| 摘要 |
PURPOSE:To obtain the titled composition wherein glass viscosity in a time of heat treatment is high and softening deformation in heat treatment is small by using SiO2, B2O3, Al2O3, MgO, CaO, Li2O, Na2O, K2O, SrO, ZnO and BaO of special composition. CONSTITUTION:A molded body having glass composition which consists of 43-65wt% (herein after %) SiO2, 0-8% B2O3, 5-18% Al2O3, 0-10% MgO, 10-30% CaO, 0-5% (SrO+ZnO+BaO), 15-30% total of bivalent metallic oxide (MgO+CaO+SrO+ZnO+BaO), 0-1% LiO2, 0-3% Na2O, 2-15% K2O and 2-15% total of alkali metallic oxide is heat-treated at 600-900 deg.C and after performing work such as crushing, if necessary, it is immersed in a mineral acid aq. soln. to elute a soluble component and a porous body is obtained.
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