The rapidly solidified powder of AlFeCrZrVSi aluminum alloy was prepared using multistage atomization and consolidated by hotextrusion, the evolution of microstructure of the extruded materials during thermal exposure...The rapidly solidified powder of AlFeCrZrVSi aluminum alloy was prepared using multistage atomization and consolidated by hotextrusion, the evolution of microstructure of the extruded materials during thermal exposure was studied with optical microscope, Xray diffraction and transmission electron microscope(TEM). The results show that the majority of dispersions present in the asextruded alloy are metastable Al12(Fe, Cr, V)3Si, which has excellent thermaldynamical stability and coarsening resistance; the coarsening ratecontrolling process of the Al12(Fe, Cr, V)3Si phase is considered to be diffusion of Fe atom along grain boundaries instead of bulk diffusion of Fe atom.展开更多
Solidification/stabilization （S/S） is one of the most effective methods of dealing with heavy metal contaminated soils. The effects of cyclic wetting and drying on solidified/stabilized contaminated soils were inves...Solidification/stabilization （S/S） is one of the most effective methods of dealing with heavy metal contaminated soils. The effects of cyclic wetting and drying on solidified/stabilized contaminated soils were investigated. A series of test program, unconfined compressive strength （UCS） test, TCLP leaching test and scanning electron microscopy （SEM） test, were performed on lead and zinc contaminated soils solidified/stabilized by fly ash. Test results show that UCS and the leaching characteristics of heavy metal ions of S/S contaminated soils are significantly improved with the increase of fly ash content. UCS of S/S soils firstly increases with the increase of the times of drying and wetting cycles, after reaching the peak, it decreases with it. When the pollutant content is lower （1 000 mg/kg）, the TCLP concentration first slightly decreases under cyclic drying and wetting, then increases, but the change is minor. The TCLP concentration is higher under a high pollutant content of 5 000 mg/kg, and increases with the increase of the times of drying and wetting cycles. The results of scanning electron microscopy （SEM） test are consistent with UCS tests and TCLP leaching tests, which reveals the micro-mechanism of the variations of engineering properties of stabilized contaminated soils after drying and wetting cycles.展开更多
为研究环保材料对铅污染土固化/稳定化效果,以干旱半干旱地区重金属铅污染及固体废弃物资源化利用为研究背景,使用固体废弃物高炉矿渣协同水泥制备新型固化材料地质聚合物,探讨其固化重金属铅的宏观力学表现及微观机理变化。基于水泥基...为研究环保材料对铅污染土固化/稳定化效果,以干旱半干旱地区重金属铅污染及固体废弃物资源化利用为研究背景,使用固体废弃物高炉矿渣协同水泥制备新型固化材料地质聚合物,探讨其固化重金属铅的宏观力学表现及微观机理变化。基于水泥基固化重金属铅污染土,探究不同比例下地聚物-水泥的强度表现及毒性浸出表现,对性能突出组进行微观试验表征。试验结果表明:80%的矿渣地聚物协同水泥相比水泥基及其他分组拥有更好的固化/稳定化重金属铅的表现,污染程度③下抗压强度及毒性浸出结果显著优于其他分组;X射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscope,SEM)、核磁共振(nuclear magnetic resonance,NMR)等试验显示80%矿渣地聚物内部结构完整且连结密实,水泥固化体内部变化剧烈,水化反应受到重金属抑制,整体结构松散,存在密度低且不连续。展开更多
文摘The rapidly solidified powder of AlFeCrZrVSi aluminum alloy was prepared using multistage atomization and consolidated by hotextrusion, the evolution of microstructure of the extruded materials during thermal exposure was studied with optical microscope, Xray diffraction and transmission electron microscope(TEM). The results show that the majority of dispersions present in the asextruded alloy are metastable Al12(Fe, Cr, V)3Si, which has excellent thermaldynamical stability and coarsening resistance; the coarsening ratecontrolling process of the Al12(Fe, Cr, V)3Si phase is considered to be diffusion of Fe atom along grain boundaries instead of bulk diffusion of Fe atom.
基金Foundation item： Projects（41172273, 40802079, 51108288） supported by the National Natural Science Foundation of China Project（KLE-TJGE-B1106） supported by the Opening Fund of Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education （Tongji University）, China
文摘Solidification/stabilization （S/S） is one of the most effective methods of dealing with heavy metal contaminated soils. The effects of cyclic wetting and drying on solidified/stabilized contaminated soils were investigated. A series of test program, unconfined compressive strength （UCS） test, TCLP leaching test and scanning electron microscopy （SEM） test, were performed on lead and zinc contaminated soils solidified/stabilized by fly ash. Test results show that UCS and the leaching characteristics of heavy metal ions of S/S contaminated soils are significantly improved with the increase of fly ash content. UCS of S/S soils firstly increases with the increase of the times of drying and wetting cycles, after reaching the peak, it decreases with it. When the pollutant content is lower （1 000 mg/kg）, the TCLP concentration first slightly decreases under cyclic drying and wetting, then increases, but the change is minor. The TCLP concentration is higher under a high pollutant content of 5 000 mg/kg, and increases with the increase of the times of drying and wetting cycles. The results of scanning electron microscopy （SEM） test are consistent with UCS tests and TCLP leaching tests, which reveals the micro-mechanism of the variations of engineering properties of stabilized contaminated soils after drying and wetting cycles.
文摘为研究环保材料对铅污染土固化/稳定化效果,以干旱半干旱地区重金属铅污染及固体废弃物资源化利用为研究背景,使用固体废弃物高炉矿渣协同水泥制备新型固化材料地质聚合物,探讨其固化重金属铅的宏观力学表现及微观机理变化。基于水泥基固化重金属铅污染土,探究不同比例下地聚物-水泥的强度表现及毒性浸出表现,对性能突出组进行微观试验表征。试验结果表明:80%的矿渣地聚物协同水泥相比水泥基及其他分组拥有更好的固化/稳定化重金属铅的表现,污染程度③下抗压强度及毒性浸出结果显著优于其他分组;X射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscope,SEM)、核磁共振(nuclear magnetic resonance,NMR)等试验显示80%矿渣地聚物内部结构完整且连结密实,水泥固化体内部变化剧烈,水化反应受到重金属抑制,整体结构松散,存在密度低且不连续。
