Leppinen, FTIR studies

Leppinen, J. 0., Basilio, C. I, Yoon, R. H., 1989. In-situ FTIR study of ethyl xanthate adsorption on sulphide minerals under conditions of controlled potential. Int. J. Miner. Process, 26 259 - 274... 

Figure 4.51. SEC-MIR cell constructed for in situ FTiR studies of reactions on mineral-particle bed electrodes. Reprinted, by permission, from J. O. Leppinen, C. I. Basilic, and R. H. Yoon, Int. J. Min. Process. 26, 259 (1989), p. 260, Fig. 1. Copyright 1989 Elsevier Science Publishers B.V.

Leppinen (1990) used FTIR-ATR techniques to study the adsorption of ethyl xanthate on pyrite, pyrrhotite and chalcopyrite. The FTIR spectra of the reaction products on pyrite, pyrrhotite and chalcopyrite after treatment with 1x10 mol/L KEX solution at pH = 5 is presented in Fig. 1.7. He found that the FTIR signals... 

Leppinen et developed an electrochemical cell in which FTIR spectroscopy could be carried out in situ on mineral particles under potential control. This approach provided a much better means of controlling the surface condition and allowed the results to be related to findings derived from complementary electrochemical techniques. In addition, ex situ FTIR spectroscopy has been applied to the study of the interaction of thiols with sulfide and metal surfaces as a function of potential. 

Figure 19 shows the reflectance spectra reported by Leppinen etal for the interaction of ethyl xanthate with chalcopyrite. The peaks at 1240 and 1260 cm" are characteristic of dixanthogen, and the spectra indicate that this species was the initial surface product. Copper xanthate has characteristic peaks near 1190 cm" and it can be seen from Fig. 19 that this compound is deposited additionally at the higher potentials applied. This order of product formation is as expected from studies of chalcopyrite oxidation (see Section VII. 1). Leppinen et found that the development of FTIR intensity correlated with the growth of voltammetric currents. No evidence was reported for adsorption of xanthate at lower potentials than dixanthogen deposition as would be expected from the UV-vis results of Richardson and Walker." The absence of a clearly discernible xanthate spectrum in the potential range expected for chemi-... 

A different conclusion regarding the flotation of chalcopyrite was reached by Leppinen et based on in situ FTIR spectroscopic studies. 

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