Solidification behaviour of soluble Mn in blended cement with metallurgical slag

IF 8 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials Pub Date : 2025-10-25 DOI:10.1016/j.conbuildmat.2025.144192

Qiang Liu , Guangye Tu , Meng Wu , Guodong Xu , Jianming Gao , Yunsheng Zhang , Cheng Liu

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引用次数: 0

Abstract

The utilization of metallurgical slag for the partial substitution of clinker to produce blended cement is an effective approach for the harmless and resourceful disposal of industrial solid waste. Nevertheless, the influence of metallurgical slag on the solidification behavior between clinker minerals and heavy metals remains unclear in blended cement. In this study, the blended cement is composed of cement, synthetic amorphous phase (eliminating the influence of physical-chemical characteristics of different metallurgical slags), and different levels soluble Mn. The study applied various characterization methods focusing on the solidification behaviour of Mn in the hydration process of blended cement. The results reveal that Mn exhibits a dual effect on the reaction of C₃S, with the appearance time of the main peak in the hydration heat curve extending from 10 h to 17 h (when Mn dosage reaches 0.9 wt%). However, with the increase of Mn, the main peak appeared early at 5.6 h. The primary inhibitory factor for the C₃S hydration reaction is Mn-bearing hydrate phases on the surfaces of cement particles. However, when the soluble Mn content exceeds a certain threshold (2.7 wt% in this study), the clinker reaction is enhanced due to the formation of additional nucleation sites by Mn-hydrate precipitates. Mn is predominantly solidified within the gel-like hydration products and ettringite through lattice confinement and physical encapsulation. The introduction of Mn promotes the formation of ettringite-like products. This reaction consumes gypsum and thus accelerates the secondary hydration of C₃A. The improved hydration kinetics model is employed to reveal the hydration mechanism of blended cement containing Mn. The hydration process of blended cement follows a diffusion-controlled behaviour, which is influenced by the Mn-precipitation layer. These findings provide comprehensive insights into reaction kinetics and the solidification of heavy metals, contributing to the sustainable application of metallurgical slag in the environment.

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可溶性锰在冶金渣水泥中的凝固行为

利用冶金渣部分替代熟料生产水泥是实现工业固体废物无害化资源化处理的有效途径。然而，冶金渣对水泥中熟料矿物与重金属固化行为的影响尚不清楚。在本研究中，混合水泥由水泥、合成非晶相（消除了不同冶金渣理化特性的影响）和不同水平的可溶Mn组成。本研究采用了多种表征方法，重点研究了Mn在混合水泥水化过程中的固化行为。结果表明，Mn对C3S反应具有双重影响，水化热曲线主峰出现时间从10 h延长至17 h （Mn用量为0.9 wt%时）。随着Mn的增加，主峰出现时间较早，为5.6 h。C3S水化反应的主要抑制因素是水泥颗粒表面的含锰水化相。然而，当可溶性Mn含量超过一定阈值（本研究中为2.7 wt%）时，由于Mn水合物沉淀形成额外的成核位点，熟料反应增强。锰主要通过晶格约束和物理包封在凝胶状水化产物和钙矾石中固化。Mn的引入促进了钙矾石样产物的形成。该反应消耗石膏，加速了C3A的二次水化。采用改进的水化动力学模型揭示了掺Mn水泥的水化机理。混合水泥的水化过程受mn沉淀层的影响，遵循扩散控制的规律。这些发现为重金属的反应动力学和固化提供了全面的见解，有助于冶金渣在环境中的可持续应用。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Construction and Building Materials 工程技术-材料科学：综合

CiteScore

13.80

自引率

21.60%

发文量

3632

审稿时长

82 days

期刊介绍： Construction and Building Materials offers an international platform for sharing innovative and original research and development in the realm of construction and building materials, along with their practical applications in new projects and repair practices. The journal publishes a diverse array of pioneering research and application papers, detailing laboratory investigations and, to a limited extent, numerical analyses or reports on full-scale projects. Multi-part papers are discouraged. Additionally, Construction and Building Materials features comprehensive case studies and insightful review articles that contribute to new insights in the field. Our focus is on papers related to construction materials, excluding those on structural engineering, geotechnics, and unbound highway layers. Covered materials and technologies encompass cement, concrete reinforcement, bricks and mortars, additives, corrosion technology, ceramics, timber, steel, polymers, glass fibers, recycled materials, bamboo, rammed earth, non-conventional building materials, bituminous materials, and applications in railway materials.