Voordouw Gerrit
Department of Biological Sciences, Petroleum Microbiology Research Group, University of Calgary, Calgary, Alberta, T2N 1N4, Canada.
Biopolymers. 2013 Apr;99(4):257-62. doi: 10.1002/bip.22156.
Production of bitumen by surface mining of Alberta's oil sands has given rise to tailings ponds, containing large volumes of finely dispersed clays (10(8) m(3)), which settle only slowly. The mature fine tailings (MFT) in these ponds are operationally defined as consisting of particles smaller than 44 μm with a solids content in excess of 30% (w/w). Increasing the rate of densification of MFT is a rate-limiting step in tailings pond reclamation. Accelerated densification has been achieved through mixing of MFT with sand in the presence of calcium sulfate as a binding agent to generate consolidated tailings. Addition of negatively charged polymer, together with either calcium or magnesium ions, is similarly effective. Although toxic to higher aquatic life, tailings ponds harbour a wide variety of mainly anaerobic microbes. These convert residual hydrocarbon, causing methane emissions of up to 10(4) m(3) day(-1). Interestingly, anaerobic microbial activity also accelerates tailings pond densification. Hence, many technologies designed to accelerate densification move tailings, at least conceptually, towards soil in which sand and clay particles are linked by large amounts of humic and fulvic acid polymers supporting large numbers of microbes in a mechanically stable structure.
通过对艾伯塔省油砂进行露天开采来生产沥青，产生了尾矿池，其中含有大量细分散的粘土（10⁸立方米），沉降速度很慢。这些尾矿池中的成熟细尾矿（MFT）在操作上被定义为粒径小于44微米且固体含量超过30%（w/w）的颗粒。提高MFT的致密化速率是尾矿池复垦中的一个限速步骤。通过在作为粘结剂的硫酸钙存在下将MFT与沙子混合以生成固结尾矿，实现了加速致密化。添加带负电荷的聚合物以及钙或镁离子同样有效。尽管对高等水生生物有毒，但尾矿池中有各种各样主要为厌氧的微生物。这些微生物会转化残留的碳氢化合物，导致甲烷排放量高达10⁴立方米/天。有趣的是，厌氧微生物活动也会加速尾矿池的致密化。因此，许多旨在加速致密化的技术，至少在概念上，会使尾矿朝着土壤的方向转变，在这种土壤中，沙子和粘土颗粒通过大量腐殖酸和富里酸聚合物连接在一起，在机械稳定的结构中支持大量微生物。
