Evaluating the efficiency of a novel rotary reactor for the treatment of acid mine drainage using armored limestone

This study evaluates the efficiency of a novel rotary mechanical system designed to treat acid mine drainage (AMD) generated by coal mining activities, aiming to reactivate limestone affected by surface armoring during neutralization process. Characterization via X-ray diffraction and scanning electron microscopy revealed the formation of goethite, siderite, and gypsum within the passivating layer developed on the limestone. The results demonstrate the effectiveness of the rotary system in mechanically removing this passivating layer, thereby restoring limestone reactivity, and significantly improving the physicochemical quality of the treated AMD. Implementing this mechanical approach enhances overall process efficiency while reducing limestone replacement and maintenance requirements.