Process Mineralogy of Lithium and Rubidium in the Diantan Polymetallic Mining Area, Tengchong, Southwest China

Abstract

Highly differentiated granite often contains abundant key metal resources, such as lithium and rubidium. The Tengchong area of Yunnan hosts a large number of highly differentiated granites from the Cretaceous age. Among these, granite samples from the Diantan tin–lead–zinc polymetallic mining area exhibit Li contents exceeding 0.02% and Rb contents surpassing 0.1%. This suggests a promising potential for Li and Rb mineralization. However, the occurrence status and process mineralogical characteristics of Li and Rb remain unclear, directly impacting the assessment of the region’s comprehensive utilization potential for these key metals. This study focuses on representative granite samples from the Diantan mining area to conduct petrographic and process mineralogical research, examining single mineral chemical composition, physical properties, element occurrence state, and mineral embedding particle size. The results indicate that mica minerals primarily contain Li, while both feldspar and mica minerals are the main carriers of Rb. Zinnwaldite not only contains the highest Rb proportion among the samples but also plays a significant role in Li occurrence. Based on the dissociation characteristics, it is recommended to grind the material to a fineness of −0.075 mm, comprising 80% of the particles, before proceeding to the final flotation process. This would result in approximately 95% dissociation of the mica in the sample. Since mica is predominantly distributed between quartz and feldspar particles, with relatively low binding force, it facilitates mineral dissociation during the grinding process. Therefore, the actual beneficiation process may consider a moderately coarser grinding fineness based on the aforementioned findings.