Accession Number:

AD0606185

Title:

THE SOLUBILITY OF QUARTZ IN H2O IN THE RANGE 1000-4000 BARS AND 400-550C,

Descriptive Note:

Corporate Author:

CALIFORNIA UNIV BERKELEY

Personal Author(s):

Report Date:

1964-07-07

Pagination or Media Count:

30.0

Abstract:

The solubility of quartz in H2O has been measured between 1-4 kilobars at 400, 450, 500, and 550 C. Two rate studies at 400 and 625 C are consistent with an equation of the form dxdt a-bx for the rate of solution of quartz in H2O, where x is the concentration of SiO2 in solution at time t. The temperature dependence of the two specific rate constants, a and b, give values of approximately 16.5 and 14.5 kcalmole for the activation energies of the dissolution and crystallization processes respectively. The temperature and pressure dependence of solubility used in conjunction with the most widely accepted reaction for the solution of quartz, SiO2 qtz 2H2O reversibly yields Si OH4, lead to thermodynamic calculations indicating unreasonable behavior of the assumed solute species. It is suggested that these anomalies may reflect the inability of the accepted solution reaction to represent the heterogeneous equilibrium between quartz and solution over a large range of temperature and pressure. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE