两种垃圾焚烧炉灰渣的重金属成分与放射性检测

Analysis of heavy metals and radioactivity of slag and fly ash between two different MSW incinerators

对8种重金属As、Hg、Mn、Cr、Cu、Cd、Co、Ni和Pb在两种垃圾焚烧炉灰渣中的浓度分布,浸出毒性及放射性进行检测。样品(炉渣和飞灰)分别取自北京(循环流化床焚烧炉CFBI)和深圳(炉排焚烧炉)两台不同燃烧方式的垃圾焚烧炉。研究表明,CFBI炉渣及飞灰中的重金属As、Mn、Cu、Cd、Co含量在炉渣中含量最低,中灰次之,飞灰中含量最高。重金属Hg在炉渣和飞灰中的含量相当,在中灰中的含量最低;Cr和Ni在炉渣中的含量也偏高,在中灰和飞灰中的含量相当;Pb含量依中灰、炉渣和飞灰的顺序逐渐升高。浸出毒性检测结果显示,循环流化床垃圾焚烧后炉渣及飞灰中的重金属浸出毒性远低于国家标准1～2个量级,重金属总体排放量较低。炉排炉垃圾焚烧的炉渣及飞灰中的重金属含量却高很多,尤其是Cr、Pb、Cd和Cu。放射性检测结果表明,两种焚烧所产生的灰渣放射性均低于国家标准。在排放时无需作任何放射性方面的处理。最后,对焚烧灰渣的稳定化技术进行了讨论。

This paper introduces the authors' analysis on eight targeted heavy metals (As, Hg, Mn, Cr, Cu, Cd, Co, Ni, Pb) as to their distribution and concentration in the residue and fly ash from the two different incinerators by testing their ash sampling from the circulating fluidized bed incinerators in Beijing, Shenzhen, and the other places respectively. Our analysis shows that the concentration of As, Mn, Cu, Cd and Co in the above samples keeps increasing as in the following order: fly ash > middle ash > slag. As to Pb, the order comes in the middle from ash > fly ash > slag, with Hg being of equivalent concentration in slag and fly ash and lowest in middle ash, and Cr and Ni the equivalent concentration in middle ash and fly ash. Heavy metal leaching tests also help to reveal that the leaching concentration of heavy metals from CFBI was below the national standard even by one or two order. However, the concentration of heavy meals from grate incinerator was some more above the standard, especially for Cr, Pb, Cd, Cu. Results of radioactivity tests indicate that the radioactivity of both samples from two incinerators were below the national standard, hence leaving the necessity for any particular radioactivity treatment when discharged, though further discussion remains necessary as to the stabilization techniques for incineration residues.