Download or read book Electrochemical Recovery of Rare Earth Elements in Molten Salt Systems written by Stephanie Castro Baldivieso and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fission products are generated from the production of nuclear energy via the nuclear fission of uranium atoms. Used nuclear fuel (UNF) constitutes of fission products, where U and Pu isotopes represent the majority, and a small portion of this fuel contains actinides, rare-earth elements, and alkaline earth elements. The UNF is not recycled: it is stored in cooling pools due to its heat emanation and radioactivity from the actinides, and later it is kept in dry casting underground storage. Pyroprocessing of UNF allows the recycling of U and Pu from the waste, and it consists of 4 different stages: (1) oxide reduction unit, (2) electro refiner, (3) cathode processor and (4) fuel fabrication furnace. In the first stage, the oxide reduction unit, the UNF oxide gets reduced to metal at the cathode in molten LiCl-Li2O. This process is feasible for most of the fission products in the molten salt. However, rare-earths are very stable in their oxide form (e.g., Nd2O3) in chloride salts and it is very challenging to reduce them to metal. Electrochemical recovery and reduction pathways in which rare earth oxides (e.g., La2O3) can be readily reduced are investigated in this dissertation by mixing these oxides with transition metal oxides (e.g., NiO). At first, the feasibility of reducing transition metal oxides (e.g., NiO) was evaluated to characterize the standard reduction potentials and how efficient the transition metal oxide can be reduced in molten LiCl-Li2O electrolyte at 650 °C. Secondly, NiO was mixed with La2O3 respectively, using their atomic ratios (1:5) according to its phase diagram (La-Ni) and sintered into pellet materials. Furthermore, the reduction pathways of this alloy by electrolysis were investigated in LiCl, and LiCl-Li2O. In the next stage of the pyroprocess, the metallic UNF is used in the electrorefiner as the anode, and it is dissolved into a LiCl-KCl molten salt electrolyte, which allows the recovery of U and Pu at the cathode using an inert metal rod. However, the process becomes inefficient over time due to the accumulation of impurities (e.g., remaining fission products) in the molten salt electrolyte. The accumulation of these impurities reduces the recovery efficiency of U over time. The recovery of the rare earth fission products from the molten LiCl-KCl-RECl3 electrolyte used in the electrorefiner unit is investigated in this dissertation by evaluating the recovery efficiency of rare earth elements (specifically Gd) using liquid metal electrodes (e.g., Bi). At first, thermodynamic properties of Gd-Bi were determined using electromotive force (emf) measurements, in which enthalpies, entropies, activity and activity coefficients of Gd-Bi alloys were evaluated. The inconsistencies of the Gd-Bi phase diagrams were also evaluated using x-ray diffraction (XRD), differential scanning calorimetry (DSC) and coulometric titrations to examine the solubility of Gd in liquid Bi. The low activity of Gd-Bi alloys indicate strong interactions between the rare earths and liquid metals, and the kinetic properties (e.g., diffusivity, coulombic efficiencies, resistances) probed by electrochemical impedance spectroscopy (EIS), cyclic voltammetry, and deposition-removal cycles suggest a reversible process of Gd(III) ions in the molten LiCl-KCl-GdCl3 salt using an inert cathode; and Gd(III) ions maintain a constant ohmic and charge transfer resistances when deposited into Bi at different range of temperatures. This work will provide fundamental knowledge on how rare earth oxides can be reduced in a feasible manner to metals by alloy formation with transition metals, and how feasible is to recover Gd using liquid Bi electrode by studying its thermodynamic and kinetic properties in the molten salt electrolyte. Rare earth oxide reduction also provides cheaper alternatives to fabricate alloy systems used in Ni-metal hydride batteries (LaNi5 alloys).

