辽宁省主要煤田含煤岩系放射性特征分析

通过对煤田钻孔天然伽玛测井资料的二次解译，发现辽宁省内部分煤田含煤岩系存在放射性异常.筛查钻孔3437个，发现异常孔841个，其中与煤层相关的异常钻孔49个，异常值为50~123γ，个别钻孔异常峰值高达260 γ.采集康平、蒲河等5处煤矿原煤作为分析对象，对5处煤矿原煤样品和燃烧后的煤灰进行分析，确定²³⁸U、²³²Th、²²⁶Ra、⁴⁰K、²¹⁰Pb、²¹⁰Po在燃烧后迁移的比例及其影响因素.²³⁸U、²³²Th、²²⁶Ra、⁴⁰K、²¹⁰Pb元素在煤/灰活度比与煤燃烧后灰分比对比结果显示两者相近，表明元素在燃烧过程中未发生挥发及化学反应，元素含量几乎全部富集于灰分中；而²¹⁰Po元素煤/灰活度比与煤燃烧后灰分比相差较大，认为在煤的燃烧过程中Po易以气态形式迁移到空气中.因此应重视与煤炭开采利用直接相关含煤岩系的放射性异常，避免对环境产生放射性污染.

ANALYSIS ON THE RADIOACTIVE CHARACTERISTICS OF COAL-BEARING SERIES FROM MAJOR COALFIELDS IN LIAONING PROVINCE

The radioactive anomalies of coal-bearing series from some coalfields in Liaoning Province are found through a second interpretation of natural gamma-ray logging data of boreholes. Among the 3437 screened boreholes, 841 are discovered with anomalies, including 49 related to coal seams with abnormal values of 50-123 γ and individual peak value up to 260γ. The raw coal and ash samples collected from five coal mines are analyzed to determine the post-combustion migration ratios of ²³⁸U, ²³²Th, ²²⁶Ra, ⁴⁰K, ²¹⁰Pb and ²¹⁰Po and their influencing factors. The results show that the coal/ash activity ratios and ash rates of the former five elements are similar, indicating no volatilization or chemical reaction occurred during the combustion process, and almost all the element contents are concentrated in ash;while those of the element ²¹⁰Po is quite different for it is easily transported into air in the form of gas in coal burning. Therefore, it is necessary to pay attention to the radioactive anomalies of coal-bearing formations directly related to coal mining and utilization to avoid their pollution on environment.