Keulen A, van Zomeren A, Dijkstra J J
Eindhoven University of Technology, Department of the Built Environment, Eindhoven, The Netherlands; Mineralz (part of Renewi), Eindhoven, The Netherlands.
TNO-Bio-energy, Petten, The Netherlands.
Waste Manag. 2018 Aug;78:497-508. doi: 10.1016/j.wasman.2018.06.019. Epub 2018 Jun 23.
This study explores the leaching of oxyanionic metalloid species (As, Mo, Se, V and Cr) from alkali activated slag-fly ash materials (AAM), dependent on various mixture parameters i.e., activator molarity, slag-fly ash precursor/binder compositions, liquid to binder ratio, curing time and strength. The analyses focusses on the leaching of potentially hazardous elements in a monolithic and granular material state. For monolithic state AAMs (concrete) overall leaching is within comparable range with traditional Portland cement and in both systems their leaching is far below the regulatory leaching limit values even though AAM strongly differs in mixture composition. For granular state AAMs (aggregate) the parameters, activator alkalinity and the slag-fly ash precursor/binder composition, significantly influence the leaching. The release of As and V strongly increases with a higher activator molarity as an effect of changes in the system alkalinity and related material pH. The release of As, Mo, Se and V strongly increase with a higher fly ash content within the precursor/binder composition. Overall, the leaching of aggregate state AAMs meets the Dutch leaching limits for open application of granular building materials, when the fly ash content within the binder composition ≤ ≈30 wt%. Typically, the pH dependent leaching data show oxyanionic metalloid species have a relatively high leaching potential, being less effectively bound as a result of the amorphous AAM microstructure. However, the leachable concentrations of a AAM system are within the bandwidth with that of blended (slag and or fly ash) Portland cement system.
本研究探讨了碱激发矿渣-粉煤灰材料（AAM）中氧阴离子类金属物种（砷、钼、硒、钒和铬）的浸出情况，该浸出情况取决于各种混合参数，即活化剂摩尔浓度、矿渣-粉煤灰前驱体/粘结剂组成、液固比、养护时间和强度。分析重点在于整体和颗粒材料状态下潜在有害元素的浸出。对于整体状态的AAM（混凝土），总体浸出情况与传统波特兰水泥处于可比范围内，并且在这两种体系中，即使AAM的混合组成有很大差异，其浸出量也远低于监管浸出限值。对于颗粒状态的AAM（骨料），活化剂碱度和矿渣-粉煤灰前驱体/粘结剂组成等参数对浸出有显著影响。由于体系碱度和相关材料pH值的变化，随着活化剂摩尔浓度的提高，砷和钒的释放量显著增加。在前驱体/粘结剂组成中，随着粉煤灰含量的增加，砷、钼、硒和钒的释放量大幅增加。总体而言，当粘结剂组成中的粉煤灰含量≤≈30 wt%时，骨料状态AAM的浸出符合荷兰颗粒建筑材料露天应用的浸出限值。通常，pH值依赖性浸出数据表明，氧阴离子类金属物种具有相对较高的浸出潜力，由于AAM的无定形微观结构，它们的结合效果较差。然而，AAM体系的可浸出浓度与混合（矿渣和/或粉煤灰）波特兰水泥体系的浓度在同一范围内。
