2016 Volume 30 Issue 2 Pages 150-157
Studies on the carburization rate of metallic iron through CaO-SiO2-Al2O3 slag phase and its mechanism have been introduced as a fundamental of slag-design for the low-temperature and high-speed of iron carburization. The carbon solubility in slag increases with an increase of slag basicity, and the rate of iron carburization through slag is faster when the slag basicity is higher. From these facts, it is concluded that the iron carburization proceeds faster when the slag basicity is higher, the carbon solubility is higher, and the partial pressure of oxygen is lower. On the other hand, the carburization rate is much slower than the rate of direct carburization or carburization through slag including iron oxide (FeO). That is to say, when iron ore agglomerates including carbon source are used as a raw material, in order to enhance the carburization reaction, it is important to proceed ‘melting and carburization’ according to the following mechanism: slag component is melted not after the reduction of iron oxide (formation of metallic iron) by the carbon source, but before iron oxide is perfectly reduced to metallic iron so that iron oxide can dissolve into slag.
