Novel Processes for Treatment of Syncrude Fine Transition and Marine Ore Tailings

Abstract

Syncrude Canada Ltd. has compiled a substantial amount of work on tailings research and development to determine the most effective treatment and deposition processes to increase reclamation options, water reuse and thermal energy recovery. This research has shown that the conventional processes using a single flocculant, a single coagulant or a coagulant-flocculant combination are ineffective for transition and marine ore tailings. For example, using a single flocculant to treat transition or marine ore tailings resulted in a thickener overflow of 1∼4% solids content compared with the target solids content of <0.5% obtained with estuarine ore. On the other hand, new processes including Coagulation-Flocculation-Coagulation (CFC), Flocculation-Coagulation (FC) and Flocculation-Coagulation-Flocculation (FCF) have been found to be acceptable options. However, the FCF process outperformed the CFC and FC processes because the FCF process produced huge flocs resulting in fast initial settling rates. The key components of these technologies consist of the recipe of chemicals and their sequences of addition. With these technologies, almost all submicron clay minerals are aggregated together and settle as a whole resulting in a clear supernatant of less than 0.13% solids.