RECOVERY OF WATER AND BITUMEN FROM THE ATHABASCA OIL SAND TAILINGS PONDS

Various methods to recover bitumen and water from the oil sand tailings pond were explored. It was shown that removal of free bitument from the tailings tends to destabilize heavy sludges and also improves drying rates dramatically. A heavy sludge was fractionated to yield a number of distinct mineral fines fractions, including a solid associated with the oil phase, a fraction which remained in colloidal suspension in the aqueous phase and a fraction which settled from the aqueous phase. All three solids contained significant quantities of organic matter. The oil-phase solid also showed considerable enrichment in heavy metals compared to the other solids. The tailings from Canada's Athabasca oil sand deposits were used in these tests.