Physicochemical characteristics and environmental risk of ash/slag in typical sections of MSW incineration
The apparent,chemical,and leaching characteristics of five types of ash/slag samples(waste heat boiler ash/slag S1,semi-dry deacidification ash S2,bag dust removal ash S3,raw fly ash S4,and chelator stabilized fly ash S5)in typical sections of MSW incineration were studied,and the environmental risks of heavy metals in ash/slag samples were evaluated.The results showed that S1 exhibited significant differences in apparent characteristics compared to other samples,with a yellowing color,uneven particle size,and high Si and Al content,indicating a great potential for resource utilization.A higher content of soluble chloride salts and highly toxic heavy metals(Pb,Cd)were enriched in S3,which could be treated separately for dechlorination and detoxification.In terms of particle size distribution,there were two peaks in the range of 7-20μm and 40-120μm for S5,which had certain defects in its stabilization effect.The exchangeable and carbonate bound states of Cr(4.45%)in S1 and Pb(3.04%)and Cd(4.28%)in S3 were relatively high,indicating a high potential leaching environmental risk.Special attention should be paid to their harmless treatment and resource utilization,especially in acidic(such as acid rain or landfill leachate leaching)disposal or application scenarios.The potential environmental risk level of S1 containing heavy metals was much lower than the other four ash samples.Under the simulated landfill leachate leaching environment,the comprehensive environmental risk level of heavy metals in the five ash/slag leaching solutions was higher than that in the simulated acid rain leaching environment,and the leaching environmental risk level of Cd in S1,S3,S4,and S5 showed an"extremely strong"level.The research results could provide theoretical basis for the classification and utilization of ash/slag in typical MSW incineration sections,refined management,and scientific environmental risk assessment.
国家科技期刊平台
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