REDUÇÃO DIRETA DE PÓS DE HEMATITA POR PLASMA FRIO DE HIDROGÊNIO

The goal of this work was to study the reduction kinetics of hematite powders (Fe2 O3 ) using cold hydrogen plasma as reducing agent. Reduction experiments were carried out in a DC pulsed plasma reactor, under hydrogen flow-rates of 300 cm3 /min, at pressure of 400 Pa, times from 30 to 120 minutes and temperatures of 320, 340, 360 and 380°C. Fe2 O3 powders after reduction experiments were characterized by X-ray diffraction, weight loss of oxygen (gravimetric analyses) and light microscopy. The results show that using a reduction temperature of 380°C after 120 min allows obtaining α-iron with a reduction fraction of about 0.93. The powder particles are transformed into two steps: Fe2 O3 →Fe3 O4 →Fe-α. The apparent activation energy experimentally established for the reduction of Fe2 O3 is about 98.4 kJ/mol