利用磷酸亚铁铵对5倍铅（GB 15618-1995三级标准）污染土壤进行固化，并通过TCLP和Tessier连续提取法对固化效果进行分析。结果表明，磷酸亚铁铵的加入使可交换态和碳酸盐结合态铅显著减少，降低了重金属Pb的有效性，可有效固化土壤中的重金属Pb。磷酸亚铁铵质量分数为1.5%时能达到固化要求，且加入的固化剂量越大，稳定效率越高。利用XRD和SEM对土壤进行结构表征，结果表明，经固化处理后形成的磷酸铅盐（PbH₂PO₄、Pb₃（PO₄）₂）、类磷氯铅矿（Pb-PO₄-Cl/OH）及混合重金属沉淀物（Fe-PO₄-Pb-OH）结构稳定，使得重金属离子难以浸出。

Ferrous ammonium phosphate is used to solidify the five times lead contaminated soil (content of lead is 2 500 mg/kg,five times the allowance regulated by Grade Ⅲ Standard in GB 15618-1995),and the solidification effect is analyzed by TCLP and Tessier sequential extraction method.The results show that the addition of ferrous ammonium phosphate can significantly reduce the content of exchangeable lead and carbonate-bound lead in soil,therefore the effectiveness of heavy metal lead is decreased,lead in the contaminated soil can be effectively solidified.When the adding amount of ferrous ammonium phosphate is 1.5%,the solidification requirement can be achieved.The greater the adding amount of curing agent,the higher the stability efficiency.The structure of soil is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM),which reveals the mechanism of solidification.XRD and SEM analysis results proves that lead phosphate (PbH₂PO₄,Pb₃(PO₄)₂),pyromorphite (Pb-PO₄-Cl/OH) and mixed heavy metal precipitate (Fe-PO₄-Pb-OH) formed in solidification all have stable structures,in which heavy metal lead is difficult to leach out.

杜小称(1992-),女,在读硕士生,主要从事肥料与土壤重金属污染修复研究,1921637355@qq.com