Concentrations of rare earth (REE), U, Th, and other trace elements (TE) were measured using LA-ICP-MS along transects across five Late Eocene brontothere bones from the terrestrial Late Eocene Chadron Formation of Nebraska and four Miocene marine mammals from the Atlantic Coastal Plain. Samples were analyzed to determine REE diffusion periods, and to determine if histological factors affect post mortem uptake of REE/TE. In terrestrial fossil bones, concentrations of REE are highest at the bone surface and decrease with depth into the trabecular bone, consistent with diffusion-limited models. Histology may affect REE incorporation. An outer circumferential layer (OCL) is preserved along the outer 1 mm of the brontothere rib (F08-10) and femur (F08-09). REE concentrations in the OCL are much lower than in the underlying bone, indicating either lower incorporation or post fossilization leaching. REE concentrations are sometimes elevated in trabecular bone and Haversian systems, which may act as secondary diffusion pathways. REE concentration gradients are generally steeper in marine fossils than in terrestrial fossil bones, indicating longer periods of REE uptake in terrestrial fossils. Calculated periods of diffusion in terrestrial environments are 2.2 +/- 0.5 to 54.8 +/- 1.5 ka (based on a wetness factor of 0.5 +/- 0.1). Periods of diffusion for marine environments range from ca. 0.9 +/- 0.2 to 2.8 +/- 0.6 ka. However, within some terrestrial samples U is introduced into the bone over a much longer time span, possibly as a function of fluctuating redox conditions. If these values are representative, diffusion-fossilization periods are shorter in marine/lacustrine/spring/channel environments due to constant water saturation. Saturation of a bone during diffusion may also affect the morphology of REE signatures within the bone. In terrestrial bones, REE are strongly fractionated with depth, producing signatures varying from light-REE enriched at the surface to middle-REE depleted at depth. However, depth fractionation of REE is much less pronounced in marine bones, which may result from the introduction of fluid unreactive. These differences in REE fractionation are consistent with a greater influence of multiple secondary REE/TE diffusion paths in marine samples. Periods of diffusion for terrestrial samples differed within a single bonebed accumulation (2.2 +/- 0.5 to 54.8 +/- 1.5 ka). However, REE signatures are internally consistent with one another within the bonebed indicating that groundwater chemistry did vary during fossilization. If groundwater chemistry changes during diffusion, bone could be recording different signals, which has implications for using post-mortem REE/TE/Isotopes for paleoenvironmental reconstruction. Previous studies of soft tissue preservation in fossilized bone have inferred shorter periods of diffusion and suggested that the rate of diffusion must outpace the rate of decay. Diffusion periods in bone from well drained terrestrial settings are too long to preserve soft tissue. However, periods of diffusion in marine fossil bones are much shorter, suggesting the possibility for bio-molecule preservation. / Geology

Rare earth elements (REE) exhibit particular and unique properties that render them essential to technological applications. Of particular interest is their involvement in the transition toward global sustainability and their military applications. The magnetic properties of the rare earth elements is of primordial importance to sustainable development. More specifically, terbium and dysprosium are two elements with no known substitutes in critical applications and with no domestic or allied sourcing available. These elements are currently mined by in-situ leaching of ion-absorbed clays, mostly from illegal operations in Myanmar financed by Chinese companies. The demand from both elements, and for the other magnet rare earths is projected to growth at very high rates through 2035 while the world undergoes a transition toward sustainability, and a drastic reduction in greenhouse gases emissions. Our team has been evaluating the potential of acid mine drainage (AMD) as a source of rare earth elements and critical materials (CM). Acid mine drainage is the result of in-situ generation of sulfuric acid due to the weathering of sulfide ores. It is a significant legacy environmental issue and one of the largest pollutants in many mining districts throughout the world. The objective of the present work is to provides a roadmap for the utilization of AMD as a critical material feedstock to preserve the independence of the United States of America with regards to these materials. To that effect, a fundamental economic assessment of REE/CM recovery from AMD using a network sourcing strategy in addition to a robust, flexible feedstock separations and refining facility was undertaken. A techno-economic analysis of the extraction, refining, separation and reduction to metal is presented along with a sensitivity analysis.The results of this analysis