Treatment of fluid fine tailings with silica

摘要

Management of fluid fine tailings remains an environmental challenge to the oil sands industry. Recently enacted ERCB directive 074 requires fine tailings be treated to generate a trafficable surface. The ERCB directive dictates the minimum undrained shear strength of the deposited fines shall be 5kPa at 1 year after treatment and 10kPa after 5 years. Rheological modification of the fluid fine tailings can be easily accomplished by in-situ polymerization of silica. Yield stress of the tailings can be increased an order of magnitude within minutes after treatment. With minimal dewatering the treated tailings can exceed the one and five year shear strength requirements. Dewatering of the treated tailings can be accomplished by a number of different techniques. The in-situ silica polymerization treatment has been demonstrated to work over a wide range of fine tailings compositions. This paper will discuss rheology modification of oil sands fluid fine tailings using silica and the subsequent dewatering of the tailings.