Process for recovery of residual bitumen from tailings from oil sand extraction plants

Abstract From the Canadian patent

Abstract of the Disclosure, Bitumen in primary separation vessel underflow and bitumen plus diluent naphtha in aqueous effluent from centrifugation plants that together represent losses of 8 to 12% of oil in oil sand feed to a hot water extration plant may be substantially recovered by settling and flotation scavenging after tailings fractions have been subjected to a tumbling mixing or shearing process. The, process of the present invention includes the possibility of dilution of the sand while raising the bitumen content of the primary separation vessel underflow by admixture with centrifugation plant tailings unscavenged primary, separation vessel middlings or bituminous sludge from a …