Research On Leaching Properties And Stabilization Of Solid Wastes Incineration Fly Ash’s Heavv Metal

With the development of our national’s economy, the amount of municipal refuse isincreasing. Incineration is a increasingly effective method of garbage, But the burning processof fly ash contains a lot of heavy metal pollutants such as this will bring serious andsecondary pollution problems.The thesis studies pollution properties of six heavy metals Cu,Pb,Zn Cd, Cr, Ni in Tai’an MSW fly ash, which include distribution, leachingtoxicity andeffect factors.The studies design separate and combined experiment,that Analysis the effect ofheavy metal’s chemical stability in fly ash.Through the study, a series of valuable results are obtained as follow:（1）In Tai’an’s WSW incineration fly ash,the Pb、Cd’s leaching toxicity exceed thestandard,it Show that the fly ash is hazardous solid waste,we should Adopt certain methods tostabilize or solidification the heavy metal, reduce the leaching toxicity,then let it enter thehazardous waste landfill.（2）The leaching properties are influenced by pH value, liquid/solid ratio, leaching time.Generally, with the increasing of acidity, the leaching concentration of heavy metals increases;With the increase of leaching time, leaching concentration of heavy metals in fly ash areincreasing; With the increasing of liquid-solid ratio, the leaching content of Pb,Zn,Cr, Cd,Nishow ascending trend, While the Cu’s leaching rule is not clear.（3）The stabilization effect of Pb in different chemical stability agent is EDTA-2Na>NaH₂PO₄>Na₂S;the Cd’s stabilization effect is EDTA-2Na> Na₂S> NaH₂PO₄.With theincrease of agent’s addition,the learching concentration of pb and Cd all shows the trend ofdecreasing.（4）The stabilization effect of Pb and Cd is best,when the dosing radio is0.4%and there reagent’s adding proportion is1:1:1. But considering the cost and the two processingproblems, Compared comprehensively,when1:1:4（Na₂S:EDTA-2Na:NaH₂PO₄） are mostideal.