A STUDY OF MONOMOLECULAR FILMS BY TRACER TECHNIQUE
The variation of surface concentration with solution concentration when xanthate is adsorbed from water solution by pyrite and galena has been determined by making use of sulfur-35 labelled potassium ethy santhate of high specific activity. Surface concentration was found to increase with solution concentration up to 2 to 4 mg. per liter of solution, whereupon a limiting vlue of suface concentration was reached: 9.94x1013 ions/cm.2 for pyrite and 3.65x1014 ions/cm.2 for galena. Although the limiting value was reached in a conditioning time of five minutes, immersion of conditioned mineral in water for ninety minutes did not decrease the surface concentration. It is proposed, therefore, that the formation of unsaturated surface films is due to lack of sufficient time for adsorption of a saturated layer.