Conversion of hazardous waste into calcium sulfoaluminate cement: effect of alkalinity modulus on mineral composition and Fe2O3 incorporation in Ye'elimite

IF 13.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research Pub Date : 2025-09-03 DOI:10.1016/j.cemconres.2025.108028

Di Yu , Jie Li , Mengxia Xu , Jun He , Bo Li , Yin Wang

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引用次数: 0

Abstract

The production of calcium sulfoaluminate (CSA) cement using hazardous wastes can enhance its sustainability and economic benefits. Incorporating Fe₂O₃ into ye'elimite can reduce the Al₂O₃ demand in waste-based CSA cement, while the influence of alkalinity modulus (Cm) on this incorporation remains unclear. This study synthesised CSA cement clinker from hazardous wastes with varying Cm. Results show that forming inert phases like C₂AS and Fe₂SiO₄ hinders the synthesis of hydraulically active minerals, requiring a higher Cm of 1.10 to attain the highest 28-day compressive strength of 76.4 MPa. Additionally, increasing Cm reduces the Fe/(Al + Fe) ratio in ye'elimite, particularly in low-aluminium clinkers. This contributes to the transformation of C₄A₃

\bar{S}

-o to C₄A₃

\bar{S}

-c and the slowed hydration. However, facilitated ye'elimite formation under higher Cm and increased Al₂O₃ content in feedstock leads to more Fe₂O₃ being incorporated into ye'elimite. This study provides guidance on regulating Fe₂O₃ incorporation in the production of waste-based CSA cement clinker.

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危废转化为硫铝酸钙水泥：碱度模量对叶铝石矿物组成及Fe2O3掺入量的影响

利用危险废物生产硫铝酸钙水泥可以提高其可持续性和经济效益。在废基CSA水泥中掺入Fe2O3可以减少Al2O3的用量，但碱度模数（Cm）对掺入量的影响尚不清楚。本研究以不同Cm的危险废弃物为原料合成CSA水泥熟料。结果表明：C2AS、Fe2SiO4等惰性相的形成阻碍了水力活性矿物的合成，需要较高的Cm（1.10）才能达到最高的28天抗压强度76.4 MPa；此外，增加Cm可降低铝铝熟料中的Fe/(Al + Fe)比，特别是在低铝熟料中。这导致C4A3S¯S¯-o向C4A3S¯S¯-c的转变，水化速度减慢。然而，在较高的Cm条件下，有利于极限值的形成和原料中Al2O3含量的增加导致更多的Fe2O3被掺入极限值中。该研究对控制废基CSA水泥熟料中Fe2O3掺入量具有指导意义。

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来源期刊

Cement and Concrete Research 工程技术-材料科学：综合

CiteScore

20.90

自引率

12.30%

发文量

318

审稿时长

53 days

期刊介绍： Cement and Concrete Research is dedicated to publishing top-notch research on the materials science and engineering of cement, cement composites, mortars, concrete, and related materials incorporating cement or other mineral binders. The journal prioritizes reporting significant findings in research on the properties and performance of cementitious materials. It also covers novel experimental techniques, the latest analytical and modeling methods, examination and diagnosis of actual cement and concrete structures, and the exploration of potential improvements in materials.