Hot water processing of U.S. tar sands -- Water recycle and tailings disposal

Tailings disposal and water recycle are vital factors for the industrial development of a hot water process for the recovery of bitumen from U.S. tar sands. Based on batch laboratory experiments, with 4 to 12 kg tar sand charge, tailings sedimentation behaviours are presented and discussed for tar sand samples originating from six U.S. deposits. Recycle of 90% of the water is possible after 10-20 minutes clarification assuming 10% solids content in the flotation cell. Sand and silt, which make up about 95-99% of the total quartz minerals present in five domestic tax sands (with the exception of McKittrick), settle completely (40% porosity with water saturation). Very fine particles (< 25 nm) which amount to up to 10% of the tailings stream still retain about 30 wt% water after 2 weeks of thickening.