The increasing demand for critical raw materials such as copper and cobalt highlights the need for efficient beneficiation of low-grade ores. This study investigates a copper–cobalt sulfide ore (0.99% Cu, 0.028% Co) using froth flotation to produce high-grade concentrates. Various types of surfactants are applied in different ways, each serving an essential function such as acting as collectors, frothers, froth stabilizers, depressants, activators, pH modifiers, and more. A series of flotation tests employing different collectors (SIPX, PBX, AERO, DF 507B) and process conditions was conducted to optimize recovery and selectivity. Methyl isobutyl carbinol (MIBC) was consistently used as the foaming agent, and 700 g/L was used as the slurry density at 25 °C. Dosages of 30 and 100 g/t¹ were used in all tests. Notably, adjusting the pH to ~4 using HCl significantly improved cobalt concentrate separation. The optimized flotation conditions yielded concentrates with over 15% Cu and metal recoveries exceeding 80%. Mineralogical characterization confirmed the selective enrichment of target metals in the concentrate. The results demonstrate the potential of this beneficiation approach to contribute to the European Union’s supply of critical raw materials.

Rare earth elements (REEs), including yttrium, scandium and lanthanides, are essential for advanced technologies, particularly in electronics, defense and renewable energy systems. The main primary REE sources include bastnaesite, monazite and ion-adsorption clays, while secondary sources comprise permanent magnets, phosphors, LEDs and other technological waste. The growing demand, together with China’s dominant position in the global REE market and export restrictions, has increased concerns regarding the security of the REE supply in the European Union. This study evaluates selected primary REE resources and their processing possibilities using hydrometallurgical methods, with an emphasis on the thermodynamic aspects of REE leaching. The research focuses on the construction and analysis of Eh–pH diagrams generated using HSC Chemistry software to predict the stability of dissolved and solid species under different leaching conditions. These diagrams help identify suitable conditions for selective REE extraction and improve the understanding of the mechanisms governing hydrometallurgical processing. The results provide insight into the stability regions of REE species and indicate favorable conditions for selective leaching and recovery.

Flotation is one of the most widely used separation methods in mineral processing, and its performance is strongly influenced by complex physicochemical and hydrodynamic conditions. Flotation behaviour is commonly described using kinetic models. This study investigates the application of laboratory-derived flotation kinetic models for the simulation of a pilot-scale flotation circuit treating a polymetallic sulfide ore containing critical raw materials. Laboratory flotation experiments were conducted using Denver flotation cells, and kinetic parameters were determined by fitting first-order, two-component, and three-component kinetic models. The obtained parameters were implemented into an HSC SIM process model to evaluate the influence of flotation circuit configuration and residence time on process performance. The simulation indicated that the optimum circuit configuration consisted of two rougher and two scavenger flotation cells with an overall residence time of 28 min. The multi-component kinetic models provided a substantially better description of flotation behaviour than the classical first-order model and enabled a more realistic prediction of flotation performance. The simulation results were subsequently validated using a continuous pilot-scale flotation experiment. The simulated cleaner concentrate Cu grade (9.02 wt.%) was in good agreement with the experimental value (9.27 wt.%), confirming the capability of the proposed methodology to predict pilot-scale flotation performance. Although minor differences in product composition were observed, the overall flotation trends were reproduced successfully. The remaining discrepancies were mainly attributed to scale-up effects and differences in hydrodynamic conditions. The proposed methodology demonstrates that laboratory-derived kinetic parameters can be successfully applied to pilot-scale flotation process simulation and provides a practical tool for flotation circuit design and process optimization.