Effects of charcoal carbon crystallinity and ash content on carbon dissolution in molten iron and carburization reaction in iron-charcoal composite

Charcoal use instead of fossil fuel is one of the possible technologies for mitigation of CO2 emission in the steel industry because charcoal can be considered as "carbon-neutral" material. In this study, the possibility of utilization of charcoal as carbon source for carburization reaction was examined; more specifically effects of carbon crystalinity and ash in charcoal on carbon dissolution into molten iron and iron carburization reaction in iron-charcoal composite were investigated. Two kinds of experiments were carried out. One is measurement of charcoal carbon dissolution rate in iron bath. Another is observation of isothermal reaction between iron and charcoal in a composite sample. Several kinds of charcoal with relatively low ash content were applied as experimental samples. Charcoal samples were treated with several heating patterns to control their carbon crystallinity. Additionally, charcoal samples were treated with acid solutions, HCl and HF, to control the ash content in them. From these investigations, following results were revealed. Charcoal heat-treated at low temperature, 1273K, has advantage for carbon dissolution reaction into iron bath. Charcoal ash strongly prevents the carburization reaction between iron and carbon in the composite sample.