抚顺西露天矿油页岩干馏废渣的浸淋特性分析

油页岩属于非常规油气资源，在低温干馏过程中会产生大量干馏废渣，长期堆积可能会对地下水体造成污染。以抚顺西露天矿回填油页岩干馏废渣为研究对象，在模拟抚顺降水条件下，探究了油页岩干馏废渣浸溶与淋溶过程中pH、电导率、SO₄2-、NO₃-的溶出特性。结果表明:在酸性条件下，废渣中的Ni和Fe溶出浓度超过GB/T 14848—2017《地下水质量标准》Ⅲ类饮用标准，会对周围地下水环境产生一定影响。因油页岩干馏废渣中有大量的碱性氧化物、酸性氧化物以及有机质，其有较强的pH缓冲能力，但在浸溶5 d后，pH急剧下降至5.5，可能是废渣中的有机物发酵分解产生小分子酸。此外，油页岩干馏废渣中NO₃-的溶出规律存在明显特异性，在浸溶时，在酸性和中性条件下，NO₃-溶出浓度随着时间延长逐渐降低；而在淋溶时，NO₃-浓度逐渐提高至600 mg/L，并产生了大量的NO₂-。这可能是因为浸溶为缺氧/厌氧条件，油页岩干馏废渣中的反硝化菌等微生物可能在缺氧环境下将NO₃-还原。而淋溶为微氧/好氧条件，在氨化细菌、亚硝酸盐细菌和硝酸盐细菌等作用下，将有机氮逐渐氧化为NO₂-和NO₃-，导致NO₂-和NO₃-的大量累积。因此，可通过控制油页岩干馏废渣的氧化还原环境来减少有害物质的溶出。

LEACHING AND DISSOLVING CHARACTERISTICS OF OIL SHALE RETORTING SOLID WASTE FROM FUSHUN WEST OPEN PIT

Oil shale is a kind of unconventional oil and gas resource. Nevertheless, the solid waste produced in oil shale retorting caused groundwater pollution when accumulated for a long term. In this experiment, backfill (oil shale retorting solid waste) from Fushun West Open-pit was taken as the research object, under the simulated Fushun precipitation condition, to explore the characteristics of pH, conductivity, SO₄2-, NO₃- in the process of leaching oil shale retort waste residue. The results showed that under acidic condition, the leaching concentration of Ni and Fe in the waste residue exceeded the class Ⅲ in drinking standard specified in the Groundwater Quality Standard (GB/T 14848-2017), which would have a certain impact on the surrounding environment. Moreover, due to plenty of basic oxides, acid oxides and organic matters, oil shale retorting waste residue had strong pH buffer capacity. However, after 5 days of leaching, the pH value dropped sharply to 5.5, which probably caused by the fermentation and decomposition of organic matters in the waste residue to produce small molecular acids. In addition, the dissolution regulation of NO₃- had obvious specificity. During leaching process, with the extension of time, the concentration of NO₃- gradually decreased under acidic and neutral conditions; while in leaching process, the concentration of NO₃- gradually increased to 600 mg/L, and high concentration of NO₂- appeared. Due to the anoxic/anaerobic condition of leaching, denitrifying bacteria and other microorganisms in oil shale retorting waste residue might reduce NO₃-. Under the action of ammoniating bacteria, nitrite bacteria and nitrate bacteria, organic nitrogen could be gradually oxidized to NH₄+, NO₂- and NO₃-, which led to the accumulation of NO₂- and NO₃-. Therefore, the dissolution of harmful substances could be reduced by controlling the redox environment of oil shale retorting waste residue.