The Solubility of Antimony (Sb) in Liquid Hydrocarbons and Its Implication for the Ore-Forming Process of Orogenic Antimony-Gold Deposits in Southern Tibet
Author:
Su Yue1, Sun Xiaoming123ORCID, Ding Zhengpeng13
Affiliation:
1. School of Earth Sciences and Engineering, Guangdong Provincial Key Laboratory of Geodynamics and Geohazards, Sun Yat-Sen University, Zhuhai 519082, China 2. School of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Sun Yat-Sen University, Zhuhai 519082, China 3. CSIRO Mineral Resources, Australian Resources Research Centre, Kensington, WA 6151, Australia
Abstract
Orogenic antimony-gold deposits contribute significantly to the global antimony resource base. China’s orogenic antimony-gold deposits are primarily in southern Tibet. Investigations indicate that antimony combines and migrates with sulfur hydroxides in ore-forming fluids. Previous research on fluid inclusions in orogenic antimony-gold ores with sedimentary rock accommodation revealed the presence of organic inclusions, including liquid hydrocarbons, alongside common components such as CO2, H2O, CH4, and NaCl. However, the impact of liquid hydrocarbons on antimony migration and mineralization is still debatable. To investigate the transportability of antimony by liquid hydrocarbons in orogenic antimony ores, we selected n-dodecanethiol and n-dodecane as the subjects. We measured the solubility and occurrence form of antimony in these compounds at various temperatures and durations. The results indicate that after 5 and 10 days of reaction at 100 °C, the antimony concentrations in the n-dodecanethiol and n-dodecane groups were 67.44 ± 7.62 ppm, 75.15 ± 16.74 ppm, 1.40 ± 1.02 ppm, and 3.02 ± 3.09 ppm, respectively. At 150 °C for 5 and 10 days, the respective concentrations were 50.58 ± 5.39 ppm, 77.26 ± 45.20 ppm, 2.66 ± 3.08 ppm, and 2.41 ± 2.03 ppm. At 200 °C for 5 and 10 days, the corresponding concentrations were 339.76 ± 71.94 ppm, 218.97 ± 25.03 ppm and 6.53 ± 7.17 ppm, 2.27 ± 0.82 ppm (n = 3). The measured solubility of antimony in the n-dodecanethiol group increased gradually with rising temperature. The solubility of antimony in the n-dodecane group was low and notably inferior to that observed in the n-dodecanethiol group. X-ray photoelectron spectroscopy (XPS) analysis demonstrated a distinct thiol (R-SH) peak at 163.31 eV and compound peaks of antimony reacting with thiols at 162.06 and 160.87 eV. This suggests that antimony predominantly forms complexes with thiols for migration. Our findings suggest that specific liquid hydrocarbon components, predominantly thiols, can interact with antimony at metallogenic temperatures and persist in ore-forming fluids, facilitating migration and mineral enrichment. Earlier experimental studies on gold and crude oil have indicated that liquid hydrocarbons also play an essential role in the transportation and enrichment of gold during the formation of gold deposits, thus indicating that liquid hydrocarbons possess the considerable potential to act as an ore-forming fluid during orogenic antimony-gold deposit formation in southern Tibet.
Funder
National Natural Science Foundation of China National Key Research and Development Program of China International Program for Candidates, Sun Yat-Sen University
Subject
Geology,Geotechnical Engineering and Engineering Geology
Reference61 articles.
1. Mineralization process of the Mazhala Au-Sb deposit, South Tibet: Constraints from fluid inclusions, H-O-S isotopes, and trace elements;Li;Ore Geol. Rev.,2023 2. Metallogenic characteristics and genetic model of antimony and gold deposits in south Tibetan detachment system;Yang;Acta Geol. Sin.,2006 3. The distribution, mineralization types and prospecting and exploration of the gold deposits in Xizang;Feng;Tethyan Geol.,1999 4. Identifying geochemical anomalies associated with Sb-Au-Pb-Zn-Ag mineralization in North Himalaya, southern Tibet;Sun;Ore Geol. Rev.,2016 5. Li, Y., Song, Y., Tang, J.X., Chen, W., and Sun, H. (2023). Study on the distribution, type and metallogenic regularity of antimony deposit in Tibet. Geol. China, 1–34.
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