Direct reduction rotary kiln with improved air injection

摘要

In the direct reduction process for reducing iron ore to sponge iron of the type disclosed in U.S. Pat. No. 3,890,138 to Hockin wherein all of the air supply tubes along the rotary kiln inject air toward the discharge end of the kiln it has been found that by reversing the direction of injection of the air from one or more of the tubes in the preheat zone of the kiln the condition of the off-gases can be considerably improved without affecting the process in the reduction zone and ultimately the quality of the resulting product and improved preheating of the kiln charge can be effected without the formation of undesirable kiln accretions.