An experimental and computational study of sodium-aluminum complexing in crustal fluids

Enhanced Geothermal Systems Research and Development: Models of Subsurface Chemical Processes Affecting Fluid Flow

“…In fitting the data (≈ 0° -300 o C), we found that the β 2 parameter became large and negative at high temperature. This is consistent with the use of an associated NaAl(OH)4(aq) ion species in the analysis of Diakonov et al (1996). However, for the level of association found we have shown that specific interaction model can provide better accuracy ).…”

“…However, for this high temperature range there is a considerable body of well determined boehmite solubility data to high pH that can be used for parameterization and validation. We used the solubility measurements of from 170° to 250 o C (pH > 8.0), which had very low concentrations (.01 m NaCl + NaOH), as well as the solubility measurements of Diakonov et al (1996) from 125° to 250 o C at 1 m NaCl. These data sets were selected because they provide the initial solution compositions and total aluminum concentrations, and we were interested in the possibility of ion association between the Na + and the Al(OH) 4¯ ions..…”

Heat capacities of aqueous sodium hydroxide/aluminate mixtures and prediction of the solubility constant of boehmite up to 300°C

“…The applications of such data include the quantitative description of the processes occurring during the formation or dissolution of aluminiumcontaining minerals, including gibbsite, boehmite, diaspore and other aluminium (oxy-) hydroxides (Wesolowski, 1992;Verdes et al, 1992;Bourcier et al, 1993;Castet et al, 1993;Diakonov et al, 1996;Bénézeth et al, 2001;Tagirov and Schott, 2001;Bénézeth et al, 2008), aluminosilicates (Wilkin and Barnes, 1998;Mashal et al, 2005), and the sodium aluminate-carbonate mineral, dawsonite, which has attracted recent interest in relation to the geochemical sequestration of the greenhouse gas CO 2 (Bénézeth et al, …”

The replacement of plagioclase feldspars by albite: observations from hydrothermal experiments

“…The absence of any secondary Al-bearing mineral phase except for albite demonstrates high solubility and therefore high mobility of Al in the experimental fluid. Diakonov et al (1996) demonstrated that the Al-solubility in a crustal fluid is mainly controlled by the formation of Na-Al complexes such as NaAl(OH) 4 0 . The association constant of these complexes and thus the solubility of Al 2 O 3 increases with increasing temperature and Na ?…”