PROCESS FOR SECONDARY RECOVERY OF BITUMEN IN HOT WATER EXTRACTION OF TAR

摘要

"IMPROVEMENT PROCESS FOR SECONDARY RECOVERY OF BITUMEN IN HOT WATER EXTRACTION OF TAR SAND" It has been found that tank-type air flotation cells. are more efficient, when treating hot water process middlings containing in excess of about 3% bitumen, than trough-type air flotation cells. Also, it has been found that the trough-type cells are more efficient than the tank-type cells when treating middlings containing less than about 3% bitumen. Thus a secondary recovery circuit is proposed wherein the middlings are first treated in one or more tank-type cells in series and the underflow from the last tank-type cell is treated in one or more banks of trough-type cells.