Maintaining Permeability for Continuous Mature Fine Tailings Dewatering

保持连续熟细尾矿脱水的渗透性

• 批准号: 532050-2018
• 负责人: Liu, Qi
• 金额: $ 4.33万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=697894
• 关键词: Maintaining; Permeability; Continuous; Mature; Fine

Oil sands tailings dewater extremely slowly once they form the so-called "mature fine tailings" (MFT). The accumulated MFT volume is over 800 million cubic meters and counting. Over the last few decades the industry has developed a number of dewatering techniques (composite tailings, thickened tailings, in-line thickening/thin lift, centrifugation, filtration) to speed up the solid-liquid separation of the oil sands tailings. However, the performance of treatment is generally unsatisfactory, and the tailings could not be dewatered beyond ~55 wt% solids by mechanical means, making the target of >=75 wt% solids (required for reclamation) seem un-achievable. Our recent results show that the difficulty of dewatering the oil sands tailings could be attributed to the residual bitumen in MFT rather than the small size of the fine solids in the tailings. Our results show that an aqueous slurry of 35 wt% fine kaolinite (d50 = 4 µm) could easily filter to ~70 wt% solids using 50 g/t polyacrylamide (PAM) under 6 bar pressure. However, after blending in 3 wt% of the residual bitumen, the kaolinite slurry could only be filtered to ~60 wt% solids at >1,500 g/t PAM, behaving like MFT. Based on these results, we ask the question: are the typically used PAM flocculants the best in dealing with the residual bitumen? In the proposed project, we will answer this question and identify appropriate binders to alleviate the detrimental effect of the residual bitumen. The research techniques will include: 1) jar tests to evaluate the interaction of potential bitumen binders with residual bitumen isolated from MFT; 2) isothermal titration calorimetric (ITC) study to investigate the binding strength between residual bitumen and bitumen binders, and between fine solids and bitumen binders; 3) filter press tests of the MFT after treatment by the bitumen binders to observe the dewatering effect and the achieved cake % solids content; 4) micro computed tomography and cryogenic scanning electron microscopy to study the pore structures of the filter cake after the treatment, and to investigate the reasons for the poor and improved dewatering performances.

油砂尾矿一旦形成所谓的“成熟细粒尾矿”（MFT），其沉降速度就非常缓慢。的 累计MFT量超过8亿立方米，并在不断增加。在过去的几十年里， 工业上已经开发了许多脱水技术（复合尾矿、浓缩尾矿、在线 增稠/稀提、离心、过滤）以加速油砂尾矿的固液分离。 但处理效果普遍不理想，尾矿不能脱水 通过机械方式超过~55重量%的固体，使目标为>=75重量%的固体（回收所需） 似乎无法实现。 我们最近的研究结果表明，油砂尾矿脱水的困难可能归因于 这是由于MFT中的残余沥青，而不是尾矿中细小固体的小尺寸。我们的研究结果表明， 35重量%细高岭石（d50 = 4 μm）的含水浆料可以使用50 g/t容易地过滤至约70重量%固体 聚丙烯酰胺（PAM）在6巴压力下。然而，在掺混3重量%的残余沥青之后， 在> 1，500 g/tPAM下，高岭石浆料只能过滤至约60重量%固体，表现类似于MFT。 基于这些结果，我们提出了一个问题：通常使用的PAM絮凝剂是否是处理 残留的沥青在拟议的项目中，我们将回答这个问题，并确定适当的活页夹， 减轻残留沥青的有害影响。研究技术将包括：1）罐试验， 评价潜在的沥青粘合剂与从MFT分离的残余沥青的相互作用; 2）等温 滴定量热法（ITC）研究，以调查残余沥青和沥青之间的结合强度 粘结剂之间，以及细固体和沥青粘结剂之间; 3）MFT在处理后的压滤机试验， 沥青粘合剂，以观察脱水效果和实现的饼%固体含量; 4）微计算 层析成像和低温扫描电子显微镜，以研究过滤后滤饼的孔结构。 处理，并调查的原因差，提高脱水性能。