A Pitzer-based characterization of aqueous magnesium chloride, calcium chloride and potassium iodide solution densities to high temperature and pressure

A comprehensive characterization of densities/apparent molar volumes for the aqueous solutions of magnesium chloride, calcium chloride and potassium iodide to high temperatures and pressures has been performed based on the Pitzer equations. The unusual availability of overlapping high quality independent sets of experimentally measured data for these systems allows the relevant thermodynamic quantities to be calculated with a high degree of confidence over wide ranges of conditions (< 8 mol kg−1; 273–573 K; 0.1–100 MPa). A realistic assessment of experimental uncertainty indicates that an adequate description of volumetric behaviour is achieved by the standard Pitzer model without extensions. The experimental accuracy implied by differences between independent observers, however, is more than one order of magnitude worse than typically claimed estimates of experimental precision.

► Pitzer-based density model for MgCl2(aq), CaCl2(aq) and KI(aq). ► Independent authors have published data up to high temperature and pressure. ► Data trends are well represented to high concentration. ► Differences between investigators commonly exceed combined data uncertainties.