Identification of rare earth elements in synthetic and natural monazite and xenotime by visible-to-shortwave infrared reflectance spectroscopy

To support the role of proximal and remote sensing in geological rare earth element (REE) resource exploration, we studied the reflectance spectroscopy of synthetic single- and mixed-REE phosphate phases. Synthesis yielded monazite for the elements La to Gd, and xenotime for Dy to Lu and Y. Visible-to-shortwave infrared (350–2500 nm) reflectance spectra of synthetic single-REE monazites and xenotimes can be used to identify the ions responsible for the absorption features in natural monazites and xenotimes. Nd3+, Pr3+ and Sm3+ produce the main absorption features in monazites. In natural xenotime, Dy3+, Er3+, Ho3+ and Tb3+ ions cause the prevalent absorptions. The majority of the REE-related absorption features are due to photons exciting electrons within the 4f subshell of the trivalent lanthanide ions to elevated energy levels resulting from spin-orbit coupling. There are small (&lt; 20 nm) shifts in the wavelengths of these absorptions depending on the nature of the ligands. The energy levels are further split by crystal field effects, manifested in the reflectance spectra as closely spaced (∼ 5–20 nm) multiplets within the larger absorption features. Superimposed on the electronic absorptions are vibrational absorptions in the H2O molecule or within [OH]−, [CO3]2− and [PO4]3− functional groups, but so far only the carbonate-related spectral features seem usable as a diagnostic tool in REE-bearing minerals. Altogether, our study creates a strengthened knowledge base for detection of REE using reflectance spectroscopy and provides a starting point for the identification of REE and their host minerals in mineral resources by means of hyperspectral methods.</p

Multispectral and Hyperspectral Remote Sensing Data for Mineral Exploration and Environmental Monitoring of Mined Areas

In recent decades, remote sensing technology has been incorporated in numerous mineral exploration projects in metallogenic provinces around the world. Multispectral and hyperspectral sensors play a significant role in affording unique data for mineral exploration and environmental hazard monitoring. This book covers the advances of remote sensing data processing algorithms in mineral exploration, and the technology can be used in monitoring and decision-making in relation to environmental mining hazard. This book presents state-of-the-art approaches on recent remote sensing and GIS-based mineral prospectivity modeling, offering excellent information to professional earth scientists, researchers, mineral exploration communities and mining companies

Phosphonium/ammonium-based ionic liquids for rare earth minerals beneficiation : case of monazite and bastnäsite

