关键词: 锌尾矿, 水泥熟料, Zn²⁺固化, 组成与结构, 性能

Abstract:

Zinc tailings are harmful industrial wastes.Clean and efficient utilization of zinc tailings not only has important environmental value，but also generates significant economic benefits.In this study，a silicate cement clinker was prepared with sphalerite tailings as additive，and the effect of tailings on the phase composition，microstructure，and hydration performance of clinker was studied.The transfer behavior of Zn²⁺ during the hydration process of clinker was explored.The passivation mechanism of Zn²⁺ leaching activity was also investigated at last.The results showed that the introduction of sphalerite tailings promoted the dissolution of f-CaO into liquid phase，thus accelerating C₃S grain growth.While the synthesis of C₃A phase was prevented after the addition of the sphalerite tailings，because of a reaction occurrence between ZnO and C₃A to generate Ca₁₄Al₁₀Zn₆O₃₅.As a consequence，the 3 d compressive strength of cement slurry was gradually decreased，but the gradual improvements in 7 d and 28 d compressive strengths were present as a function of tailings addition.When 12% sphalerite tailings was introduced.A rubber sand specimen exhibited a 43.49 MPa compressive strength after 28 d curing.The passivation mechanism of Zn²⁺ leaching activity showed that some Zn²⁺ could be solid dissolved in C₃S phase.But most of Zn²⁺ were distributed in the intermediate phase，and it was solidified through the synthesis of anhydrous Ca₁₄Al₁₀Zn₆O₃₅. More over，C₃S containing Zn²⁺ generated hydrated calcium silicate gel after hydration，which could physically wrap the ion and restrain its leaching activity，thus collectively endowing the product with good environmental safety.The research results provided a new approach for the clean and efficient utilization of zinc tailings.

Key words: zinc tailings, cement clinker, Zn²⁺ solidification, composition and microstructure, performance