show that, with the exception of the minimum price scenario, all operational configurations have positive economic indicators with rates of return varying from 25% to 32% for the contemporary price scenario. This is primarily due to the very high enrichment in terbium and dysprosium of AMD. The optimal configuration was determined to be production of Co, Mn, and all REEs except for mischmetal, which is not recovered. Sensitivity analysis and Monte Carlo Simulation show that capital cost and HCl consumption are the two major factors influencing rate of return, thus indicating opportunities for future technology development and cost optimization. In order to reduce both the capital and operation cost of the facility, alternative ionic liquids extractants based on conventional acidic extractants where synthesized and investigated. The results show that the ionic liquids varied in performance, with [c101][D2EHP] and [c101][EHEHP] performing poorer than their conventional counterparts and [c101][c572] performing better. The performance of [c101][c572] was 13% superior to Cyanex 572, 20% superior to EHEHPA and 27% superior to D2EHPA the current commercially used extractants. Recommendations for further study on [c101][c572] include stripping tests, continuous pilot testing, and techno-economic analysis. The test work revealed that zinc and to a lesser extent calcium were significant deleterious elements in the solvent extraction circuit, and that selective removal would significantly reduce the acid-base consumption of the separation circuit. A process was developed to selectively remove calcium and zinc from AMD-derived feedstock and from REE products. The ammonium chloride leach process offer many advantages, including the possibility of closing the cycle by using carbon dioxide sequestration as a step to regenerate the ammonium chloride in a zero-discharge process. / Doctor of Philosophy / A younger me: - What are these elements in the bottom of the periodic table? My high school chemistry teacher: - "Don't waste time there, these are of no concern." Twenty years later, technological developments and the imperative to transition away from fossil energy to mitigate climate change have brought the rare earth elements, a series of 17 elements with unique properties to the forefront of the conversation. In addition to an organic increase in demand, the recent supply chain consolidation by China is adding a geopolitical risk to the equation. The magnetic properties of the rare earth elements is of primordial importance to sustainable development and to our military technology. More specifically, terbium and dysprosium are two elements with no known substitutes in critical applications and with no domestic or allied sourcing available. These elements are currently mined from illegal operations in Myanmar, with the support of Chinese companies. The demand from both elements, and for the other magnet rare earths is projected to growth at very high rates through 2035 while the world undergoes a transition toward sustainability, and a drastic reduction in greenhouse gases emissions. Given the important of the rare earth elements, and the absence of significant deposits in the united states, with the exception of the Bear Lodge and Elk Creek deposits, the Department of Energy has mandated academic institution of evaluating alternative sources of rare earth elements. Our team has been evaluating the potential of acid mine drainage as a source of rare earth elements and critical materials. Our team has surveyed many acid mine drainage sources and determined that many sites are highly enriched in terbium and dysprosium. Acid mine drainage is a legacy environmental issue related to past problematic mine development techniques. In the problematic mines. these acidic mine waters are permanently generated and if not treated can have severe impacts on water streams in which they flow. The toxicity of the acid mine drainage on the environment is due to its high acidity and significant levels of toxic metals. Acid mine drainage can be recognized by their yellow to red tint. It is treated by reacting it with a neutralization agent, which results in treated water and a sludge. The sludge is dewatered and stored in tailing impoundments. I have designed a process for the economical recovery of rare earth elements and critical materials from acid mine drainage. The cost to build and operate the facility was derived and it was determined that the project could be further enhanced by reducing the plant chemical reagent consumption. One specific category of chemical referred to as extractant, is central to the rare earth separation process. A novel variation on the standard extractants has been evaluated and promises to provide significant savings. While the extractants were investigated, it was noticed that some impurities such as zinc and calcium created issues in the circuit. I then developed a process for their selective removal. The process also provide a net carbon dioxide sequestration potential.

