Viscosity for aqueous Li2SO4 solutions at temperatures from 298 to 575 K and at pressures up to 30 MPa

Viscosities of four aqueous Li2SO4 solutions [(0.10, 0.28, 0.56, and 0.885) mol(.)kg(-1)] have been measured in the liquid phase with a capillary flow technique. Measurements were made at four isobars [(0.1, 10, 20, and 30) MPa]. The range of temperatures was from (298 to 575) K. The total uncertainties of viscosity, pressure, temperature, and concentration measurements were estimated to be less than 1.5%, 0.05%, 10 mK and 0.014%, respectively. The reliability and accuracy of the experimental method were confirmed with measurements on pure water for three isobars [(10, 20, and 30) MPa] and at temperatures between (298 and 575) K. The experimental and calculated values from the IAPWS (International Association for the Properties of Water and Steam) formulation for the viscosity of pure water show excellent agreement within their experimental uncertainty (AAD is about 0.51%). A correlation equation for viscosity was obtained as a function of temperature, pressure, and composition by a least-squares method from the experimental data. The AAD between measured and calculated values from this correlation equation for the viscosity was 0.7% for pure water and 0.74% for the solutions. The measured values of viscosity at atmospheric pressure were compared with the data reported in the literature by other authors.