CHEMISORPTION OF ETHYL XANTHATE ON SILVER GOLD-ALLOYS

The characteristics of the interaction of ethyl xanthate with silver-gold alloys have been compared with those of the pure component metals. Voltammograms for silver and silver-gold alloys (50:50 and 20:80 (wt.%)) in the presence of ethyl xanthate show that xanthate is chemisorbed on silver sites in the alloy surfaces at potentials below those at which silver ethyl xanthate is formed. The coverage of chemisorbed xanthate was determined for the alloys as a function of potential and found to fit the Frumkin isotherm previously derived for silver. when the decreased activity of silver in the alloys was taken into account. The potentials at which finite contact angles developed correlated with those for the onset of chemisorption. It is concluded that the presence of silver in native gold will render gold-bearing ores easier to float with ethyl xanthate as collector.