Geochemical Characteristics of Trace Elements in the No. 6 Coal Seam from the Chuancaogedan Mine, Jungar Coalfield, Inner Mongolia, China

Lin Xiao,Zhixiang Shi,Bin Zhao,Piaopiao Duan,Mingyue Lin,Jialiang Ma

doi:10.3390/min6020028

Abstract

Fourteen samples of No. 6 coal seam were obtained from the Chuancaogedan Mine, Jungar Coalfield, Inner Mongolia, China. The samples were analyzed by optical microscopic observation, X-ray diffraction (XRD), scanning electron microscope equipped with an energy-dispersive X-ray spectrometer (SEM-EDS), inductively coupled plasma mass spectrometry (ICP-MS) and X-ray fluorescence spectrometry (XRF) methods. The minerals mainly consist of kaolinite, pyrite, quartz, and calcite. The results of XRF and ICP-MS analyses indicate that the No. 6 coals from Chuancaogedan Mine are higher in Al2O3, P2O5, Zn, Sr, Li, Ga, Zr, Gd, Hf, Pb, Th, and U contents, but have a lower SiO2/Al2O3 ratio, compared to common Chinese coals. The contents of Zn, Sr, Li, Ga, Zr, Gd, Hf, Pb, Th, and U are higher than those of world hard coals. The results of cluster analyses show that the most probable carrier of strontium in the coal is gorceixite; Lithium mainly occurs in clay minerals; gallium mainly occurs in inorganic association, including the clay minerals and diaspore; cadmium mainly occurs in sphalerite; and lead in the No. 6 coal may be associated with pyrite. Potentially valuable elements (e.g., Al, Li, and Ga) might be recovered as byproducts from coal ash. Other harmful elements (e.g., P, Pb, and U) may cause environmental impact during coal processing.

Highlights

Coal is the main fossil fuel resource and energy source in China
The results provide new data on trace element enrichment in coal
Minerals inresults the Coal data show that the minerals in the Chuancaogedan are mainly composed data show that the minerals in the No 6 coal from Chuancaogedan are mainly composed of clay

Summary

Introduction

Coal is the main fossil fuel resource and energy source in China. China’s energy consumption has grown and will continue to grow along with its economic growth [1]. In the process of coal utilization, the recovery of valuable elements from fly ash, as well as the impact on environment from harmful trace elements, have become important research topics [2,3]. Ge, Ga, Li and U can be enriched to higher levels than usual economic grades [4], while As, Pb, Hg, and F are potentially toxic. The modes of occurrence of trace elements in coal control the stratus of their emission in coal combustion processes [5]. Sr, Ba, B, and V have great significance to the environment regarding coal formation [5]

Methods

Discussion

Conclusion