THE PVT PROPERTIES OF CONCENTRATED AQUEOUS-ELECTROLYTES .9. THE VOLUME PROPERTIES OF KCL AND K2SO4 AND THEIR MIXTURES WITH NACL AND NA2SO4 AS A FUNCTION OF TEMPERATURE

The densities of KCl and K2SO4 were measured from dilute solutions to saturation from 5 to 95°C. The data were combined with literature data to produce density and apparent molal volume, Vφ, equations from 0 to 100°C and to saturation. The standard deviations of the density equations were 30×10-6 g-cm-3 and 32×10-6 g-cm-3, respectively, for KCl and K2SO4. Pitzer equations were used to fit the Vφ data. The resulting infinite dilute partial molal volumes, Vo, were in reasonable agreement with literature data. The densities of the mixtures of the six combinations of the salts KCL, K2SO4 NaCl and Na2SO4 were measured at I=2.0 and t=5, 25, 55 and 95°C. The resulting volumes of mixing were fitted to equations of the form {Mathematical expression} where v 0 and v 1 are interaction parameters. The cross square rule is valid over the entire temperature range although the deviations are larger at higher temperatures. Pitzer θ NaK v and {Mathematical expression} parameters were determined from the common ion mixtures. The values of θ NaK v were small and not strongly dependent upon temperature. The values of {Mathematical expression} were also small and changed considerably with temperature. © 1990 Plenum Publishing Corporation.