Niobium (Nb) and Rare Earth Elements (REE’s) have in recent years received considerable attention because of their importance to the modern technical industry, and more specifically the enhanced sustainability that comes with them. The main source for Nb and REE’s on Earth are carbonatites and associated alkaline silicate rocks. This report examines the magnetic properties of rocks from the Oldoinyo Dili carbonatite complex in northern Tanzania. Previous workers have suggested a link between the Fe-bearing mineralogy and the formation of Nb-mineralizations at Oldoinyo Dili. This hypothesis is further examined in this report by combining detailed petrographic observations and withnew measurements of magnetic susceptibility. The aim is to see if any correlation exists between occurrence of Nb-mineralizations and the types of Fe-minerals present at Oldoinyo Dili. Based on the magnetic susceptibility measurements, at least two different species of Fe-minerals arefound in the examined samples. These are characterized by different magnetic trends during heating/cooling and also by their separate Curie temperatures (Tc). In combination with the petrographic observations these minerals are interpreted to be magnetite (Fe2O4) with Tc ~580°C, and a mineral that most likely represents a solid solution between ilmenite (FeTiO3) and hematite (Fe2O3) with Tc ~300°C. Here, no clear link between the type of opaque mineral(s) present and the total Nb content of the carbonatites can be conclusively determined based on the petrography and the magnetic measurements alone. Although the results of this report provide an important first step towards understanding the relationship between Nb-mineralizations and the magnetic mineralogy at Oldoinyo Dili, more detailed analyses of the mineral chemistry is a necessity to fully understand their complex relations and the specific conditions under which they formed. / Niob (Nb) och sällsynta jordartsmetaller (REE’s) har på senare år fått stor uppmärksamhet för sin betydelse för den moderna tekniska industrin, och specifikt för den förhöjda hållbarhet som de bidrar med. Den huvudsakliga källan till Nb och REE’s på jorden är karbonatiter och associerade alkalisilikater. Denna rapport undersöker de magnetiska egenskaperna för karbonatit-komplexet Oldoinyo Dili i norra Tanzania. Forskare har tidigare anat att det finns en koppling mellan Fe-bärande mineralogi och bildandet av Nb-mineraliseringar vid Oldoinyo Dili. Denna hypotes undersöks vidare i denna rapport genom att kombinera detaljerade petrografiska observationer med nya mätningar av magnetisk susceptibilitet. Syftet är att undersöka om det finns någon korrelation mellan förekomst av Nb-mineraliseringar och de typer av järnmineral som finns vid Oldoinyo Dili. Baserat på de genomförda magnetiska susceptibilitets-mätningarna så finns det åtminstone två olika sorters järnmineral i de undersökta proverna. De karaktäriseras av olika magnetiska trender vid upphettning/nedkylning och även av sina olika Curietemperaturer (Tc). Kombinerat med petrografiska observationer uttolkas att dessa mineral är magnetit (Fe2O4) med Tc ~580°C, samt en mineral som troligen är en solid solution av ilmenit (FeTiO3) och hematit (Fe2O3) med Tc ~300°C. Det går inte att senågon tydlig koppling mellan förekommande opaka mineral och det totala Nb-innehållet i karbonatiterna med säkerhet enbart utifrån petrografin och de genomförda magnetiska mätningarna. Resultaten av denna rapport utgör ett bra första steg mot att förstå relationen mellan Nb-mineraliseringar och den magnetiska mineralogin för Oldoinyo Dili, men mer detaljerade analyser av mineralkemin är nödvändigt för att till fullo förstå de komplexa förhållanden som råder vid bildning av dessa.

Master of Science / Department of Geology / Sambhudas Chaudhuri / The exploration and development of unconventional shale plays provide an opportunity to study the hydrocarbon generation process. These unconventional plays allow one to investigate the interactions between the fluid, mineral, and organic material that occur in a hydrocarbon-generating source bed, before any changes in composition that may occur during secondary migration or post migration processes. Previous studies have determined the chemical constituents of formation waters collected from conventional reservoirs after secondary migration has occurred. This investigation targets formation waters collected from the Woodford shale that acts as both source and reservoir, therefore samples have yet to experience any changes in composition that occur during secondary migration. This investigation focuses on the major element and trace element chemistry of the formation water (Cl, Br, Na, K, Rb, Mg, Ca, Sr, and Rare Earth Elements), which has been compared to chemical constituents of the associated crude oil and kerogens. Analytical data for this investigation were determined by the following methods; Ion Chromatography, Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). The information is used to assess the presence of different sources of water that constitute the formation water, and also to investigate interaction between different minerals and formation waters within the source beds. The formation water data also yields new insights into compartmentalization of oil-gas rich zones within the source beds.

