Preparation of nickel–cobalt tailings-based cementing materials by mechano-chemical activation: Performance and mechanism

Abstract

Currently, the stock of nickel–cobalt tailings (NCT) exceeds 30 million tons, and effective utilization is crucial for addressing environmental pollution. This study focuses on modifying NCT and bottom ash (BA) using the mechanochemical method to create cementitious materials. The research findings indicate that when the cement clinker content is below 3 %, the maximum compressive strength of the specimens can reach 4.803 MPa. After 28 days of curing, the leaching concentrations of nickel and cobalt in the consolidated sample decreased from 5.824 and 1.281 mg/L to 0.803 and 0.179 mg/L, respectively. These levels meet the standard set by China for mine repair and backfilling. The consolidation process primarily involves the recombination of elements such as Si, Ca, and Mg in the amorphous material, resulting in the encapsulation of most ions within the structure and eliminating the risk of contamination. This technology enables the treatment and transformation of NCT and BA waste into cementitious materials suitable for backfilling local mining pits. It holds great potential for various civil environmental applications in fields such as green construction materials.