Speaker
Level for award<br> (Hons, MSc, <br> PhD)?
MSc
Apply to be<br> considered for a student <br> award (Yes / No)?
yes
Main supervisor (name and email)<br>and his / her institution
Prof P.E. Ngoepe, phuti.ngoepe@ul.ac.za
, University of Limpopo
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
yes
Abstract content <br> (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>
Pentlandite (Co,Fe,Ni)9S8 is the most abundant iron-nickel sulphide ore containing mineral and has a wide range of applications in industries. The mineral is of commercial importance and can be extracted using floatation processes; one of the processes is oxidation. The oxidation plays a significant role in forming air bubbles that float the pentlandite mineral. Despite reports that oxidation tend to depress the sulphide minerals, it has good preferential oxidation of iron. The present study investigated the clean and oxidised nickel-rich {110} pentlandite surface using ab-initio density functional theory (DFT). The Bader analysis have been evaluated for clean and oxidized surfaces and suggests that both Fe and Ni have 2+ and 3+ oxidation state, respectively. Furthermore, when oxygen is adsorbed at the (fcc hallow site, on Fe-top site) and on Ni-top site, it was found that the {110} pentlandite surface oxidises as (Fe-O-Fe) and Ni-O-O, respectively. Oxidation had also shown preferential oxidation of iron and we noted a charge transfer from the metals to the oxygen molecule. We also observed that the oxygen (O1) coordinated to the Fe accepts electrons to σs and Πp bonding orbitals, while the oxygen (O2) coordinated to O1 only occupies the Πp antibonding for the fcc hallow site and Fe-top site adsorption. The Ni-top site adsorption is observed to occupy similar to the just mentioned case however, we noted that the Πp antibonding orbital is occupied on O1 atom. This study gives an understanding of oxidation of pentlandite naturally and during flotation.
