Open Collections

Abstract

All oil sands plants operating in Alberta, Canada use the Clark Hot Water Extraction process. This process causes production of mature fines tailings (MFT) at 30-35% solids content which remains in a fluid state for decades because of its very slow consolidation rate. Existing mature fines tailings inventory is approaching 10⁹ m³, remediation of which by thin layer deposition and centrifuging are being tested by oil industry. Residual bitumen in mature fine tailings can complicate remediation, as it can interfere with the performance of coagulants and polymers which hinders the dewatering process. To support oil industries mature fine tailings remediation effort, we have investigated a method that reduces residual bitumen content, facilitates dewatering of the mature fine tailings and improves process water chemistry, simultaneously, by using lime as a process aid between 750 to 1500 mg-CaO/kg-MFT dosages. Experimental observations suggest that the residual bitumen of the mature fine tailings could be recovered by flotation process with about 5-10 minutes retention time. This investigation shows that use of lime could enhance the performance of mature fine tailings remediation processes.