作者：SATOI KANATANI;EIZO MAEDA;KATSUFUMI JONO;
作者單位：Material Development Dept., JFE Refractories Corporation 1576-2, Higashioki, Nakahiro, Ako-shi, Hyogo, 678-0232 Japan;Material Development Dept., JFE Refractories Corporation 1576-2, Higashioki, Nakahiro, Ako-shi, Hyogo, 678-0232 Japan;Material Developmen
刊名：Journal of the Technical Association of Refractories
ISSN：0285-0028
出版年：2009-01-05
卷：29
期：1
起頁：26
止頁：34
分類號：TQ175
語種：英文
關鍵詞：Low-cement castable;Setting mechanism;Coagulation;Superfine powder;Ca~(2+) ion;
內容簡介The setting mechanism of low-cement castables was investigated from several viewpoints. From the results obtained, the setting mechanism was concluded to be as follows: The setting of castables entails the coagulation of a hydrophobic colloid of superfine ceramic powder stabilized by a deflocculant. Ca~(2+) ions dissolve from alumina cement into the mixing water of the castable. When the Ca~(2+) ion concentration increases above a certain value the colloid becomes unstable due to the Ca~(2+) ions and coagulation occurs. The role of the alumina cement in the mechanism is the supplier of Ca~(2+) ions. The Ca~(2+) ion dissolution rate is considered to be determined by Ca element diffusion in the surface layer of the alumina cement grains. In the castables containing sodium tri-poly-phosphate (STTP), a chelate is formed initially and a secondary precipitate is formed by the reaction of Ca~(2+) ions and tri-poly-phosphate ions. After STTP is consumed by the reaction, the Ca~(2+) ion concentration increases and coagulation occurs.
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