Isopiestic investigation of the osmotic coefficients of MgBr2(aq) and study of bromide salts solubility in the (m1KBr+m2MgBr2)(aq) system at T=323.15K. Thermodynamic model of solution behaviour and (solid+liquid) equilibria in the MgBr2(aq), and (m1KBr+m2MgBr2)(aq) systems to high concentration and temperature

Solubility measurement and solid-liquid equilibrium model for the ternary system MgBr2 + MgSO4 + H2O at 288.15 K

“…According to the parameters and the measured solubilities of the ternary system in this work, the equilibrium constants of the minerals in the ternary system at 288.15 K were fitted for each stable solution by a method using the activity product constant. For MgBr 2 ·6H 2 O at 288.15 K, the lnKsp is 11.6742, which is very close to the data in the literature (Christov, 2011;Meng, 2013). For MgSO 4 ·7H 2 O, the lnKsp calculated using the pure electrolyte parameters and the solubility data in our study is -4.7194, which is very close to the data in the literature (Marion and Farren, 1999), but the lnKsp for magnesium sulfate hydrate at the other points in the solubility isotherm are very different.…”

“…These average equilibrium constants (lnK aver ) and uncertainties for the equilibrium solid salts of MgSO 4 ·7H 2 O, MgSO 4 ·6H 2 O are presented in Table 4. Christov, 2011Christov, 2011Christov, 2011Marion and Farren, 1999Marion and Farren, 1999Marion and Farren, 1999Marion and Farren, 1999Christov, 2012b This work …”

“…The Pitzer binary parameters for MgBr 2 , and the mixing parameters 4 Br,SO θ were calculated from the temperature-dependent equations presented in the literature (Christov, 2011;Christov, 2012b). The Pitzer binary parameters for MgSO 4 can be gotten from the literature (Spencer et al, 1990;Marion and Farren, 1999), but the parameter β (2) for MgSO 4 is not mentioned in the literature (Spencer et al, 1990).…”

“…The phase equilibria of some three-, four-or fivecomponent bromine-containing systems have been reported (Sang et al, 2011;Cui et al, 2013;Christov, 2012aChristov, , 2012bChristov, and 2012cChristov, 2011). The ternary system MgBr 2 + MgSO 4 + H 2 O has previously been investigated at 273.15, 298.15 and 308.15 K since the 1960s, but the solubility data and the reports of the corresponding equilibrium solid phases are not complete.…”

“…Single ion activity coefficients, which are more convenient to use in solubility calculations, are given in the Harvie and Weare modelling approach (Harvie and Weare, 1980;Harvie et al, 1984). On the basis of the Pitzer approach and its extension the Harvie-Weare (HW) model (denoted hereafter as the Pitzer and HW model), the solubilities of the systems containing bromine were predicted (Meng, 2013;Christov, 2012aChristov, , 2012bChristov, and 2012cChristov, 2011), and these predictions demonstrated that the Pitzer and HW model could be expanded to calculate the solubility of bromine minerals in complex brines accurately. However, studies modelling the ternary system MgBr 2 + MgSO 4 + H 2 O at 288.15 K are still lacking in the literature.…”