Derouiche Rania, Lemougna Patrick Ninla, Hernandez Guillermo Meza, Gu Jun, Baklouti Samir, Rahier Hubert
Department of Materials and Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
Laboratory of Advanced Materials, National School of Engineers of Sfax, University of Sfax, Sfax 3038, Tunisia.
Materials (Basel). 2023 Sep 17;16(18):6249. doi: 10.3390/ma16186249.
In general, phosphate cements have a very rapid setting reaction at room temperature. The same holds for copper slag-based phosphate cements. This means that using them as a binder, for instance as mortar, is always possible on a small scale, but very difficult on a large scale. In this paper, the heat treatment of the copper slag was shown to be an effective way to increase the setting time and keep the mix workable for an adequate period. The main objective of this research was to examine the changes in the phase composition of quenched copper slag after exposure to 500 °C and to evaluate the impact of these changes on the reactivity of the material in an acidic environment, as well as on the mechanical properties, microstructure, and structure of the produced phosphate cement materials. Various experimental methods were utilized to characterize the raw materials and the obtained phosphate cementitious materials, including isothermal microcalorimetry (TAM Air), thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), as well as the determination of the chemical composition using X-ray fluorescence (XRF) and the particle size distribution. Furthermore, compressive strength tests were conducted to gauge the mechanical resistance of the materials. The main findings of this work revealed that subjecting the copper slag to a thermal treatment of 500 °C induced a partial transformation in its structure. The high temperature caused the oxidation of some of the divalent iron oxide in the slag, leading to the formation of hematite. This treatment increased the setting time and reduced the reactivity of the copper slag with phosphoric acid, ultimately enabling the production of a dense phosphate-based cementitious material with outstanding mechanical properties. The compressive strength of the newly developed cement was recorded to be greater than 78.9 MPa after 7 days, and this strength continued to increase, reaching 82.5 MPa after 28 days.
一般来说，磷酸盐水泥在室温下具有非常快速的凝结反应。基于铜渣的磷酸盐水泥也是如此。这意味着，例如将它们用作粘结剂，如砂浆，小规模使用总是可行的，但大规模使用则非常困难。本文表明，对铜渣进行热处理是延长凝结时间并使混合物在足够长的时间内保持可加工性的有效方法。本研究的主要目的是研究淬火铜渣在500℃下暴露后的相组成变化，并评估这些变化对材料在酸性环境中的反应活性以及对所制备的磷酸盐水泥材料的力学性能、微观结构和结构的影响。采用了各种实验方法来表征原材料和所获得的磷酸盐胶凝材料，包括等温微量热法（TAM Air）、热重分析（TGA）、红外光谱（FTIR）、X射线衍射（XRD）、扫描电子显微镜（SEM），以及使用X射线荧光（XRF）测定化学成分和粒度分布。此外，还进行了抗压强度试验以评估材料的机械抗性。这项工作的主要发现表明，对铜渣进行500℃的热处理会导致其结构发生部分转变。高温导致炉渣中的一些二价氧化铁氧化，形成赤铁矿。这种处理延长了凝结时间并降低了铜渣与磷酸的反应活性，最终能够生产出具有优异力学性能的致密磷酸盐基胶凝材料。新开发的水泥在7天后的抗压强度记录大于78.9MPa，并且该强度持续增加，28天后达到82.5MPa。
