Oil sands contain a so-called organic rich solids component (ORS), i.e., solids whose surfaces are strongly associated with toluene insoluble organic matter (TIOM). Typically, humic material is the major component of TIOM. It provides sites for adsorption and chemical fixation of bitumen. This bound bitumen is “unliberated”, and considerable mechanical or chemical energy may be required to release it. In order to establish a correlation between bitumen recovery and ORS content, a few selected oil sands were processed in a Batch Extraction Unit (BEU). Analysis of the middlings and coarse tailings streams from these tests indicated a relatively constant bitumen to ORS ratio of 2.8±0.7. This value allows the liberated-unliberated bitumen balance (LUBB) to be calculated for any given oil sands. The amounts of bitumen recovered as primary froth during the BEU experiments are close to the estimated liberated bitumen contents in each case tested. This observation indicates that the liberated-unliberated bitumen calculation is an important quantitative parameter for prediction of bitumen recovery under specific recovery conditions. Preliminary results indicate that the ORS content of an oil sands may be estimated from the carbon content of bitumen free oil sands solids.
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