抄録
The authors studied the influence of zircon on the reaction between alumino-silicate materials and magnesium oxide for cordierite formation in the fire clay refractories.
Specimens were fired at SK 14 (1410°C) in a tunnel kiln for 40 hours. The measurements of thermal expansion and linear changes of the specimens by reheating were carried out. The crystal phase of the specimens were examined by X-ray analysis.
The results obtained are as follows:
(1) By the addition of zircon to the mixture of clay and magnesium oxide the following reaction is promoted at about 1400°C,
3(3Al2O3·2SiO2)+6(MgO·SiO2)+5SiO2→3(2MgO·2Al2O3·5SiO2).
(2) The formation of glassy phase in the refractories is inhabited by the promoting the above reaction.
(3) The inversion of hexagonal form to orthorhombic form of cordierite is caused by such addition of zircon.
