The Wuliping ion-adsorption deposit, Guizhou Province, South China: A new type of rhenium (Re) deposit

Abstract

Rhenium (Re) is an extremely rare element and was also the last stable (non-radioactive) element discovered. Owing to the extremely high melting point, Re is ideal for high-temperature applications, for example, as an alloying metal for jet engine turbine blades. This, in turn, leads to an increasing demand for Re resources. Previous studies show that the most common host minerals for Re in the Re-bearing deposits are sulfides (especially molybdenite), and to a lesser extent, U minerals and organic matter. In this study, we report high Re grades and the corresponding host minerals in the weathered Shangsi Formation (dominated by mudstone) of the Wuliping Pb-Zn-Mo polymetallic deposit, based on whole-rock major and trace element geochemical, TOC, XRD, SEM-EDS, and LA-ICP-MS analyses. We find that all weathered samples from the Shangsi Formation display noticeable enrichment of Re (and also Mo), with Re concentrations ranging from 12.61 to 93.13 ppm (averaging 28.23 ppm versus <0.1 ppb in the upper continental crust). However, the high Re concentrations are not found in either sulfides (e.g., molybdenite) or organic matter; rather, our results reveal that Re is mainly adsorbed by kaolinite. We propose that the Wuliping ion-adsorption deposit should be a new type of ion-adsorption Re deposit, which is noticeably different from known Re deposit types. We suggest that ion-adsorption deposits, such as the one explored in this study, may become one of important sources of critical metals in this era of ever increasing demand.