INTERFACIAL PHENOMENA AND REACTION KINETICS BETWEEN CARBON AND SLAG CONTAINING MnO

Wettability of graphite by synthetic SiO2-Al2O3-CaO-MnO slags with varied MnO content and by industrial slags was studied at 1350-1600 °C using sessile drop method under argon atmosphere. Initial contact angle was the lowest (110-115o) for the MnO-free slag. For slags with 10-40 wt % MnO, the initial contact angle was in the range 125-135o. The contact angle decreased with the contact time. The change in the contact an-gle with slag mass was found insignificant. The surface tension of slags obtained from the drop shape analy-ses was 500-800 mN/m and varied in a narrow range with temperature and MnO concentration. The reduction rate increased with increasing MnO content in the synthetic slag from 20 wt % to 40wt % and tem-perature. Increasing temperature also increased the rate of reduction. No correlation was observed between the reduction rate and MnO content in the synthetic slags in the range 0-20 wt % and in the industrial slags. The rate of SiO2 reduction from the molten slag was close to the rate of MnO reduction. The MnO-free slag had the largest contact area with graphite substrate