J
Johan P.R. de Villiers
Researcher at University of Pretoria
Publications - 35
Citations - 1117
Johan P.R. de Villiers is an academic researcher from University of Pretoria. The author has contributed to research in topics: Crystal structure & Pyrrhotite. The author has an hindex of 14, co-authored 31 publications receiving 995 citations. Previous affiliations of Johan P.R. de Villiers include Council for Scientific and Industrial Research.
Papers
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Journal ArticleDOI
Strain-Specific Ureolytic Microbial Calcium Carbonate Precipitation
TL;DR: It is shown that strain-specific calcification occurred during ureolytic microbial carbonate precipitation, mainly due to differences in urease expression and the response to calcium.
Journal Article
The nature of invisible gold in arsenopyrite
Louis J. Cabri,Stephen L. Chryssoulis,Johan P.R. de Villiers,J. H. Gilles Laflamme,Peter R. Buseck +4 more
TL;DR: The arsenopyrite from these two deposits of widely different ages contains structurally bound Au, thus making the mineral refractory to metallurgical treatment by cyanidation as mentioned in this paper.
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V oxidation state in Fe–Ti oxides by high-energy resolution fluorescence-detected X-ray absorption spectroscopy
Amélie Bordage,Etienne Balan,Johan P.R. de Villiers,Robert Douglas Cromarty,Amélie Juhin,Claire Carvallo,Georges Calas,P. V. Sunder Raju,Pieter Glatzel +8 more
TL;DR: In this article, the authors used high-energy resolution fluorescence-detected X-ray absorption spectroscopy (HERFD-XAS) to determine the local environment and oxidation state of vanadium.
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The flotation of magnetic and non-magnetic pyrrhotite from selected nickel ore deposits
TL;DR: In this paper, a series of pyrrhotite samples derived from Canada, South Africa and Botswana whose mineralogy is well characterised, were selected in order to develop the relationship between mineralogy and flotation performance.
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The oxidation state of vanadium in titanomagnetite from layered basic intrusions
Etienne Balan,Etienne Balan,Johan P.R. de Villiers,Sigrid Griet Eeckhout,Pieter Glatzel,Michael J. Toplis,Emmanuel Fritsch,Emmanuel Fritsch,Thierry Allard,Laurence Galoisy,Georges Calas +10 more
TL;DR: The redox conditions prevailing during the formation of vanadiferous titanomagnetites from three layered intrusions (Bushveld; Koillismaa; Skaergaard) have been estimated from the valence state of vanadium using synchrotron X-ray absorption near edge structure spectroscopy (XANES) as mentioned in this paper.