| 摘要 |
<p>The present invention relates to a protection tube for protecting heaters and sensors used in melting furnace for reprocessing of incinerator ash, other melting furnace, and various other furnaces, the protection tube being excellent in resistance to heat and resistance to corrosion so as to be usable favorably for a long period. The heat- and corrosion-resisting protection tube is formed in a tubular body closed at an end, being composed of ceramics, and the ceramics have a softening point over 1700 DEG C in the air atmosphere, a three-point bending strength of 150 MPa or more at 1450 DEG C, a resistance to heat shock of DELTA T of 150 DEG C or more by water quenching method, and a mean grain size of 2 mu m or more, having a composition of 50 mol % or more of Al2O3 and 50 mol % or less of MgO.</p> |
