| 摘要 |
<p>This invention is an improvement on the hot water process for recovering bitumen from tar sand. The aqueous slurry of tar sand is introduced into a first vessel, termed the sand separation cell, containing a body of hot water. The coarse sand settles out and is discharged as tailings. The top product, comprising bitumen, water and fine sand, is transferred to a second vessel, termed the froth formation cell, containing a second body of hot water. In this latter cell, the bitumen forms froth and is recovered, and the fine solids and some water are recycled to the lower end of the sand separation cell. Because the coarse sand has previously been removed in the sand separation cell, good distribution of the feed across the cross-sectional area of the froth formation cell is achieved. This leads to good recoveries and froth quality. By recycling the fines from the froth formation cell to the vicinity of the tailings outlet of the sand separation cell, the fines can be eliminated from the system without the need for a middlings dragstream, as is required in the prior art.</p> |
