One of the promising directions in metallurgy is the use of iron-containing waste, such as converter production sludge, iron-containing concentrates, rolling scale, iron ore processing waste and others. Development of new resource-saving technologies using such waste requires preliminary research and accumulation of information in the field of iron recovery. The paper considers the processes of iron recovery from oxides under various conditions. The authors used the method of thermodynamic modeling based on the search for the entropy maximum. The thermodynamic modeling tool was TERRA software package created at the Bauman Moscow State Technical University. TERRA complex is designed to calculate the thermodynamic properties and composition of the phases of equilibrium state of arbitrary systems with chemical and phase transformations. Using this software package, studies of the processes of iron recovery by various reducing agents (carbon, manganese, and silicon) in model thermodynamic systems were carried out, and optimal conditions for temperature and consumption of reducing agents were determined. The paper presents the results of a study of processes in the metal-slag system in equilibrium. The analysis of the metal-slag system equilibrium state was carried out for the temperature range of 1773 - 1973 K with different amounts of slag. Boundaries of the areas of redox processes were determined and the influence of metal components on conditions for iron oxides recovery from slag to metal was evaluated. The dependences of the system equilibrium composition on temperature at different ratios of metal and slag were obtained, as well as the optimal conditions for iron recovery.