Reduction Extraction Kinetics Of Titania And Iron From An Llmenite By H_2-ar Gas Mixtures

摘要

Reduction of an ilmenite concentrate as a natural concentration containing 49.78 mass% TiO_2 and 27.96 mass% total Fe by H_2-Ar gas mixtures was investigated from 1 073 to 1 273 K. Both the reduction degree and reduction rate increased with the increase of temperature and hydrogen content. The reduction degree of the ilmenite decreased due to the presence of impurities including manganese and silicon oxides in the ilmenite concentrate. During the reduction, the formation of manganese and silicon oxide-enriched zones prevented complete reduction of Fe~(2+). The reduction products were characterized using X-ray diffraction, scanning electronic microscope with energy disperse spectroscopy and optical microscopy analysis, respectively. The main phases in reduced products were reduced iron, rutile, reduced rutiles, pseudobrookite and Ti_3O_5. The reduction reaction proceeded topochemically and the reduction kinetics was discussed. It was found that the rate controlling step was the diffusion of hydrogen gas in the reduced layer.