The Uitkomst Complex is a mineralized, layered basic to ultrabasic intrusion, hosted by sedimentary rocks of the lower part of the Transvaal Supergroup. It is situated on the farms Uitkomst 541JT and Slaaihoek 540JT, about 25 km north of Badplaas and 50 km east of the eastern limb of the Bushveld Complex in the Mpumalanga province of South Africa. The intrusion plunges between 8 to 10º to the northwest with an established length of 12 km and a total thickness of 850 m. It is divided into seven lithological Units (from base to top), the Basal Gabbro (BGAB), Lower Harzburgite (LHZBG), Chromitiferous Harzburgite (PCR), Main Harzburgite (MHZBG), Pyroxenite (PXT), Gabbronorite (GN) and Upper Gabbro units (UGAB). A detailed petrographic and geochemical investigation of borehole core SH176, which provided a complete intersection of the Uitkomst Complex was carried out. The study shows that the Complex may have crystallized in a dynamic magma conduit setting. The whole rock geochemical trends indicate that there is a reversed fractionation in the basal portion of the Complex and a lack of fractionation in much of the MHZBG. Trace and REE variations show a decrease in concentration with height, contrary to what is expected of a progressively differentiating magma in a close system. Further, the platinum-group element concentration of the four basal units show no depletion with increasing height, suggesting that the individual units are not related to each other by means of in situ fractionation. Instead, a model whereby the individual units crystallized from distinct pulses of magma best explains the data. By comparing Nd isotopes and ratios of highly incompatible trace elements like [Th/La]n and [Sm/Ta]n from the Uitkomst Complex and Bushveld Complex it is seen that the Uitkomst magmas are of a similar lineage as the B1 magma of the Bushveld Complex, supporting a genetic link between the two complexes. The upper portion of the Uitkomst Complex shows values more akin to B3 magmas indicating the possible presence of more than one type of magma. Based on the available S isotope and trace element data, the sulphides of the Complex appear to have formed within the Complex, probably in response to contamination of the magma with dolomite. Entrainment of sulphides from depth is considered unlikely. The relatively low Cu/Ni ratios of the sulphides in the LHZBG, PCR and MHZBG (Cu/Ni 0.03 to 0.8) may be modelled by sulphide segregation from B1 magma and not from fractionation of sulphides that were later entrained in the streaming magma. / Dissertation (MSc)--University of Pretoria, 2006. / Geography, Geoinformatics and Meteorology / Unrestricted

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Oxide materials exhibit a wide variety of structures and properties. In particular, transition metal oxides tend to be highly stable while exhibiting a wide range of properties that can be used for numerous applications. This work focuses on investigating how the structures��� of 4d and 5d transition metal oxides influences their properties. Specifically oxides of Ru, Rh and Ir were investigated. A complete solid solution was found between isostructural Pb���Mn���O������ and Pb���Rh���O������. Pb���Rh���O������ shows a Verwey-type transition at 185 K. This transition remains with a 3 % substitution of Mn for Rh but disappears with a 4 % substitution of Mn for Rh. The structure was found to expand in the direction perpendicular to the layers of the structure, which is the c-axis, despite a contracting unit cell. Bi for Pb substitution in Pb���Mn���O������ was found to be limited as compared to in Pb���Rh���O������. Alkali metal substitution on the A-site of the orthorhombic perovskite SrRuO��� showed only low substitution levels were possible. Nonetheless, the substituted phases showed decreased ferromagnetic Curie temperatures, increased electrical resisitivity and relatively unchanged Seebeck coefficients. Thermoelectric studies of Sr[subscript 2-x]La[subscript x]CoRuO��� perovskite phases showed Sr���.���La���.���CoRuO��� with the best thermoelectric performance. This system showed possible correlations between cation ordering on the B-site and the charge carrier transport. A similar thermoelectric study of (RhV)[subscript 1+x]Ti[subscript 1-2x]O��� phases crystallizing in a disordered trirutile structure was done. Electron carriers were found to be dominant and dependent on Ti content. The electron carriers appear to become diminished at higher temperatures. Sr���IrO��� crystallizes in a K���NiF���-type structure. Effects of Ti, Fe and Co substitution for Ir were investigated. A complete Sr���Ir[subscript 1-x]Ti[subscript x]O��� solid solution was synthesized and characterized while limited solubility was found for Fe and Co substitutions. All substitutions showed a decrease in the c-cell parameter coupled with a decrease in octahedral tilting. All substitutions also showed a decrease in magnetic susceptibility and an increase in the paramagnetic effective moment was observed for Co and Fe doped samples. An incomplete solid solution was formed for Sr���Ti[subscript 1-x]Rh[subscript x]O��� phases; however effects of increased octahedral tilting with higher Rh content were observed. / Graduation date: 2013

