Oxide Melts Studied by High Temperature High Pressure Calorimetry

点击翻译按钮获取中文摘要

Oxide melts like silicate,borate,and aluminosilicate are important in the field of metallurgy,glass ceramics as well as earth science.In the present progect it was intended to measure the thermodynamic heat contents directly in molten state in a calorimeter,along with other studies with electrochemical and spectroscopic techniques.A high temperature calorimeter of Tian-Calvet type was constructed and applied to measure(1) the heat contents of silica-alumina non-crystalline powder prepared by the sol-gel method and(2) the heat of reaction of sodium carbonate with boric oxide melt.In the former, the powder samples of various heat treatment was dissolved in 2PbO・B_2O_3 solvent.Heat content variation which increases with the alumina content suggests coordination change around Al atom with heat treatment.In the latter,due to the viscous nature of the solution CO_2 evolution was not smooth enough to give reproducible results.This measurement was carried out to find proper condition to handle the system associated with water vapor.A linear sweep voltammetry for redox equilibrium measurement was applied in varous melts in parallel with the calorimetry.Molecular bynamics simulations as well as quantum mechanical calculation were also attempted for better understanding of the oxide melts.