Oscillatory rheometry to characterize polymer flocculation of fluid fine tailings

Polymeric flocculation represents a widely used approach to accelerate consolidation of fluid fine tailings (FFTs), generated by mining bitumen from oil sands. Questions remain, however, regarding the structure produced by polymer addition, and its evolution over time. Dynamic strain amplitude sweep tests on undisturbed specimens show that flocculation leads to an improvement in stiffness and strength, delays yield, and modifies the damping properties. These effects are attributed to the percolated network formed as the polymer aggregates mineral particles, and further bridges these aggregates. This structure dominates the response of the material and controls the solid-to-fluid transition, which has characteristics typical of a highly networked system. Increasing disturbance causes rapid and irreversible degradation of the response, evidence of the sensitivity of the structure. The data for FFTs from two tailings ponds demonstrate the uniqueness of these materials with differences observed in the response before and after flocculation, and in the water release process.