This project investigates the optimisation of platinum-group metals recovery at the Mimosa Mine in Zimbabwe. The first part of this research investigates how collector performance can be improved by using collector combinations (mixtures) of the standard sodium iso-butyl xanthate with a secondary collector. The synergistic effect of the sodium-iso-butyl-xanthate (SIBX) combined with trithiocarbonates (TTCs) or dithiophosphates (DTP) was investigated. The short chain and the long chain TTCs were investigated. These collector combinations were studied at various molar percent ratios. The SIBX:DTP combination was studied at a 1:1 mass ratio or molar ratio of 1:1.3. Amongst all the collector combinations, it was established that the SIBX/DTP combination improved sulphur recoveries by 10% and subsequently the PGE+Au recovery by 10% compared to when the SIBX was used on its own. The C4-TTC showed poor performance in the sulphur recovery; however an improvement in PGE + Au recovery was noticeable. There was generally no significant metallurgical improvement with respect to final grades and recoveries with C10 and C12TTC mixtures with SIBX. However, the 6.25 molar per cent substitution of SIBX by C12TTC appeared to show some improvement on sulphur but not on PGM+Au recovery and grade. It was therefore concluded that the SIBX/DTP combination at 1:1 mass ratio (total moles of 0.64) showed a potential to improve the grades and recoveries of the Mimosa Mine. The Mimosa ore is characterised by an unusually large amount of talc, which often causes problems during the flotation of the PGM minerals due to the fact that talc consumes high amount of reagents. Therefore the purpose of the second part of this thesis was to investigate the possibility of removing talc prior to the flotation process by de-sliming. Two cyclones (36.9 mm and 76.0 mm) were used for de-sliming the flotation feed. De-sliming the ore was able to reduce the depressant dosage up to 300 g/t as opposed to 500 g/t that is used at Mimosa Mine. / Dissertation (MSc)--University of Pretoria, 2008. / Materials Science and Metallurgical Engineering / unrestricted

This diploma thesis in the theoretical part analyses the characteristic feature of individual platinum group elements, their toxicity, anthropogenic sources and the presence of platinum group elements in the environment of the Czech Republic. In addition, there are specified types of bioindicators focusing mainly on lichens, mosses and needles. There are described individual bioindication techniques and pre-treatment of samples for platinum metals determination in bioindicators. The subject of the experimental part is to verify the sorption efficiency and ability of platinum and palladium using the SPE method and to determine the actual platinum metal contamination in selected localities in the city of Brno. There was also the additionally subject to verify the sorption potential of selected bioindicators and determination of the environmental pollution by platinum metals using the bag technique. In the experimental part, the bioindicators of moss Pleurozium schreberi, lichen Xanthoria parietina, lichen Flavoparmelia caperata and needles Pinus nigra were used.

An environmental friendly and simple approach to synthesis of Platinum (Pt), Palladium (Pd), Rhodium (Rh) and Osmium (Os) nanoparticles via gamma radiolysis is demonstrated. Herein, we report on the effect of gamma rays radiation on Platinum (Pt), Osmium (Os), Rhodium (Rh) and Palladium (Pd) salts solutions for synthesis of nanoparticles. Pt, Os, Rh and Pd salts solutions of different concentrations were exposed to intense gamma rays irradiation with doses varying from 70 to 120 kGy. The metal ion salt solutions were easily converted into metal nanoparticles (MNP) using radiolysis method. The radiolytic conversion effect produced MNP suspended in the solution. For Pt, Pd and Rh a metal coating on the edges of the polypropylene tube used as a container, was unexpectedly observed but not for the Os solution. Physical/chemical properties of γ-ray produced nanoparticles were reported. UV-Vis spectroscopy, X-ray diffraction (XRD) and High resolution transmission electron microscopy (HRTEM) analyses confirmed that both the coating and the MNP correspond to the pure metal coming from the reduction of the initial salt. HRTEM analysis shows the particles size and particle distribution of the produced nanoparticles. Quantitative analysis of the XRD patterns shows information about the size and stress of the converted metals. The functional groups in the solvent are analysed by Fourier Transform Infrared spectroscopy (FTIR). The production of a metal coating on polypropylene plastic tubes by gamma-rays irradiation is presenting an interesting alternative to conventional techniques of metal deposition especially for coating the inner part of a tube. / Physics / D. Lit. et Phil. (Physics)

