Abstract MgO is pointed out as an alternative binder for refractory materials, mainly for systems where the presence of CaO might not be desired. Selecting the most suitable magnesia source is an important step as its purity and reactivity should influence the hydration reaction, leading to binding effect or cracks. This work investigated the design of vibratable high-alumina compositions bonded with MgO fumes [which is a very fine powdered oxide (d 2 formation and control the crystal growth of this phase. The green mechanical strength and thermomechanical performance (cold and hot mechanical strength, thermal shock, refractoriness under load, corrosion, etc.) of designed MgO-bonded compositions were analyzed. Improved green mechanical strength and crack-free samples were obtained when adding up to 6 wt% of MgO fumes to the refractories and processing them with aqueous solutions with 3 wt% of formic acid. The compositions with 6 wt% of magnesia fumes resulted in samples with flexural strength in the range of 12.0 MPa after curing at 50 °C/24 h and similar green mechanical strength (12.9 MPa) as the ones bonded with 4.0 wt% of calcium aluminate cement after drying at 110 °C for 24 h, which highlights the great potential of this MgO source. Despite the enhanced green mechanical strength, alumina-based castables containing 6 wt% of MgO (fumes, dead-burnt or their blend) showed low mechanical strength at intermediate temperatures and high linear expansion, as a consequence of the in situ spinel phase formation above 1200 °C. Thus, better densification, improved HMOR, thermal shock resistance and corrosion behavior were obtained for the castables prepared with less MgO fume contents.

中文翻译：

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氧化镁烟气作为含耐火浇注料的原位尖晶石的潜在粘合剂

摘要 MgO 被指出作为耐火材料的替代粘合剂，主要用于可能不需要 CaO 存在的系统。选择最合适的氧化镁源是重要的一步，因为其纯度和反应性会影响水合反应，导致结合效应或裂纹。这项工作研究了与 MgO 烟气结合的可振动高氧化铝组合物的设计 [这是一种非常细的粉末氧化物（d 2 形成并控制该相的晶体生长。生坯机械强度和热机械性能（冷和热机械强度，分析了设计的 MgO 键合组合物的热冲击、负载耐火度、腐蚀等）。当向耐火材料中加入高达 6%（重量）的 MgO 烟雾并用含 3%（重量）甲酸的水溶液对其进行处理时，可以获得提高的生坯机械强度和无裂纹样品。含有 6 wt% 氧化镁粉的组合物在 50 °C/24 h 下固化后产生的样品弯曲强度范围为 12.0 MPa，生坯机械强度 (12.9 MPa) 与使用 4.0 wt% 铝酸钙粘合的样品相似水泥在 110°C 下干燥 24 小时后，突出了这种 MgO 源的巨大潜力。尽管生坯机械强度有所提高，但含有 6 wt% MgO（烟气、重烧或它们的混合物）的氧化铝基浇注料在中温下显示出低机械强度和高线性膨胀，这是由于上述原位尖晶石相形成的结果1200℃。因此，更好的致密化，