Abstract

The routine analysis of tar sands for bitumen content normally involves the direct measurement of water and sand using the modified Dean-Stark (Soxhlet) extraction technique with the bitumen determined by difference. Any errors in the measurement of water or sand result in errors of equal magnitude in the reported bitumen content. Analytical procedures which determine the bitumen content directly and, therefore, provide a closed mass balance are reported. These procedures add very little time and/or equipment requirements to the assay procedure and provide an automatic quality control check on each sample run. Three methods of direct bitumen measurement are reported: gravimetric, spectrophotometric, and liquid chromatographic. The data presented includes comparisons of the results obtained with the standard API RP-40 difference method for bitumen with each of the proposed direct bitumen measurements using several different tar sands and heavy oils from Utah, California, and Wyoming.