淮北煤田煤中汞的赋存状态

Study on Modes of Occurrence of Mercury in Coals from the Huaibei Coalfield

系统采集淮北煤田10、7、5、4和3煤层的29个煤样品,采用逐级化学提取方法研究了煤中汞的赋存状态,根据提取步骤和汞的特性,将煤中的汞分为水溶态、离子交换态、有机态、碳酸盐结合态、硅酸盐结合态和硫化物结合态,利用FlowInjectionMercurySystem(FIMS)分析了样品中总汞和不同形态中汞的含量.测试结果表明,与华北石炭-二叠纪煤、中国煤以及美国煤含量相比较,淮北煤田煤中汞的含量明显富集.逐级化学提取实验结果和煤中汞与硫、灰分的相关分析结果表明,岩浆的侵入对煤中汞的赋存状态有较大的影响,不受岩浆侵入影响的10、4和3煤层煤中的汞主要以有机态和硫化物结合态存在,受岩浆侵入影响的5和7煤层中的汞主要以硅酸盐结合态存在.

Sequential extraction tests using Flow Injection Mercury System （FIMS） were done on 29 coal samples collected from the number 3, 4, 5, 7, and 10 coal seams in the Huaibei coalfield. The average total Hg concentrations for the coal seams 3, 4, 5, 7, and 10 were 0. 13, 0. 18, 0. 54, 0. 34, and 0. 19 mg/kg respectively. The average value of Hg for all of the coal samples was 0. 26 mg/kg, which is higher than that of most Chinese and U. S. coals. Six modes of Hg occurrence were recognized, including water-leachable, ion-exchangeable, organic-bound, carbonate-bound, silicate-bound, and sulfide bound Hg ones. With rare exception, little Hg was found in water-soluble, ion-exchangeable or carbonate-bound forms. Sulfide-bound Hg and organic-bound Hg dominated seams 3, 4, and 10, whereas silicate-bound Hg dominated seams 5 and 7. The relatively high Hg values observed in seams 5 and 7, especially in parting samples, are attributed to Hg enrichment by magmatic intrusions.