机构地区：[1]安徽理工大学地球与环境学院,安徽淮南232001 [2]矿山地质灾害防治安徽省高校重点实验室,安徽淮南232001
出 处：《煤炭科学技术》2024年第5期191-208,共18页Coal Science and Technology
基 金：国家自然科学基金面上资助项目(41972173,42372189);矿山地质灾害防治安徽省高校重点实验室开放基金资助项目(2022-MGDP-05)。
摘 要：钪(Sc)具有较高熔点、较小密度,是最好的阻挡金属,广泛应用于照明、合金、陶瓷、催化剂等工业领域。在特定地质条件下,部分煤富集钪,可成为战略金属资源予以利用,因此,钪地球化学是煤地质学研究领域的热点问题之一。为阐明我国煤中钪的地球化学特征,在全面收集我国煤中钪测试数据的基础上,并结合安徽淮南煤、重庆南桐煤、四川宝鼎煤和云南勐托煤等实例,系统总结了我国煤中钪的含量水平、时空分布、赋存状态和富集成因,并初步评价了我国的煤系钪资源。结果表明:我国大多煤中钪含量正常,钪的平均含量为4.02 mg/kg,仅略高于世界硬煤。贵州、重庆、安徽、广西、内蒙古、山西、云南等局地煤中钪含量较高,最高达139 mg/kg。煤层顶、底板围岩及夹矸岩石较煤富集钪。我国富钪煤大多为二叠纪烟煤,晚侏罗–早白垩世煤中钪含量普遍较低。一般而言,高灰煤和腐泥煤因具较高的矿物质含量,常富集钪。钪为亲石元素,在煤中主要与矿物质结合,多赋存于高岭石等硅酸盐矿物和磷钇矿等自生矿物中,部分与有机质结合,与腐植质有关。我国煤中钪的主要富集成因类型包括:①基性源岩贡献型,钪为相容元素,基性岩中钪含量高于中酸性岩,因此,物源区基性源岩风化可导致部分煤中钪富集;②海陆过渡沉积环境贡献型,海水入侵导致泥炭沼泽的pH值增大,从而利于钪的迁移,此外,在泥炭沼泽的还原环境中,大量腐植酸生成,钪易与有机质结合而富集;③地下水淋滤贡献型,地下水淋滤围岩的含钪矿物导致煤层中钪局部富集;④热液贡献型,热液与围岩发生交代反应使钪迁移,改变煤的矿物质组成导致煤富集钪;⑤岩浆及变质贡献型,岩浆侵入导致煤阶提升,从而减少有机质结合态的钪,同时,伴随灰分的升高,煤中矿物结合态的钪相应增加;⑥同沉积火山灰贡献型,煤系Scandium(Sc),which has a high melting point and a low density,is widely used in lighting,alloys,ceramics,catalysts,and other industrial fields.Under a specific geological condition,Sc could be enriched in certain coal.As one of strategic metals hosted in coals,the geochemistry of Sc is a hot topic in coal geology.In order to clarify the geochemical characteristics of Sc in Chinese coals,based on a comprehensive collection of the data of Sc concentrations in Chinese coals and four cases of the Huainan coals of Anhui,the Nantong coals of Chongqing,the Baoding coals of Sichuan,and the Mengtuo coals of Yunnan,the content,temporal and spatial distribution,modes of occurrence,and enrichment mechanism of Sc in Chinese coals were discussed,and the Sc resources hosted in coal measures was assessed as well.Results indicated that the scandium in Chinese coals was at normal level with an average of 4.02 mg/kg,which was slightly higher than that of world hard coal.The concentrations of scandium in certain coals from Guizhou,Chongqing,Anhui,Guangxi,Inner Mongolia,Shanxi,and Yunnan were elevated,and with the maximum Sc concentration of 139 mg/kg.Regarding a coalbed,Sc was prefer-ably enriched in country rocks,e.g.,the roof,floor,and parting rocks,relative to coal benches.Most Sc-rich Chinese coals were bitumin-ous and with a coal-forming period of Permian,while the Late Jurassic-Early Cretaceous coals were of a low Sc content.Overall,due to a high mineral matter content in the high-ash and sapropelic coals,its Sc concentrations increased.As a lithophilic element,Sc in coals was dominantly hosted in minerals,especially silicate minerals,e.g.,kaolinite,and some authigenic minerals,e.g.,xenotime.Sc was also par-tially bounded to organic matter,especially the humic matter in low rank coals.The genetic types of Sc enrichment in Chinese coals in-cluded:①Mafic source rock type.As a compatible element,Sc was of a higher concentration in mafic rocks than that of intermediate and felsic ones.Correspondingly,the weathering of mafic sour
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