Interaction of Silicate Melts with Hematite

Abstract

The interaction of sintered hematite Fe2O3 with melts in the PbO–SiO2 system at 900°C and melts in the Na2O–SiO2 system at 1150°C is investigated by the annealing–quenching technique with the use of standard physicochemical methods (X-ray powder diffraction analysis, scanning electron microscopy, quantitative X-ray microprobe analysis). The melting diagrams of the PbO–Fe2O3–SiO2 and Na2O–Fe2O3–SiO2 systems are calculated and constructed on the basis of the model of regular solutions. An analysis of the experimental and calculated data demonstrates that the diffusion dissolution of hematite at the “hematite–melt” heterogeneous interface can be observed only for the PbO melt. For lead and sodium silicate melts, the diffusion process is accompanied by the concurrent redox reaction with the liberation of gaseous oxygen, which appreciably promotes the erosion of solid hematite.