With current energy demands globally and locally, nuclear energy remains one of the top competitors for cleaner and sustainable energy. The nuclear industry requires more inherent safety and proliferation resistance in reactor design. Thorium has therefore been identified as a possible fuel for future nuclear reactors that can comply with these requirements. However current extraction techniques are expensive, time consuming and generate large quantities of hazardous waste. A possible alternative to conventional solvent extraction of thorium is SFE (Supercritical Fluid Extraction). A monazite sample from the Steenkampskraal mine was investigated using SEM (Scanning Electron Microscope) analysis methods to determine the distribution of thorium in the grains that could potentially complicate the effectiveness of the SFE extraction method if zoning is present. The results show a homogeneous distribution with no discernable zonation in the grains. The concentration of Th, Ce and Nd was determined by quantitative MPA (Micro Probe Analysis). The results obtained from the MPA point analysis on several grains show average Th, Ce and Nd concentrations of 6.5 wt. %, 24.1 wt. % and 9.7 wt. % respectively. The extraction of Th+4 from a filter paper was conducted to verify the extraction procedure and extractability of transition elements employing SFE. The extraction was conducted using supercritical CO2 and methanol as co-solvent with TBP (Tributyl Phosphate) and HFA (Hexafluoroacetylacetone) added in situ as chelates. ICP-MS results for the Th+4 extraction procedure showed extraction efficiency of 53 % compared to 83 % in literature (Kumar et al. 2009). This marked difference in extraction efficiency is attributed to ineffective trapping methods employed and lack of prior maintenance and support on the extraction apparatus. Subsequently all further extracted samples of Th from monazite were tested using XRF analysis methods. Due to the lack of prior maintenance on the extraction apparatus several technical breakdowns were encountered and addressed from a mechanical engineering standpoint. The operational effectiveness of the modified apparatus was verified through the extraction of marula seed oil and compared with another supercritical fluid (SF) extractor to show 50 % extraction efficiency in each case. A review of the literature indicated that the crystal chemical requirements for substitution of trivalent (Ce+3) for tetravalent (Th+4) may be fulfilled during SFE processes. Experimental substitution extractions were conducted by addition of different chelates and were conducted by subjecting the monazite samples to 20 MPa pressure for 180 min static flow and 10 min continuous flow extraction times with a CO2 flow rate of 2 mL/min with 10 % co-solvent flow rate. The results of the two sets of substitution extractions namely α and β show no clear indication of Th extraction. The maximum theoretical efficiency obtainable under current extraction equipment limitations was calculated as 12%. The XRF analysis error margin was given by the analytical laboratory as 10 %. The literature has shown the substitution of trivalent cations for tetravalent cations in the monazite structure to be a valid reaction mechanism. The experimental results showed little or no success in extracting thorium from monazite. In order to prove the practical feasibility of thorium extraction several changes to the experimental operating conditions is required. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

With current energy demands globally and locally, nuclear energy remains one of the top competitors for cleaner and sustainable energy. The nuclear industry requires more inherent safety and proliferation resistance in reactor design. Thorium has therefore been identified as a possible fuel for future nuclear reactors that can comply with these requirements. However current extraction techniques are expensive, time consuming and generate large quantities of hazardous waste. A possible alternative to conventional solvent extraction of thorium is SFE (Supercritical Fluid Extraction). A monazite sample from the Steenkampskraal mine was investigated using SEM (Scanning Electron Microscope) analysis methods to determine the distribution of thorium in the grains that could potentially complicate the effectiveness of the SFE extraction method if zoning is present. The results show a homogeneous distribution with no discernable zonation in the grains. The concentration of Th, Ce and Nd was determined by quantitative MPA (Micro Probe Analysis). The results obtained from the MPA point analysis on several grains show average Th, Ce and Nd concentrations of 6.5 wt. %, 24.1 wt. % and 9.7 wt. % respectively. The extraction of Th+4 from a filter paper was conducted to verify the extraction procedure and extractability of transition elements employing SFE. The extraction was