Electrokinetic thickening of mature fine oil sands tailings

Abstract

Mature fine oil sands tailings (MFT) are the fine parts of oil sands tailings that remain suspended in tailings disposal pond for decades because of the low sedimentation/consolidation rate. This study applies electrokinetics to thicken, that is, to increase the solid content, of the MFT suspension. The geotechnical properties of MFT solids and chemical analysis of tailings pore water are measured, followed by electrokinetic (EK) tests. The results of this study indicate that EK thickening is very effective for the settling of MFT suspensions under an applied voltage of 219 V/m, the final solid content of the sediment reached 18·75% from an initial 5% after 7 h. The EK treatment is also very effective in clarifying the supernatant. The final turbidity of the supernatant is 30·6 NTU under 219 V/m applied voltage gradient. Regression models are developed using statistical software MINITAB 15 in coded and uncoded units to relate the final solid content of the sediment with the initial solid content and applied voltage gradient. The models and the independent variables are statistically significant at 95% confidence level based on F test and t test results, respectively.