2015 Volume 55 Issue 10 Pages 2056-2063
The carburizing, melting, and dripping behavior of iron through graphite and coke beds was investigated by an in-situ observation technique with increasing temperature from room temperature to 1773 K. An iron sample placed on the graphite bed was fully melted at 1490 K, whereas that on the coke bed was not melted at 1773 K. From the microscopic analysis of the sample after experiments, it was revealed that solid ash formed at the metal-coke interface prevented the carburization and melting of the iron sample. In order to examine the role of gangue and flux materials in sinter, iron samples mixed with slag powders at different weight fractions (15, 30, and 50 wt%) were prepared and similar experiments were carried out. The sample containing 15 wt% slag powders was not melted, but the samples containing 30 and 50 wt% slag powders were carburized and fully melted at 1773 K after holding the sample at that temperature for 342 and 37 s, respectively. It was considered that the liquid slag absorbed solid ash formed at the coke surface, yielding carburization and melting of the iron.