conducted using supercritical CO2 and methanol as co-solvent with TBP (Tributyl Phosphate) and HFA (Hexafluoroacetylacetone) added in situ as chelates. ICP-MS results for the Th+4 extraction procedure showed extraction efficiency of 53 % compared to 83 % in literature (Kumar et al. 2009). This marked difference in extraction efficiency is attributed to ineffective trapping methods employed and lack of prior maintenance and support on the extraction apparatus. Subsequently all further extracted samples of Th from monazite were tested using XRF analysis methods. Due to the lack of prior maintenance on the extraction apparatus several technical breakdowns were encountered and addressed from a mechanical engineering standpoint. The operational effectiveness of the modified apparatus was verified through the extraction of marula seed oil and compared with another supercritical fluid (SF) extractor to show 50 % extraction efficiency in each case. A review of the literature indicated that the crystal chemical requirements for substitution of trivalent (Ce+3) for tetravalent (Th+4) may be fulfilled during SFE processes. Experimental substitution extractions were conducted by addition of different chelates and were conducted by subjecting the monazite samples to 20 MPa pressure for 180 min static flow and 10 min continuous flow extraction times with a CO2 flow rate of 2 mL/min with 10 % co-solvent flow rate. The results of the two sets of substitution extractions namely α and β show no clear indication of Th extraction. The maximum theoretical efficiency obtainable under current extraction equipment limitations was calculated as 12%. The XRF analysis error margin was given by the analytical laboratory as 10 %. The literature has shown the substitution of trivalent cations for tetravalent cations in the monazite structure to be a valid reaction mechanism. The experimental results showed little or no success in extracting thorium from monazite. In order to prove the practical feasibility of thorium extraction several changes to the experimental operating conditions is required. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: At Skorpion Zinc mine, in south-west Namibia, zinc oxide ore is refined through sulphuric acid leaching, solvent extraction, electrowinning and casting of the final 99.995 % Zn metal. Over the last four years, the rare earth element concentrations, with particular reference to Y, Yb, Er and Sc, have significantly increased in the circulating electrolyte and the zinc-stripped organic phase streams in the electrowinning and solvent extraction processes. This project had two main objectives: firstly, the effect(s) of rare earths on the zinc solvent extraction and electrowinning processes were to be determined; based on these results, the second objective was to find a suitable method for removing rare earth elements from the organic phase during zinc solvent extraction. The investigation into the effect of the rare earths on zinc electrowinning showed that an increase of 100 mg/l in the electrolyte Y concentration caused a decrease of 6 % in current efficiency. The elemental order of decreasing current efficiency was found to be: Y > Yb > Er > Sc. In the zinc solvent extraction process, it was found that an increase in the total organic rare earth elements and iron concentration from 3100 to 6250 mg/l resulted in doubled viscosity and an increase in phase disengagement time from 100 to 700 seconds. The organic zinc loading capacity after two extraction stages was reduced by 1 – 3 g/l depending on the pregnant leach solution used. The detrimental effect of rare earth elements on solvent extraction and electroplating of zinc therefore justified the development of a rare earth element removal process. Stripping of low concentrations of rare earth elements from 40% D2EHPA diluted in kerosene to produce a clean organic for zinc extraction was investigated using bench-scale experiments in a glass jacketed mixing cylinder. For the rare earths, the best stripping agent was found to be H2SO4, followed by HCl and then HNO3. Hydrochloric acid achieved better Fe stripping than sulphuric acid. Acid concentration was tested in the range of 1 to 7 M, organic-to-aqueous ratio for the range of 0.25 to 6.0 and temperatures between 30 and 55 °C. More than 80% stripping of yttrium and erbium could be achieved at an optimum hydrochloric acid concentration of 5 M and more than 90% rare earth element (specifically Y, Er, Yb) stripping from the organic phase could be achieved with 5 M sulphuric acid. Stripping was improved by reducing the organic-to-aqueous ratio to as low as 0.5 and increasing the temperature. Stripping increased with increasing temperature in an S-shaped curve, flattening off at 50°C. The effect of O:A ratio was more significant than the effect of temperature on rare earth stripping. The results showed good repeatability, and were