AQUEOUS HIGH-TEMPERATURE SOLUBILITY STUDIES. II. THE SOLUBILITY OF BOEHMITE AT 0.03 M IONIC STRENGTH AS A FUNCTION OF TEMPERATURE AND PH AS DETERMINED BY IN SITU MEASUREMENTS

Abstract

The solubility of pure synthetic boehmite (γ-AlOOH) has been measured over a wide range of pH (2-10, depending on temperature), and temperature (100-290°C) at 0.03 mol . kg-1 ionic strength (NaCl) in a hydrogen-electrode concentration cell (HECC), which provided continuous in situ measurement of hydrogen ion molality (Palmer et al. 2001). A least-squares regression of the results obtained was used to determine the molal solubility quotients (Qs0 to Qs4) of boehmite. The solubility products (Qsn) were extrapolated to infinite dilution (Ksn), permitting calculation of the thermodynamic properties of aqueous species of aluminum for comparison with previous works, such as Bourcier et al. (1993) and Castet et al. (1993). These results are generally consistent with the latter study conducted near infinite dilution, although some significant differences are apparent, particularly near the solubility minimum.