Theses and Dissertations at Montana State University (MSU)
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/732
Browse
6 results
Search Results
Item Biorecovery of rare earth elements and critical minerals via Gluconobacter oxydans(Montana State University - Bozeman, College of Engineering, 2024) Kessler, Kendall Rhea; Co-chairs, Graduate Committee: Ross Carlson and Ryan AndersonThe depletion of high-grade ore deposits, accumulation of electronic waste, and the geopolitical challenges in sourcing critical materials have emphasized the need for sustainable metal recovery methods and recycling efforts in the United States. Conventional metal recovery approaches, including pyrometallurgy and hydrometallurgy, are not only environmentally unsustainable but also inadequate for the retrieval of metals from low-grade deposits. Biorecovery, defined by microorganism-mediated metal recovery, provides an advantageous alternative to traditional recovery methods due to increased sustainability, lower operational costs, and high efficiencies observed for the recovery of low-grade feedstocks. This study investigates the potential of bioleaching as an eco-friendly alternative in the recycling of two distinct waste feedstocks: magnetic swarf and lithium-ion batteries (LIBs). Cultivation of Gluconobacter oxydans was investigated under varying growth medium compositions, wherein increased concentrations of yeast extract were substituted for KH 2PO 4, to determine the subsequent impact on the base metal and rare earth element recovery through the application of the cell-free biolixiviant. This substitution resulted in increased growth yields and enhanced recovery with respect to magnetic swarf, whereas negligible improvement was observed for LIBs. Biorecovery has also been demonstrated for the recovery of metals from ore, where yields are a function of comminution and concentration efficiencies. Typical compressive comminution practices account for the largest proportion of energy expenditures in a mining process. Transcritical CO 2 (tCO 2) comminution, wherein ore is fractured through overcoming a rock's tensile strength, was examined to determine whether physical differences in particle generation were present as compared to traditional fracture techniques. An ore deposit in British Columbia, rich in a nickel-iron alloy mineral phase called awaruite, was examined through scanning electron microscopy, backscatter electron imaging, and energy dispersive spectroscopy to determine the impact of comminution method on awaruite recovery. Image processing was used to investigate shape factors for the individual particles. Preliminary evidence indicates despite a lack of distinct particle differences, tCO 2 comminution resulted in increased liberation and recovery of awaruite ore. Abiotic leaching studies were conducted to determine whether the method of comminution impacted leaching efficiencies. Although samples could not be quantitatively measured, initial qualitative results indicate tCO 2 comminution provides increased yields.Item Hardware and software development for implementation of fast and safe charging of commercial lihtium-ion batteries(Montana State University - Bozeman, College of Engineering, 2023) Hedding, Noah Robert; Chairperson, Graduate Committee: Hongwei GaoFrom single cells in handheld electronics to enormous packs in battery electric vehicles (BEV), batteries govern modern life. Lithium ion batteries (LIB) present the best available commercially available products for these applications; they have the highest energy densities and can output currents many times their capacity. But safely charging LIBs requires a slow and detailed process which is typically unacceptable for use in BEV and other rugged handheld devices; therefore, decreasing the required charging time would be greatly beneficial. Fast charging methods do present dangers and concerns. Unmonitored fast charging of LIBs allows for the potential of lithium plating where the lithium ions within the cell are converted to metallic lithium at the battery anode. Lithium plating can remove these ions from the charging and discharging process causing reductions in battery capacity. The metallic lithium structures formed also present the dangers of short circuit and thermal runaway. In this thesis, a charging protocol is developed using equivalent circuit models and experimentation with the goal of the elimination of lithium plating. First, equivalent models of a test cell were determined and validated. Then, this test cell was used to find the fast charging protocol both experimentally and through the use the equivalent circuit elements. Custom power electronics and software were then developed to implement the proposed charging protocol on commercial LIBs for 350 cycles. The results of this experiment show that the charging protocol did not create noticeable lithium plating while decreasing the charging time required by a typical constant current - constant voltage (CC/CV) from 50 minutes to 29 minutes. The proposed charging protocol decreased the charging time without stressing the LIB beyond its set limitation.Item Synthesis and characterization of boron-doped graphitic carbon for energy storage applications(Montana State University - Bozeman, College of Letters & Science, 2023) McGlamery, Devin Gray; Chairperson, Graduate Committee: Nicholas P. Stadie; This is a manuscript style paper that includes co-authored chapters.Carbonaceous materials offer great utility as a medium for electrochemical energy storage of ions or for the storage of chemical fuels. The low molecular weight of the second-row element carbon affords access to materials that express remarkably high gravimetric energy densities, and the robust nature of carbon-carbon bonds allow for good cyclability and longevity of carbon-based materials for use in energy storage applications. With the growing popularity and recent advancement of electric vehicles, current battery technologies are pushed to their limits in terms of capacities as well as in minimizing charging times. This has motivated great efforts to discover new lightweight materials that outperform what has traditionally been used in these applications. Alternative energy carriers, such as hydrogen, are also critical for the development of our energy landscape yet are plagued with their own technical challenges; mainly low volumetric energy densities and safety concerns associated with high pressure gas storage systems. Chapter 2 reviews hydrogen storage in today's society as well as provides a review of past synthetic methods to generate high boron content graphite (BC 3'); being a promising metastable material for the storage of alkali metal ions as well as for solid state hydrogen storage at near ambient conditions. Chapter 3 focuses on the discovery of a new lithium storage mechanism within a novel carbon-based material possessing a high hydrogen content that is tolerant of extremely fast charging, yet still expresses high reversible capacities. Chapter 4 presents a systematic investigation for the detection of chemical environments within BC 3' through an examination of unique spectroscopic properties that originate from the materials phonon structure. Chapter 5 explores the generation of boron and carbon binary phases by the co-pyrolysis of molecular precursors and establishes a density functional theory based approach to align the cracking temperatures of molecular feedstocks; affording access to bulk metastable materials that contain a homogeneous distribution of chemical environments. This work is concluded with an assessment of the materials investigated herein from the perspective of energy storage, as well as provides directions for future work.Item Multi-component oxide powder processing dynamics & synergy towards multi-functionality(Montana State University - Bozeman, College of Engineering, 2022) Heywood, Stephen Kevin; Chairperson, Graduate Committee: Stephen W. Sofie; This is a manuscript style paper that includes co-authored chapters.Multi-component or multi-cation ceramic oxides are particularly sensitive to processing-properties variation, in which a single defined chemical stoichiometry can embody dramatic variability in measured properties simply through the steps of synthesis and processing to reach the desired form. Hence, the tailoring of complex oxides is often convoluted by chemical doping and changes in stoichiometry when the influence of processing is not understood. Mixed conducting, multi-valent double perovskite Sr 2-x V Mo O 6-delta (SVMO) shows extraordinary electrical conductivity relative to comparable double perovskites. The technical hurdles of synthesizing and processing bulk powders of SVMO to optimize studies of fundamental electrical transport mechanisms otherwise convoluted by porosity in prior literature were overcome. The basis of various synthesis conditions via rapid microwave assisted sol-gel synthesis were discerned for their contribution to either open porosity of SVMO or enhanced densification. Enhanced resistance to particle coarsening under reducing contrast to inert atmosphere and a means to generate electrical percolation via solid-solution stability of SVMO were two key discoveries among fundamental breakthroughs understanding particle consolidation behaviors. It was discovered that SVMO's elastic modulus was well in excess of other oxide materials, approaching 300 GPa and in correspondence with the mixed V/Mo valency system provides an explanation for low thermal diffusion during sintering. The advanced solid lithium conducting garnet Li 6.25 La 3 Zr 2 Al 0.25 O 12 (LLZO) demonstrates high ionic conductivity for all solid-state batteries, however, it must be paired with an active cathode and anode to enable high energy storage capacity. The study presented here identifies methods to process LLZO materials into dense and porous constituents to satisfy the design architecture of a solid-state battery emphasizing the sensitivity of LLZO performance to lithium content and the desired cubic phase. The aim was to calibrate synthesis techniques towards minimizing sensitivity to thermal processing that contributes towards lithium loss. Studies of sintering optimization and excess lithium content in conjunction with novel freeze based tape casting methods to generate low tortuosity pores were explored. Development of these novel microstructures represents a backbone of processing methodology necessary to incorporate multivalent double perovskites in fuel-electrolysis cells and improve solid state lithium battery technologies.Item A dielectric and nuclear magnetic resonance study of lithium hydrazinium sulfate and its deuterated isomorph(Montana State University - Bozeman, College of Letters & Science, 1971) Parker, Robert SanfordItem The electrochemical oxidation of lithium-ammonia solutions(Montana State University - Bozeman, College of Engineering, 1968) Bennett, John Edwin