not limited by the rare earth concentration, agitation rate or equilibrium time in the range of set points used in the experiments. Statistical models were compiled to fit the experimental data obtained for Y, Yb, Er and Fe when stripped with sulphuric and hydrochloric acid respectively. All models showed dependence on the acid concentration and squared-concentration and interaction effects between the O:A ratio and temperature and stripping agent concentration were significant. The models were compiled for the experimental data obtained from stripping synthetically prepared organic and then tested on results obtained when stripping the plant organic phase. The following three process solutions were discussed for implementation on a plant scale for the removal of rare earths from the organic phase during zinc solvent extraction: Sulphuric acid stripping mixer settler or stripping column, improvement of available HCl stripping section and replacement of the organic inventory. The possibility of an oxalic acid precipitation process to obtain value from the rare earths as by-product was also discussed. It was concluded that the current process that uses HCl to strip off iron and rare earths would be the best practically and financially feasible process. Value can be gained from the rare earths if a rare earth element - oxalic acid precipitation section that is financially feasible can be established. / AFRIKAANSE OPSOMMING: By Skorpion Zinc myn, in suidwes Namibië, word sinkoksied erts gesuiwer deur middel van swaelsuur-loging, oplosmiddel ekstraksie, elektroplatering en gieting van die finale 99.995 % Zn metaal. Oor die afgelope vier jaar het die seldsame aardmetale konsentrasie, spesifiek Y, Yb, Er en Sc, noemenswaardig in die sirkulerende elektroliet en sink-gestroopte organiese fase toegeneem. Hierdie projek het twee hoofdoelstellings gehad: eerstens moes die effek van seldsame aardmetale op die sink oplosmiddel ekstraksie en elektroplatering prosesse bepaal word; gebaseer op hierdie resultate, was die tweede doelstelling om ‘n geskikte metode vir die verwydering van seldsame aardmetale vanaf die organiese fase gedurende sink oplosmiddel ekstraksie te vind. Die ondersoek na die effek van seldsame aardmetale op sink elektroplatering het gewys dat ‘n verhoging van 100 mg/l in die elektroliet Y konsentrasie ‘n verlaging van 6 % in kragdoeltreffendheid veroorsaak het. Die element-orde van verminderende kragdoeltreffendheid was Y > Yb > Er > Sc. Vir die sink oplosmiddel ekstraksie proses, is gevind dat ‘n verhoging in die totale organiese seldsame aardmetaal- en yster konsentrasie van 3100 tot 6250 mg/l ‘n verdubbelde viskositeit en ‘n verlenging in faseskeidingstyd van 100 tot 700 sekondes tot gevolg gehad het. Die organiese sink ladingskapasiteit na twee ekstraksie stappe is met 1 – 3 g/l verminder afhangende van die logings oplossing wat gebruik is. Die nadelige effek van seldsame aardmetale op oplosmiddel ekstraksie en sink elektroplatering het die ontwikkeling van ‘n seldsame aardmetale verwyderingsproses regverdig. Die verwydering van lae konsentrasies seldsame aardmetale vanaf die D2EHPA-keroseen organiese fase om ‘n skoon organiese fase vir sink-ekstraksie te verkry is ondersoek deur banktoetsskaal eksperimente. Vir die seldsame aardmetale is bevind dat H2SO4 die beste stropingsagent is, gevolg deur HCl en dan HNO3. Soutsuur het beter yster verwydering as swaelsuur bewerkstellig. Suurkonsentrasies van 1 tot 7 M, O:A verhoudings van 0.25 tot 6 en temperature tussen 30 en 55°C is getoets. Meer as 80% verwydering van yttrium en erbium kon bereik word met ‘n optimum HCl konsentrasie van 5 M en meer as 90% seldsame aardmetale (spesifiek Y, Er en Yb) verwydering vanaf die organiese fase met 5 M swaelsuur. Seldsame aardmetale en yster verwydering kon verbeter word deur die organies-tot-waterfase (O:A) verhouding te verminder tot so laag as 0.5 en deur die temperatuur te verhoog. Stroping het in ‘n S-kurwe verhoog soos die temperatuur verhoog het, en het afgeplat teen 50°C. Die effek van die O:A verhouding was belangriker as die effek van temperatuur op stroping. Die resultate het goeie herhaalbaarheid gewys, en is nie deur massaoordrag beperk nie. Statistiese modelle is saamgestel om die eksperimentele data wat vir Y, Yb, Er en Fe verkry is vir stroping met swaelsuur en soutsuur te pas. Al die modelle het afhanklikheid van die suurkonsentrasie en kwadratiese suurkonsentrasie gewys en interaksie effekte tussen die O:A verhouding, temperatuur en suurkonsentrasie was belangrik. Die modelle is saamgestel vir die eksperimentele data wat verkry is vanaf stroping van ‘n sintetiese organiese fase en is toe getoets op resultate wat verkry is vanaf stroping van die aanleg se organiese fase. Die volgende drie proses-oplossings is oorweeg vir implementering op ‘n aanlegskaal vir die verwydering van seldsame aardmetale vanaf die organiese fase gedurende sink oplosmiddel ekstraksie: Swaelsuur stroping menger-afskeidingstenk of stropingskolom, verbetering van die bestaande HCl aanleg en vervanging van die organiese inventaris. ‘n Moontlike oksaalsuur presipitasie proses om waarde vanaf die seldsame aardmetale as by-produk te verkry is ook bespreek. Daar is tot die gevolgtrekking gekom dat die huidige proses wat HCl gebruik om yster en seldsame aardmetale van die organiese fase af te stroop, die beste praktiese en finansieel vatbare proses huidiglik is. Waarde kan vanaf die seldsame aardmetale verkry word as ‘n seldsame aardmetale – oksaalsuur presipitasie afdeling wat finansieel haalbaar is daargestel kan word.

