Waste rocks from the industrial mining process: hazard metals stabilization behavior evaluating and reusing as construction materials

Recycling wastes to renewable resources with proper methods deserve world’s extensive efforts. In this work, antimony mining waste rocks from the industrial mining process contenting hazard metals are incorporated as substitutes for aggregate to produce cement mortars and concrete products. The stabilization behaviors of hazard metals in those products are evaluated and the stabilize mechanisms are discussed. The solidification and stabilization effectiveness are evaluated by examining the leaching behavior of the contained hazard metals including Sb, As and Pb. The leaching results indicate that the concentrations of the evaluated hazard metals in cement mortars and concrete products are reduced over time, and the cement mortars exhibit higher reducing rate. The reduced leaching behavior can be attributed to the increased hydration products of silicate precipitation. The main contents of antimony mine waste rocks and compressive strength of cement mortar and concrete produced with different amounts of antimony mining waste rocks incorporated are also analyzed to evaluate their resource possibility. The results reveal that the main contents in antimony mining waste rocks are similar to the benchmark cement (SiO2 + CaO + Al2O3 > 75%). In addition, much better compressive strength over 42.5 MPa is obtained at 28 days curing period when antimony mining waste rocks were added as substitutes for standard sands to produce cement mortar. The improved compressive strength can be attributed to the reduced porosity and improved pore structures. The improved compressive strength and decreased hazard metals concentration indicate the antimony mining waste rocks a promising material reused as renewable resource.