The composition and structure of chromite during reduction with carbon

Examination of grains of chromite, subjected to varying degrees of reduction by heating chromite-graphite mixtures, using a scanning electron microscope and electronprobe microanalyser. Initially reduction of iron from chromite to form metallic iron, with a small chromium content, at the surface. Iron diffusion from within the grains to the surface with continued reduction and contraction of the core of unaltered chromite. Reduction of chromium as the main reaction when the core has disappeared and observation of a second skrinking core, this time of chromium. Increase of the chromium content of the metal phase and forming of the carbide (Cr, Fe)₇C₃ during this period. Reduction within the grains when the chromium core has disappeared. MgAl₂O₄ containing up to 6 percent chromium as final residue of the original chromite for the experimental conditions.