The influence of alkaline activator on immmoblization of metals in alkali-activated blast furnace slag

Abstract

In this work the influence of alkaline activator on immobilization of lead and copper in alkali-activated blast furnace slag was investigated. A total of five alkali activators were used; sodium waterglass, potassium waterglass, sodium hydroxide, potassium hydroxide and sodium carbonate. The leaching test according to ČSN EN 12457 -4 was used to evaluate the level of immobilization of heavy metals, the leached solutions were analyzed by ICP-OES. For a better understanding of immobilization process, the selected samples were characterized by analytical methods (SEM, XPS). It was found that the degree of immobilization of Pb2+ and Cu2+ in AAS was very high regardless of the type of alkaline activator used. The high degree of immobilization is caused by formation of insoluble or poorly soluble lead and copper compounds in an alkaline environment while the insoluble compounds have been confirmed by SEM and XPS.In this work the influence of alkaline activator on immobilization of lead and copper in alkali-activated blast furnace slag was investigated. A total of five alkali activators were used; sodium waterglass, potassium waterglass, sodium hydroxide, potassium hydroxide and sodium carbonate. The leaching test according to ČSN EN 12457 -4 was used to evaluate the level of immobilization of heavy metals, the leached solutions were analyzed by ICP-OES. For a better understanding of immobilization process, the selected samples were characterized by analytical methods (SEM, XPS). It was found that the degree of immobilization of Pb2+ and Cu2+ in AAS was very high regardless of the type of alkaline activator used. The high degree of immobilization is caused by formation of insoluble or poorly soluble lead and copper compounds in an alkaline environment while the insoluble compounds have been confirmed by SEM and XPS.