Abstract In this investigation, low-cement castables were prepared using 70% alumina grog aggregates obtained from crushed alumina brick waste. The aggregates were thermally treated at 1550 °C for 3 h. Four types of low-cement castables were prepared with various types of aggregates (alumina grog with or without thermal treatment) and fillers (with or without zircon addition), and they were evaluated in terms of their physical, thermal, and chemical properties. Microstructural analysis via scanning electron microscopy (SEM) was performed on the castables before and after slag attack. Compared to the other fabricated castables, the thermally treated alumina grog castables with zircon showed better physical properties, such as a higher bulk density, cold crushing strength, and modulus of rupture and a lower apparent porosity and water absorption. In addition, they had a higher positive linear thermal expansion, refractoriness under load, permanent linear change, and hot modulus of rupture. The results of the SEM with energy dispersive X-ray analysis of the prepared castables confirmed that the mullite and anorthite phases were predominant when zircon was not added and the zircon–mullite phase additionally appeared upon the incorporation of zircon. A quantitative elemental analysis via X-ray fluorescence spectroscopy was employed to determine the composition of the castables. X-ray diffraction analysis showed that the alumina grog castables had a high mullite and low anorthite content, and the thermally treated alumina grog had a high anorthite, low mullite, and high zircon content. The improvement in the mechanical and thermo-mechanical properties of the castables with thermally treated alumina grog and added zircon can be attributed to the formation of the zircon–mullite phase with a low mullite phase content.

中文翻译：

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热处理和添加锆石对再生氧化铝熟料低水泥浇注料性能的影响

摘要 在本研究中，使用从粉碎的氧化铝砖废料中获得的 70% 氧化铝熟料骨料制备低水泥浇注料。将骨料在 1550°C 下热处理 3 小时。用不同类型的骨料（经热处​​理或不经热处理的氧化铝）和填料（加或不加锆石）制备了四种低水泥浇注料，并对其物理、热和化学性能进行了评估。通过扫描电子显微镜 (SEM) 对熔渣侵蚀前后的浇注料进行微观结构分析。与其他预制浇注料相比，锆石热处理氧化铝熟料浇注料显示出更好的物理性能，如更高的堆积密度、冷压强度和断裂模量，以及更低的表观孔隙率和吸水率。此外，它们具有更高的正线性热膨胀、负载耐火度、永久线性变化和热断裂模量。SEM 和所制备浇注料的能量色散 X 射线分析结果证实，当不添加锆石时，莫来石和钙长石相占主导地位，而在掺入锆石时，还会出现锆石-莫来石相。使用通过 X 射线荧光光谱法进行的定量元素分析来确定浇注料的组成。X射线衍射分析表明，氧化铝熟料浇注料具有高莫来石和低钙长石含量，热处理后的氧化铝熟料具有高钙长石、低莫来石和高锆石含量。