垃圾焚烧飞灰中Pb及特征药剂稳定化处理

筛选几种重金属药剂用于稳定垃圾焚烧飞灰，以重金属Pb为处理目标，通过单一或复配形式研究药剂的稳定效果并采用红外光谱（FT-IR）和X射线衍射（XRD）分析重金属稳定机理.结果表明，有机药剂稳定后Pb的螯合率高于无机药剂，投加质量分数为2%二乙基DTC能使Pb的浸出满足危险废物填埋污染控制标准（GB 18598-2019）要求，然而5%的硫化钠和磷酸二氢钠稳定后Pb的浸出浓度仍不达标；药剂处理后，Pb的部分不稳定态被转化为稳定态，且相比于无机药剂，有机药剂稳定后Pb的残渣态占比更高，抗酸碱能力更强；无机药剂处理后Pb的浸出性与养护时间成负相关，而有机药剂则由于特征官能团的氧化等因素而成正相关.成本核算结果表明，0.9%二乙基DTC和3%磷酸二氢钠复合药剂稳定飞灰在满足GB 18598-2019要求的基础上，成本相比于单一二乙基DTC处理降低26.72%.复合药剂处理后，飞灰中出现了N、S、P的特征吸收峰，重金属主要以螯合、沉淀作用稳定，同时整个体系的矿物组成并未发生改变，但结晶相的吸收峰强度明显减弱.

Stabilization of Pb and characteristic agents in municipal solid waste incineration fly ash

Several agents were selected for the stabilization of Pb in municipal solid waste incineration (MSWI) fly ash, wherein, the stabilization effects of single and compound agents were studied. Furthermore, the stabilization mechanism was investigated via infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The chelation rate of Pb with organic chelating agents (OCA) addition was higher than that of the inorganic agents (IA), and the Pb leaching concentration could meet the requirements of Hazardous Waste Landfill Pollution Control Standard (GB 18598-2019) with the addition of 2% sodium diethyldithiocarbamate (SDD). For IA, both 5% dosages of sodium sulfide and sodium dihydrogen phosphate could not reach the standard effect. After the stabilization treatment, the proportion of residual state increased, which was more prominent for OCA system, suggesting a better stability against acid and alkali; Leaching concentration of Pb with IA addition was negatively correlated over time, while the OCA addition was opposite due to the oxidation of characteristic functional groups. Cost analysis showed that a compound agent of 0.9% SDD and 3% sodium dihydrogen phosphate could reduce the cost by 26.72% compared with single SDD agent. The characteristic absorption peaks of N, S and P were visible after treatment of the compound agent, and the heavy metals were mainly stabilized via chelation and precipitation. Meanwhile, the mineral composition was no change, but the absorption peak intensity of the crystalline phase weakened.