The influence of microwaves on residual impurities during pig iron production

The application of high power microwaves is a promising, energy efficient alternative to the traditional ohmic heating. Furthermore, microwaves in material sciences are facing growing interest, in particular for processing of microscopic systems at strong thermal non-equilibrium. The application of microwaves in the iron industry may be characterized by a high potential for an essential reduction of carbon dioxide emission. A series of microwave experiments have been conducted to prove the effectiveness of rapid and high purity refinement of iron ores under oxygencontaining environment. Very promising results have been achieved. Experiments performed at 2.45 GHz in nitrogen atmosphere with natural irons ores demonstrate that high purity pig-iron can be produced with less than 1/10 of impurities as compared to pig-iron that modern blast furnaces can produce. Moreover, such a microwave process can reduce the carbon consumption by 1/3. Of course, essential prerequisites for reaching the target of reduced CO₂ emission and for satisfying the needs of steel industry with respect to production capacity are the availability of powerful microwave sources and sufficient supply of electric power which is not based on fossil energy. This motivates further microwave assisted experiments at a frequency of 30 GHz by use of an industrial 15 kW gyrotron system. The latest results of microwave assisted iron production will be described including the influence on residual impurities.