Abstract
The relationships between composition and solution properties, such as density, viscosity, electrical conductivity and refractive index, in the concentration process of brines obtained by the ion exchange membrane were examined. Moreover estimation models of each solution property were formulated. Each solution property changes with an increase in magnesium ion content (CMg) as a barometer of concentration degree. The behavior of each change differs in the following ranges of concentration degree; they are the unsaturation range, the deposition range of sodium chloride, and the deposit range of sodium chloride and potassium chloride. Moreover, the purity of sodium chloride in brine (PNaCl) and temperature (t) affect the relationship between each property and magnesium ion content. From the data obtained, empirical formulas for estimating each property were developed using applying CMg, PNaCl and t as predictor variables. It has been suggested that each property can be estimated with high precision using these empirical formulas, in the range of CMg=5% (22.4% as MgCl2 content) and less, PNaCl=87-93%, and t=50-90°C.
