AN INVESTIGATION OF THE WEATHERING BEHAVIOR OF COAL-DERIVED PYRITE SURFACES BY X-RAY PHOTOELECTRON-SPECTROSCOPY

The effects of relative humidity and oxygen partial pressure on the relative rates of surface oxidation of pyrites derived from various coal seams have been measured using X-ray photoelectron spectroscopy (XPS). The surface oxidation rate of the coal-derived pyrites was influenced to a greater extent by relative huumidity than by oxygen partial pressure. Pyrites derived from separate coal seams were found to oxidize at different rates and ultimately to different extents under the same weathering conditions. The observed differences in oxidation rates may partly be related to the level of impurities in the pyrites.