Direct reduction process in a rotary kiln

摘要

An improved process for the direct reduction of iron oxide-containing materials to form sponge iron which takes place in a rotary kiln by treatment with a solid carbonaceous reducing agent having a high content of volatile combustible constituents is disclosed. The charge is moved through the rotary kiln opposite to the direction of flow of the kiln atmosphere. Oxygen-containing gases are blown at controlled rates through nozzle blocks into the charge disposed over the nozzle blocks in the heating-up zone in that region thereof defined by the occurrence of ignitable particles of the solid reducing agent and ending before the reduction zone. Oxygen-containing gases are blown in at controlled rates through shell tubes into the free kiln space at least in that region. In accordance with the invention, at least a part of the solid carbonaceous reducing agent comprises disintegrated waste rubber. Preferably more than 80% of the solid carbonaceous reducing agent comprises waste rubber.