Abstract
Fire resistant stone (FRS) in Niijima island of Tokyo consists mainly of glassy aluminosilicate. The purpose of this study is to develop a fluorophlogopite mica glass-ceramic from crashed FRS powder. A batch of starting materials was prepared by mixing 100 parts by weight FRS, 15 of magnesium oxide, 15 of potassium carbonate, 15 of magnesium fluoride and 10 sodium borate (anhydrous). The batch was melted at 1450°C for 2 hours and quenched in air. The gray glass obtained was reheated at 1150°C for 6 hours. The resulting light brown fluorophlogopite mica glass-ceramic had the following properties, i.e., thermal expansion coefficient of 100×10-7/°C, Shore hardness of 85, specific gravity of 2.6 and almost the same machinability as “Macor”.
