A Property-Process Matrix for Valorizing Copper Extraction Wastes: Enabling Technology Selection and Resource Classification

A comprehensive characterization of copper extraction wastes, namely, tailings, electrostatic precipitator (ESP) dust, and slag, was conducted to establish a baseline for selecting efficient metal recovery flowsheets at a screening level. Analytical techniques, including ICP-OES, XRD, and SEM-EDS, revealed distinct properties for each waste stream from a single plant of global relevance. ESP dust was identified as a critical metal-rich stream with high concentrations of copper (173 g/kg) and cobalt (360 mg/kg), but also poses a significant environmental hazard because cadmium leaching exceeds regulatory limits (2.12 mg/L). Its fine particle size and soluble copper minerals make it ideally suited for hydrometallurgical processing, provided that integrated hazardous-element removal is included. Conversely, slag’s refractory fayalite matrix and entrapped copper phases suggest alternative routes, such as pyrometallurgical re‑smelting or vitrification. Tailings, with their acidic pH and low‑grade, poorly liberated metals, indicate potential for bioleaching. This study provides a novel screening‑level property‑process matrix that links material characteristics to hypothesized recovery pathways. The detailed technical and environmental data enable a preliminary UNFC screening assessment; full classification would require additional sampling, volume estimation, and process validation. The findings provide a scientifically justified framework for converting complex metallurgical wastes into valuable secondary resources while highlighting the need for further dynamic testing.