Download or read book Electrochemical Recovery of Rare Earth Metals in Molten Salts written by Aida Abbasalizadeh and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrochemical and Thermodynamic Properties of Neodymium Alloys in Molten Salts for Their Recovery written by Sanghyeok Im and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recovery of rare-earth elements is an essential process technology to achieve energy sustainability for nuclear power by closing the fuel cycle and for renewable energy by securing rare-earth supply. In detail, rare-earth fission products that accumulate into molten salts (e.g., LiCl-KCl) during reprocessing for used nuclear fuel must be recovered to reuse the salts and minimize nuclear waste. Rare-earth permanent magnets are an essential component for wind turbines and electric vehicle motors but face supply concerns with the rapid deployment of clean energy technologies. In the design of electrochemical processes for rare-earth recovery, thermodynamic and electrochemical properties of rare-earth elements are important to achieve high efficacy but are not widely available in the literature due to the high reactivity of rare-earth metals in molten salt electrolytes. Thus, the primary objective of this thesis is to comprehensively examine the essential fundamentals of rare-earth alloys in molten salt electrolytes with reliable property measurements, focusing on the binary Nd-Sn, Nd-Bi, and Nd-Fe systems. To determine the thermodynamic properties of Nd in molten salts, electromotive force (emf) measurement is introduced. Based on the established emf relation between Nd-based alloys and pure Nd via a solid fluoride electrolyte or a transient technique, less reactive two-phase alloys were employed as a stable reference electrode for reliable emf measurements, instead of pure Nd having uncertainty in molten salts. From an electrochemical cell including the Nd-Sn (xNd = 0.10) reference electrode with a two-phase (liquid + NdSn3), the measured emf values of Nd-Bi alloys (xNd = 0.15--0.40) and Nd-Sn alloy (xNd = 0.10) were stable and reproducible without an indication of cell degradation during the measurements. Furthermore, the potential difference between two identical Nd-Sn reference electrodes was measured before/after the electrochemical evaluation for 45 days, and the stability of the cell for long-term operation was verified by showing only 3 mV difference. The thermodynamic properties for the selected liquid Bi and Sn electrodes to overcome side reactions using their strong chemical interaction with Nd were investigated through coulometric titration emf measurement. Both liquid metals exhibited similar emf values, which translate to extremely low activity of Nd (aNd) at 973 K as 1.1 x 10-13 in Bi and 5.8x10--13 in Sn, confirming their strong chemical interactions with Nd. In addition, using the emf trajectory at each temperature, the solubility of Nd at 973 K was estimated at 1.46 mol% for liquid Sn, compared to 5.65 mol% for liquid Bi. For the Bi electrode with high recovery capacity, the thermodynamic description (Phase diagram) of the Nd-Bi system was updated via CALPHAD modeling with the addition of new data, including activity and solubility by emf measurements, phase transition temperatures by DSC, and the recently observed Nd3Bi7 compound. Highly efficient recovery of Nd into liquid metals of Bi and Sn was achieved in molten LiCl-KCl-NdCl3 electrolyte at 773-973 K by leveraging the strong interactions of Nd. Both liquid metals demonstrated high round-trip coulombic efficiencies (>99.3%) during deposition-removal cycles of 10-50 mA cm-2 and high recovery capacity up to approximately 20 mol% Nd beyond the solubility limit. In addition, high recovery yield (84--90%) was confirmed based on chemical analysis of electrolysis products in Bi after constant current electrolysis (--50 mA cm-2) at 873-973 K. Overpotentials during the Nd deposition process were attributed to charge-transfer and mass-transport resistances by the current-potential curve and electrochemical impedance spectroscopy. The charge-transfer kinetics of Nd deposition into liquid metals was facile with high exchange current densities at ~220 mA cm-2. Due to the importance of permanent NdFeB magnet alloys for renewable energy technologies, the thermodynamic properties of binary Nd-Fe alloys with varying mole fractions of Nd (xNd = 0.05-0.78) were investigated via electromotive force measurements in molten chloride at 773--1073 K. The Nd-Fe alloys were heat-treated at 923 K for 7 days to stabilize equilibrium phases and then the measured emf values were consistent between alloy compositions, as shown by equivalent thermal trajectories in distinct two-phase regions of [Fe + Nd2Fe17], [Nd2Fe17 + Nd5Fe17], [Nd5Fe17 + Nd], [L + Nd2Fe17], and [L + Nd5Fe17]. The measured emf results were further validated using open-circuit potentiometry in which Nd was deposited onto a Fe electrode at 973 K, resulting in a difference of less than 18 mV for the identical two-phase alloy between the two methods. It is believed that the data are crucial in developing electrolytic processes for rare-earth alloys (e.g., Nd-Fe) and in materials simulation for reliable prediction of rare-earth alloys and compounds.

Download or read book Integrated Study of Rare Earth Drawdown by Electrolysis for Molten Salt Recycle written by Evan Wu and published by . This book was released on 2017 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pyroprocessing is an electrochemical method that is capable of separating uranium (U) and minor actinides from LiCl-KCl eutectic salt where used nuclear fuel (UNF) is dissolved. During the process, fission products including rare earth metals (RE) continually accumulate in the salt and eventually affecting uranium recovery efficiency. To reduce the salt waste after uranium and minor actinides recovery, electrolysis is performed to drawdown rare earth materials from molten salt to restore salt initial state. Present research focus on the development of RE fundamental physical properties in LiCl-KCl eutectic salt. These properties includes apparent potential, activity coefficient, diffusion coefficient and exchange current density. Additional properties including charge transfer coefficient and reaction rate constant are calculated during the analysis. La, Nd and Gd are three RE that we are particularly interested in due to the high ratio of these elements in UNF (La, Nd), the well-studied properties in dilute solution to provide a base for comparison, and the highest standard potential among all RE (Gd).

