Outotec Sweden AB works in the field of precious metal refining. Silver electrorefining is one of Outotec’s technologies widely applied in numerous silver refining plants worldwide. During this project a specific section in a silver refinery plant has been investigated. Today’s system provided by Outotec utilises gravity as a means of transport of the slurry consisting of refined silver crystals and silver electrolyte. The slurry is directed from the electrolysis cells through pipes mounted in an angle towards a separation tank. This solution requires three floors of the building of the refinery plant. The goal of this project was to develop concepts which would transport the slurry of silver crystals from the electrolysis cells to a separation tank within a single floor of the building. The implementation of such a system would result in lowering the overall investment cost of the refinery by at least 7 %. Ulrich & Eppinger’s product development process has been utilised in this thesis work which is a six step sequential method for development of products. Through this process, four concepts for transportation of silver crystal slurry were developed, analysed and cost estimated - Syringe, Drop to circulation tank, Suction Pump and Conveyor. The syringe concept eliminated the need for a single floor of the refinery, which translated to total projected investment cost of 337 000 SEK and an overall investment savings of 8.3 %. Drop to circulation tank eliminated the need for two floors which lead to a total estimated cost of 862 000 SEK. This corresponded to an overall investment savings of 16.5 %. The two final concepts - suction pump and conveyor was estimated to cost 346 000 and 337 000 SEK respectively. Both of the concepts resulted in a total projected savings of the overall investment by 8.3%, eliminating the need for one of the three floors in the refinery. The conclusion is that each of the concepts developed surpassed the goal of lowering the overall investment of the refinery by at least 7%. Three of the four concepts eliminated the need for one floor while the final one, drop to circulation tank, eliminated the need for two of the three floors. The concepts must be tested before implemented. This could either be conducted by approximating the electrolyte as water and silver crystals as metal shavings or by sludge. It would however be beneficial if a test rig is constructed for each concept and they are tested with the same mixture of silver slurry that is transported in Outotec’s existing refineries. The circulation tank should also be installed on the same floor as the electrolysis cells and the separation tank for the syringe, conveyor and suction pump concepts. This was never investigated by the authors since it was a limitation stated as the project was initiated. This component was however included in the drop to circulation tank concept since it was considered being part of the transportation system. If the circulation tank is installed on the same floor as the other components it will result in eliminating the need for two floors, which would ultimately lead to a substantial decrease in overall investment cost.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22011号 / 工博第4623号 / 新制||工||1720(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 酒井 伸一, 教授 高岡 昌輝, 准教授 平井 康宏 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

<p> Freegold Mountain is part of a northwesterly trending volcanoplutonic arc comprising the eastern portion of the Yukon Crystalline Terrane. Plutonic rocks in the area intrude Paleozoic metasediments and consist of a Late Triassic to Early Cretaceous granodiorite intruded by the Big Creek Syenite dated at 138 ± 10 Ma. A suite of K-rich intrusive volcanic rocks comprise an early period of basalt-andesite-dacite volcanism and a later rhyolitic volcanism dated at 78 ± 6 Ma. Volcanic rocks at Freegold Mountain can be correlated with Mt. Nansen Volcanics.</p> <p> Two sets of fracture planes, oriented at 165/70E and 18/80W, show dextral and sinistral displacement, respectively. Rhyolite dykes and gold-quartz veins predominantly oriented NNE have been emplaced along the 18/80W extensional fracture systems. These fractures may be modelled as high-angle Reidel shears, although evidence indicates that fracture orientations and fault movement have been complicated by changing stress fields from middle Cretaceous to Tertiary time.</p> <p> The gold-bearing quartz veins at Freegold Mountain are high grade, low-tonnage deposits with grades ranging from 0.4 to 1.0 oz/t. Fluid inclusions from the lower portions of the Laforma mine homogenize at 185° C with salinity ranging between 2 and 4.5 wt. % NaCl equivalent. A boiling zone has been detected above the deeper ore where fluid inclusions show extreme ranges in homogenization temperatures (165-430° C) and salinity (4 - 43 wt. % NaCl). Fluid inclusion waters have stable isotopic signatures indicative of meteoric water with 𝛿D = -138 and 𝛿^18O = -18.4. Boiling of the Laforma fluid has caused a shift towards heavier hydrogen and oxygen isotopic values, mineral deposition and appears to enhance gold precipitation over non-boiling zones. Stable isotopic evidence indicates that the paleolatitude of Freegold Mountain during late Cretaceous time was south of the present day Yukon-B.C. border.</p> <p> The Emmons Hill (Dart) prospect is a gold-bearing vein-breccia with a mineral assemblages of barite, stibnite, marcasite, cinnabar, orpiment, Fe and Mn carbonates and chalcedonic silica. Fluid inclusions from these deposits homogenize between 140-185° with salinities of 0-0.5 wt. % NaCl. This property shows marked similarities to acid-sulphate type precious metal deposits in New Zealand and western United States.</p> <p> Large (x to xx Mt) northwesterly trending diatremes appear to be structurally controlled by small transcurrent faults parallel to and coeval with displacement along the Tintina fault. The Antoniuk diatreme (3.7 Mt @ 1.14 g/t Au) consists of heterolithic and monolithic breccias intruded by dacite and rhyolite dykes. Diamond drilling indicates that a large body of fine to medium grained alaskite is present beneath the auriferous breccia. The deposit formed by the explosive escape of volatile components evolved from the retrograde boiling of a silicic magma chamber. Gold mineralization in the breccia is associated with pyrite and arsenopyrite formed at temperatures around 300°C and salinities of about 4.5 wt. % NaCl.</p> / Thesis / Master of Science (MSc)

