Process and apparatus for a direct reduction of iron oxide containing materials to form Fe3C

摘要

In order to effect a reduction and a carburization to form Fe3C to the highest possible degree in a relatively short time in an economical process, a treatment in two stages is effected in fluidized beds. The first stage is effected in a circulating fluidized bed system, in which the amount of solids circulated per hour is at least five times the weight of solids contained in the fluidized bed reactor and a major part of the iron content of the charge is pre-reduced. The remaining reduction and the partial or complete conversion to Fe3C are effected in the second stage in a conventional fluidized bed. Water is condensed from the exhaust gas from the circulating fluidized bed system and that gas is strengthened by an addition of reducing gases and is reheated to the temperature which is required for the process. A part of the reheated recycle gas is supplied as a fluidizing gas to the conventional fluidized bed and the other part of the recycle gas is supplied as a fluidizing gas to the fluidized bed reactor of the circulating fluidized bed. The exhaust gas from the conventional fluidized bed is supplied as a secondary gas to the fluidized bed reactor of the circulating fluidized bed system.