Download or read book Rare Metal Technology 2020 written by Gisele Azimi and published by Springer Nature. This book was released on 2020-01-20 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: This collection presents papers from a symposium on extraction of rare metals as well as rare extraction processing techniques used in metal production. Rare metals include strategic metals that are in increasing demand and subject to supply risks. Metals represented include neodymium, dysprosium, scandium and others; platinum group metals including platinum, palladium, iridium, and others; battery related metals including lithium, cobalt, nickel, and aluminum; electronics-related materials including copper and gold; and refectory metals including titanium, niobium, zirconium, and hafnium. Other critical materials such as gallium, germanium, indium and silicon are also included. Papers cover various processing techniques, including but not limited to hydrometallurgy (solvent extraction, ion exchange, precipitation, and crystallization), electrometallurgy (electrorefining and electrowinning), pyrometallurgy, and aeriometallurgy (supercritical fluid extraction). Contributions are focused on primary production as well as secondary production through urban mining and recycling to enable a circular economy. ​A useful resource for all involved in commodity metal production, irrespective of the major metal Provides knowledge of cross-application among industries Extraction and processing of rare metals that are the main building block of many emerging critical technologies have been receiving significant attention in recent years. The technologies that rely on critical metals are prominent worldwide, and finding a way to extract and supply them effectively is highly desirable and beneficial.

Download or read book Molten Salts Chemistry written by Frederic Lantelme and published by Newnes. This book was released on 2013-08-14 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molten salts and fused media provide the key properties and the theory of molten salts, as well as aspects of fused salts chemistry, helping you generate new ideas and applications for fused salts.Molten Salts Chemistry: From Lab to Applications examines how the electrical and thermal properties of molten salts, and generally low vapour pressure are well adapted to high temperature chemistry, enabling fast reaction rates. It also explains how their ability to dissolve many inorganic compounds such as oxides, nitrides, carbides and other salts make molten salts ideal as solvents in electrometallurgy, metal coating, treatment of by-products and energy conversion.This book also reviews newer applications of molten salts including materials for energy storage such as carbon nano-particles for efficient super capacitors, high capacity molten salt batteries and for heat transport and storage in solar plants. In addition, owing to their high thermal stability, they are considered as ideal candidates for the development of safer nuclear reactors and for the treatment of nuclear waste, especially to separate actinides from lanthanides by electrorefining. - Explains the theory and properties of molten salts to help scientists understand these unique liquids - Provides an ideal introduction to this expanding field - Illustrated text with key real-life applications of molten salts in synthesis, energy, nuclear, and metal extraction

Download or read book Rare Earths written by Jacques Lucas and published by Elsevier. This book was released on 2014-09-09 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-technology and environmental applications of the rare-earth elements (REE) have grown dramatically in diversity and importance over the past four decades. This book provides a scientific understanding of rare earth properties and uses, present and future. It also points the way to efficient recycle of the rare earths in end-of-use products and efficient use of rare earths in new products. Scientists and students will appreciate the book's approach to the availability, structure and properties of rare earths and how they have led to myriad critical uses, present and future. Experts should buy this book to get an integrated picture of production and use (present and future) of rare earths and the science behind this picture. This book will prove valuable to.non-scientists as well in order to get an integrated picture of production and use of rare earths in the 21st Century, and the science behind this picture. - Defines the chemical, physical and structural properties of rare earths. - Gives the reader a basic understanding of what rare earths can do for us. - Describes uses of each rare earth with chemical, physics, and structural explanations for the properties that underlie those uses. - Allows the reader to understand how rare earths behave and why they are used in present applications and will be used in future applications. - Explains to the reader where and how rare earths are found and produced and how they are best recycled to minimize environmental impact and energy and water consumption.

Download or read book Electrochemical Technology of Molten Salts written by C.A.C. Sequeira and published by Trans Tech Publications Ltd. This book was released on 1993-10-28 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past several years there has been remarkable interest and activity in two fields of the fused salt chemistry, namely Molten Salt Extractive Metallurgy and High-Temperature Fuel Cells. The required fundamental investigations for improving industrial processes are necessarily devoted to all aspects of the reactivity in molten salts. Therefore, most of the relevant disciplines are represented here: electrochemistry, spectroscopy and computer modelling.

