THERMODYNAMICS AND KINETICS OF THE DEHYDROXYLATION OF HYDROUS MINERALS.
Final rept. for Aug 64-Jun 65,
PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB
Pagination or Media Count:
The evolution of water from serpentine and kaolinite has been studied in relation to temperature and water vapor pressure. For both minerals, the dehydroxylation reaction is controlled primarily by a diffusion process. Additional data are presented for the dehydroxylation of brucite which show the intrinsic difficulties of establishing the basic dehydroxylation mechanisms of hydrous minerals. The previously reported high pressure dehydration data are extended to the mineral diaspore, and additionally a summary is provided of the temperatures of dehydration of a number of minerals at water vapor pressures of 1 atm, 100 psi, 1000 psi, and 10,000 psi, together with values for the heats of reaction, deltaH, in calg of mineral at 1 atm. vapor pressure. A preliminary exploration was made of the possible effects of proton bombardment such as can arise by solar wind on the lunar surface on retention of protons by minerals, and on their dehydration behavior. Insofar as protons are captured, there is the possibility of an additional source of lunar water and insofar as minerals are disordered by the bombardment, there is the possibility of an easier release by hydroxyl water. The tentative results obtained indicate the possibility of both these effects, though their magnitude under lunar conditions and with geological time are still unknown.