作者：Jianjun Chen; Guoqing Xiao; Donghai Ding; Xue Li; Chaofan Yin; Qingfeng Wang; Yunfei Zang; Binbin Dong; Junrui Yang
作者單位：School of Materials Science and Engineering, Luoyang Institute of Science and Technology, Luoyang, 471023, China;College of Materials Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China;College of Materials Science and Engineering, Henan University of Science and Technology, Luoyang, 471023, China
刊名：Ceramics International
ISSN：0272-8842
出版年：2024-10-10
卷：50
期：21
起頁：43635-43643
止頁：
分類號：
語種：英文
關鍵詞：Hydrated magnesium citrate cement;Corundum-spinel castable;Thermal shock resistance;Workability
內容簡介The hydrated magnesium carboxylate cement (HMC) with varying C6H5O72−/Mg2+ ratios was prepared by adjusting the ratio of citric acid to magnesia in this study, and its effect on the performances of corundum-spinel refractory castables were investigated. The results revealed that the HMC bonded castable's workability was improved by increasing the C₆H₅O₇3⁻/Mg2⁺ ratio. Specifically, the sample C-EX (citric acid/magnesia = 4.5) compared to the standard sample NO (citric acid/magnesia = 3.5), the setting time was extended by 100 min, and the flow value increased by 77.6 %. Hydration kinetics experiments demonstrate that this phenomenon was due to the excess citric acid inhibiting HMC ionization. Furthermore, increasing the C₆H₅O₇3⁻/Mg2⁺ ratio also enhanced castables' medium-temperature mechanical properties and thermal shock resistance. The excess citric acid enhanced the castable slurry's performance, resulting in a 37.8 % increase in cold modulus of rupture for the C-EX sample after sintering at 500 °C compared to the sample NO. The fracture strength after thermal shock is 27.9 % higher in sample C-EX than in sample NO. This improvement is attributed to the 82.1 % increase in toughness of the sample C-EX, which facilitates the micro-cracks formation but inhibits their propagation. However, it should be noted that increasing the proportion of citric acid reduced the aspect ratio of HMC hydration products, leading to decreased mechanical properties of the castables.
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