Tableau d'honneur de la Faculté des études supérieures et postdoctorales, 2017-2018Cette thèse de doctorat porte sur l'application des liquides ioniques à base de phosphonium et d'ammonium pour l'enrichissement des minéraux à base d'éléments de terres rares. Le manuscrit de thèse a été divisé en quatre parties principales. Tout d'abord, l'utilisation des liquides ioniques à base de phosphonium et d'ammonium a été explorée dans trois procédés différents pour la valorisation des minéraux de terres rares. Ces trois approches ont été examinées pour des minéraux à base d’éléments de terres rares contenus dans un minerai complexe en provenance du gisement Niobec au Québec ainsi que des minéraux modèles de monazite et de bastnäsite associés à la gangue du minerai Niobec. Par la suite, l'application de ces liquides ioniques à l'extraction par solvant des éléments des terres rares a été étudiée par simulation à l’aide d’outil de chimie quantique. Dans le premier cas de valorisation des minéraux de terres rares, l'application d'un liquide ionique à base de phosphonium /ammonium comme collecteur aqueux pour la flottation par moussage de minéraux des terres rares a été étudiée. Dans cette étude, le liquide ionique a été identifié pour posséder des performances supérieures à celles offertes par les collecteurs classiques utilisés en industrie comme les collecteurs dérivés de l'acide hydroxamique industriel. Les interactions anioniques et cationiques du liquide ionique durant la flottation des minéraux d’éléments de terres rares ont été scrutées en détail pour révéler qu’une voie de synergie interne explique en partie les résultats de la flottation en terme de chimisorption de la partie anionique et de la physisorption et de la partie cationique du liquide ionique. Dans le deuxième cas d'enrichissement des minéraux de terres rares, le potentiel de la séparation minérale liquide (aqueuse)-liquide (organique) au moyen de trois types de liquides ioniques à base de phosphonium /ammonium a été étudié. Cette approche s'est avérée supérieure à la micro-flottation conventionnelle appliquée aux mêmes minéraux en termes de sélectivité. De même, il a été démontré que ce procédé peut être appliqué avec efficacité sur une large gamme de pH (4-9) et pour des particules finement broyées (- 105 μm) pour fins de valorisation des minéraux de terres rares. Il a été révélé que l'interaction du liquide ionique sur les surfaces minérales se produisait en phase aqueuse, en phase aqueuse-organique et également en phase organique favorisant ainsi l'activation des minéraux et la séparation subséquente. Dans le troisième cas d'enrichissement des minéraux de terres rares, le potentiel de séparation dans un mélange de deux liquides ioniques immiscibles a enfin été exploré. Un liquide ionique à base de phosphonium / ammonium comme phase dispersées sous forme de gouttelettes et trois liquides ioniques différents faisaint office de phase continue ont été utilisés pour évaluer cette nouvelle approche d'enrichissement des minéraux d’éléments de terres rares. Ce processus s’est avéré très prometteur en tant qu'alternative d'enrichissement des minéraux à base d’éléments de terres rares comparativment aux deux approches précédentes en termes de sélectivité et de récupération des éléments de terres rares. Enfin dans la dernière partie de la thèse, des simulations de type chimie quantique basée sur la théorie de la densité fonctionnelle (DFT) ont été mises en oeuvre pour proposer une méthode de classification reposant sur la stabilité de la formation de complexes à partir de trente différents liquides ioniques à base de phosphonium aidant à l'extraction par solvant des éléments de terres rares solvatés. Cette étude a d'une part montré que les liquides ioniques choisis peuvent être appliqués plus efficacement pour l'extraction par solvant des éléments de terres rares contenus dans les solutions aqueuses après digestion acide des minéraux par l’acide nitrique ou chlorhydrique plus que lors d’un recours à l'acide sulfurique. Il a ensuite été démontré que les groupements anioniques des liquides ioniques testés sont capables de former directement des liaisons covalentes par complexation avec les éléments des terres rares solvatés. Au contraire, les interactions des groupements cationiques ont été plus faibles se résumant à des interactions de sphère externe par rapport au complexes formés. Ce travail de recherche a permis d’explorer la faisabilité dans l'application des liquides ioniques à base de phosphonium au traitement des minéraux et des métaux de terres rares. Les résultats obtenus durant cette étude pourront contribuer à une meilleure compréhension de l’apport des liquides ioniques au secteur des industries des terres rares afin en ayant pour cible l'amélioration de l'efficacité des procédés d'enrichissement des minéraux et d'extraction par solvant des éléments de terres rares dissous.This Ph.D. thesis examines the application of phosphonium/ammonium based ionic liquids in the beneficiation of rare earth element bearing minerals. It has been divided into four main parts. Firstly, the use of phosphonium/ammonium based ionic liquids in three different approaches for rare earth element minerals beneficiation has been explored. These three processes were examined for actual rare earth elements bearing complex ore from Niobec deposit as well as for its constitutive model minerals consisting of monazite and bastnäsite associated with other gangue minerals. Subsequently, application of phosphonium based ionic liquids in rare earth elements solvent extraction has been studied from quantumchemistry point of view. In the first process in rare earth element minerals beneficiation, application of a phosphonium/ammonium based ionic liquid as an aqueous collector for froth flotation of rare earth element minerals was studied. In this study, the ionic liquid revealed superior performance to recover rare earth elements bearing minerals as compared with industrial hydroxamic acid collectors. The ionic liquid anionic and cationic moieties interactions during rare earth element minerals flotation were rationalized in terms of an inner synergistic pathway, meaning that the uptake of both cationic and anionic moieties through ionic liquid collector adsorption occurred altogether. In the second process in rare earth element minerals beneficiation, the potential of liquid-liquid mineral separation mediated by means of three types of phosphonium/ammonium based ionic liquids to beneficiate rare earth elements bearing minerals was studied. This process was found to outperform micro-flotation of the same minerals in terms of selectivity. Likewise, it was shown that this process can be effectively applied over a wide range of pH (4-9) and for fine particle sizes (-105 μm) in rare earth element minerals beneficiation. Interaction of the ionic liquid on the mineral surfaces occurred in aqueous phase, aqueousorganic phases interface and also in the organic phase thereby promoting minerals activation and next separation. In the third process in rare earth element minerals beneficiation, the potential of ionic liquid-ionic liquid mineral separation process as a novel ionic liquid-based system to beneficiate rare earth elements bearing minerals was investigated. A phosphonium/ammonium based ionic liquid as droplet phase and three different ionic liquids as continuous phase were used to assess this approach of beneficiation of rare earth elements bearing minerals. This process revealed high potential, as an alternative, to beneficiate rare earth elements bearing ore as it even outperformed the two previous processes in terms of selectivity and rare earth elements recovery. In the last part of this thesis, quantum chemistry simulations based on DFT have been undertaken to rank the complex-forming ability of thirty different phosphonium based ionic liquids in solvent extraction of rare earth elements. This study firstly indicated that phosphonium based ionic liquids can be applied more effectively for solvent extraction of rare earth elements in pregnant solutions resulting from nitric and hydrochloride acids leaching process, and less by means of sulfuric acid leaching. It was also demonstrated that while anionic moieties of phosphonium based ionic liquids are able to make directly covalent bonds during complexation with rare earth elements, their cationic moieties can be involved in complexation through outer-sphere interactions. The implications of this research work include new insights towards application of phosphonium based ionic liquids into mineral and metal processing especially rare earth elements processing. Finding from this work can contribute to the rare earth industry in order to improve efficiency of mineral beneficiation and solvent extraction processes

