Identifying the mechanism of tailings dewatering by lime using surface vibrational spectroscopy

使用表面振动光谱确定石灰尾矿脱水的机理

• 批准号: 531600-2018
• 负责人: GibbsDavis, Julianne
• 金额: $ 1.82万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Engage Grants Program
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=651837
• 关键词: Identifying; mechanism; tailings; dewatering; lime

The Athabasca oil sands are one of the largest oil reserves in the world. Yet one challenge in the oil sands**extraction process is how to deal with the large quantities of waste material. This waste, referred to as fine**tailings, consists of fine sand and clay particles as well as water, residual oil, and additives and salts used in**extraction. After the extraction process, a large fraction of water remains strongly bound to the sand and clay**particles, leading to a sludge consistency, which makes reclamation of tailings ponds difficult. Indeed, the**amount of water needs to be reduced to <20% by mass for the tailings solids to be able to bear the weight**required for land reclamation (i.e. ability to sustain top soil, vegetation, roads, etc.). There are currently no**commercial solutions to reliably achieve this target for oil sands fine tailings. However, recently researchers of**Graymont Western Canada Inc. (Graymont), a Canadian-owned company that specializes in the use of lime,**found that lime addition followed by pressure treatment led to facile dewatering of tailings, yielding tailings**solids with low water content and high strength. To understand this remarkable phenomenon, we will utilize**the surface-specific spectroscopic technique in our lab: vibrational sum frequency generation (SFG). SFG is**sensitive to the amount of water ordered at interfaces, and we hypothesize that it is the ideal tool to monitor**dewatering, which is water released from clay and sand surfaces. We will explore the amount of surface**associated water on silica and clay-particle coated silica as a function of lime concentration in the presence and**absence of bicarbonate. Furthermore, we will look for signatures of salts directly interacting at the clay/water**interface and correlate these results with tailings settling and dewatering measurements and surface potential**analysis. The ultimate goal is to facilitate the expansion of Graymont into tailings treatment based on our**ability to characterize the mechanism of tailings dewatering by lime. This collaboration will benefit Canada by**demonstrating a solution that accelerates the reclamation of oil sands tailing ponds, minimizing the**environmental impact on the Wood Buffalo region.

阿萨巴斯卡油砂是世界上最大的石油储量之一。然而，油砂开采过程中的一个挑战是如何处理大量的废料。这种废物被称为细尾矿，由细砂和粘土颗粒以及水、残油和用于提取的添加剂和盐组成。在提取过程后，很大一部分水仍然与沙子和粘土颗粒紧密结合，导致污泥稠度，这给尾矿库的回收带来了困难。实际上，尾矿固体的水量需要减少到<20%的质量，才能承受复垦所需的重量（即维持表层土壤、植被、道路等的能力）。目前还没有商业解决方案能够可靠地实现油砂细尾矿的这一目标。然而，最近加拿大一家专门使用石灰的公司**Graymont Western Canada Inc.（以下简称Graymont）的研究人员**发现，添加石灰后进行压力处理，尾矿容易脱水，得到的尾矿固体含水量低，强度高。为了理解这一非凡的现象，我们将在我们的实验室中使用表面特定光谱技术：振动和频率生成（SFG）。SFG对界面上有序的水量很敏感，我们假设它是监测脱水的理想工具，即从粘土和沙子表面释放的水。我们将探索在碳酸氢盐存在和不存在的情况下，二氧化硅和粘土颗粒包覆二氧化硅表面相关水的数量与石灰浓度的关系。此外，我们将寻找盐在粘土/水界面直接相互作用的特征，并将这些结果与尾矿沉降和脱水测量以及表面电位分析相关联。最终目的是基于我们对尾矿石灰脱水机理的描述能力，促进Graymont在尾矿处理领域的扩展。此次合作将通过展示一种加速油砂尾矿池回收的解决方案，最大限度地减少对Wood Buffalo地区的环境影响，从而使加拿大受益。