Effect of dispersants on the hydrate morphologies of spinel-containing calcium aluminate cement and on the properties of refractory castables

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• 作者：Yulong Wang ; Boquan Zhu ; ^{zhuboquan@wust.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Xiangcheng Li ; ^{lixiangcheng@wust.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Pingan Chen
• 关键词：Dispersants ; Spinel-containing calcium aluminate cement ; Hydrate morphologies ; Long-column AH3
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：42
• 期：1
• 页码：711-720
• 全文大小：9912 K

文摘

This research studied the effects of several dispersants on the morphologies of cement hydrates and properties of refractory castables. The results showed that the cement hydrate morphologies were closely related to the types of dispersants used. With naphthalene sulfonate formaldehyde condensate (FDN) and sodium tripolyphosphate (STPP) as dispersants, the cement hydrate of C₃AH₆ obtained anomalistic shapes, and the AH₃ particles showed a diameter of not more than 1 μm. When propionic acid (PA) was added, C₃AH₆ formed inerratic cubical grains, whereas AH₃ changed from particles to long column agglomerates; the ratio of the long radius increased with increasing PA concentrations. The addition of PA as dispersant generated CaCH₃CH₂CO₂⁺, which resulted in a decrease in Ca²⁺ concentration. Also, the relatively higher apparent porosity satisfied the space requirement for the growth of C₃AH₆, eventually resulting in larger inerratic cubical grains. The H⁺ hydrolyzed from PA accelerated the growth on the (100) and (110) crystal planes of AH₃; thus, gibbsite stretched along the c-axis. The maximum values of CCS and CMOR for refractory castables prepared with PA as dispersant were 5.6 MPa and 46.6 MPa, respectively, which were higher than those for refractory castables with FDN and STPP. The observed excellent performance in strength might be related to the bridging effect resulting from the long-column AH₃.