Spatial Heterodyne Raman Spectroscopy for Planetary Surface Exploration.

M.S. Thesis. University of Hawaiʻi at Mānoa 2017

Extracting Martian Meteorite Mineral Spectra for Remote Sensing of the Surface Geology of Mars

The source craters of the Martian meteorites remain unknown. This PhD extracted pyroxene mid-infrared spectra directly from the shergottites to supplement the current spectral libraries in modelling the geology of the Martian surface. Models using planet-representative spectral end members improves the spectral fit of the modelling, and the accuracy of the mineral abundance determination

2018 Summer Intern Program for Undergraduates Lunar and Planetary Institute

Sponsored by Lunar and Planetary Institute, NASA Johnson Space CenterThe Orientation of the Bladed Terrain Feature in Tarturus Dorsa, Pluto and Possible Reorientation of Pluto / Nicholas Wagner -- Constraints on Crater Formation Ages on Dione from Cassini VIMS and ISS / Andy López-Oquendo -- Location and Degradation State of Chaos Across Europa: Is There Old Chaos? / Mitzi Cruz Quijano -- Alexander Holmwood -- Mineralogy and Petrology of Dark Clasts in Polymict Eucrites / Alexander Holmwood -- Potassium-Feldspar Bearing Main Group and Stannern Group Eucrites: Petrographical and Geochemical Investigations of Mafic Crust Formation Processes on Vesta / Devin McQuaig -- Xenolithic Fe,Ni Metal in Polymict Ureilite Meteorites / Yoana Boleaga -- Petrology and Geochemistry of Lithic Fragments in Elephant Moraine 79001 / Ethan Kuehl -- Water Content and Mineral Abundance at Gale Crater, Mars as Inferred from OMEGA and CRISM Observations / Federico Stachurski -- Acidic Dissolution of Phosphate-Rich and Phosphate-Poor Basalts: Implications for the Stimson Sandstone Unit, Gale Crater / Nathan Hadland -- Chemistry and Crystallography of Diagenetic and Authigenic Potassium Feldspar: Implications for Sedimentary Petrology in Gale Crater, Mars / Jacob Ott -- Petrologic Analysis of Green-Black Impact Melt Breccia with a History of Hydrothermal Alteration at Chicxulub / Elisha Jhoti -- LRO LAMP Far Ultraviolet Investigation of Cold Spots and a New Impact Crater on the Moon / Elisha Jhoti -- Tracing a Lunar Magmatic Epoch Through Apollo 14 Samples / Hannah O'Brien -- Anomalous Radar Properties at Venus’ Mountaintops: Refined Spatial Resolution from Stereo Altimetry / Frank Wroblewski

