美国印地安那南部积贮煤泥的岩石学描述与氧化作用研究(英文)

PETROGRAPHIC DESCRIPTION AND OXIDATION RESEARCH OF IMPOUNDED COAL FINES IN SOUTHERN INDIANA,USA

对印地安那南部Lynnville煤泥积贮地的样品进行了详细的煤岩学研究，并就煤泥的自然氧化作用进行探讨。与原煤比较，煤泥的可见矿物体积分数增加了4～5倍，由5％改变为24％，其中黄铁矿由1％变为5％。煤泥除了黄铁矿。方解石、粘土、石英等煤系煤层的原生矿物，还含有地表土壤混入物。煤泥积贮他的入口处，沉积物自然形成高出潜水面的突起，黄铁矿在此大量富集，高粘土含量的细粒成分在煤泥地的末端富集，输入带（入口150m范围内）煤泥相应具有高硫、高灰特征。作为氧化产物，少量的褐铁矿和石膏分别在镜下和通过X射线行射分析被发现。黄铁矿比有机显微组分更易氧化并经历揭铁矿化到铁质胶体出溶变化过程。石膏主要形成于煤泥输入带。相对较强的氧化作用发生在输入带的推断得到了水化学分析结果的进一步验证。尽管如此，高潜水面及滞留水有效地限制了煤泥地内氧化作用的进行。根据煤泥入注时的自然分选效应，避开输入带，可提高煤泥回收利用率。研究成果为煤炭洗选废弃物（煤泥）的回收利用与排放环境的评价监测提供了新的方法和依据。

Coal Petrographic studies were carried out on sarnples from the Lynnville slurry pondin Southern Indiana. The extent of oxidation of coal fines was also investigated. The impounded coal fines have four to five times the mineral content of the source coals. The voltime fractionof total mineral content trpically increases from 5 % to 24 % while the volum fraction of pyritecontent increases from 1 % to 5%. The maor prirnary minerals in the coal fines are pyrites,quartz, clays and calcite. At the inlet of the study pond there is a high concentration of pyritesand the sediments form a natural heave above the groundwater. The higher clay contents wereevident in the finest fractions at the distal end of the pond. Correspondingly, the highest sulfurand ash values occurred in the inlet zone (within 150 m from the inlet of the pond). Limoniteis only rarely observed at microscopic scale and minor amounts of gypsum were identified by Xray diffraction analysis. There are some evidence of leaching oxidation of pyrite to limonite toresolvable ferric colloid. Grosurn was evident at the pond inlet zone and decreased progressivelydown the pond. The data of water chemistry presented here support the hmpthesis that relatively intense leaching oxidatdri is occurring in the inlet zone of the ponds. Overall however,oxidation is proceeding at a very slow rate within the pond where oxidation was effeCtively limited by high groundwater table and backwater. Efficiency of coal fine recovery can be increaedwhen the inlet zone is avoided.