發(fā)布時間：2018-11-25 18:34

【摘要】：砷元素作為一種有毒有害的微量元素,其在煤燃燒過程中造成的污染和危害日益突出,因此對煤及其燃燒產(chǎn)物中砷元素的研究逐漸成為國內(nèi)外研究熱點之一。本文以內(nèi)蒙古錫林浩特勝利煤礦礦區(qū)為研究對象,通過掃描電鏡、EDS、XRD和逐級化學(xué)提取方法對煤及其燃燒產(chǎn)物中砷的賦存形態(tài)進行分析,通過煤燃燒實驗和粉煤灰淋溶試驗對不同條件下砷的析出特征進行研究。煤樣、粉煤灰和灰渣樣品中均富含Ca、S、AS、Fe等元素,煤中砷元素的礦物組成主要是與鐵、鈣的結(jié)合態(tài),而粉煤灰和灰渣中砷元素主要是與鈣的結(jié)合態(tài),鐵的結(jié)合態(tài)較少。煤燃燒溫度為450℃～1000℃時,5、6號煤層煤樣砷的釋放率分別由39.52%和21.88%升高至73.77%和65.89%,表明砷的釋放率隨著溫度的升高而增大。煤中砷主要富集于無機組分中,難于提取;燃煤產(chǎn)物粉煤灰中砷主要以碳酸鹽結(jié)合態(tài)(37.4%)和水溶態(tài)(21.2%)存在,灰渣中砷主要以碳酸鹽結(jié)合態(tài)(31.7%)和可交換態(tài)(22%)存在,易提取。粉煤灰淋溶過程中,淋溶液pH越低,淋出液砷含量越高,表明砷的析出與降水pH有關(guān),與正常降水相比,酸雨更有利于粉煤灰中砷元素的析出。粉煤灰的淋出液均為堿性,淋溶100 mL后,pH值均趨于平衡,受淋溶液pH值的影響較小。
[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，

本文編號：2357051