Origin and geochemical significance of antimony in Chinese coal

Abstract

A total of 159 coal samples from different regions, periods and ranks across China were systematically analyzed for antimony (Sb) isotopic composition (ε123Sb), trace element contents and total sulfur content (TS) in this study. Here, we discuss the origin of Sb in coal from different regions of China. Antimony in coal from SW and NE China is primarily of hydrothermal fluid and leachate origins, respectively. In comparison, Sb in northern Chinese coal mainly comes from terrigenous materials and hydrothermal fluid. Antimony in coal from NW China may be influenced by the superposition of hydrothermal activity and leaching solution. Inorganic minerals (e.g., sulfide) and organic matter in coal are the determining factors for Sb enrichment in coal. The Sb isotopic fingerprint of Chinese coal is 2.46 ± 1.01 ε (weighted mean ± 1 SD, ranging from −4.45 to +9.72 ε). Accordingly, the isotopic composition of Sb in coal has great potential not only for researching Sb isotope fractionation in hydrothermal systems but also for tracing Sb release and transport in the supergene eco-environment. Furthermore, the establishment of Sb isotopic fingerprint for coal could largely reduce the uncertainty in the application of Sb isotope methods.