Download or read book Technology for Restarting Molten Salt Nuclear Fuel Chemistry at MU written by Eric A. Schwarz and published by . This book was released on 2011 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear fuel reprocessing is a responsible choice for the continued expansion of a secure, safe and clean source of energy. While the classical method for recycling nuclear fuel is an aqueous liquid-liquid extraction, the use of a dry, non-aqueous electrochemical means of separating constituents is gaining attention. In the 1990's, the University of Missouri (MU) performed molten chemical experiments on mixed lanthanide and actinide systems appropriate for the separation of species known to be encountered when nuclear fuel is recycled. This project was completed by 2000 and new equipment must be ready to restart this electrochemical research. This work describes the technology that is now available to continue this work. Specifically, the containment required for keeping a clean environment for operations is described as well as a new reference electrode designed for molten salt electrochemistry that does not require Vycor or quartz in its construction and demonstrates good reliability. Some electrochemical examinations were conducted on samples of green mill tailings from a hematite mine in southeastern Missouri. These tailings are rich in rare-earth elements (lanthanides) which are technologically important for electronics manufacture. Separation of these elements into pure metals can be accomplished with far fewer waste products using a dry molten salt.

Download or read book Refractory Metals in Molten Salts written by D.H. Kerridge and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: This NATO Advanced Research Workshop was devoted to a specialized topic in molten salt chemistry and was held in an exotic location (as far as Westerners were concerned) well within the Arctic Circle. It nevertheless facilitated a fruitful week, both ofscience and ofhuman contacts. The 42 oral presentations and posters from nine countries enabled the 59 participants to learn a great deal about many areas of recent research in the molten salt chemistry of refractory metals, while making new contacts as well as renewing old friendships. The time ofinformal contact ledto the beginningofa numberofnew research cooperations with interchangeofpersonnel. Thus the twin aimsofadvancing science and improving East-West understanding were both amply fulfilled. Indeed a warm and happy family atmosphere was very tangible doth during the scientific sessions and the social events, which participants, accompanying persons and local staffall enjoyed. This opportunity of living for a short time within the Arctic Circle was a novelty for most Westerners, who generally appreciated the very warm weather (the hottest for 20 years according to some residents), as well as the beautiful surroundings ofvery green birch/pine forest, rushing rivers,vast lakes and rounded mountains,frequently illuminated by wonderful sunsets. The evening barbeque beside Lake Imandra (100 km long) and the coach tour beside the beautiful White Sea dotted with islands in the Kandalaksha Recreational Area (National Park), to sample Pomor culture, dancing and fresh salmon soup, were high spots ofthe social programme.

Download or read book Molten Salt Technology written by David G. Lovering and published by Springer. This book was released on 2014-11-14 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molten Salts and Ionic Liquids 19 written by W. Reichert and published by The Electrochemical Society. This book was released on 2014 with total page 661 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Extractive Metallurgy of Niobium written by A.K. Suri and published by Routledge. This book was released on 2017-11-13 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The growth and development witnessed today in modern science, engineering, and technology owes a heavy debt to the rare, refractory, and reactive metals group, of which niobium is a member. Extractive Metallurgy of Niobium presents a vivid account of the metal through its comprehensive discussions of properties and applications, resources and resource processing, chemical processing and compound preparation, metal extraction, and refining and consolidation. Typical flow sheets adopted in some leading niobium-producing countries for the beneficiation of various niobium sources are presented, and various chemical processes for producing pure forms of niobium intermediates such as chloride, fluoride, and oxide are discussed. The book also explains how to liberate the metal from its intermediates and describes the physico-chemical principles involved. It is an excellent reference for chemical metallurgists, hydrometallurgists, extraction and process metallurgists, and minerals processors. It is also valuable to a wide variety of scientists, engineers, technologists, and students interested in the topic.

