シラスの工業的利用に関する研究-17-シラスガラス-カルシウム-マグネシア系ガラスの結晶化

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Shirasu volcanic glass (shorten as SVG) separated from the original Shirasu obtained in southern Kyushu has a fixed chemical composition and contains about 75% SiO_2 by weight.In this paper, SVG was assumed to be a component and the glass-forming region in the system SVG-CaO-MgO was investigated by quenching the melts produced at 1400~1500°C into cold water. The obtained SVG-CaO-MgO glass crystallized above 900°C. The crystal phases precipitated in the heat-treated SVG-CaO-MgO glass at 1100°C for 1 h were akermanite, diopside and forsterite.Physical, optical, chemical and thermal properties and bending strength of the glasseswere investigated. Results are as follows : apparent density 2.67~2.76g/cm^<3>, bending strength 539~882kg/cm^<2>, hardness (D.P.H) 613~713kg/mm^<2>, refractive index 1.578~1.622 ± 0.003,thermal expansion co-efficient (room temperature~700°C) 5.9~9.3×10^<-6>/°C. The glassesshowed high resistance to alkaline solution, namely the mean weight loss of the glasses whichhad been treated by 2N-NaOH solution at 100°C for 14 h was so small as to be 0.7%.
鹿児島大学,カゴシマダイガク,Kagoshima Universityの論文