Abstract A large amount of waste rock, coal discards and coal fines result from the extraction and beneficiation of coal. These wastes may present a major environmental hazard. Exposure of their sulphidic mineral content, mainly pyrite, to moisture and oxygen causes acidic runoff or leachate from waste rock dumps, coal discard dumps and tailings facilities, referred to as acid rock drainage (ARD). Whereas sulphide can be removed from fine coal waste by physical separation, it is sufficiently unliberated in coal discards or waste rock for ready physical separation. This requires either further liberation followed by removal using separation (energy consuming and costly) or removal by reaction. Heap bioleaching, a technology predominantly used for the recovery of base metals from low grade metal sulphide-containing ores, provides a sustainable option for the accelerated reaction of the pyritic fraction within the coal discards, allowing its removal in solution under controlled conditions during the life of mine for the long-term prevention of ARD. Easily implementable, heap bioleaching may constitute an economically viable prevention alternative to traditional ARD treatment methods. Further, such accelerated sulphide removal by reaction is expected to produce an environmentally benign discard with value prospects. The desulphurization reactions are sustained by iron- and sulphur oxidising microorganisms. The iron oxidizers catalyse the regeneration of the leach agent Fe3+ from its Fe2+ form, and the sulphur-oxidising microorganisms produce sulphuric acid from elemental sulphur and sulphides. These maintain highly acidic conditions which support further Fe2+ to Fe3+ oxidation and ongoing oxidation and leaching of the pyrite. In this study, proof of concept experiments were performed in laboratory scale columns over 380 days, simulating coal discard heaps. Coal discards containing 10.4% by mass pyritic sulphur were used. Results obtained indicated more than 50% desulphurisation in 250 days with a terminal duration of ~600 days predicted. This confirms the potential of heap bioleaching as a viable strategy for the desulphurisation of high sulphur-containing coal discards during life of mine, with their potential re-purposing as saleable coal or risk-reduced disposal.

中文翻译：

---

使用加速堆浸法脱硫高硫煤废料

摘要 煤炭的开采和选矿产生了大量的废石、废煤和煤粉。这些废物可能会造成严重的环境危害。将它们的硫化矿物成分（主要是黄铁矿）暴露在水分和氧气中会导致废石堆、煤炭废弃堆和尾矿设施产生酸性径流或渗滤液，称为酸性岩排水 (ARD)。虽然硫化物可以通过物理分离从粉煤废料中去除，但它在煤废料或废石中充分释放，可以进行物理分离。这需要进一步释放，然后通过分离（消耗能量且成本高）或通过反应去除。堆生物浸出，一种主要用于从低品位含金属硫化物矿石中回收贱金属的技术，为废煤中黄铁矿部分的加速反应提供了一种可持续的选择，允许在矿山寿命期间在受控条件下将其在溶液中去除，以长期预防 ARD。易于实施，堆生物浸出可能构成传统 ARD 治疗方法的经济可行的预防替代方案。此外，这种通过反应加速的硫化物去除有望产生具有价值前景的环境友好型废弃物。脱硫反应由铁和硫氧化微生物维持。铁氧化剂催化浸出剂 Fe3+ 从其 Fe2+ 形式再生，硫氧化微生物从元素硫和硫化物产生硫酸。这些保持了高酸性条件，支持进一步的 Fe2+ 到 Fe3+ 氧化以及黄铁矿的持续氧化和浸出。在这项研究中，概念验证实验在实验室规模的柱子中进行了 380 多天，模拟了煤废弃堆。使用了含有 10.4% 黄铁矿硫的废煤。获得的结果表明，250 天内脱硫率超过 50%，预计最终持续时间约为 600 天。这证实了堆生物浸出作为在矿山生命周期内对高含硫煤废料进行脱硫的可行策略的潜力，并具有将其重新用作可销售煤或降低风险的处置的潜力。模拟煤炭废弃堆。使用了含有 10.4% 黄铁矿硫的废煤。获得的结果表明，250 天内脱硫率超过 50%，预计最终持续时间约为 600 天。这证实了堆生物浸出作为在矿山生命周期内对高含硫煤废料进行脱硫的可行策略的潜力，并有可能将其重新用作可销售煤或降低风险的处置。模拟煤炭废弃堆。使用了含有 10.4% 黄铁矿硫的废煤。获得的结果表明，250 天内脱硫率超过 50%，预计最终持续时间约为 600 天。这证实了堆生物浸出作为在矿山生命周期内对高含硫煤废料进行脱硫的可行策略的潜力，并具有将其重新用作可销售煤或降低风险的处置的潜力。