重庆垃圾焚烧飞灰中重金属浸出特征研究

Heavy Metals Leaching Characteristics in Municipal Solid Waste Incineration Flying Ash of Chongqing

研究了重庆垃圾焚烧飞灰四季的腐蚀性和浸出毒性,并以秋季的焚烧飞灰为代表研究了Pb,Zn,Ni,Cr,Cu,Cd,Mn等7种重金属在不同液固比、浸出时间和初始pH值下的浸出特性.结果表明:春夏两季飞灰的浸出液pH值在10.30左右,而秋冬两季的浸出液pH值在12.00左右,四季飞灰都不具腐蚀性;所研究的7种重金属都没有浸出毒性,秋冬两季的Pb,Cr,Cu浸出量较高,夏季的Mn,Ni,Cr浸出量较高,而重金属浸出总量秋冬两季高于春夏两季;重金属的浸出量通常随液固比的增加而增加.重金属的浸出量随浸出时间的增加也呈增大的趋势.重金属的浸出量随pH值的增大呈减小趋势,各重金属在pH=1时浸出量最大,表明在酸性环境下较易浸出.

This paper studied the leaching toxicity, causticity and leaching characteristics of seven heavy metals with different impact factors, such as solid-liquid ratio, leaching time and pH value in Chongqing municipal Solid Waste Incineration （MSWI） flying ash. The results showed that flying ash in the different seasons are not corrosive because the leaching solution pH of spring and summer is about 10.30, and that of autumn and winter is about 12.00. The seven heavy metals researched do not have leaching toxicity. The leached content of Pb, Cr, Cu in flying ash in autumn and winter is higher than in spring and summer while that of Mn, Ni, Cr is higher in Summer. But the total content of heavy metals in autumn and winter is higher than spring and summer. The leached content of heavy metals increases with an increasing ratio of liquids to solids and increasing time, while decreases with an increasing pH value. The leached content is the highest at pH = 1, which shows leaching of heavy metals is easier in acidic conditions.