Assessing the feasibility of using lime to mitigate chemical flux in oil sands end pit lakes

评估使用石灰减少油砂坑湖化学通量的可行性

• 批准号: 515022-2017
• 负责人: Ulrich, Ania
• 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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=640571
• 关键词: Assessing; feasibility; using; lime; mitigate

In northeastern Alberta, large volumes of fluid fine tailings (FFT) are produced during bitumen extraction fromsurface-mined oil sands ore. FFT is comprised of water, fine clays, naphthenic acids (NAs), residual bitumenand other unrecovered hydrocarbons. FFT takes decades to dewater in tailings ponds. Hence, the growinginventory compels operators to seek alternative tailings management strategies. End pit lakes (EPLs) with FFTbelow a water cap in mined out pits are one of the potential options. The expectation is that EPLs will slowlydevelop into self-sustaining aquatic ecosystems. Potential issues with EPLs may include movement ofconstituents of potential concern (COPCs) from the FFT into the overlying cap water contributing to on-goingsources of possible toxicity. Thus, research has been undertaken to resolve these issues and determine thefeasibility of EPLs as a reclamation strategy.Graymont Western Canada Inc. is an emerging global leader in the supply of lime and limestone products.Graymont has conducted preliminary tests showing that 1) lime addition to FFT in the range of 750 to 1500mg-CaO/kg-FFT improves FFT dewatering and facilitates the release of residual bitumen, and 2) lime additionto oil sands process-affected water (OSPW) induces calcium naphthenate precipitate formation at pH 12. Thesepreliminary findings can be leveraged by further investigating how lime treatment can mitigate COPC fluxacross the FFT-water cap interface in EPLs. Both of these issues are of relevance for the timely development ofEPLs in the oil sands industry.In this study, lime will be tested for its ability to enhance FFT dewatering and NA removal in lab-scale batchexperiments representative of an EPL. The purpose of this study to assess the feasibility of using lime as apre-treatment step in EPLs for efficient and economical oil sands tailings reclamation.

在阿尔伯塔省东北部，从露天开采的油砂矿石中提取沥青时会产生大量流体细尾矿 (FFT)。 FFT 由水、细粘土、环烷酸 (NA)、残余沥青和其他未回收的碳氢化合物组成。 FFT 需要数十年才能对尾矿池进行脱水。因此，不断增长的库存迫使运营商寻求替代的尾矿管理策略。在采空坑的水帽以下进行 FFT 的末坑湖 (EPL) 是潜在的选择之一。预计EPL将慢慢发展成为自我维持的水生生态系统。 EPL 的潜在问题可能包括潜在关注成分 (COPC) 从 FFT 移动到上覆盖水中，从而导致可能的毒性持续来源。因此，我们进行了研究来解决这些问题并确定 EPL 作为填海策略的可行性。Graymont Western Canada Inc. 是石灰和石灰石产品供应领域的新兴全球领导者。Graymont 进行的初步测试表明：1) 石灰添加750 至 1500mg-CaO/kg-FFT 范围内的 FFT 可改善 FFT 脱水并促进残留沥青的释放，以及 2) 将石灰添加到油砂中受工艺影响的水 (OSPW) 在 pH 12 时会诱导环烷酸钙沉淀形成。通过进一步研究石灰处理如何减轻 EPL 中 FFT-水盖界面上的 COPC 通量，可以利用这些初步发现。这两个问题都与 EPL 在油砂行业的及时发展相关。在这项研究中，将在代表 EPL 的实验室规模批量实验中测试石灰增强 FFT 脱水和 NA 去除的能力。本研究的目的是评估在 EPL 中使用石灰作为预处理步骤以实现高效且经济的油砂尾矿回收的可行性。