School of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, China; National-local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore Resources, Shenyang, 110819, China.
School of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, China; Institute for Frontier Technologies of Low-Carbon Steelmaking, Northeastern University, Shenyang, 110819, China.
J Environ Manage. 2024 Apr;356:120594. doi: 10.1016/j.jenvman.2024.120594. Epub 2024 Mar 18.
Almost all iron ore tailings (IOTs) required activation prior to use as SCMs, which limited their application in building materials. This study investigated HMPT-IOTs and discovered that they possess latent hydraulic and pozzolanic properties. In order to better utilize as SCM, mechanical properties, hydration reactions, hydration products, microstructure, and pores were comprehensively studied through mechanical tests, hydration heat tests, XRD, SEM, TG, and MIP. The results show that when HMPT-IOTs replace cement at 10 wt%, 20 wt% and 30 wt%, the compressive strength at 28 days is 41.9 MPa, 47.9 MPa and 37.5 MPa, respectively. When the substitution amount reaches 30 wt%, it will reduce the cumulative heat of hydration and promote early hydration reactions. The main hydration products are ettringite and Ca(OH). As the nucleation site of C-S-H, hydration products are interconnected, making the microstructure denser. At this substitution level, Ca(OH) consumption was about 2% at 28 days of age. Simultaneously, the total pore volume was only 0.01 mL/g greater than that of the control group, and the number of micropores and transition pores decreased by approximately 3%.
几乎所有的铁矿尾矿（IOT）在用作 SCM 之前都需要活化，这限制了它们在建筑材料中的应用。本研究考察了 HMPT-IOTs，并发现它们具有潜在的水硬性和火山灰性。为了更好地用作 SCM，通过力学性能测试、水化热测试、XRD、SEM、TG 和 MIP 对机械性能、水化反应、水化产物、微观结构和孔隙进行了综合研究。结果表明，当 HMPT-IOTs 分别替代水泥的 10wt%、20wt%和 30wt%时，28 天抗压强度分别为 41.9MPa、47.9MPa 和 37.5MPa。当替代量达到 30wt%时，会降低水化总热量，促进早期水化反应。主要水化产物为钙矾石和 Ca(OH)。作为 C-S-H 的成核点，水化产物相互连接，使微观结构更加致密。在这个替代水平下，28 天时 Ca(OH)的消耗约为 2%。同时，总孔体积仅比对照组增加了 0.01mL/g，微孔和过渡孔的数量减少了约 3%。
