Effect of bitumen composition and process water chemistry on model oilsands separation using a warm slurry extraction process simulation

Variability in ore composition and process parameters is known to affect bitumen recovery from natural oilsands. In this work, we extend our earlier studies with model oilsands (MOS) systems to investigate the effects caused by the presence of asphaltene and divalent cations on the interaction between bitumen and silica particles. The absence of both asphaltene and fines was found to have significant effects on bitumen recovery. With a typical oilsands, addition of small amounts of caustic improves recovery but overdosing causes a drastic loss of yield through bitumen emulsification. Without asphaltene and in the presence of fines, the typical drop in bitumen recovery above pH 10 did not occur, indicating that the source of emulsifying agents had been eliminated. With deasphalted bitumen, recovery in the absence of silica fines was very poor at all NaOH dosages. The strong, negative effect of divalent cations on “normal” bitumen recovery was almost completely eliminated when asphaltene was absent.