shown that this equation was valid for relatively concentrated solid gas systems.