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

In this thesis the relationship between Brent oil prices, LME copper prices, Turkish gold and silver spot prices, XU100 index, interest rate and exchange rate is examined. Their long run Granger causality relationship is investigated by looking at Wald statistics. The short run relationship between them is examined by using generalized impulse responses. The data range is from January 2, 2002 to February 24, 2011. Due to the oil crisis in 2008, we divide the data into three periods: January 2, 2002 to December 31 as first period, 2007, from January 1, 2008 to December 31 as second period, 2008 and January 1, 2009 and February 24, 2011 as third period. We conduct each test separately for these periods but in third period we use Toda-Yamamoto procedure since maximum order of integration is 1.

A neutron activation analysis procedure for the simultaneous determination of Au, Pd and Ir, and separate determination of Os is described and applied to the determination of these metals in the Mount Albert ultramafic pluton, Quebec. The Mount Albert is an alpine-type ultramafic body whose petrography, geology and geochemistry has been discussed in some detail by MacGregor (1962, 1964). It consists mainly of serpentinized dunite and peridotite. However, it is distinguished by the presence of an eastern lobe which is essentially unserpentinized. In addition to ferromagnesians, two varieties of spinel including disseminated accessory chrome spinel and massive, discordant chromite veins or schlieren are important mineralogical constituents. Twenty samples were analyzed including 5 fresh dunites and peridotites, 8 serpentinized equivalents, 4 disseminated chrome spinels, 1 clinopyroxenite, and 2 massive chromite. The concentrations (in p. p. b.) of average fresh ultramafics and their serpentinized equivalents are:-------------------------------------- ---------------------Pd----Os----Ir----Au------------------------------------------- Fresh rocks------------7.7----7.2--2.5--0.99------------------------------------------- Serpentinized rocks---10----6.6--2.2---2.4-------------------------------------------- The piuton was intruded as a nearly solid mass of olivine and some orthopyroxene with about 15 weight per cent melt. A small concentration of the precious metals, a factor of 2 to 3, in the melt relative to crystalline phases appears to have occurred. The disseminated chrome spinel and massive chromite appear to concentrate the precious metals. In particular, Os and Ir content of the massive chromite is approximately 10 times that of fresh or serpentinized whole rocks. There is little change in average precious metal content with serpentinization. Pd shows a slight increase, and Ir and Os slight decreases in concentration with degree of serpentinization. Only Au appears significant to be enriched in serpentinized rocks where a twofold increase occurs. The variation in precious metal content of all four metals increase when the rocks are serpentinized: When normalized to chondrite meteorites, the precious metal data give fractionation trends similar to that of average chondrite. These trends are compatible with a model in which alpine ultramafics are regarded as residua from the partial melting of parental material of approximately chondritic composition. / Thesis / Master of Science (MSc)

