我国煤中砷的含量赋存特征及对环境的影响

Features of As content,occurrence in coal and its affect on environment in China

在检测了 15 6个煤样中砷含量的基础上 ,收集了近 2 0 0 0个煤样的资料 ,分析了我国煤中砷元素的含量和赋存特征及砷富集的地质因素。结果表明 ,我国多数煤中砷含量处于 0 8× 10 -6～ 2 0×10 -6,算术平均值为 4× 10 -6;砷的赋存方式主要为 :a 类质同象置换硫赋存于黄铁矿中 ;b 低变质煤可赋存于有机质中 ;c 以粘土矿物和稀有的含砷矿物为载体。煤中砷富集的地质因素 ,一是后期热液带入煤层 ;二是由陆源物质带入泥炭沼泽 ;三是同沉积时期海水的影响。燃用富砷煤是引发环境污染的基本原因 ,但是燃煤方式也是重要因素。多数煤中砷含量并不高 ,控制和预防砷的危害还是可以做到的。

Based on the measurement of As content in 156 coal samples from different coal areas and the all sided and systematic collections of 2000 coal samples from the pubished papers,this article analyses the As content and occurrence in coal and the geological factors of As accumulation.Most of the As contents of coals in China are between 0.8×10 -6 and 20×10 -6 ,and the arithmetic mean is 4×10 -6 .The types of As occurrence in coal can be divided to three types:a.isomorphic substituting for S in pyrite in coal;b.cohering with organic matter in low metamorphic coal;c.existing with the carriers,clay minerals or the rare minerals consisting of As.It is not sure that As exists in high metamorphic coal by cohering with organic matter.The geological factors of As accumulation are the followings:①being carried into coal beds by hydrothermal at the latter stages;②being carried into peat marshes by terrigenous sediment;③accumulating with sea water at the depositional stage.Although As is one of the most noxious elements in coal and burning high As coal is the general reason for environmental pollution,the types of burning coal are important.As content in most of coal is not so high that controlling of and preventing from As are not very difficult.