Electrical conductances and ionization constants of calcium chloride and magnesium chloride in aqueous solutions at temperatures to 600oC and pressures to 4000 bars.

Abstract

Electrical conductances of calcium chloride and magnesium chloride in dilute aqueous solutions have been measured from 25o-600oC at pressures up to 4000 bars. The high-temperature conductance and association behavior of these two salts, present in natural waters, are of fundamental interest in understanding geothermal systems. Solution compositions of the salts used were between 0.001-0.005 molal. This low range of concentration was necessary for suitable application of conductance theory in calculating limiting equivalent conductances (LAMBDA0) and ionization constants. The results show that in CaCl2 and MgCl2 solutions with compositions <0.005 molal the salts exist primarily as Ca2+, Mg2+, and Cl- ions at temperatures below 400oC and densities >0.75g cm-3. Limiting equivalent conductances were computed in this temperature-density range.-Authors