ABSTRACT

The reactivity of sulphidic cemented paste tailings (CPT) is an indicator which can be used to assess their environmental performance and durability. However, the reactivity is influenced by several factors either alone or in combination with other factors, such as temperature, curing time, and initial sulphate content. In this paper, the combined effect of the initial sulphate content and curing temperature on the reactivity of CPT is experimentally investigated with oxygen consumption (OC) tests. Microstructural analyses of the CPT samples are also performed to understand the impact of the microstructure of the CPTs on their reactivity. The results show that regardless of the binder type, the reactivity of the CPT system is significantly dependent on the curing temperature and initial sulphate content and their interaction. As curing temperature and sulphate concentration increase, the reactivity increases (except for the CPT samples with 5,000 ppm of sulphate). Moreover, the CPT sample with high contents of sulphate (25,000 ppm) and cured at 50°C has the highest reactivity regardless of the type of binder. The addition of mineral admixtures as a partial substitute for Portland cement also has a significant role in reducing the reactivity as compared to samples made only with Portland cement.

摘要

硫化胶泥尾矿（CPT）的反应性是可用于评估其环境性能和耐久性的指标。但是，反应性受单独或与其他因素（例如温度，固化时间和初始硫酸盐含量）结合的几种因素影响。本文通过耗氧量（OC）测试实验研究了初始硫酸盐含量和固化温度对CPT反应性的综合影响。还对CPT样品进行了微结构分析，以了解CPT的微结构对其反应性的影响。结果表明，无论粘合剂类型如何，CPT系统的反应性都显着取决于固化温度和初始硫酸盐含量及其相互作用。随着固化温度和硫酸盐浓度的增加，反应性增加（具有5,000 ppm硫酸盐的CPT样品除外）。而且，不管粘合剂的类型如何，具有高含量硫酸盐（25,000 ppm）并在50°C固化的CPT样品都具有最高的反应性。与仅用波特兰水泥制成的样品相比，添加矿物掺合料作为波特兰水泥的部分替代品在降低反应性方面也具有重要作用。