Experimental Study on the Preparation of Cementitious Materials Through the Activation of Lead—Zinc Tailings

The pozzolanic activity of lead–zinc tailings (LZTs) was enhanced through mechanical grinding, enabling the preparation of a lead–zinc tailing based composite cementitious material (LZTCC) by combining LZTs with ground granulated blast furnace slag (GGBS), steel slag (SS), and desulfurized gypsum (DG). The compressive strength of LZTCC was evaluated under varying water–cement ratios (W/C) and LZTs dosages. The hydration mechanism was studied via phase composition and microstructural analyses of hydration products. The results revealed that the 28-day pozzolanic activity of LZTs improved to 76% after 2 h of mechanical grinding. LZTCC formulated with 60% LZTs, 22% GGBS, 8% SS, and 10% DG achieved compressive strengths of 13.8 MPa at 7 days and 15.7 MPa at 28 days under a W/C ratio of 0.4. XRD and SEM characterization demonstrated that AFt and amorphous C-S-H gel, along with the unreacted LZT particles, contributed to the overall microstructure, while the former two phases played a significant role in the strength development of LZTCC mortar due to their cementitious reactivity. Heavy metal pollution levels were minimized throughout the process, and the research results could provide a scientific basis for the harmless treatment and resource utilization of LZTs.