Interaction between sodium silicate melts with concentration gradient of sodium and silicon oxides

A study is undertaken on the interaction between 30Na(2)O.70SiO(2) and 15Na(2)O.85SiO(2) melts in the temperature range 850-1050 degrees C for reaction times of 2, 4, and 8 h. It is found that the concentration profiles plotted on the N-(x/root t) coordinates coincide very closely. This fact provides support for the diffusion kinetics of interaction. The effective diffusion coefficients for the silicon-oxygen associates at 850, 950, and 1050 degrees C are equal to 1.3 x 10(-10), 1.8 x 10(-10), and 2.5 x 10(-10) cm(2)/s, respectively. The activation energy for diffusion is 11 +/- 2 kcal/mol. The kinetic and energy parameters of the interaction are discussed in terms of oxygen ion activity. The interdiffusion and viscous flow processes are considered.