【摘要】 探讨了液固比、初始pH值及浸出时间对飞灰中重金属Pb、Cr、Cd、Ni、Cu、Mn、Hg、As的浸出影响.结果表明:各重金属的浸出量都随着液固比增加而增加,其中Ni、Cu、Mn、Cd的浸出量在液固比大于25后变化较平缓,As在液固比大于60后浸出量有所降低;重金属在浸取液的pH≤1.95时的浸出浓度远远大于其在浸取液的pH≥6.13时的浸出浓度;随着浸出时间的增加,Hg的浸出浓度先下降后上升,Cr的是先上升,30h后变化不大;Cd、Cu、Pb、Ni、Mn浸出时间在2h-6h后浸出浓度迅速减小,As则快速增加,而后都变化不大;在液固比、初始pH值及浸出时间三个影响因素中,pH值对重金属的浸出影响较大,重金属在酸性环境下较易浸出,但Pb在碱性情况下也易于浸出.更多还原

【Abstract】 This paper describes TCLP experiment has been performed to study the relationships between liquid-to-solid ratio(L/S),initial pH value, extraction time and leaching characteristics of heavy metals (Hg, As, Pb, Cr, Cd, Ni, Cu, Mn) in fly ash from municipal solid waste incinerator. The results suggest that the leaching weight of heavy metals increases with the rise of L/S, in which the leaching weight of Ni, Cu, Mn, Cd changes slightly when L/S exceeds 25, leaching weight of As changes hollow when L/S exceeds 60; The leaching concentration of heavy metals at initial pH≤1.95 is larger greatly than that at initial pH≥6.13; With the increase of extraction time, the leaching concentration of Hg reduces first, and then increases, the leaching concentration of Cd, Cu, Pb, Ni, Mn is decreases or As is increases in then 2h-6h; Among the three factors which are L/S, initial pH and extraction time, the effect of initial pH on heavy metals leaching is the largest. Heavy metals leaching from fly ash is more easily in acidic liquor than in basic liquor, the leaching concentration of lead is increased at pH≥12 being likely built in complex of Pb2+ and OH- ions.更多还原