THE KINETICS OF THE TRANSFORMATION OF QUARTZ TO TRIDYMITE IN THE PRESENCE OF OTHER OXIDES.
Abstract
The investigation is concerned with the kinetics of the transformation of quartz to tridymite, two of the polymorphs of silica (SiO2). The transformation was studied by heating quartz in the presence of other oxides in the temperature and composition range of tridymite stability. The systems studied were: Na2O-SiO2, PbO -SiO2, FeO -SiO2, and Cu2O-SiO2. The formation of cristobalite as an intermediate metastable phase in the tridymite stability range was reconfirmed. The reaction proceeds slowly at temperatures near the upper range of tridymite stability. As the firing temperature is decreased the rate is increased until a maximum is reached. Below this point the rate again decreases. A semilogarithmic plot of time versus temperature gives a C-curve. The rate of transformation was shown to be dependent on the amount of liquid present and the type of oxide added to the original quartz. As the amount of liquid is increased the rate of transformation is increased. The rate of transformation is affected by the type of liquid as follows: Na2O (fastest), PbO, FeO, Cu2O (slowest). An empirical relationship was developed to describe the kinetics of the transformation process.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1965
- Accession Number
- AD0617940
Entities
People
- Gerald I. Madden
Organizations
- University of Michigan