Download or read book Determination of Fundamental Thermodynamic Properties of Alkali Alkaline Earth Elements in Liquid Metals for Recovery from Molten Salt Solutions written by Nathan Douglas Smith and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the nuclear industry, uranium is recovered from used nuclear fuel using a process known as electrorefining in which a metallic used nuclear fuel anode is oxidized into molten LiCl-KCl-UCl3 electrolyte and pure U is preferentially reduced onto an inert cathode. While electrorefiner systems facilitate the recycling of substantial amounts of uranium from used nuclear fuel, they also contribute to the production of nuclear waste due to the build-up of dangerous elements including 90Sr and 137Cs in the molten salt electrolyte as they are more active in the salt than U and will therefore oxidize out of the anode before U. The accumulation of Sr and Cs in the electrolyte presents a problem as Sr and Cs isotopes have high heat densities and produce large amounts of highly ionizing radiation; these hazards combined with difficulty in removing the highly stable Sr and Cs from the electrolyte necessitates frequent replacement and disposal of the electrolyte, which then contributes to the overall volume of nuclear waste. This dissertation focuses on evaluating the viability of using liquid metal electrodes as a method for electrochemical separation of Sr and Cs from LiCl-KCl-based molten salts due to their strong atomic interactions with alkali/alkaline-earth elements, which cause a shift in relative stability of the alkali/alkaline-earths in the electrolyte. Thermodynamic properties, including activities, partial molar entropies, and partial molar enthalpies, were determined using electromotive force measurements for the Sr-Bi, Sr-Sb, and Sr-Sn binary systems in order to elucidate the strength of interactions between Sr and each liquid metal. By combining the fundamental thermochemical data with phase characterization of each of the binary systems using X-ray diffraction (XRD) and differential scanning calorimetry (DSC), a comprehensive understanding of both thermodynamic phase behavior was developed for all three binary systems. Activities as low as aSr = 10-13 at xSr = 0.04 at T = 888 K were measured as well as liquid state solubilities as high as 40 mol% at 988 K. Experimental data was used as input data towards computational efforts involving first-principles calculations as well as the CALPHAD technique in the case of the Sr-Sb system to develop an improved Sr-Sb phase diagram and provide further basis for the use of computational models in elucidating strongly interacting binary systems. Attempts to remove Sr from molten salt electrolyte using an electrochemical cell with liquid metal (Bi, Sb, Sn) cathodes were successful, with post-mortem elemental analysis of the electrodes confirming significant quantities of Sr (4.0-6.5 mol%) deposited into Bi and Sb. Furthermore, deposition results correlated well with the deposition behavior predicted from the aforementioned electromotive force measurements, inviting the possibility of using liquid metal electrodes as a method for selectively removing Sr from molten LiCl-KCl electrolyte and for reducing the total volume of nuclear waste left accumulating in on-site repositories throughout the US.

Download or read book EPD Congress 2015 written by Yurko and published by John Wiley & Sons. This book was released on 2015-02-13 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: EPD Congress is an annual collection of conference proceedings that addresses extraction and processing metallurgy. The papers in this book are drawn from symposia held at the 2015 Annual Meeting of The Minerals, Metals & Materials Society. The 2015 edition includes papers from the following symposia: Materials Processing Fundamentals Solar Cell Silicon High-Temperature Electrochemistry II

Download or read book Rare Earths Industry written by Ismar Borges De Lima and published by Elsevier. This book was released on 2015-09-10 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rare Earths elements are composed of 15 chemical elements in the periodic table. Scandium and yttrium have similar properties, with mineral assemblages, and are therefore referred alike in the literature. Although abundant in the planet surface, the Rare Earths are not found in concentrated forms, thus making them economically valued as they are so challenging to obtain. Rare Earths Industry: Technological, Economic and Environmental Implications provides an interdisciplinary orientation to the topic of Rare Earths with a focus on technical, scientific, academic, economic, and environmental issues. Part I of book deals with the Rare Earths Reserves and Mining, Part II focuses on Rare Earths Processes and High-Tech Product Development, and Part III deals with Rare Earths Recycling Opportunities and Challenges. The chapters provide updated information and priceless analysis of the theme, and they seek to present the latest techniques, approaches, processes and technologies that can reduce the costs of compliance with environmental concerns in a way it is possible to anticipate and mitigate emerging problems. - Discusses the influence of policy on Rare Earth Elements to help raise interest in developing strategies for management resource development and exploitation - Global contributions will address solutions in countries that are high RE producers, including China, Brazil, Australia, and South China - End of chapter critical summaries outline the technological, economic and environmental implications of rare earths reserves, exploration and market - Provides a concise, but meaningful, geopolitical analysis of the current worldwide scenario and importance of rare earths exploration for governments, corporate groups, and local stakeholders

Download or read book Proceedings of the 8th Pacific Rim International Conference on Advanced Materials and Processing PRICM 8 written by FernD.S. Marquis and published by Springer. This book was released on 2017-03-21 with total page 3431 pages. Available in PDF, EPUB and Kindle. Book excerpt: PRICM-8 features the most prominent and largest-scale interactions in advanced materials and processing in the Pacific Rim region. The conference is unique in its intrinsic nature and architecture which crosses many traditional discipline and cultural boundaries. This is a comprehensive collection of papers from the 15 symposia presented at this event.