Experimental study on leaching behavior of trace elements in the residues of “three zones” from underground coal gasification
Abstract：Coal combustion ashes,gasification ashes,and pyrolysis chars were used to simulated the residues of "three zones" from underground coal gasification,which are oxidization zone,reduction zone and dry distillation zone.The distribution characteristics of mercury,arsenic,fluorine,chromium,lead five trace elements in the leaching solution was analyzed,and compared with that in raw coal,in order to investigate their potential threat to groundwater.The results indicate that total contents of the five trace elements in the leaching solution of raw coal and the residues of "three zones" follow the order of dry distillation zoneoxidization zonereduction zoneraw coal,within the scope of of national standard GB 20426—2006.The contents of Pb follow the order of dry distillation zoneraw coaloxidization zonereduction zone,they are very low and the average value of Pb is only 0.003 0 mg/L.The contents of As follow the order of oxidization zone reduction zonedry distillation zoneraw coal,and the residues in oxidization zone have the highest As leaching content of 0.1450 mg/L,almost 63 times of that in raw coal.The contents of F-follow an order of dry distillation zoneoxidization zonereduction zone raw coal,and 476 times higher than that of the other four heavy metals.The leaching of Hg and Cr are not detected.
Keywords：underground coal gasificationtrace elementsleaching behaviorresidue
Publication Date：2012-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 2092-2096 )