Optimization of Cementitious Material with Thermal-Activated Lead–Zinc Tailings Based on Response Surface Methodology

Abstract

The accumulation of lead–zinc tailings will cause a series of problems, including geological disasters and environmental pollution. Efficient secondary utilization of lead–zinc tailings is crucial. In this study, the activity of lead–zinc tailings was stimulated by thermal activation. The optimal thermal activation parameters are a thermal activation temperature of 900 °C and a holding time of 30 min. Based on the response surface methodology, the effect of raw materials content on cementitious material strength was analyzed, and the relational model between cementitious material strength and experimental variables was established. The results show that the sensitivity order of cementitious material strength at 28 days curing age is sand/cement ratio > water/cement ratio > fly ash content > tailing content. According to the relational model, the optimal materials ratio is as follows: tailing/fly ash/cement = 28.99%:14.58%:56.43%, and the sand/binder ratio and water/binder ratio are 1:1 and 0.47, respectively. The corresponding cost is CNY 290.965 per ton, which is the lowest. The strength of cementitious material with these parameters can reach 20 MPa, which meets the requirements of “Technical specification for application of solid waste cementitious material (T/CECS 689-2020)”.