In situ FTIR study of ethyl xanthate adsorption on gold, silver and copper electrodes under controlled potential

Abstract

The applicability of a spectroelectrochemical metbod to the problems related to flotation was studied. The object of the study was to investigate the adsorption of ethyl xanthate on gold, silver and copper surfaces. Spectra were obtained using subtractively normalized interfacial Fourier tramform infrared spectrowopy, which allows potential control of the electrode while recording an infrared spectrom at the electrode surface. For each metal, a good correlation exists between the spectral intensities of the product of the surface reaction and the voltammogram of the metal electrode immersed in xanthate solution. On gold, xanthate is oxidized to dixanthogen, which is then adsorbed onto the gold surface. In the case of both silver and copper, xanthate reacts with the surface in two separate steps. The first comprises chemisorption of xanthte, the result beiig a monolayer of metal xanthate-like surface compound. The second, more anodic, step is the formation of multilayers of metal xanthte.

AFM force measurements between gold and silver surfaces treated in ethyl xanthate solutions: Effect of applied potentials

“…The voltammogram obtained in the presence of 10 À3 M KEX was similar to those reported by others (Talonen et al, 1991;Woods, 1971). The anodic peak observed at 450 mV was due to the following reaction,…”

Temperature effect on xanthate sorption by chalcopyrite

“…Research studies on collector adsorption in various systems have been discussed in a number of publications [1][2][3][4][5]. As far as the sulfide ores are concerned, after long and controversial debates, it has now widely been accepted that there are two different mechanisms by which xanthate adsorbs on sulfide minerals: the chemisorption [6][7][8][9][10] process which results in the presence of chemisorbed metal xanthate at the mineral surface and an electrochemical [11,12] process where an oxidation product is formed at the surface of the sulfide.…”

Flotation of Gold and Gold-Bearing Ores

“…The adsorption of ethyl xanthate on silver is generally thought to take place through an electrochemical mechanism of metal xanthate formation on the surfaces (Talonen et al, 1991;Woods et al, 1992;Yoon and Basilio, 1993). The positive effect that silver has on gold floatability was first recognized in experiments using plates of pure gold, silver, and goldesilver alloys.…”