Influence of Water Vapor on the Rate of the Sluggish Inversion of Silliceous Stone

Abstract

It is a well known fact that the rate of the conversion of silicates is considerably accelerated by the presence of water vapor. Adsorbed water vapor on the surface of silicates serves as the starting point in the growth of crystals. It is perhaps attributed to the contra polarization accomplished by water molecule. As qualitative acceleration until now has been reported, the author attempted to find the rate constant of the conversion of siliceous stone in water vapor.Photomicrograph of the sample of siliceous stone and its chemical analysis were shown in Fig. 1 and in Table 1. Air in the furnace tube was driven off, and water vapor of one atmospheric pressure was introduced. And siliceous stone samples put in platinum boat were fired in this tube. Linear relation between log k and 1/T was satisfied for the primary reaction in the presence of water vapor of one atmospheric pressure also. The rate of the reaction in water vapor of one atmospheric pressure was compared with that in air which contained water vapor of about ten mm Hg. (Fig. 2). On their behavior above 1600°C the author could not obtain any accurate experimental data.According to W. Jander and W. Stamm energy of activation did not varied in the presence of water vapor, but only the frequency coefficient has varied, in the case of solid reaction of two components; i.e. BaCO3+SiO2, BaCO3+WO3, CaCO3+MoO3. But in the case of sluggish inversion of siliceous stone both activation energy and frequency coefficient have varied.According to T. Ao influence of steam on the sintering velocity has become greater as the firing temperature approached to the melting point of samples. On the contrary, about the transformation of the siliceous stone the influence of water vapor on the transformation velocity was smaller as the temperature rose and approached to the melting point of siliceous stone.