Fine Structure in XPS and XANES Spectra Acquired from a Series of Sphalerite Samples

Abstract

The fine structure of high resolution XPS and XANES S L3,2-edge spectra collected from a series of high quality sphalerite samples are examined and discussed. Each of the sphalerite samples had a characteristic iron concentration and the range was from <0.01 wt % Fe to 14.79 wt% Fe. XPS spectra acquired from sphalerite surfaces leached in ferric sulphate-sulphuric acid media are presented and discussed. XANES near-edge spectra were evaluated by comparing S L3,2 -edge spectra acquired from unreacted sphalerite samples. The XPS data show that the sphalerite dissolution proceeds via the formation of a metal deficient sulphide that evolves into a surface dominated by polysulphide species. The XANES data show that S 2p electron transitions to empty S 3s and S 3d states occur across an energy range above the absorption edge. A chemical shift associated with iron to sulphur bonds is identified and a pre-edge feature associated with S - Fe bonding in sphalerite is identified.