The Behaviour of Softening and Melting of Hematite Pellet and Sinter during Heating in a Reducing Atmosphere

Softening and melting characteristics of some pellets and sinter during heating in a CO gas stream were examined by using an X-ray TV apparatus. The effect of load applied to the burden on its behaviour was also examined. The results are as follows: 1) In the case of experiments without load, the reduction of iron oxide was nearly completed at the temperature lower than the melting point of wustite and the separation of slag from the metallic shell was not observed until the reduced iron began to melt. When some residual iron oxide existed at temperature higher than the melting point of wustite, the flowing out of molten slag was observed at relatively low temperatures, depending upon the reduction degree.2) Under load, the temperature at which the permeation of slag into the metallic shell and its flowing out of the pellet began was lowered and strongly depended upon the properties of the formed slags.3) The EPMA analysis showed that the slag formed in Hirohata pellet at 1 360°C contained a small amount of iron oxide but that in Robe River pellet at 1 168°C contained much iron oxide of about 50%. Such a high content of iron oxide lead to the formation of slag of low melting point and brought about the lowering of dripping temperature of Robe River pellet.