Chemical weathering reactions are important for the physical, chemical, and biological development of the critical zone. We present findings from aqueous phase chemical analyses of surface and soil pore waters during a 15 month study in a small semi-arid mountain catchment of the Santa Catalina Mountain Critical Zone Observatory. Stream water geochemical solutes are sourced to two distinct locations - fractured bedrock baseflow stores and soil quickflow stores. Solid phase observations of albite, anorthite, and K-feldspar transformation to Ca-montmorillonite and kaolinite are supported by stream water saturation states calculated via a PHREEQC geochemical model. While differences in mineral assemblages, soil depths, and horizonation suggest greater weathering in schist versus granite lithologies and in hillslope divergent versus convergent zones, soil pore water solute ratio analysis does not readily distinguish these differences. However, preliminary investigation of aqueous rare earth elements suggests detectable lithologic and landscape positional differences warranting focus for future research efforts.

Master of Science / Department of Geology / Matthew Totten / The REE distribution patterns and total concentrations of the organic matter of the Woodford shale reveal a potential avenue to investigate hydrocarbon maturation processes in a source rock. Ten samples of the organic matter fraction and 10 samples of the silicate-carbonate fraction of the Woodford shale from north central Oklahoma were analyzed by methods developed at KSU. Thirteen oil samples from Woodford Devonian oil and Mississippian oil samples were analyzed for REE also. REE concentration levels in an average shale range from 170 ppm to 185 ppm, and concentration levels in modern day plants occur in the ppb levels. The REE concentrations in the organic matter of the Woodford Shale samples analyzed ranged from 300 to 800 ppm. The high concentrations of the REEs in the Woodford Shale, as compared to the modern-day plants, are reflections of the transformations of buried Woodford Shale organic materials in post-depositional environmental conditions with potential contributions of exchanges of REE coming from associated sediments. The distribution patterns of REEs in the organic materials normalized to PAAS (post-Archean Australian Shale) had the following significant features: (1) all but two out of the ten samples had a La-Lu trend with HREE enrichment in general, (2) all but two samples showed Ho and Tm positive enrichments, (3) only one sample had positive Eu anomalies, (4) three samples had Ce negative anomalies, although one was with a positive Ce anomaly, (5) all but three out of ten had MREE enrichment by varied degrees. It is hypothesized that Ho and Tm positive anomalies in the organic materials of the Woodford Shale are reflections of enzymic influence related to the plant physiology. Similar arguments may be made for the Eu and the Ce anomalies in the Woodford Shale organic materials. The varied MREE enrichments are likely to have been related to some phosphate mineralization events, as the Woodford Shale is well known for having abundant presence of phosphate nodules. The trend of HREE enrichment in general for the Woodford Shale organic materials can be related to inheritance from sources with REE-complexes stabilized by interaction between the metals and carbonate ligands or carboxylate ligands or both. Therefore, a reasonable suggestion about the history of the REEs in the organic materials would be that both source and burial transformation effects of the deposited organic materials in association with the inorganic constituents had an influence on the general trend and the specific trends in the distribution patterns of the REEs. This study provides a valuable insight into the understandings of the REE landscapes in the organic fraction of the Woodford Shale in northern Oklahoma, linking these understandings to the REE analysis of an oil generated from the same source bed and comparing it to oil produced from younger Mississippian oil. The information gathered from this study may ultimately prove useful to trace the chemical history of oils generated from the Woodford Shale source beds.

