Production of iron/carbon composite from low rank coal as a recycle material for steel industry

Utilization of low rank coal is indispensable to qualify the future demand of energy. Low rank coal, however, has several disadvantages such as small calorific value, so we should develop a new technology of using effectively it. On the other hand, as for the steel manufacturing process, we must think about an effective utilization of iron sludge and scrap from the standpoint of recycle. In this paper, we presented a new method to produce an iron/carbon material by utilizing a large amount of functional groups in low rank coal which can be used as an iron recycling media to revolving furnaces. The method is as follows: The low rank coal was oxidized for 2 h at 70 °C by nitric acid to introduce a large amount of carboxyl functional group and was impregnated by FeCl3. Through pyrolyzing the Fe-impregnated coal pure iron crystal/carbon composite was successfully produced above 760 °C. As an option, Fe2O3 or Fe3O4/carbon composite was also successfully produced by the oxidation or gasification of it at low temperature. The irons in these composites were reduced by carbon with evolving CO and CO2 at high temperature. Thus, it is clarified that the proposed method is attractive for producing a recycle material for the iron melting furnace prior to revolving furnaces from waste iron using low rank coal.