Previous mineralogical investigations (QemSCAN) performed on all effluent flotation streams of Mimosa mine (Zimbabwe) indicated the presence of appreciable amounts of platinum group minerals (PGMs), which are not recovered. Most, generally in excess of 70%, of the liberated PGMs in these streams belonged to the Pt-Pd-Bi-Te class in all the samples investigated. In the first part of this work, electrochemical investigations, electrochemically-controlled contact angle measurements and Raman spectroscopy have been employed to investigate the interaction of ethyl xanthate with Pd-Bi-Te and PtAs2. Impedance measurements showed lower capacitance values in solutions containing KEX indicating the formation of a continuous surface layer. Anodic and cathodic polarization diagrams show the mixed potential to be higher than the reversible potential of the xanthate-dixanthogen equilibrium reaction, hence the formation of dixanthogen on the surface is possible. Electrochemically controlled in situ Raman spectroscopy has confirmed the co-presence of xanthate with dixanthogen indicating that xanthate retains its molecular integrity when it adsorbs on the surface of the Pd-Bi-Te. The result of this investigation has shown dixanthogen to be present on both the minerals (PtAs2 and Pd-Bi-Te) when the surfaces are anodically polarized. Chemisorbed xanthate could be identified within 120 seconds yielding a hydrophobic surface as indicated by electrochemically-controlled contact angle measurements. Maximum contact angles of 63o were measured in the case Pd-Bi-Te. As a result the mineral surface is expected to be hydrophobic and a lack of collector interaction with the mineral is not the reason for low PGM recoveries experienced. Secondly, the flotation recovery of synthetically prepared Pd-Bi-Te was compared with that of chalcopyrite (a typical fast-floating mineral) and pyrrhotite (a typical slow-floating mineral), with microflotation tests. These indicated Pd-Bi-Te to be a fast-floater with flotation rates exceeding that of chalcopyrite. Predicted flotation rate constants (from the Ralston model) were significantly lower for small particles (with diameters similar to those lost to the effluent streams) compared with those of particle with intermediate sizes. This supports the suggestion that losses to effluent streams are caused by particle size effects. / Thesis (PhD (Metallurgical Engineering))--University of Pretoria, 2006. / Materials Science and Metallurgical Engineering / unrestricted

No description available.

The corrosion susceptibility of selected metallic materials frequently employed in prosthetic dentistry has been examined with electrochemical methods. Results have been compared with data derived from breakthrough potential measurements performed with these materials before. Mostly agreement and/or close correlation were found, discrepancies are discussed and tentatively assigned to the different experimental conditions.

Gold Foil Figures or guldgubbar (henceforth GFFs) are precious metal artefacts from the Scandinavian Late Iron Age. This master's essay offers a new approach to GFFs. As opposed to the established understanding of GFFs as representational images with real or mythic referents, belonging to an aristocratic milieu, this essay instead attends to GFFs in terms of their material and Figural traits. The material for this study consists if 42 GFFs from the find site of Västra Vång, Blekinge, Sweden. A comprehensive presentation of this artefact material is a secondary aim of this essay. With the aid of a neomaterialist theoretical apparatus that draws heavily on the work of Gilles Deleuze, Félix Guattari, and Wilhelm Worringer, the 42 GFFs undergo two separate analyses. In the first, the material traits expressed in the sequence of GFF production and deposition is studied in terms of a chaîne opératoire. In the second, I attend to the non-significatory expressive qualities of form and expression, or Figural traits, belonging to these 42 GFFs within the wider artistic milieu of Animal Style Ornamentation. I conclude that GFFs were as a rule artefacts made for purposes of immediate disposal, not display, as a mode of dispersing gold. Västra Vång’s GFFs offer several indications that handling between the cutting operation and deposition was minimal, such as the fresh, unworn edges. The thin, brittle foils are ill suited to display. Approaching the designs on these artefacts as various sets of Figural traits being expressed allows me to contextualise the GFFs within the wider artistic milieu of Animal Style Ornamentation. New territorial rhythms can be established only as certain elements are freed from a settled state, and made to act together with new elements, in new terrains. GFFs bring about new territorial rhythms of form and expression to gold matter, gold made to circulate as it becomes deterritorialised from a monetary function within the Roman economy. A flow of gold is extended as gold is brought to Scandinavia from continental economies. The influx of this flow of gold is not contained to an élite social stratum. Individuals in possession of minute amounts of gold returned to Scandinavia, having acquired gold as payment for involvement in military operations on the continent. This ownership of gold may have hindered their harmonious reintegration into a society based on other economic principles. The GFFs emerge as a vector of dispersing gold. The artistic expression of Figural traits is equally energised by movements of de- and reterritorialisation. Understanding that the Figural traits expressed on the GFFs from Västra Vång are part of a wider artistic milieu of Animal Style Ornamentation, alongside other systematised expressions making up parts of a collective assemblage of enunciation, makes their appearance on artefacts that were deposited immediately upon their manufacture easier to grasp. The particular procedures of miniaturisation allowed for an acceleration of the expression of variation in the conjunction of a flow of artistic expression onto a flow of gold matter. The dispersive handling of gold must be traced to both the material premises and the expressive artistic ones. Gold is not chosen because it is precious, or because of what it connotes, but because it is available, because the artisan smith is attendant to its traits as a metal matter.