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为研究生活锅炉燃煤释放微量元素对环境的影响,应用同步辐射X射线荧光(SR-XRF)测定了锅炉原煤、底灰、飞灰及其PM2.5中V、Cr、Mn、Co、Ni、Cu、Zn、As、Pb等元素含量,探讨了微量元素在煤炭燃烧过程中的转移特性和富集规律。还进行了As的K边X射线吸收近边谱(XANES)测量,研究As在煤炭燃烧排放过程中的价态变化特征。结果表明,V在飞灰中亏损,在底灰富集;Mn、Co在底灰中亏损;Cr、Ni、As、Cu、Pb、Zn等在飞灰和底灰中呈富集状态,As、Cu、Pb、Zn在PM2.5中高度富集。在煤中,As大部分以As5+存在,少部分以As3+存在,As5+占总砷的71%。经过高温燃烧,As富集在飞灰和细颗粒中。在底灰、飞灰和PM2.5中,As主要以As5+存在,相对含量分别为总As的84%、81%和87%。
In order to study the environmental impact of micro-elements released from coal combustion in domestic boilers, SR-XRF was used to determine the contents of V, Cr, Mn, Co and Ni in PM2.5 , Cu, Zn, As, Pb and other elements were discussed. The transfer characteristics and enrichment rules of trace elements in coal combustion process were discussed. A K-edge X-ray absorption near edge spectroscopy (XANES) measurement of As was also carried out to study the valence state changes of As during coal combustion. The results show that V is depleted in fly ash and enriched at the bottom ash; Mn and Co are depleted in the bottom ash; Cr, Ni, As, Cu, Pb, Zn etc. are enriched in fly ash and bottom ash, , Cu, Pb and Zn are highly enriched in PM2.5. In coal, most of As is present in As5 +, a small portion is present in As3 +, and As5 + is 71% of total arsenic. After high-temperature combustion, As is enriched in fly ash and fine particles. In the bottom ash, fly ash and PM2.5, As is mainly present in As5 +, with relative contents of 84%, 81% and 87%, respectively, of total As.