Thermodynamic and technico-economic analyses of the HCl-leach of magnesiteand serpentine

Commercial HCl-leaching of magnesite and serpentine yields highly concentra ted aqueous solutions containing 25 mass % to 33 mass % MgCl2. The partial molar enthalpies and heat capacities, the ionic activities of Mg2+ and Cl- and the Raoultian activity of H2O have been assessed for the concentrated M gCl2-H2O solutions at temperatures of 348 to 373 K. These thermodynamic dat a are used to calculate the pH of aqueous MgCl2 solutions saturated with a Mg-bearing mineral such as magnesite, serpentine, brucite, forsterite, enst atite or talc On the basis of these thermodynamic data, technico-economic a spects are discussed as to neutralization with pulverized MgCO3, water evap oration from the MgCl2 solutions and ore composition including such minor c onstituents as CaCO3, FeCO3 and Fe3O4.