作者：SATOI KANATANI;EIZO MAEDA;KATSUFUMI JONO;

作者单位：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

起页：26

止页：34

分类号：TQ175

语种：英文

关键词：Low-cement castable;Setting mechanism;Coagulation;Superfine powder;Ca~(2+) ion;

内容简介

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.