MODIFICATION OF SURFACE-TENSION IN AQUEOUS-SOLUTIONS OF SODIUM OLEATEACCORDING TO TEMPERATURE AND PH IN THE FLOTATION BATH

A study has been carried out on the modification of surface tension in aqueous solutions of the collector sodium oleate, with temperatures i n the bath ranging between 293 and 323 K, and pH between 4 and 12. The results obtained indicate that surface tension is greatly affected by these two parameters. As temperature is increased in the bath, the su rface tension of the solution decreases in all cases for the range of sodium oleate concentrations between 7.3 x 10(-6) and 6.2 x 10(-4) M. Minimum values for surface tension were also found to shift toward the pH 10 value as the agent concentration is increased, regardless of th e temperature of the solution. Certain thermodynamic magnitudes associ ated with the adsorption of sodium oleate at the solution-air interfac e were also obtained. A decrease in free standard energy was also note d on adsorption of the surfactant at this interface. (C) 1995 Academic Press, Inc.