Abstract
As a fundamental experiment intended to examine a high caking tendency of refined salt, the authors studied a crystallizing process of two types of brine (A type was sulfate ion-rich, while B type was magnesium ion-rich) by concentrating them at 25°C and 55°C. Results were discussed from the viewpoints of changes in chemical composition, solid phase during crystallization, changes in the density of mother liquid and the ratio of sodium ion crystallized to total sodium ion. As a consequence, the following results were obtained:
1. In concentrating A type brine at 25°C, Na2SO4 crystallized, and the crystallizing process agreed with calculated process. During the concentration of B type brine, astrakanite crystallized, and the process agreed fairly well with calculated process. In case of B type brine, the mother liquid had a tendency to super-saturate with sulfate ion.
2. In concentrating A type brine at 55°C, Na2SO4 and vanthoffite crystallized. The process did not agree with calculated process because the concentrated solution super-saturated with sulfate ion. During the concentration of B type brine, astrakanite and loeweite crystallized. However, the process did not agree with calculated process.
3. During the crystallization, the density of mother liquid of B type brine increased more rapidly than that of A type brine.
4. During the crystallization, the sodium ion crystallized from B type brine was larger in ratio than that crystallized from A type brine.
