Zemánek David, Nevřivová Lenka
Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00 Brno, Czech Republic.
Materials (Basel). 2022 Aug 26;15(17):5918. doi: 10.3390/ma15175918.
Colloidal silica is used in many kinds of industry. It is an aqueous dispersion of SiO nanoparticles. SiO colloidal solutions are commercially available in different concentrations, with different particle sizes and are stabilized with different ions. Colloidal SiO was used in this study as a cement replacement in refractory castable. The present study, in its first stage, offers an assessment of five different SiO colloidal solutions. The particle size of the solutions was 15 nm, the particle concentration was 30% and 40% and the colloidal solutions were stabilized with Na, OH and Cl ions. The effect of the colloidal solutions on selected characteristics of the refractory pastes and on their mineralogical composition after firing at 1000 °C and 1500 °C was described. The most suitable SiO colloidal solution from the first stage was subsequently used for the refractory castable test samples' preparation in the second stage. Refractory castables, unlike paste, contain a coarse aggregate (grog) up to a grain size of 6 mm. Four types of coarse refractory grog were evaluated. Their effect on selected characteristics of the refractory castable and on its mineralogical composition after firing at 1000 °C and 1500 °C was described. The selected characteristics, within the scope of this study, include bulk density, apparent porosity, cold modulus of rupture and linear changes after firing. Finally, the study describes the effect of the sol particle concentration and the effect of pore size distribution on corrosion resistance and on the internal structure of the material. Mineral and chemical compositions and microstructures of both the raw materials and designed aggregates were thoroughly investigated by the means of X-ray fluorescence spectroscopy, powder X-ray diffraction and scanning electron microscopy. An analysis of the transition zone between corrosive media (KCO) and tested castables showed better corrosion resistance for a sol-gel castable than an ultra-low cement castable.
胶体二氧化硅应用于多种工业领域。它是SiO纳米颗粒的水分散体。SiO胶体溶液有不同浓度、不同粒径且用不同离子进行稳定化处理，在市场上均可买到。本研究中，胶体SiO用作耐火浇注料中的水泥替代物。本研究的第一阶段对五种不同的SiO胶体溶液进行了评估。溶液的粒径为15纳米，颗粒浓度为30%和40%，胶体溶液用Na、OH和Cl离子进行稳定化处理。描述了胶体溶液对耐火浆料选定特性以及在1000℃和1500℃焙烧后其矿物组成的影响。第一阶段最合适的SiO胶体溶液随后用于第二阶段耐火浇注料测试样品的制备。与浆料不同，耐火浇注料含有粒度达6毫米的粗骨料（熟料）。评估了四种类型的粗耐火熟料。描述了它们对耐火浇注料选定特性以及在1000℃和1500℃焙烧后其矿物组成的影响。在本研究范围内，选定的特性包括体积密度、显气孔率、常温抗折强度和焙烧后的线变化。最后，该研究描述了溶胶颗粒浓度的影响以及孔径分布对耐腐蚀性和材料内部结构的影响。通过X射线荧光光谱法、粉末X射线衍射和扫描电子显微镜对原材料和设计的骨料的矿物和化学成分以及微观结构进行了全面研究。对腐蚀介质（KCO）与测试浇注料之间的过渡区分析表明，溶胶-凝胶浇注料比超低水泥浇注料具有更好的耐腐蚀性。
