The partitioning and environmental characteristics of trace elements in a coal-fired power plant: a case study at Huaibei, China

Abstract

The trace elements (TEs) in coal are of great concern due to their toxicity and bioavailability. The coal, bottom ash, fly ash and gaseous species were sampled to study the partitioning and environmental behaviors of TEs during coal combustion. The mineral and phase characterizations of coal combustion residue were determined by X-ray powder diffraction (XRD) and fourier transform infrared spectroscopy (FTIR), respectively. The gaseous emission, risk assessment code and leaching experiment EN 12457 Part 2 procedure were employed to assess the potential environmental impacts. The concentrations of TEs in all the collected samples were determined by inductively coupled plasma mass spectrometry (ICP-MS). During combustion, the mineral compositions of coal (kaolinite, quartz, illite, pyrite and calcite) were changed to mullite, quartz, hematite, lime, magnetite and anhydrite. Arsenic, Cd, Cu, Pb and Zn were emitted mainly in fly ash and gaseous phases. In the current unconfined deposits, the TEs (As, Cu, Pb and Zn) in bottom ash and fly ash may pose a medium risk to the environment. High regularization and management countermeasures including immobilization/stabilization, re-utilization of combustion ash, and controlled disposal should be conducted to eliminate/minimize environmental and ecological risks in coal activities areas.