Infrared Evaluation of Composition and Structure of Ethyl Xanthate Monolayers Produced on Chalcopyrite, Tetrahedrite, Tennantite at Controlled Potentials
✍ Scribed by J.A. Mielczarski; E. Mielczarski; J.M. Cases
- Book ID
- 102579305
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 194 KB
- Volume
- 188
- Category
- Article
- ISSN
- 0021-9797
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✦ Synopsis
it is still difficult to obtain high-grade components with satis-Spectroscopic studies of the interaction of ethyl xanthate solufactory efficiency. In order to control a selective separation tion (C 2 H 5 OCS 0 2 ) with mineral samples of chalcopyrite (CuFeS 2 ), to a fair degree, it is necessary to monitor the composition tetrahedrite (Cu 12 Sb 4 S 13 ), and tennantite (Cu 12 As 4 S 13 ) at different and structure of the topmost layers at a molecular level bepotentials were carried out by infrared reflection spectroscopy. cause the submonolayer and monolayer coverages by ad-The formation of the adsorbed products was investigated at potensorbed molecules are quite sufficient to change surface proptials from open circuit potential (OCP) for each mineral to values erties from hydrophilic to hydrophobic. Determination of the about 200 mV higher than OCPs, i.e., in range 180-420 mV adsorbed layer structure and understanding in detail the role (SHE). The experimental results were compared with simulated data of hypothetical surface layers with assumed compositions, of adsorption conditions are essential to the preparation of structures, and thicknesses in order to quantitatively evaluate the surface layers with specific properties.
produced surface monolayers on all minerals. The adsorption Selective separation of chalcopyrite (CuFeS 2 ), tetraheproduct observed spectroscopically on these three minerals was drite (Cu 12 Sb 4 S 13 ), and tennantite (Cu 12 As 4 S 13 ) from their the cuprous ethyl xanthate complex (C 2 H 5 OCS 2 Cu). Ethyl dixanmixture, important from an environmental point of view thogen (dimmer, (C 2 H 5 OCS 2 ) 2 ) as the second adsorption product (presence of antimony and arsenic), is difficult because all was only observed on chalcopyrite. Cuprous ethyl xanthate was of them contain copper; hence, copper complexing selective found as the most stable product on these minerals in an amount reagents will form copper surface complexes with all of from submonolayer to a few statistical monolayers. The dixanthothem modifying similarly their hydrophobic properties. Regen which was observed only at the chalcopyrite surface was procent spectroscopic in situ and ex situ studies (1) of the duced at a potential about 100 mV higher than that calculated from the thermodynamic data. There are thermodynamic and kiadsorption products of ethyl xanthate (C 2 H 5 OCS 0
2 ), which netic limitations of ethyl dixanthogen formation on these minerals. is the most commonly used separation reagent for sulfide Diffusion of copper atoms to mineral-solution interface plays an minerals, show the formation of hydrophobic products on important role in the formation of surface products. These findings all the minerals at open circuit potentials (OCPs). The most are very different from those observed for amyl xanthate when complex surface layer was found in the case of chalcopyrite amyl dixanthogen was produced simultaneously with cuprous where three different adsorption products were determined: amyl surface complex on these minerals. The difference between (i) cuprous ethyl xanthate, (ii) ethyl dixanthogen, and (iii) the interactions of ethyl xanthate with oxidized and ''fresh'' sama product temporarily assigned to an iron xanthate complex. ples of these three minerals was discussed in detail and mecha-Tetrahedrite and tennantite show the formation mainly of nisms of ethyl xanthate adsorption on different mineral surfaces cuprous ethyl xanthate. All these xanthate adsorption prodwere proposed.