A simple and efficient method for characterizing the pozzolanic activity of iron tailing powders using electrical conductivity

Iron tailings, with large quantities and low utilization rates, pose significant environmental challenges. The potential for utilizing these tailings is closely linked to their pozzolanic activity. Previous studies have used saturated lime solution method to evaluate the pozzolanic activity of materials. However, the solution preparation is complex and the test time is too long. In this study, a new NaOH solution method was proposed to characterize the pozzolanic activity of iron tailing powders using electrical conductivity. The test parameters, including NaOH concentration, iron tailing powder mass, and reaction temperature, were optimized. A difference between the new proposed NaOH solution method and the traditional saturated lime solution method was compared. The feasibility of the proposed method was further verified through the strength activity index method. The results indicated that under optimal conditions (0.4M NaOH solution, 12g iron tailings powder, and 40°C reaction temperature), the electrical conductivity tends to stable after 900 s. A strong linear relationship was found between electrical conductivity loss at stabilized time and the strength activity index at 90 days, with a coefficient of determination (R²) of 0.93. Additionally, grinding and calcining treatments can significantly enhance the pozzolanic activity of iron tailing powders. Therefore, the new proposed method was a simple and efficient technique for characterizing the pozzolanic activity of iron tailing powders, and provided a solid foundation for the utilization of iron tailings.