Current status of copper tailings resource utilization: technology, problems and challenges

Copper tailings, which are primarily generated as solid waste from copper ore dressing and metallurgical processes, exceed 100 million tons in annual production. The comprehensive utilization rate of these tailings has remained low for an extended period, leading to large-scale stockpiling. This not only occupies significant land resources and increases the risk of geological disasters but also poses environmental hazards due to the migration of heavy metals. Additionally, the recovery rate of valuable components, such as copper, within the tailings is insufficient, resulting in substantial resource wastage. To achieve the goals of resource recovery and environmental safety in copper tailings management, this study systematically examines the current technological status, key challenges, and future development directions for their utilization. The primary resource recovery pathways are categorized into four types: extraction of valuable elements （Cu, S, Fe, and other metals）, production of construction materials （non-fired bricks, autoclaved bricks, cement additives, and glass-ceramics）, development of ecological remediation materials （soil conditioners and reclamation substrates）, and application as underground backfill materials. Recent technological progress is demonstrated through multiple achievements: copper recovery rates exceeding 85% through combined bioleaching-flotation processes, concrete with 38 MPa compressive strength developed via multi-solid-waste synergistic activation mechanisms, porous ceramic materials achieving porosity control accuracy within ±5%, and eco-remediation fillers attaining ≥2 MPa strength through gel-solidification techniques. However, the deep utilization of copper tailings faces three major bottlenecks: ① difficulty in separating complex components （Al₂O₃/SiO₂）; ② low removal efficiency of associated hazardous elements （As, Cd, Pb）; ③ insufficient development of high-value products. Future research priorities are directed toward breakthroughs in mineral dissociation-component separation synergy enhancement technologies, development of solid-waste-based ultra-high-performance concrete, and establishment of multi-stage utilization models integrating underground backfilling, construction material production, and rare/precious metal extraction. Critical challenges requiring resolution include characterization of mineral storage properties, control of secondary pollution during leaching processes, and standardization gaps in policy frameworks （e.g., certification systems for recycled building materials）. Addressing these issues is essential for achieving synergistic optimization of environmental benefits and resource value, thereby advancing sustainable development in the mining sector.