Mitigating the Adverse Effects of Ultrafines in Pressure Filtration of Oil Sands Tailings

油砂尾矿管理的最终目标是使尾矿流中的固形物含量达到70wt；%，从而为回收利用做好准备。过去几十年的研究表明，要实现这一最终目标，必须结合化学修饰(如聚合物絮凝剂+混凝剂)和机械处理。在机械处理技术中，加压过滤是最有前途的。在不列颠哥伦比亚省温哥华举行的2019年尾矿与矿山废物会议上报告的几个案例研究表明，典型的尾矿可以使用商业压滤机脱水到&gt；=85wt%的固体。而同样的工艺处理油砂尾矿，压滤滤饼的固形物含量仅为60wt%左右。申请人过去的研究发现，从成熟的细粒尾矿中离心得到的超细组分，含有超细亚微米粘土和水包沥青乳状液液滴的混合物，是成熟细尾矿压力过滤较差的主要原因。在拟议的项目中，我们将继续进行研究，以确定组成材料(粘土类型、粒度、沥青涂层和游离沥青)在超细粒中的作用，并开发缓解技术，以消除它们对压滤机操作的不利影响。主要的焦点不是试图分离/去除超细组分，而是选择性地聚集超细组分以形成高强度的凝聚物、絮凝体和/或地质聚合物。这项研究有望使油砂尾矿用压滤机快速脱水至70wt%固体在技术上和经济上都是可行的。

The ultimate goal of oil sands tailings management is to achieve >70 wt% solids in the tailings stream so that it is ready for reclamation. Research in the past several decades indicates that a combination of chemical amendment (e.g., polymer flocculants + coagulants) and mechanical treatment is necessary to achieve this ultimate goal. Of the mechanical treatment techniques, pressure filtration holds the most promise. Several case studies reported in the Tailings & Mine Wastes 2019 Conference in Vancouver, BC, show that typical mine tailings could be dewatered to >= 85 wt% solids using commercial filter press. However, when the same technology was used in oil sands tailings, the pressure filtration cake only reached about 60 wt% solids. The applicants' past research identified an ultrafine fraction, which was centrifuged from mature fine tailings and contained a mix of ultrafine sub-micron clays and bitumen-in-water emulsion droplets, as the main reason for the poor pressure filtration of the mature fine tailings. In the proposed project, we would continue the research to identify the roles of the constituent materials in the ultrafine fraction (clay types, size, bitumen coating and free bitumen) and develop mitigation technologies to eliminate their detrimental effects in filter press operation. The main focus is not to attempt to separate/remove the ultrafine fraction, but to selectively aggregate the ultrafine fraction to form high strength coagula, flocs and/or geo-polymers. The research is expected to make rapid dewatering of the oil sands tailings to >70 wt% solids by filter press technically and economically feasible.