Description:
<jats:p>The purpose of the article is to assess the application possibility of methane of various conversion methods (СО2, Н2О, О2) for combined reduction of iron and non-ferrous metals (nickel, copper, lead and zinc) from B2O3-CaO-Fe2O3-МеО oxide melts in the temperature range of 1273-1673 K. Thermodynamic modeling is carried out using a technique, which allows to estimate the variations in phase compositions depending on the amount of the reducing agent induced. The technique differs from the known ones by sequential calculation cycles with the removal of the formed gases and the metal phase from the working fluid composition. It is found that regardless of gas composition the process goes on in several stages. In the case of the combined reduction of iron and nickel (lead or zinc), the first stage is reduction of Fe2O3 to Fe3O4 and FeO. The content of Fe2O3 decreases, while the contents of FeO and Fe3O4 increase (at the end of the stage the content of Fe3O4 reaches its maximum value). At the second stage, there is the transition of Fe3O4 → FeO when the values of the contents of Fe2O3 and Fe3O4 decrease to negligible values. The third stage features the manifestation of the metallic phase. In the case of the combined reduction of iron and copper, the process can be divided into three stages according to the variations of the content of iron oxides, and into two stages according to the variations of the content of CuO and Cu2O. The first stage of iron reduction ends at the moment when the content of magnetite reaches its maximum value, the second stage finishes when the metallic phase appears. The first stage of copper reduction includes the transition of CuO to Cu2O and achievement of the maximum value of Cu2O content. The second stage includes the reduction of copper from Cu2O. A gas with the increased content of hydrogen, which corresponds to methane steam reforming is shown to be the most effective reducing agent. The results obtained make it possible to predict the parameters of the metal reduction process during oxide systems bubbling by methane conversion products. The results will be useful for the development of technologies for selective reduction of metals.</jats:p>