Preliminary investigation into direct reduction of iron in low temperature hydrogen plasma

Abstract

There has been an increasing interest in reduction of iron ore by hydrogen. This study deals with the reduction of haematite in a microwave assisted non-thermal hydrogen plasma. The plasma is composed of excited hydrogen molecules, hydrogen atoms, and ionic hydrogen among other gaseous species. The reduction in hydrogen plasma occurred even at temperatures as low as 573 K. In contrast, the same could not be achieved by merely introducing hydrogen gas to the reducing environment without creating the plasma. It is only ∼1073 K that the extent of reduction by gaseous means is comparable to that of reduction by hydrogen plasma. Based on the experiments, as well as the data available from literature, it was deduced that the reduction of haematite at a low temperature in hydrogen plasma could have been due to the contribution of vibrationally excited hydrogen molecules to the reduction process.