Discovery of anomalous molybdenum enrichment in Ordovician and Silurian stone coal: Relevance, origin and recommendations. (April 2023)

• Record Type: Journal Article
• Authors: Long, Jie; Zhang, Shixi; Luo, Kunli
• Is Part Of: Chemosphere. Volume 320(2023)
• Publication Date: 2023-04
• Subjects: Critical mineral -- Black rock series -- Comprehensive utilization -- Molybdenum deposits; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2023.137975
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Molybdenum (Mo) is a strategic element but has a notably low concentration at the Earth's surface. Consequently, competition for molybdenum resources at the national strategic level has begun to emerge, and in recent years, large-scale mining has led to the gradual depletion of molybdenum deposit resources. Here, thirty-four element enrichment patterns of Ordovician and Silurian stone coals in central China are reported. Molybdenum is the most enriched element, with an average of 208 mg/kg (58.2–440 mg/kg), which is 99 times the global hard coal average, and this molybdenum enrichment is associated with Ba–Ga–U–Cr–Na–K–-Cu–Se–Zn enrichment and elevated SiO2, CaO, K2 O, MgO, Na2 O, MnO and P2 O5 concentrations. These analyses reveal four stone coal samples with molybdenum concentrations of 260, 312, 403 and 440 mg/kg, which meet the grade for the molybdenum mineral exploitation formulated standard, indicating that the Ordovician and Silurian stone coal deposits should be considered promising alternative sources of molybdenum. The crude reserve estimate of molybdenum is approximately 29.2 × 10 4 tons. The anomalous molybdenum in the studied stone coal was sourced from a complex combination of hydrothermal fluids, original biomass and terrigenous materials. The unique paleogeographic location and geological structure in central China resulted in the anomalous molybdenum concentrations in the stone coal forming at that time, producing a unique type of coal-hosted molybdenum deposit. Future studies will consider the ecological effects of the molybdenum extraction mode and the cost savings effects of extracting molybdenum from stone coal. A comprehensive utilization plan is also needed. Next, a thorough study of molybdenum exploration related to black rock series must be performed to increase the total molybdenum resources and support Chinese international competitiveness. Graphical abstract: Image 1 Highlights: The reports revealed 34 elemental concentration and enrichment patterns of stone coal before 490 to 410 million years ago. Molybdenum is anomalously enriched and associated with Ba–Ga–U–Cr–Na–K–Cu–Se–Zn enrichment. Stone coal deposits should be considered promising alternative sources of molybdenum. The unique paleogeographic location and geological structure determined the unique type of molybdenum-enriched deposit. The primary anomalous molybdenum source came from hydrothermal fluids.