Estimation of particle size distribution in Athabasca oil sands by indirect instrumental neutron activation analysis

Instrumental neutron activation analysis (INAA) was used to predict the relative amounts of various sizes of fine particles in Athabasca oil sands. The method is based on regression analysis of element concentration data for 529 oil sand test portions, determined by INAA, against particle size distributions determined by three currently used methods. The most important elements for the estimation of particle sizes below 44 µm were found to be aluminum, sodium, and manganese. The INAA estimation method works because variation in elemental composition within particle size fractions in oil sands up to at least 44 µm is relatively small, whereas the variation between size fractions is significant. The new method does not involve the use of organic solvents, is faster and simpler to perform than the methods currently in use, and is comparable in precision. It has the added advantages that it can be readily automated, and concentrations of elements of special interest in oil sand processing, such as chlorine, are obtained simultaneously.Key words: instrumental neutron activation analysis, oil sand, particle size distribution.