Migration of Trace Elements in Fushun Oil Shale during Self-Combustion and its Environmental Significance

Abstract

Self-combustion of oil shale has been occurring and widespread in a long term while oil shale was considerably piled in Fushun dumping sites. After collecting samples of high- and low-grade oil shale from Fushun West Open Mine, the self-combusted oil shale from Fushun West Dumping Site, and designing the indoor high-temperature incineration experiments to simulate the self- combustion process, we tested trace elements in them and their ashes of 700°C, 1000°C by means of ICP-MS. Based on the analysis and comparison of the test dada, we studied content characteristics and migration pattern of elements during self-combustion. The results showed that elements were distributed in the similar way in samples and contents of Zr, Sr, Cr, V, Zn, Ni, Rb and Li were very high. A large amounts of trace elements were found to enter the atmosphere through volatilization in the process of Self-combustion, especially those higher volatile elements, such as Sb, Zn, Pb, W, Sn, Ta and Cd, while a few elements preferred to concentrate in solid-phase ashes. Different distribution and migration capacities of elements might be the main reason for the higher concentration of some elements in self-combusted oil shale than their background values in Liaoning soil.