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This Final Report includes a summary and discussion of results obtained under this project on the solubilities in subcritical aqueous solutions of Mont St. Hilaire analcime, Wikieup analcime, and Castle Creek Na-clinoptilolite. Also included here are the methods and results of hydrothermal flow-through experiments designed to measure the rates of Na-clinoptilolite dissolution and precipitation at 125{degree}C. In this report, high-temperature solubility measurements made in our lab are integrated and discussed along with the low-temperature measurements made at Yale University. The final report prepared by the group at Yale University (Lasaga et al.) includes a synthesis of dissolution rate measurements made between 25{degree} and 125{degree}C on the Na-clinoptilolite.

The principal effort has been concentrated on the preparation of clean clinoptilolite, quartz, and boehmite and then reaction of the natural clinoptilolite solid solution to the Naendmember, plus measurements of the endmember solubility to derive an accurate equilibrium constant for the clinoptilolite dissolution reaction, correctly speciated. We are very pleased with the consistency between the best calorimetrically measured and modeled equilibrium constants and those we have determined from 125{degrees}C to 265{degrees}C. These results now provide a basis for relating measurements of reaction rates to departures from equilibrium.