Study on Stability and Applicability of Calcium Carbide Slag-Dealkalized Red Mud and Solid Waste Composite Materials...

The storage of highly alkaline red mud (RM) consumes land and threatens the environment, making its reuse crucial. The study used calcium carbide slag to dealkalize it, and analyzed the changes in mineral particles in RM using a CT scan. It then evaluated the stabilization effects of different materials and explored the mechanism of RM solidification through analysis of micro-mechanisms. The results showed that after dealkalization with CCS, RM particles form more agglomerates and the overall structure becomes more compact, and the Na⁺ content in RM decreased from 10.44 wt% to 0.86 wt%. After treatment with stabilization materials, the mechanical strength of low-alkalinity RM was greatly improved, and the stabilization effect of composite slag was the best. When the partial replacement ratio was 12%, the 28 d compressive strength was 4.51 MPa. After soaking in water for one day and night, the strength decreased by 24.3%, which had good stability. This study found that the strength gains were mainly due to crystal substances like Ca₃Al₂O₆ and non-crystalline substances such as C-S-H filling pores and wrapping particles. This study provides a new method for RM stabilization and promotes the utilization of industrial by-products.