冶金渣胶结材料对超细全尾砂固化特性的影响

Effect of metallurgical slag cementitious material on solidification characteristics of ultra-fine tailings backfill

通过X射线衍射、热重、扫描电镜等手段联合强度实验,从宏微观角度对比分析了3种典型胶结料的水化特性,考察胶结料种类、温度、料浆配比、超细颗粒含量对全尾砂固化特性的影响。结果表明:冶金渣胶结材料通过碱激发、盐激法、耦合激发可完全消耗自身产生的氢氧化钙,生成额外凝胶类水化产物,有利于尾砂胶结;冶金渣胶结材料仅需水泥一半的灰砂比即可获得同等固化性能;超细颗粒对充填体早期强度的影响更显著;在40℃高温养护下,充填体的早期强度与20℃养护的后期强度有线性关系,可据此实现材料质量的快速检测。冶金渣充填胶结材料在实际应用中需考虑成本、地域性特征,完善等级标号相关标准与评价体系,关注热应力对充填体长期稳定性的影响。

The hydration properties of 3 typical backfill binders were experimentally investigated from macro and micro perspectives through X-ray diffraction, thermogravimetry, scanning electron microscope and strength tests.The effects of binder type, temperature, mixture composition and ultra-fine particle content on the tailings solidification characteristics were explored. The findings reveal that metallurgical slag-based binder(MSB) can completely consume self-generated calcium hydroxide to produce more gel-like products through alkali, sulfate and combined activation methods, which is favorable for binding ultra-fine tailings. The similar mechanical strength is obtained for MSB-CPB at halved cement to tailings ratio compared to ordinary Portland cement. Ultrafine particles have a more significant impact on the backfill early strength. High-temperature of 40 ℃ curing accelerates the early MSB-CPB strength, which is proportional to the long-term strength at normal 20 ℃ curing.This correlation can be applied for the material quality fast check. The material cost and regional variance should be considered when employing the MSB in a practical case. Some related standards and grade level evaluation systems should be improved. Attention should be paid to the effects of heat stress and high ambient temperature on the MSB-CPB long-term stability.