Process Mineralogy Research on Copper-silver Polymetallic Tailings in Inner Mongolia

Objective To achieve the high-value utilization of tailings from a Cu-Ag polymetallic mine in Inner Mongolia, Method this study conducted systematic process mineralogical characterization by integrating chemical analysis, field emission scanning electron microscopy (FESEM), and the AMICS automated mineral analysis system. Result The tailings assayed 977 g/t Cu and 12 g/t Ag, with a TFe₂O₃ content of 13.24%. The predominant metallic minerals are pyrite and arsenopyrite, whereas chalcopyrite (0.08%) and silver minerals (<0.01%, mainly matildite) occur in low abundances and exhibit complex modes of occurrence. Gangue minerals are primarily quartz and feldspar. Chalcopyrite grains are concentrated in the 5～20 μm size fraction, exhibit low liberation degree, and are closely intergrown with quartz, chlorite, and iron-bearing minerals. The iron-bearing minerals are mainly composed of pyrite (2.63%), magnetite (1.17%), and siderite (1.13%), with minor ilmenite. Among these, pyrite and magnetite show relatively coarse particle sizes and high liberation degrees, demonstrating substantial recoverable potential. An integrated process route is proposed, involving oxidative roasting pretreatment followed by magnetic separation for magnetite recovery, flotation for the concentration of chalcopyrite and pyrite, and cyanide leaching for silver extraction. Conclusion This study provides a critical mineralogical basis and process guidance for the high-value treatment of similar refractory tailings.