Research and Implementation Program on Phase Equilibria and Thermodynamics of Molten Slags, Matte, Speiss, and Metal Systems for Primary and Secondary Pyrometallurgy

Modern society challenges include increasing overall metal demand and associated shortage of good quality concentrates, increasing variety of metals needed for high-technological devices, changes associated with energy transition, rapid growth of recycling, present sustainability, circular economy, and environmental constraints. These factors increase the complexity of the pyrometallurgical process chemistry that in turn require robust predictive capabilities. Significant recent progress in analytical and experimental techniques, thermodynamic theory, and computational capabilities in high-temperature research are critical to tackle this task. An integrated experimental and thermodynamic modelling research program on complex multicomponent multi-phase gas–slag–matte–speiss–metal–solids systems with the Cu₂O–PbO–ZnO–FeO–Fe₂O₃–CaO–Al₂O₃–MgO–SiO₂–S major and As–Sn–Sb–Bi–Ag–Au–Ni–Co–Cr–Na minor elements is under way in response. The program has been supported for nearly two decades by several consortia currently consisting of 15 major international companies with over 30 operations in 15 countries around the world that brings together many different groups of professionals. The experiments involve high-temperature equilibration in controlled gas atmospheres, rapid quenching, and direct measurement of equilibrium phase compositions using a combination of the microanalysis techniques including electron probe X-ray microanalysis and laser ablation ICP-MS. The thermodynamic modelling is undertaken using the FactSage™ software package with advanced thermodynamic solution models. Implementation of the research outcomes involves ongoing collaboration of researchers and industry technologists and systematic advanced professional training. An overview of recent progress in research, implementation, and applications in industrial practice will be presented in the paper. The aim of the paper is to share the authors’ experiences in developing and running this research program to facilitate possible future further developments and collaborations in the field of complex pyrometallurgy thermochemistry research.