Thermodynamic aspects of rare earth metal extraction processes

In this paper, a thermodynamic analysis of rare earth metal extraction processes is presented. The thermodynamic stability of rare earth metal oxides, fluorides, and chlorides was analyzed, as well as the conditions for their reduction using various reducing agents. The study also examines the thermodynamic basis of the halogenation process of rare earth metal oxides, with predominance diagrams used to describe phase equilibria in metal-oxygen-halogen systems. These diagrams enable clear identification of the stability regions of oxides, oxyhalides, and halides and represent an important tool in the design of industrial processes. In addition, the paper links the results of thermodynamic calculations with industrial practice through an analysis of the most important rare earth metal production technologies. Particular emphasis is placed on the thermal effects of reactions and the energy requirements of metallothermic processes. The results confirm the importance of modern thermodynamic analysis and software tools in process optimization and in the selection of efficient technologies for rare earth metal production.