Abstract:
The electric-charge and mass transfer processes in the crystal lattices of oxides are analyzed under conditions of high-temperature reduction of metals. As follows from the ionic character of the bond and defects in real oxide crystals, the electric-charge and mass transfer in them is shown to be caused by ion displacements. During high-temperature reduction, oxides are in a pseudoliquid state, where the cation sublattice is stable and provides the stability of the crystal lattice of an oxide as a whole and the anion sublattice is saturated by vacancies ensuring fast (superionic) oxygen transfer. The removal of oxygen ions from the lattice leads to the localization of "excess" electrons by the cations nearest to a vacancy and the transformation of these cations into metal atoms or cations with a lower charge. As a result, the oxide composition changes gradually from the highest oxide to a metal, and clusters whose structures correspond to all intermediate oxides form in the initial structure. © Pleiades Publishing, Ltd., 2009.