Towards integrating micro- and macro- scale processes and tools to improve dewatering and rheology assessments in soft and ultra-soft tailings

油砂开采尾矿水中含有超细粘土悬浮颗粒和残留沥青。这些稳定的悬浮液需要很长时间才能沉到池塘底部(&gt；10年)。因此，在较短的时间内减少尾矿量是一个重大挑战。此外，复垦土地的机械强度仍然较差，无法回归自然。在这些过程中添加增稠剂，如聚丙烯酰胺(PAM)，被认为是改善土壤固结的一种有吸引力的方法。尽管聚合物很便宜，但总体处理成本仍然很高。此外，此类聚合物的去向和运输以及它们的生态毒性问题仍未解决。目前还不清楚固结土的最终强度是否满足艾伯塔省政府对土工强度的最低要求。*本项目的目标是调查絮凝尾矿系统的微观结构对以软性和超软性粉尘为主的沉积物的宏观脱水和流变性的影响。絮体是一团黏土颗粒，如果加入，还会形成软尾矿的基本结构的聚合物。观察、了解和量化脱水和沉积(如剪切下)等关键过程中的絮凝机理，可能是预测固结和沉积操作的重要一大步，从而有助于油砂尾矿的有效管理。如果成功，这将允许流体尾矿的特定处理方法的选择(例如，絮凝剂的添加、混合和沉积速度)与长期脱水和强度性能(例如，深层沉积物固结率、砂分离、细粒捕获)之间的直接关联，并有可能进一步推算到长期的回收目标。

The tailings water from oil sands extraction contains suspended particles of ultra-fine clays and residual bitumen. These stable suspensions take a long time to settle to the bottom of the ponds (> 10 years). Hence, reducing the volume of tailings in a shorter duration is a major challenge. In addition, the reclaimed land still has a poor mechanical strength for it to be returned to nature. Adding thickeners such as polyacrylamide (PAM) to these processes is considered an attractive method for improved soil consolidation. Even though the polymers are cheap, the overall treatment cost remains high. In addition, the issues of fate and transport of such polymers, as well as their ecotoxicity, are still not resolved. It is also not yet clear if the final strength of consolidated soil will meet the Alberta government's minimum requirements of geotechnical strength.****The goal of this project is to investigate the influence of the micro-scale structure of the flocculated tailings systems on the macro-scale dewatering and rheological properties of soft and ultra-soft fines dominated deposits. Flocs are a clumped group of clay particles and, if added, a polymer that forms the basic structure of soft tailings. Observing, understanding and quantifying the flocculation mechanisms during critical processes such as dewatering and deposition (e.g. under shear) can potentially represent a fundamental big step forward in the prediction of consolidation and deposition operation, hence in the effective management of oil sands tailings. If successful, this allows direct correlation between the choice of a specific treatment of fluid tailings (e.g. addition of the flocculant, mixing and deposition rate) and long-term dewatering and strength performance (e.g. deep deposit consolidation rate, sand segregation, fines capture), with potential for future extrapolation to long-term reclamation objective.****** ****