煤及燃煤产物中砷的赋存形态和析出特征研究
发布时间：2018-11-25 18:34
【摘要】：砷元素作为一种有毒有害的微量元素,其在煤燃烧过程中造成的污染和危害日益突出,因此对煤及其燃烧产物中砷元素的研究逐渐成为国内外研究热点之一。本文以内蒙古锡林浩特胜利煤矿矿区为研究对象,通过扫描电镜、EDS、XRD和逐级化学提取方法对煤及其燃烧产物中砷的赋存形态进行分析,通过煤燃烧实验和粉煤灰淋溶试验对不同条件下砷的析出特征进行研究。煤样、粉煤灰和灰渣样品中均富含Ca、S、AS、Fe等元素,煤中砷元素的矿物组成主要是与铁、钙的结合态,而粉煤灰和灰渣中砷元素主要是与钙的结合态,铁的结合态较少。煤燃烧温度为450℃～1000℃时,5、6号煤层煤样砷的释放率分别由39.52%和21.88%升高至73.77%和65.89%,表明砷的释放率随着温度的升高而增大。煤中砷主要富集于无机组分中,难于提取;燃煤产物粉煤灰中砷主要以碳酸盐结合态(37.4%)和水溶态(21.2%)存在,灰渣中砷主要以碳酸盐结合态(31.7%)和可交换态(22%)存在,易提取。粉煤灰淋溶过程中,淋溶液pH越低,淋出液砷含量越高,表明砷的析出与降水pH有关,与正常降水相比,酸雨更有利于粉煤灰中砷元素的析出。粉煤灰的淋出液均为碱性,淋溶100 mL后,pH值均趋于平衡,受淋溶液pH值的影响较小。
[Abstract]:Arsenic, as a poisonous and harmful trace element, has caused more and more serious pollution and harm in the process of coal combustion. Therefore, the research on arsenic in coal and its combustion products has gradually become one of the research hotspots at home and abroad. In this paper, the occurrence forms of arsenic in coal and its combustion products were analyzed by scanning electron microscope, EDS,XRD and stepwise chemical extraction method, taking Shengli Coal Mine in Xilinhaote, Inner Mongolia, as the research object. The characteristics of arsenic release under different conditions were studied by coal combustion test and fly ash leaching test. The samples of coal, fly ash and ash are rich in Ca,S,AS,Fe and so on. The mineral composition of arsenic in coal is mainly bound with iron and calcium, while the arsenic in fly ash and ash is mainly bound to calcium, but the binding state of iron is less. When the combustion temperature of coal is 450 鈩，
本文编号：2357051
[Abstract]:Arsenic, as a poisonous and harmful trace element, has caused more and more serious pollution and harm in the process of coal combustion. Therefore, the research on arsenic in coal and its combustion products has gradually become one of the research hotspots at home and abroad. In this paper, the occurrence forms of arsenic in coal and its combustion products were analyzed by scanning electron microscope, EDS,XRD and stepwise chemical extraction method, taking Shengli Coal Mine in Xilinhaote, Inner Mongolia, as the research object. The characteristics of arsenic release under different conditions were studied by coal combustion test and fly ash leaching test. The samples of coal, fly ash and ash are rich in Ca,S,AS,Fe and so on. The mineral composition of arsenic in coal is mainly bound with iron and calcium, while the arsenic in fly ash and ash is mainly bound to calcium, but the binding state of iron is less. When the combustion temperature of coal is 450 鈩，
本文编号：2357051
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