骆静静, 张程, 刘松辉,等. NaH₂PO₄对镁渣的碳化硬化性能影响[J].河南理工大学学报(自然科学版)，doi:10.16186/j.cnki.1673-9787.2024110024.

LUO J J，ZHANG C，LIU S H, et al． Effect of NaH2PO4 on the carbonation and hardening properties of magnesium slag [J]. Journal of Henan Polytechnic University( Natural Science) ， doi: 10.16186/j.cnki.1673-9787. 2024110024.

NaH₂PO₄对镁渣的碳化硬化性能影响(网络首发)

骆静静1,2，张程1,2，刘松辉3，张宇洋1,2，汤小松1,2，史星祥1,2，宋秋磊1,2

1.苏州混凝土水泥制品研究院有限公司，江苏 苏州215004；2.江苏省高耐久性混凝土工程技术研究中心，江苏 苏州 215004；3. 河南理工大学 材料科学与工程学院，河南 焦作 454003

摘要: 目的 镁渣的物理化学性质、活性激发方法及应用途径等方面研究受到广泛研究，其中碳化养护法可解决碳减排和体积安定性问题而扩大应用范围。为了提升镁渣碳化活性，并阐述其提升机理。方法 本文研究了不同NaH₂PO₄浓度对镁渣碳化反应活性、力学性能的影响，通过x射线衍射仪(XRD)、红外光谱(FT-IR)、扫描电子显微镜和x射线能谱仪(SEM-EDS)表征、低场核磁测试(LF-NMR)测试，分析NaH₂PO₄对碳化产物的物相组成、微观结构和孔结构的影响。结果 结果表明，NaH₂PO₄的引入可提升镁渣碳化反应活性和力学性能。经过碳化24h后，五组配比的抗压强度分别为70MPa、74.6 MPa、81.9 MPa、92.2 MPa、81.8 MPa。相对比空白组，在最佳1.5mol/L NaH₂PO₄浓度下镁渣试块抗压强度和CO2吸收量分别提升了30.9%、24.1%。碳化后主要生成方解石和文石型碳酸钙、高聚合度二氧化硅凝胶；引入NaH₂PO₄后，碳化产物中碳酸钙的晶型未有显著影响，但碳酸钙的形貌发生了改变，从棒状和立方体碳酸钙逐渐转变为球状的微小颗粒。微观结构及孔结构表明，球状碳酸钙和高聚合度硅胶使得微观结构致密化，从而降低了孔隙率，这是引入NaH₂PO₄后提升力学性能的主要原因。结论 该研究结果为提升镁渣的碳化反应活性提供了新方法。利用镁渣制备固碳建材制品具备成本低、性能优良的优势，该方法为大规模利用镁渣提供了基础。

关键词: 镁渣；碳化养护；NaH₂PO₄；力学性能

doi: 10.16186/j.cnki.1673-9787.2024110024

基金项目: 国家重点研发计划项目（2022YFC3803105）

收稿日期：2023-12-22

修回日期：2024-01-20

网络首发日期：2026-07-20

Effect of NaH₂PO₄ on the carbonation and hardening properties of magnesium slag (Online)

Luo Jingjing1,2，Zhang Cheng1,2，Liu Songhui3，Zhang Yuyang1,2，Tang Xiaosong1,2，Shi Xingxiang1,2，Song Qiulei1,2

1. Suzhou Concrete and Cement Products Research Institude Co., Ltd., Suzhou 215004, China; 2.jiangsu High DurabilityConcrete Engineering Technology Research Center, Suzhou 215004, China; 3. School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China

Abstract: Objectives The physical and chemical properties, activation methods, and application pathways of magnesium slag were extensively studied. Among these, the carbon reduction and volume stability issues were solved by carbonation curing while expanding the application. This study aimed to enhance the carbonation reactivity of magnesium slag and elucidate the mechanisms behind this enhancement. Methods The effect of different NaH2PO4 concentrations on magnesium slag carbonation activity and mechanical properties was investigated. The phase composition, microstructure, and pore structure of carbonation products were analyzed using X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM-EDS), and low-field nuclear magnetic resonance (LF-NMR) testing. Results The results showed that the introduction of NaH2PO4 improved the carbonation reactivity and mechanical properties of magnesium slag. After 24 hours of carbonation, the compressive strengths of the five mixtures were 70 MPa, 74.6 MPa, 81.9 MPa, 92.2 MPa, and 81.8 MPa, respectively. Compared to the control group, the optimal 1.5 mol/L NaH₂PO₄ concentration increased the compressive strength and CO₂ uptake by 30.9% and 24.1%, respectively. Calcite and aragonite, along with highly polymerized silica gel, were primarily formed after carbonation. The crystal morphology of calcium carbonate changed from rod-shaped and cubic to spherical particles with NaH2PO4 addition. The microstructure and pore structure analysis showed that spherical calcium carbonate and highly polymerized silica gel densified the microstructure, reducing the porosity. This densification was the primary reason for the improved mechanical properties with the addition of NaH2PO4. Conclusions This study provided a new method to enhance the carbonation reactivity of magnesium slag. The preparation of carbon-sequestering building materials using magnesium slag demonstrated cost-effectiveness and excellent performance, laying the foundation for large-scale utilization of magnesium slag.

Key words: magnesium slag; carbonation curing; NaH₂PO₄; mechanical property