| 摘要 |
PROBLEM TO BE SOLVED: To enable safe operation of a furnace, by performing a impregnation treatment of colloidal silica to significantly improve the useful life longevity and minimize the amount of a matter adhered onto the internal wall surface of the furnace. SOLUTION: In this induction furnace, a lining material of an electric type induction furnace employs a melted quartz oriented material as main material. A baked refractory, a refractory which is integrally formed with a side wall 1 and fired beforehand, is impregnated with a colloidal oxide and undergoes a heat treatment at the temperature of 20 deg.C or higher. This impregnation treatment is conducted more than once. The refractory with an permeability of 10 cm cm/cm<2> .g/cm<3> .sec. is arranged as innermost lining material and the outer circumference part thereof is filled with a dry monolithic refractory having a thermal expansion coefficient more than equal to that of the lining material to build a double-layer structured furnace. |