GeoRaman 2020. 14th International GeoRaman conferences. Book of Abstracts

112 p.The main aim of this congress is to provide a scientific forum to present and promote the use of analytical techniques in the field of Geosciences. This series of conferences has a tradition since 1986, starting in Paris, and has since then been held in multiple cities in Europe, USA and Australia. The GeoRaman 2020 conference scope covers all scientific aspects where Raman spectroscopy and geology meet. GeoRaman has served as an important meeting point for scientists from different area of knowledge, to present their studies, participate in scientist discussions and find collaborative partners. Starting this year, several space agencies are going to launch missions to Mars in which for the first time Raman spectroscopy is going to be present (Perseverance and Rosalind Franklin rovers)

GeoRaman 2020. 14th International GeoRaman conferences. Book of Abstracts

112 p.The main aim of this congress is to provide a scientific forum to present and promote the use of analytical techniques in the field of Geosciences. This series of conferences has a tradition since 1986, starting in Paris, and has since then been held in multiple cities in Europe, USA and Australia. The GeoRaman 2020 conference scope covers all scientific aspects where Raman spectroscopy and geology meet. GeoRaman has served as an important meeting point for scientists from different area of knowledge, to present their studies, participate in scientist discussions and find collaborative partners. Starting this year, several space agencies are going to launch missions to Mars in which for the first time Raman spectroscopy is going to be present (Perseverance and Rosalind Franklin rovers)

International Workshop on Advanced Techniques in Actinide Spectroscopy (ATAS 2012) - Abstract Book

Modern Societies have to consider diverse tasks strongly related to geochemistry sciences. Examples intensively discussed in the public are restoration measures for contaminated industrial fallow grounds, the safe storage of chemical-toxic and radioactive waste, carbon dioxide sequestration to reduce green-house gas emissions, the construction and operation of deep geothermal power plants, the geochemical exploration of natural resources or water and waste water treatments, including desalination efforts. Direct and urgent aspects to be dealt with are analytical and geochemical consequences of the Fukushima Daiichi nuclear disaster. All these cases have one in common – they require reliable thermodynamic data in order to forecast the fate of chemicals in the respective environment. Whereas a variety of standard methods, such as potentiometry, solubility studies, liquid-liquid extraction or electrochemical titrations, are in widespread use to generate thermodynamic data, it is far less straightforward to assign correct reaction pathways and structural patterns to the underlying chemical transformations. This especially holds for systems with strong tendencies to complexation and oligomerization. Here, it is essential to have proof of evidence for all involved species, which cannot be provided by the aforementioned methods, and is still lacking for various metal-containing systems. Spectroscopic techniques in combination with approaches from quantum chemistry can be of great benefit for such tasks. However, their application ranges are often restricted with respect to the type of element (and redox state) that can be probed. Further handicaps are imposed by detection limits or other parameters such as pH or salinity. Moreover, the spectroscopic results are often difficult to interpret in an unambiguous way. To overcome these complications at least partially, this workshop has been initiated. It shall significantly extend the application areas of spectroscopic tools important for lanthanide and actinide chemistry. Emphasis shall be placed on the development of spectroscopic methods towards more challenging environmental conditions – such as very basic pH values, elevated temperatures, pressures, or salinities – extending the range of covered elements and redox states. Furthermore, the exploration of options for lowering detection limits and increasing spatial resolution at sufficiently high signal-to-noise ratios will support future investigations on more complex systems. An approach combining the extension of spectroscopic tools with respect to elements and parameters, improvements of experimental setups, and applications of quantum chemical methods in predictive as well as interpretative ways certainly can be very beneficial. The workshop hopefully will bundle and strengthen respective research activities and ideally act as a nucleus for an international network, closely collaborating with international partners. I am confident that the workshop will deliver many exciting ideas, promote scientific discussions, stimulate new developments and in such a way be successful