THE SOLUBILITY OF 1 1 NITRATE ELECTROLYTES IN SUPERCRITICAL WATER/

A novel method was developed for determining the solubility of sodium nitrate in water solutions at pressures ranging from 248 to 300 bar an d temperatures from 450 to 525 degrees C. Sodium nitrate solubilities determined by this method ranged from 293 mg kg(-1) at 248 bar and 525 degrees C to 1963 mg kg(-1) at 300 bar and 450 degrees C. A simple hy dration mechanism was used to model the data. In addition, solubilitie s were determined for potassium and lithium nitrate salts to assess th e effect of ion size on solubility. These experiments determined that the solubility was proportional to the ion size, so that solubility de creased in the order LiNO3 > NaNO3 > KNO3. These studies were motivate d by applications for sodium nitrate in hydrothermal treatment methods , especially supercritical-water oxidation.