Mineralogy, distribution, occurrence and removability of trace elements during the coal preparation of No. 6 coal from Heidaigou mine

Xiangfei Bai,Yue Wang,Wenhua Li

doi:10.1007/s40789-015-0054-5

Abstract

Optical microscopy and scanning electron microscopy in conjunction with energy dispersed X-ray spectrometry (SEM–EDX) were used to study the minerals and the concentrations of 33 trace elements in No. 6 coal from Heidaigou mine. The distributions, organic affinity and removability of 18 trace elements were studied by float-sink experiments. A determination of the maceral groups was also undertaken. A high mineral content, dominated by kaolinite, was found in No. 6 coal from Heidaigou mine. The bauxite content was relatively high and it was mainly present as individual particles in fusinite lumens or was intimately intergrown with carbonate minerals. The pyrite and quartz contents were low. Some marcasite with a parallel twin structure was observed by cross-polar reflected light. A small amount of bean-like goyazite was present in the calcite. The weighted trace element content in Heidaigou formations is relatively low, which is beneficial for coal processing and utilization. The concentrations of Ga, Hg, Pb, Se, Th, Ta are relatively high compared with the average values of Chinese coals. As, Hg, Mo, Ge, Ga, Ta, Ti, W, Mn are mainly present in minerals while B, Be, Th, P, Sc, Sr, V, Y, Yb are mainly found in organic matter. As, Ge, Hg, Mo are mainly present in sulfides and Be, Th, P, Sc, Sr, Y, Yb are mainly present in inertinite. B and V are mainly present in vitrinite. The high organic affinity and the low theoretical removability of most trace elements cause difficulties in removing them during coal preparation.

Highlights

The Heidaigou coal mine is located in the middle of the Junger coalfield in the Inner Mongolia Autonomous Region
Kaolinite is mainly dispersed in thin-layers or as individual particles (Fig. 1) and it is found in the fusinite lumens
Individual particles (Fig. 6) are the main form of bauxite, which is found in the fusinite lumens (Fig. 7) and it is intimately intergrown with carbonate minerals (Fig. 8). (3) Carbonates The carbonate mineral content is relatively high and the dominant mineral is calcite

Summary

Introduction

The Heidaigou coal mine is located in the middle of the Junger coalfield in the Inner Mongolia Autonomous Region. More than 30 million tons of raw coal is produced every year. As a preferred feedstock for power plants Heidaigou coal is primarily used for the generation of. Wang State Key Laboratory of Coal Mining and Clean Utilization, Beijing 100013, China. W. Li National Institute of Clean-and-Low-Carbon Energy, Beijing 102209, China electricity. A low degree of anogenic metamorphism is the main coalification type. The main mineable coal bed, the No 6 coal seam, was formed during the drying terrestrial delta deposition environment of the late Carboniferous period (Mao and Xu 1999)

Methods

Results

Conclusion