Abstract
The authors have made a study on the behaviors of minor components in the process of concentrating sea water. The present study dealt with the behaviors of zinc and cobalt ions by using radioactive tracer 65Zn and 60Co.
Zinc and cobalt ions behaved in the similar manner, and indicated a greater loss from the solution evaporated at higher temperature. In contrast with strontium, calcium and phosphate, however, they were never rapidly lost in the final stage of concentration. Therefore, 30-50% of them remained in the solution even after 95% of sea water was evaporated. Most of the zinc and cobalt deposited were distributed into insoluble gypsum deposit, and almost none of them were contained in soluble salt.
Zinc and cobalt in sea water were determined spectrophotometrically with zincone and nitroso R salt, after they were concentrated and separated coprecipitation with aluminium hydroxide. Zinc was concentrated and separated by ion exchange procedure, and cobalt by solvent extraction with dithizone, respectively. As the result of analysis of several sea-water samples, zinc was estimatezd at 0.3-0.5μg/1, while cobalt at 4-10μg/1.
