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:2003201215;:2003205206:(20277027);;(973)(2001CB610705):(19682),,,,.:100729629(2004)01200762051,2,1(1.,200092;2.,230022):,,.,.,,.:;;;/:TQ172;X701.2:ALeachingBehaviorsofHeavyMetalsinMSWIFlyAshandtheImmobilizationMechanismofCementYUANLing1,2,SHIHui2sheng1(1.StateKeyLaboratoryofConcreteMaterialsResearch,TongjiUniversity,Shanghai200092,China;2.DepartmentofMaterialsScienceandEngineering,AnhuiArchitectureIndustryCollege,Hefei230022,China)Abstract:MSWIflyashisaresidualthatcomesfromscrubberafterincinerationofmunicipalsolidwastes(MSWI),inwhichwaterleachableheavymetalsarecontained,soitisregardedashazardouswastesandmustbeundergoneasolidificationorstabilizationtreatmentbeforedisposal.InthisstudytheleachabilityofheavymetalsinMSWIflyashandcementsolidificationeffectwerestudied.ItisshownthatcementimmobilizationeffectofMSWIflyashisgoodandheavymetalsareimmobilizedwithincementhydrationproductsthrougheitherphysicalfixation,substitutionoradsorptionmecha2nisms.Keywords:incinerationofmunicipalsolidwastes(MSWI)flyash;heavymetal;leachingtoxicity;solidification/stabilization,,.,,.,,.,.,.7120043JOURNALOFBUILDINGMATERIALSVol.7,No.1Mar.,2004,,,[1]..,5%30%.,,.,/.,(),,..,,./,20,[2].,,.,,.11.1,360m2/kg;P52.5.1.2X2ray.[3]3050,.:1.002.00g250mL,10mL11()HNO3,,,1015min.5mLHNO3,,30min.,.,5mL,,100mL,.(ICP).20%(,),.:(GB5086.21997):5mm,100g2L,1L,10,NaOHHClpH5.86.3.,(11010)/min,40mm,8h,16h.,ICP.pH,,1pH(pH=212).22.11;2.2,,Zn,Pb,Cr,CdHg.771:1Table1ChemicalcompositionsofMSWIflyashandcementw/%SampleSiO2Fe2O3Al2O3TiO2CaOMgOSO3Cl-f2CaOILMSWIflyash24.54.017.420.6223.372.7212.0310.00.522.04Cement20.63.335.3764.201.532.190.50.21.852Table2HeavymetalscontentofMSWIflyashmg/kgZnPbCuCdCrNiFeHg32691515563.236.71157.070.621409035.781Fig.1Boilingandmeltingpointsofheavymetalsandtheircompounds(There2gionbetweentwobrokenlinesindi2catestheincineratingtemperaturerangeofShanghaiPudongYuqiaoMunicipalIncinerationPlant)Meltingpointofmetal;Boilingpointofmetal;Meltingpointofmetalchloride;Meltingpointofmetaloxide[4],,.,,.,.9001200C.1,,(Hg,PbCd);,HgO,PbO,CdOCuO;,,,.2.23.,Zn,Pb,Cd,Cr,,.3Table3HeavymetalleachingtestresultofMSWIflyashHeavymetalLeachingconcentrationofMWSIflyash/(mgL-1)HeavymetalscontentofMSWIflyash/(mgkg-1)Leachingtoxicitydiscriminatestandardofsolidwaste[5]/(mgL-1)Zn56.11326950Pb26.4715153.0Cu8.17563.250Cd1.6236.710.3Cr2.47157.01.5Hg0.0235.780.05(),3,.,,,877,,.,,.,,,;,,,,,.2.3pH4pH.4,pH,,pH10,.,.,.4pHTable4EffectofleachatepHvalueonheavymetalsleachingconcentrationmg/LHeavymetalpH=2pH=4pH=6pH=8pH=10pH=12Zn85.6275.3156.1147.8211.238.25Pb40.3732.7526.4715.255.264.21Cu13.3510.218.176.522.381.96Cd2.352.061.621.250.420.23Cr3.122.862.472.080.950.622.4,5.5,,[5].,,,..,.5Table5ChangeoftheleachabilityofheavymetalsinMSWIflyashcementsolidificationbodywithcuringtimemg/LHeavymetalCuringtime/d1372860Zn0.3770.3980.3150.0740.065Pb0.3210.1580.1640.1520.146Cu0.1050.0850.0730.0240.022Cd0.1070.0280.0250.0020.002Cr1.2840.7660.6610.5320.412/[6]:pH,OH-;C2S2H;.Yousuf[7],C2S2H,ZnC2S2HCaC2S2HCaCaZn.Pb,,Pb,.Cu,.Lin[8]CuO971:2/Fig.2Mechanismofcementsolidification/stabiliza2tionofheavymetals[9]C2S,CuOC2S,Cu2Ca2Si.Cr,C2S2H.CdCa(OH)2.2/[9]./.,.31.Zn,Pb,Cd,Cr,Cu,,.2.,.3.,,.:[1],.[J].,1999,14(3):23,24.[2]GougarMLD,ScheetzBZ,RoyDM.EttringiteandC2S2HPortlandcementphasesforwasteionimmobilization:Areview[J].WasterManagement,1996,16(4):2952303.[3].[M].,,.:,1992.[4],.[M].:,2000.[5].[M].:,1997.[6]GlasserFP.Chemistryandmicrostructureofsolidifiedwasteforms[A].ChemistryandMicrostructureofSolidifiedWasteForms[C].BocaRaton:LewisPublishers,1993.1231.[7]YousufM,MollahA.Aninfraredspectroscopicexaminationofcement2basedsolidification/stabilizationsystemsPortlandtypesVandIPwithzinc[J].EnvironSciHealth,1992,A27(6):150321519.[8]LinCF,LinTT,HuangTH.Leachingprocessesofthedicalciumandcopperoxidesolidification/stabilizationsystem[J].Toxico2logicalandEnvironmentalChemistry,1994,44(1):88290.[9]ConnerJR.Chemicalfixationandsolidificationofharzardouswastes[M].NewYork:vanNostrand2Reinhold,1990.2932298.087