Reduction and Carburization of Iron Oxide by Carbonaceous Materials

The iron nugget making process, where mixtures of iron ore powder and pulverized coal are made to heat rapidly, is regarded as a new ironmaking process. Since the iron carburization reaction is an especially important step from the viewpoint of energy saving in this process, the purpose of this study is to reveal the carburization mechanism of reduced iron formed during the heating process of the mixtures. Fe2O3 and H-2-CO-CO2 gas mixture were made react with each other to simulate the formation of iron ore and the generation of coal gas from coal during the heating process. An electric resistance furnace was used to heat the samples. A cut surface of the quenched iron product was observed by microscopy Carbon content in the iron was analyzed after reduction and carburization of Fe2O3. It is considered that there are many possibilities in the real process to carburize the reduced iron during the heating process, such as carburization with CO formed by coal combustion, solution loss reaction, and direct carburization with coal. It was observed in the present work that the carbon content in the reduced iron became the highest as Fe3C was formed during the heating process. Therefore, it became clear that the key technology for production of pig iron containing high carbon was to control the formation of Fe3C in the heating period of the mixture. The carburization mechanism was discussed in this study based on these experimental results.