Chemistry of borate in salt lake brine. XIV. phase transition and kinetics of dehydration during heating of MgO · 3B2O3 · nH2O

Abstract The temperature and enthalpy of dehydration or recrystallization of synthetic MgO · 3B 2 O 3 · n H 2 O ( n = 5, 6,7,7 1 2 ) during heating having been determined by DTA, TG, DTG and DSC. The products have been verified by X-ray powder diffraction, infrared spectrograms and chemical analysis and the thermochemical reactions have been given. The phase composition of the recrystallization at high temperature were confirmed as crystal-state 2MgO · 3B 2 O 3 and amorphous B 2 O 3 by physical analysis after the phase separated by esterification between B 2 O 3 and methol alcohol. Using TG and DTG data, the kinetic parameters have been calculated by computer and the kinetic equations of non-isothermo-dehydration reactions have been given.