Influence of hydrochloric acid pickling on dissolution behaviors of small molecules in oil shale

The oil shales from Maoming (Guangdong province) and Fushun (Liaoning province) were selected for hydrochloric acid pickling. Dichloromethane and tetrahydrofuran were used to extract oil shales before and after acid pickling. The extracts were characterized and the leaching behavior of small molecules was concluded using GC-MS analysis. The results show that the treatment by hydrochloric acid pickling can improve the extraction yield. The compositions of alkanes in extracts are less influenced by the hydrochloric acid pickling than the oxygenated small molecules. The relative content of extracts or the quantity of detectable compounds changes somewhat by comparing the extracts of the same sample before and after acid pickling. The majority extracts are alkanes and oxygenated small molecules compounds from extraction with dichloromethane and tetrahydrofuran, respectively.