不同浸取剂对垃圾焚烧飞灰浸出特性影响研究

研究了3种浸取液硝酸/氢氧化钠、冰醋酸/氢氧化钠、硝酸与硫酸混合溶液对垃圾焚烧飞灰浸出特性的影响.结果表明,①不同浸取剂对飞灰浸出液表现出不同的缓冲能力,浸取液缓冲能力大小顺序为：冰醋酸>硝酸与硫酸混合酸>硝酸;②在酸性较强时,醋酸浸取液对重金属Zn、Cd和Cr的溶解能力最强,其次为硝酸与硫酸的混合酸,而Pb的浸出浓度受浸取剂种类的影响不明显;③以醋酸浸取剂时,重金属Pb和Zn在液固比为40时出现最大浸出浓度,而Cd浸出浓度在液固比为20时出现最大值;硝酸与硫酸混合和硝酸浸取液的液固比增加时,重金属Pb、Zn、Cd和Cr浸出浓度逐渐减少.

Effect of Different Extractants on Leaching Characteristics of the Fly Ash from Municipal Solid Waste Incinerator

The effect of three extractants, which are HNO3/NaOH, CH3COOH/NaOH, and HNO3-H2SO4 , on leaching characteristics of the fly ash from municipal solid waste incinerator (MSWI) was investigated. The results showed that: (1) different extractants had different buffering capacities for the leaching solutions of the fly ash from MSWI, which are in the order of HAC > HNO3-H2SO4 > HNO3. (2) HAC showed better dissolvability to Zn, Cd, and Cr than HNO3-H2SO4, under more acidic condition, but the leaching concentration of Pb was not affected by extractant types obviously. (3) The leaching concentrations of Pb and Zn reached their maximal values at the ratio of liquid to solid of 40, while Cd leaching concentration did at the ratio of 20, and the leaching concentrations of Zn, Pb, Cd, and Cr decreased gradually with the increase of the ratios of liquid/solid when HNO3 and HNO3-H2SO4 extractants were used.