油泥热解渣对铅渣中As、Zn、Pb和Cd的同步稳定化

针对云南省个旧市泗水庄片区铅冶炼渣As、Zn、Pb和Cd等重金属污染的问题，利用油泥热解渣对其进行稳定化处理以降低这些重金属的浸出毒性。热解渣是一种含有大量纳米FeS、Fe_1-xS、CaS等的炭质复合材料，具有稳定化铅渣中重金属的潜能。研究表明，铅渣中的重金属As、Zn、Pb和Cd可高效、同步吸附在热解渣表面，降低铅渣中这些重金属的浸出毒性。当热解渣用量为4%、液固比为10:100时，铅渣中As、Zn、Pb和Cd的浸出浓度可从0.7202、3.5120、0.3800和0.0456 mg/L分别降低至0.0714、0.1668、0.0262和0.0038 mg/L，低于地表水环境质量标准（GB 3838—2002）中Ⅳ级限值。铅渣中As、Zn、Pb和Cd浸出浓度的降低是因为铅渣中的As与热解渣表面的Ca2+、Fe2+反应就地生成了稳定的砷酸钙和砷酸亚铁，铅渣中Zn2+、Pb2+和Cd2+与热解渣表面的S2-反应就地生成了稳定的ZnS、PbS和CdS，从而提高了铅渣中As、Zn、Pb和Cd的稳定性。 

Simultaneous Stabilization of As,Zn, Pb and Cd in Lead Slag by Pyrolysis Residue of Oily Sludge

To address the problem of heavy metal contamination of lead smelting slag such as As, Zn, Pb and Cd in the Sishuizhuang area of Gejiu City, Yunnan Province, oily sludge pyrolysis residue was used to stabilize them to reduce the leaching toxicity of these heavy metals. The pyrolysis residue is a carbonaceous composite containing a large amount of nano-FeS, Fe_1-xS, CaS, etc., which has the potential to stabilize the heavy metals in lead slag. It was shown that heavy metals As, Zn, Pb and Cd in lead slag could be efficiently and synchronously adsorbed on the surface of pyrolysis residue, reducing the leaching toxicity of these heavy metals in lead slag. When the weight ratio of pyrolysis residueis is 4% and liquid-solid ratio is 10:100, the leaching concentrations of As, Zn, Pb and Cd in the lead slag can be reduced from 0.7202, 3.5120, 0.3800 and 0.0456 mg/L to 0.0714, 0.1668, 0.0262 and 0.0038 mg/L, respectively, which are lower than the surface water environmental quality standards (GB 3838—2002 ) in the Ⅳ level limit value. The reduction of leaching concentration of As, Zn, Pb and Cd in lead slag is due to the reaction of As in lead slag with Ca2+ and Fe2+ on the surface of pyrolysis slag to produce stable calcium arsenate and ferrous arsenate in situ, and the reaction of Zn2+, Pb2+ and Cd2+ in lead slag with S2- on the surface of pyrolysis slag to produce stable ZnS, PbS and CdS in situ, which improves the stability of As, Zn, Pb and Cd in lead slag.