Study of aluminothermic niobium reduction by thermodynamic modeling method.

Information is provided on the areas of application of niobium in industry, the scale of its production in the world and in the Russian Federation. Information is presented on the main niobium deposits in Russia, types of ores and minerals. Thermodynamic modeling (TDM) of the aluminothermic reduction of components of the oxide system CaO-SiO2-MgO-Al2O3-TiO2−Nb2O5−Fe2O3−P2O5 was carried out in order to determine the influence of the amount of reducing agent and process temperature on the degree of reduction of elements, the composition of the metal and oxide phases and metal dephosphoration. Thermodynamic modeling was carried out for temperatures of 1500-1700 °C with a reducing agent consumption of 100-220% of the stoichiometrically required amount for the complete reduction of Nb, Fe, P and Ti. The results of thermodynamic modeling of the aluminothermic process for producing complex niobium alloys showed that with the introduction of 100% aluminum from the stoichiometrically required amount, the most complete (97-98%) reduction of iron occurs compared to other elements. It has been shown that for the reduction of niobium by 98-99% at a temperature of 1600°C, an excess of the reducing agent (aluminum) of at least 30% of the stoichiometrically required for the complete reduction of metals is required, which is explained by the formation of niobium aluminides. With increasing temperature in the range of 1500-1700 °C, the degree of phosphorus sublimation increases. The maximum degree of phosphorus sublimation is 54% at a temperature of 1700 °C for the initial concentrate containing 2% P2O5. [ABSTRACT FROM AUTHOR]