现代交通与冶金材料

赤泥作为铝土矿提炼氧化铝过程中产生的工业固体废弃物，以其强碱性、高盐分和复杂成分成为环境难题。本文针对以拜耳法赤泥、矿渣微粉等量替代水泥制备胶凝材料的协同作用机制展开研究。通过制备赤泥‑水泥（二元）与赤泥‑矿渣‑水泥（三元）复合胶凝体系，结合 XRD 与能谱分析，比较了两类体系的水化产物特征与元素分布规律。结果显示，二元与三元体系 28 d 抗压强度均超过 42.5 MPa，且三元体系强度较二元体系提升 9.4%，三元体系中赤泥与矿渣表现出显著的协同效应：C‑S‑H 凝胶质量分数提升至 51.2%，较二元体系（45.7%）和纯水泥体系（42.3%）分别提高12.0% 和 21.0%；CH 含量则分别降低33.3% 与 47.3%，体现了赤泥与矿渣的成核效应。此外，协同作用促使新生相钙霞石的生成，降低体系 pH 值，部分 Na⁺由 C‑S‑H 凝胶中转移至钙霞石晶格，形成“物理吸附+晶格固化”的双重固钠机制。能谱分析进一步显示，三元体系中 Al 元素在钙霞石区高度富集（12.3 %，原子分数），证实矿渣中的活性 Al₂O₃参与了钙霞石的形成。

Red mud as an industrial solid waste produced during the extraction of alumina from bauxite， has become an environmental problem due to its strong alkalinity， high salt content and complex composition. In this study， the collaboration mechanism between Bayer method based-red mud andslag to replace cement for the production of cementitious materials is investigated. Binary （red mudcement） and ternary （red mud-slag-cement） composite systems are prepared and analyzed with X-ray diffraction （XRD） and X-ray spectroscopy （EDS）. The hydration product characteristics and elemental distribution patterns are systematically compared. Results indicate that the compressive strength of binary and ternary systems both exceeded 42.5 MPa at 28 days， with the ternary system showing a 9.4% increase in strength compared with the binary system. Notably， red mud and slag exhibit significant synergistic effects in the ternary system. A strong complementary mechanism between red mud and slag is observed in the ternary system. The mass fraction of calciumc-silicate-hydrate （C-S-H） gel is increased to 51.2% for ternary system， which is 12.0% and 21.0% higher than that of binary system （45.7%） and pure cement （42.3%）， respectively. Meanwhile， the portlandite （CH） content for ternary system is decreased by 33.3% and 47.3% for binary system and pure cement， respectively， the "nucleation effect" of red mud and slag is reflected. Furthermore， new phase cancrinite is developed and pH value is reduced， which indicates partial migration of Na+ from the C-S-H gel into the cancrinite lattice. Thus， a dual sodium solidification mechanism， including physical adsorption and lattice incorporation， is developed. EDS analysis further reveals that aluminum enrichment within cancrinite regions in the ternary system is 12.3%（atomic fraction）， and confirms the participation of reactive Al2O3from slag in cancrinite crystallization.