高温高压密闭消解-ICP-MS测定垃圾焚烧残渣中重金属及稀土元素

采用高温高压密闭消解-电感耦合等离子体质谱(ICP-MS)测定了垃圾焚烧残渣中的Cr, Co, Ni, Cu, Zn, Zr, Cd, Ba和Pb共9种重金属元素及Sc, Y, La, Ce, Pr, Nd等16项稀土元素的含量。实验确定密闭消解罐中，以HF-HNO₃-HCl(1∶2∶1)三元混酸体系于185℃烘箱中12 h可完全消解垃圾焚烧残渣样品，同时对ICP-MS测试工作条件(包括雾室温度、雾化气流速、辅助气流速、冷却气体流速、采样深度等)进行了优化。采用Rh为内标元素进行信号漂移校正和基体补偿，得到25种分析元素标准曲线的线性相关系数(r)大于0.999 9,方法检出限在0.001～1.01 ng·g^-1,样品分析测试的相对标准偏差(RSD)小于4.5%(n=3)。测试结果表明本次分析的垃圾焚烧残渣样品中Cr, Cu, Zn, Zr, Cd, Ba和Pb元素含量偏高，其中Pb含量高达(1 459±8) mg·kg^-1,稀土元素平均总量为(199±2) mg·kg^-1,整体呈下降趋势，并显示相...

Determination of Heavy Metals and Rare Earth Elements in Bottom Ash of Waste Incineration by ICP-MS With High-Pressure Closed Digestion Method

In this work, nine heavy metals (Cr, Co, Ni, Cu, Zn, Zr, Cd, Ba and Pb) and sixteen rare earth elements in waste incineration were determined by ICP-MS combined with a high-pressure closed digestion method. The samples were completely decomposed by a mixture of acid of HF-HNO₃-HCl (1∶2∶1) at 185 ℃ in high-pressure sealed bombs and a digestion time of 12 h. The operating conditions for ICP-MS (such as temperature of spray chamber, nebulizer gas flow rate, auxiliary gas flow rate, cooler gas flow rate and sampling depth) were also optimized. Here, with Rh as the standard internal element, the obtained linear calibration plots of the studied 25 elements showed relative coefficients (r) were higher than 0.999 9, and the corresponding detection limits were within 0.001～1.01 ng·g-1. This proposed method’sdetermination relative standard deviations (RSDs) for waste incineration samples were less than 4.5% (n=3). Results showed that heavy metals of Cr, Cu, Zn, Zr, Cd, Ba and Pb were relatively high in the studied waste incineration samples, with Pb concentrations as high as (1 459±8) mg·kg-1. While the average total REEs was (199±2) mg·kg-1 with a decreasing trend and enrichment of light REEs. The successful application of this high-pressure closed digestion ICP-MS method to heavy metals and REEs quantification in waste incineration samples is of valuable guidance in the subsequent waste disposal, and future metal recycling.