Process Mineralogy of a Cobalt-bearing High-sulfur Bauxite from Guizhou

Objective To clarify the occurrence state and distribution pattern of associated cobalt resources in a high-sulfur bauxite from Guizhou and to guide the synergistic recovery of aluminum, sulfur, and cobalt resources, Method a systematic process mineralogy study was conducted using multiple analytical techniques, including multi-element chemical analysis, X-ray Diffraction (XRD), Automated Mineral Identification and Characterization System (AMICS), Electron Probe Microanalysis (EPMA), and optical microscopy. Result The main chemical components of the ore are Al₂O₃ (58.98%), TFe (7.96%), and SiO₂ (5.98%), with a Co content of 0.005 9% (59 g/t). The primary mineral composition consists of diaspore (68.3%), pyrite (17.95%), and illite (8.83%), accompanied by minor amounts of quartz, anatase, dolomite, as well as trace minerals such as chalcopyrite and cobaltite. Cobalt occurs in two distinct forms: approximately 55.21% is incorporated in pyrite via isomorphism (average Co content 163.38 g/t), while about 44.79% exists as discrete cobaltite minerals. The intergrowth between pyrite and diaspore is complex, and the extremely fine-grained cobaltite (2～4 μm), often encapsulated in chalcopyrite, presents significant challenges to its liberation, thereby constituting a key limiting factor for cobalt recovery. Conclusion This study reveals for the first time the dual occurrence state of associated cobalt in high-sulfur bauxite and its constraining mechanism during the separation process, offering new insights for the effective enrichment and comprehensive recovery of cobalt resources from this type of ore.