A extratibilidade de sais de fosfônio foi aproveitada para elaborar método de separação Ir-Rh, mediante a extração do sal de trifenil n-propil fosfônio do cloro-complexo de Ir(IV,) em clorofórmio. O coeficiente de extração de 99,2%, permite retirar o irídio do meio aquoso com grande eficiência. O irídio assim separado é determinado diretamente, por via espectrofotométrica, em 494 mµ, em faixa de concentração de 5,0 a 50,0 µg/ml. Pd(II), Pt(IV) e Os(IV) interferem e são eliminados previamente, assim como Au(III). Os ânions interferentes, I-, Br- e SCN- são também eliminados previamente. Muitos íons podem estar presentes, tais como Co(II),Cu(II), Mn(II), Fe(III), Ni(II), As(V), Sb(V), NO3-, ClO4- e SO4--. Após a separação do Ir (IV), o Rh(III) que permanece, na solução é complexado com íons azoteto e extraído em clorofórmio depois de precipitado com íons trifenil n-propil fosfônio, sendo o coeficiente de extração de 98,3%. A determinação ê também feita no próprio solvente, mediante medida espectrofotométrica em 404-408 mµ, para um intervalo de concentração de . 10,0 a 70,0 µg/ml. Uma separação envolvendo Os(IV), Pd(II)e Pt(IV) foi elaborada, eliminando-se Pd(II) e Pt(IV) por extração de ambos em metil n-butil cetona a partir de uma solução contendo SCN-. O Os(IV) é determinado na solução aquosa na forma de OsC16-- por medida espectrofotométrica em 370 mµ, válida para a faixa de concentração de 2,0 a 20,0 µg/m1. / Abstract not available.

A extratibilidade de sais de fosfônio foi aproveitada para elaborar método de separação Ir-Rh, mediante a extração do sal de trifenil n-propil fosfônio do cloro-complexo de Ir(IV,) em clorofórmio. O coeficiente de extração de 99,2%, permite retirar o irídio do meio aquoso com grande eficiência. O irídio assim separado é determinado diretamente, por via espectrofotométrica, em 494 mµ, em faixa de concentração de 5,0 a 50,0 µg/ml. Pd(II), Pt(IV) e Os(IV) interferem e são eliminados previamente, assim como Au(III). Os ânions interferentes, I-, Br- e SCN- são também eliminados previamente. Muitos íons podem estar presentes, tais como Co(II),Cu(II), Mn(II), Fe(III), Ni(II), As(V), Sb(V), NO3-, ClO4- e SO4--. Após a separação do Ir (IV), o Rh(III) que permanece, na solução é complexado com íons azoteto e extraído em clorofórmio depois de precipitado com íons trifenil n-propil fosfônio, sendo o coeficiente de extração de 98,3%. A determinação ê também feita no próprio solvente, mediante medida espectrofotométrica em 404-408 mµ, para um intervalo de concentração de . 10,0 a 70,0 µg/ml. Uma separação envolvendo Os(IV), Pd(II)e Pt(IV) foi elaborada, eliminando-se Pd(II) e Pt(IV) por extração de ambos em metil n-butil cetona a partir de uma solução contendo SCN-. O Os(IV) é determinado na solução aquosa na forma de OsC16-- por medida espectrofotométrica em 370 mµ, válida para a faixa de concentração de 2,0 a 20,0 µg/m1. / Abstract not available.

The aim of this thesis is the actual elaboration literature search concerning the issue of platinum group metals in the environment, determination of platinum and palladium in great urban agglomerations. It includes chemical and physical properties, occurrence and platinum and palladium cycle in the environment. It also contains methods for extraction and determination of platinum and palladium.