Effect of Gypsum Content on CSAB Cement-Based Immobilization of Se and SO ₄ from Industrial Filter Sludge and Sodium–Selenium Salts

Release of different heavy metals from various industries is a significant environmental hazard worldwide. In order to reduce the threat these chemicals, treatment methods are needed make them harmless. This study approaches problem by examining effect gypsum content for immobilization selenium oxyanions selenite and selenate, sulfate, with calcium sulfoaluminate belite (CSAB) cement-based ettringite binder systems. The has two experimental sections. first section, an industrial filter sludge high concentrations sulfate immobilized CSAB varying amounts gypsum. efficient reducing amount in hydrating mixture enhances incorporation both sulfate. binding occurs through encapsulation into other hydrated phases. second reagent grade sodium–selenium salts, sodium mixed not effective formed large quantities, most likely due reacting system.