Estimation of the fines content of Athabasca oil sands using instrumental neutron activation analysis

Abstract

Knowledge of the "fines" or clay-rich mineral fraction is necessary for the efficient extraction of bitumen from bulk oil sands, and has environmental implications in tailings disposal. Current methods for estimating the fines in oil sand are laborious and of questionable accuracy. We propose here their estimation directly in bulk oil sand by instrumental neutron activation analysis (INAA) of the trace and major elements determinable. Correlations between fines content and individual elements fall in the range of 0.80 to 0.81 for dysprosium, samarium, and europium, and 0.75 to 0.77 for sodium, potassium, aluminum, and titanium. These results follow the expected geochemical relationships between major and trace elements and the mineral fraction of the oil sands. Principal component analysis (PCA) using a combination of elements gave correlations with fines content no better than those obtained from individual elements. However, the PCA approach can be considered more robust. Advantages of INAA over conventional methods to estimate the fines content of unprocessed oil sand include minimal sample preparation (including elimination of the use of organic solvents), rapid turnaround time, and the potential for automation. Key words: instrumental neutron activation analysis, oil sand, elemental correlations, fines.