Viscosity, density, and refractive index of aqueous sodium and potassium aluminate solutions

The viscosities, densities, and refractive indices of synthetic sodium and potassium aluminate solutions are reported as a function of aluminum and ca ustic concentration, total caustic to Al(III) molar ratio, and temperature. The influence of hydrogen isotope was also explored through complementary studies on deuterated solutions. A significant alkali metal ion effect on t he viscosity and density is indicated, the influence of the other primary v ariables shown to range from strong to moderate. Under similar solution con ditions, the sodium ions display stronger solute interactions and greater s olution structure-making ability, reflected in higher solution viscosity (a nd enhanced density), than do potassium ions. The effect of Al(III) solute concentration, caustic to Al(III) ratio, ionic strength, and hydrogen isoto pe on the solution bulk properties is discussed and their relevance to spec iation and the interactions of species in Payer liquors is highlighted. Emp irical models for viscosity and density are proposed.