School of Infrastructure Engineering, Nanchang University, Nanchang 330031, China.
School of Infrastructure Engineering, Nanchang University, Nanchang 330031, China.
J Environ Manage. 2023 Nov 1;345:118658. doi: 10.1016/j.jenvman.2023.118658. Epub 2023 Jul 30.
In this work, one-step synthesis of high-performance C-A-S-H (calcium alumina silicate hydrate) seeds from low-calcium fly ash (FA) and carbide slag (CS) by 7 days of mechanochemical mixing was proposed and used to activate lithium slag (LS) cement. The results showed that the seeding effect of C-A-S-H seeds was increased with the increasing Ca/Si (i.e. from 1.0 to 1.5), i.e. the mortar compressive strength of 1 day and 28 days were increased by 67% and 29% with the addition of 1.0% C-A-S-H nano-seeds at Ca/Si = 1.5 in the presence of polycarboxylate superplasticizer (PCE), respectively. Moreover, the chloride resistance of lithium slag cement was improved significantly, i.e. the electric flux was decreased by more than 30% than that of plain lithium slag cement mortar. The performance difference of various C-A-S-H seeds is mainly attributed to their high proportion and polymerization degree, more stretch and three-dimensional foil-like morphology at high Ca/Si. This study provides guidance for obtaining low-cost and high-performance C-A-S-H seeds from wastes and the highly efficient utilization of LS as supplementary cementitious materials (SCMs) in the future.
在这项工作中，提出了一种通过 7 天机械化学混合从低钙粉煤灰（FA）和电石渣（CS）一步合成高性能 C-A-S-H（钙铝硅酸盐水合物）种子的方法，并将其用于激活锂渣（LS）水泥。结果表明，随着 Ca/Si 的增加（即从 1.0 增加到 1.5），C-A-S-H 种子的成核效果增加，即在聚羧酸高效减水剂（PCE）存在下，添加 1.0% Ca/Si=1.5 的 C-A-S-H 纳米种子，1 天和 28 天的水泥砂浆抗压强度分别提高了 67%和 29%。此外，锂渣水泥的抗氯离子侵蚀性能显著提高，即电通量比普通锂渣水泥砂浆降低了 30%以上。不同 C-A-S-H 种子的性能差异主要归因于其高比例和聚合度，以及在高 Ca/Si 条件下具有更多的伸展和三维箔状形态。本研究为从废物中获得低成本、高性能的 C-A-S-H 种子以及未来将 LS 作为辅助胶凝材料（SCMs）高效利用提供了指导。
