Electron mechanism of reducing processes in blast and ferro-alloy furnaces

The existing versions of the iron solid-phase reduction theory are based on atomic-molecular idea and consider reduction as an exchange between the oxide's molecules and a reducing agent (oxygen atoms). But them there are no atoms and molecules in solid oxides and metals. There are only ions and the electrons that bind them. Redox reactions are a process of exchange not by atoms, but by electrons. Therefore, it is impossible to create a consistent theory of processes taking place on another - electronic level from the standpoint of atomic-molecular representations. The electronic theory of reduction developed by the authors describes the electric and mass transfer in the gas and condensed phases, the exchange of electrons between the reducing agent and the oxide, the redistribution of electrons between cations and anions in the oxide lattice, and the transformation of the oxide crystal lattice into a metal lattice, as well as the effect of pressure and temperature on these processes. According to the theory, the direct result of the extraction of one oxygen anion from the crystal lattice on the oxide surface is the formation of an anionic vacancy and two free electrons connected with it. In complex and poor ores, vacancies and electrons are diffuse in the oxide volume, accumulate and merge at cations whose Fermi level is lower than the chemical potential of electrons in vacancies. The results known from experiments and the practice of producing cast iron and ferroalloys are explained by the participation in the oxidation-reduction reaction in the layer of low-temperature plasma charged particles solid reactants. Plasma is formed due to thermionic emission from the reducing agent surface the and thermal ionization of gases. It was shown that carbothermal reduction of active metals, as well as iron from strong complex oxides, occurs only with solid carbon. In this case, a counter-transfer of carbon to the oxide surface and oxide to the carbon surface occurs through the plasma, as a result of which carbide shells are formed on each surface of them. The formation of carbides etches the surface, slows down and stops recovery. The shells material melting and draining transfers the restoration into a kinetic process and ensures its effective flow.