A Comprehensive Analysis of Organic Matter Removal from Clay-Sized Minerals Extracted from Oil Sands Using Low Temperature Ashing and Hydrogen Peroxide

摘要

Understanding mineralogy and surface properties of clays is very vital in oil sands processing and tailings management. Clay-sized minerals (CSM) in oil sands are often contaminated by tightly adsorbed organics during hydrocarbon removal, thereby increasing surface hydrophobicity and making characterization of CSM problematic. This study evaluates the use of low temperature ashing (LTA) and hydrogen peroxide (H_2O_2) for the removal of adsorbed organic matter (OM) from CSM without changing its mineralogy. CSM isolated from tailings and bitumen froth of a Denver flotation cell after oil sands extraction was treated by H_2O_2 and LTA. Both techniques were found to be effective in removing OM from the CSM as shown by the infrared spectra of the samples. The wettability of the CSM increased with treatment. Elemental analysis showed a reduction in carbon, hydrogen, and nitrogen. Infrared band for siderite at 864 cm~(-1) was observed for the isolated and LTA-treated CSM but was absent for those treated by H2O2. The absence of siderite in the X-ray diffraction patterns of the H_2O_2-treated CSM further substantiates its oxidation by H_2O_2. Cation exchange capacity of model clays and samples was found to be unaffected by LTA treatment, unlike those treated with H_2O_2. Overall, LTA appears to be a more suitable method than H_2O_2 for organic matter removal from the isolated CSM because of its selectivity for decomposing only organics.