Grant: Alliance Grants

Rapid dewatering technology of Alberta oil sands tailings is urgently needed but currently unavailable. Rapid dewatering enables fast recycling of the warm process water and the generation of stackable reclamation-ready tailings. Such a technology can eliminate the need for large tailings ponds, significantly lower fresh water consumption, and lower energy consumption and GHG emissions associated with heating the fresh water to about 50°C. Through a preliminary test program sponsored by Imperial Oil, we have recently demonstrated the success of dewatering oil sands fluid fine tailings (FFT, 21 wt% solids, sand-to-fine ratio (SFR) of 1.0) by a combination of low-dosage chemical amendment and Volute screw press treatment. For instance, the chemical-amended FFTs were fed to the Volute screw press at up to 14.3 kg-dry solids/h throughput, yielding 65-72 wt% solids in the discharge cakes continuously and consistently and 0.2 wt% solids in the filtrate (i.e., process water). The results exceeded the current target solids content to dewater FFT (i.e., 60 wt%) in the oil sands industry, while the filtrate from the Volute screw press can be reused directly with no further treatment in oil sands extraction process.The current proposal is a continuation of the research. In the proposed project, we will evaluate the application and commercial potential of enhanced coagulant-flocculant chemistry plus Volute screw press on a range of oil sands tailings including fluid fine tailings (FFTs) with different SFRs and solids contents, thickened tailings (TT), and tailings-solvent-recovery-unit (TSRU) tailings. The results and knowledge obtained from this project will position the proposed Volute screw press technology in line with Alberta Energy Regulator's Directive 085, resulting in a rapid dewatering technology for the Alberta oil sands tailings.