Abstract：
Iron tailing solid waste not only has a high annual output but also has a low comprehensive utilization rate. Low utilization rate of iron tailings seriously restricts the development of comprehensive utilization of solid waste. In order to prepare an iron tailings-based ternary solid waste admixture and to verify its application to concrete, first, the effect of solid waste synergy on the strength of an iron tailings-steel slag-desulfurization ash admixture (ISD) system was investigated. Second, the effect of chemical activator dosing on the strength of an ISD system was studied and the mechanism of chemical activator action on the ISD system was investigated by thermogravimetric analysis (TG-DTA) Then, the effect of this admixture on the strength of concrete was studied. Finally, the mechanism of the effect of this admixture on the strength of concrete was clarified by mercury intrusion porosimetry (MIP) and backscattering electron tests (BSE). The results showed that the 7 d and 28 d compressive strengths of the ISD admixture were significantly higher than those of iron tailings single admixture. The 7 d and 28 d compressive strengths of the ISD system reached 24.9 MPa and 36.1 Mpa, respectively, when the ratio of iron tailings:steel slag:desulfurization ash = 1:1:1. Na2SiO3 is suitable for the early strength agent of the ISD admixture, but the amount of admixture should not exceed 0.6% of the admixture. TG-DTA shows that Na2SiO3 is enhancing the early strength of the ISD system by promoting the consumption of Ca(OH)2 in the ISD system to produce C-S-H. However, in the late reaction of the ISD system, Na2SiO3 inhibits the late strength development of the ISD system by suppressing Ca(OH)2 production. Concrete with ISD dosing of 30% or less meets the C40 requirement. MIP and BSE show that ISD provides a filling effect to concrete, but also causes a reduction in the active reactants of concrete and the combined effect of microfilling and active effects affects the strength development of ISD concrete. This study provides a theoretical and scientific basis for the preparation of iron tailings-based ternary solid waste dopants, and, in addition, the study promotes the consumption of iron tailings solid waste and the development of multiple solid waste dopants.
摘要：
铁尾矿固体废物不仅年产量高，而且综合利用率低。铁尾矿利用率低严重制约着固体废弃物综合利用的发展。为了制备铁尾矿基三元固废掺合料并验证其在混凝土中的应用,首先,研究了固体废物协同作用对铁尾矿-钢渣-脱硫灰掺合料（ISD）体系强度的影响。第二,研究了化学活化剂投加量对ISD系统强度的影响，并通过热重分析（TG-DTA）研究了化学活化剂对ISD系统的作用机理。研究了该掺合料对混凝土强度的影响。最后,通过压汞孔隙率法（MIP）和背散射电子测试（BSE）阐明了该外加剂对混凝土强度的影响机理。结果表明，ISD掺合料的7d和28d抗压强度明显高于铁尾矿单一掺合料。ISD系统的7d和28d抗压强度分别达到24.9MPa和36.1MPa,分别,当铁尾矿:钢渣:脱硫灰=1:1:1的比例。Na2SiO3适用于ISD外加剂的早强剂，但外加剂的用量不应超过外加剂的0.6%。TG-DTA表明，Na2SiO3通过促进ISD系统中Ca（OH）2的消耗来生产C-S-H，从而提高了ISD系统的早期强度。然而,在ISD系统的后期反应中，Na2SiO3通过抑制Ca(OH)2的产生来抑制ISD系统的后期强度发展。ISD用量为30%或更低的混凝土满足C40要求。MIP和BSE表明ISD为混凝土提供了填充效果，但也会导致混凝土活性反应物的减少，微填充和活性效应的综合作用会影响ISD混凝土的强度发展。本研究为铁尾矿基三元固废掺杂剂的制备提供了理论和科学依据,and,此外,该研究促进了铁尾矿固体废物的消耗和多种固体废物掺杂剂的开发。
