Effects Of Deep Karst Water On The Release Of Heavy-metal Ion From Coal Gangue In Abandoned Coal Mine Region
Han, Jin; Xu, Dongjing; Tian, Jinjin; Liu, Tianhao; Wang, Ying
Shandong University of Science and Technology, China, People's Republic of
Heavy-metal ions from coal gangue in abandoned coal mines significantly affect the quality and uses of water supplies in mining area all over the world [1-3]. The mining activity of coal mines in Shandong province of China has experienced aross the whole century, which caused degradation of water resources in local region. These coal mines almost have special karst groundwater and large mining depth, whose greater liquidity and hydrochemistry environment sensibility further aggravated the crisis of deep karst water contamination in abandoned coal mines. However, very detailed studies of deep karst water, different flow velocity and different water temperature on the release of heavy-metal ions from coal gangue under this special conditions have been reported.
Coal gangue was sampled from abandoned coal mines, whose particle size distribution was determined by a Malvern Mastersizer using laser diffraction technique, bulk density, water absorption and specific gravity were analyzed by Micrometrics helium pycnometer, respectively.
Its mineralogy was determined by a combination of X-ray diffraction spectroscopy (XRD) and scanning electron microscopy (SEM) analysis. Soak test of coal gangue in abandoned coal mines was carried out to study heavy-metal ions release using new apparatuses developed by ourselves, which adopted two soaking solution of deep karst water and distilled water, different flow velocity and different water temperature to make comparisons. Chemical analysis was periodically performed using inductively coupled plasma-atomic emission spectros-copy (ICP-AES) following a total HNO3/Br2/HF/HCl digestion.
Through chemical analysis we can obtain that release curve of heavy-metals ions (As, Cd, Co, Cr, Cu, Fe, Pb, and Zn) over time under different soaking solution, different flow velocity, different water temperature. It is noteworthy to mention that deep karst water has a bigger influence in the release of heavy-metal ions from coal gangue in abandoned coal mine region different from distilled water. Additionally, the release difference of heavy-metal ions from coal gangue in two soak liquid also vary slightly from flow velocity and water temperature.
We can use these results to further study the release and migration mechanism of heavy-metal ions from solid waste under the conditions of large mining depth and karst water in abandoned coal mines, which may provide reference for security theory and contamination control technology of deep karst water in abandoned coal mines.