Master of Science / Department of Geology / Matthew Totten / There are some who hold the view that liquid hydrocarbons in the upper Paleozoic formations in Kansas are being locally derived. It has been the long held belief that the liquid hydrocarbons found in Kansas have come from distant sources in Oklahoma. To shed further light on this issue about the origin of hydrocarbons in the upper Paleozoic formations in Kansas, a study was conducted to analyze the geochemical characteristics of REE in Lansing-Kansas City oils that were collected from several locations in a small area within Rooks County, Kansas. The total REE contents in these oils ranges from about 3.1 ng (or 10-12 gram) per Liter of oil to about 131 ng per Liter of oil. The pattern of relative distribution of the REEs for each oil sample has been constructed from values that were obtained by dividing the individual REE concentrations of a given oil sample by the respective concentrations of the REEs in a standard or a reference sample (such as PAAS, a representation of average argillaceous sediments in the crust that is commonly used for the analyses of a variety of crust originated sedimentary products). A standard- normalized relative distribution pattern of an oil sample can reveal an important history of chemical evolution of the oil of interest. The PAAS-normalized patterns of relative distribution of the REEs in the Lansing-Kansas City oils from Rooks County, Kansas are significantly diverse. Although nearly all oil samples investigated in this study have varied degrees of light REE-enrichment across the REE series from La to Sm, they differed in their relative Ce abundances. Some samples have positive Ce anomalies; some have negative Ce anomalies, and some others with the absence of any Ce anomaly. The oils also differed in their PAAS-normalized relative distribution of the middle rare earth elements (MREEs), ranging from Sm to Tb. All oil samples were relatively enriched in the MREEs, but with varied degrees of enrichment from a prominent one to almost a barely noticeable one. The oils differed in their relative distributions of Eu, as some were with a positive Eu anomaly, some with a negative Eu anomaly, and some with the absence of any Eu anomaly. The trends of the heavy rare earth elements (HREEs) from Tb to Lu among the oils ranged from nearly flat for the most oils to a progressive depletion across the series for few samples. Furthermore, the oils were varied in having prominently anomalous relative distributions, in some cases with a positive anomaly and in others with negative anomaly, for such elements as Tb, Ho, and Tm (MM-JS-04, MM-MC-3A, and MM-MC-01). The anomalies for Tb, Ho, Tm are reflections of enzyme activity of source material during its primary (growth) environment. The metals are known to be preferentially located at the active sites of the enzymes. The oils not only differed significantly in their REE-geochemical characteristics, they also had a wide range of K/Rb weight ratios from about 877 to about 2000. These high values are typically the ones that can be assigned to organic materials, well exceeding the range of values that are associated with common silicate minerals and rocks, having an average value of 250-350ppm. Different zones in the Lansing-Kansas City formations also show distinct REE distribution patterns. There are four broadly classified distribution patterns. MREE enrichment can be observed in samples with production from the middle Lansing-Kansas City zones (G-I). In samples with comingling Lansing-Kansas City zones, amplification of anomalies from differing source materials can be observed. The diversity in the REE distribution patterns and K/Rb ratios in oils collected from central Kansas makes a strong argument against long distance transportation from a distant source in Oklahoma