Process Mineralogical Properties of Low–Grade Copper–Nickel Ore: A Case Study from Yunnan, China

The Xinanli copper–nickel deposit in Yunnan Province, China, is a medium–sized Cu–Ni ore deposit. To facilitate the rational utilization of this mineral resource and provide mineralogical support for beneficiation process design, a process mineralogy study was conducted on the ore samples using analytical techniques such as X–ray diffraction (XRD), chemical analysis, reflected light microscopy, scanning electron microscopy (SEM), Energy Dispersive X–ray Spectroscopy (EDS), and single–mineral chemical analysis. The results show that the primary valuable elements in the ore are Cu (0.158 wt.%) and Ni (0.389 wt.%), with chalcopyrite and pentlandite being the major valuable minerals, while gangue minerals are predominantly chlorite, serpentine, and quartz. The valuable minerals exhibit fine grain sizes and complex intergrowth relationships with gangue minerals. Process mineralogy studies indicate that the ore must be ground to −0.010 mm (85% passing 400 mesh) to achieve over 90% liberation of target minerals. Additionally, attention must be paid to the impact of finely disseminated valuable minerals encapsulated in gangue on recovery rates. Based on the mineral properties, it is recommended to adopt the process of one–stage grinding—bulk flotation of copper and nickel—copper–nickel separation for the comprehensive utilization of the ore. This study provides key mineralogical data for the efficient development and comprehensive utilization of the deposit.