Metallurgy Commons^™

Recovering Sn From Ultrafine Tails At Mina San Rafael, Peru, Angelica Plenge

Honors Theses

San Rafael is currently the only mine producing tin (Sn) in Peru, operating two concentrators. In the first, called the San Rafael plant, tin concentrate is produced through gravity separation circuits consisting of jigs, spirals, and Mozley tables, followed by reverse flotation, where sulfides are floated while cassiterite (78.77% theoretical tin content) is depressed. Material containing tin values is then directed to a desliming circuit, where the pulp density is adjusted prior to sulfide reverse flotation. The tailings from this stage are subsequently processed through another flotation circuit but, in this case, the Sn is floated. Cycloning is applied throughout …

Collector Blends For The Flotation Of Rare Earth Silicates, Padmore Fosu Amankwah

Honors Theses

Rare earth elements (REEs) are critical for modern technologies, but their extraction from minerals remains challenging due to various factors, and their impact on mineral bonding and resulting crystal structure. Fundamental studies have shown that the concentration of rare earth minerals (REMs), such as rare earth silicates (RES), depends on factors such as Lanthanide contraction (LC), Coordination Number (NC), and silicate polymerization (SP). These influence flotation responses pending silicate type (e.g., sorosilicates, phylosilicates, nesosilicates, inosilicates, orthosilicates, etc.). To better understand this behavior and optimize REE recovery, samples from Halleck Creek, an American Rare Earth property in Wyoming, were obtained. Characterization …

Recycling Ndfeb Magnets I: Production Of Ree Fluorides By A Novel Lpc Process, Isaac Joseph Cobbinah

Graduate Theses & Non-Theses

Neodymium-iron-boron (NdFeB) magnets account for over 60% of global magnet sales and are widely used in high-tech, military, and clean-energy applications (Ormerod, 2022). However, they contain critical rare earth elements such as Nd, Pr, and Dy which poses supply chain and geopolitical risks for country like the United States, which rely extensively on foreign sources. Recycling end-of-life NdFeB magnets provides a sustainable solution that diminishes environmental impact, strengthens supply security, and supports stable domestic production of important rare earth elements. A three-stage process has been developed for recycling the REE-content of NdFeB magnets. While the focus is on neodymium (Nd), …

Production Of Rare Earth Elements By Molten-Salt Electrolysis, Mohammed Moro

Graduate Theses & Non-Theses

Rare earth elements (REEs) are indispensable, high-value resources that play a crucial role in renewable energy, defense systems and advanced technological systems. REEs are commonly extracted from natural ores or recycled materials such as permanent magnets using hydrometallurgical or pyrometallurgical techniques. In hydrometallurgy, the REE source is leached with acid, followed by solvent extraction and precipitation steps to obtain rare earth compounds like oxides and fluorides. Pyrometallurgy involves dissolving rare earth compounds in a molten halide bath, followed by high-temperature electrolysis to convert them into metals, which are then recovered at the cathode. This process typically includes melting, refining, and …

Process Intensification For Rare Earth Elements Adsorption By Resonant Vibratory Mixing (Rvm), Mehran Saddat

Graduate Theses & Non-Theses

Rare earth elements (REE) are crucial to the advancement of modern technologies. REE applications include electronics, defense systems, wind turbines, catalysts, magnets, and aircraft. Bastnasite, monazite, and xenotime are the primary resources, while the secondary resources, including coal ash, E-waste, and acid mine drainage, are for REE extraction. The primary processing techniques are chemical leaching, ion exchange, chemical precipitation, pyrometallurgy, solvent exchange, biosorption, and adsorption. Adsorption technique is simple, cost-effective, and environmentally friendly, with higher efficiency but at the cost of a longer mixing time. Therefore, there is a pressing need for an optimized mixing technique to improve the adsorption …

L.G. Twidwell: A Summary Of Fifty-Six Years Of Research, Larry G. Twidwell

Metallurgy

No abstract provided.

L.G. Twidwell: A Summary Of Fifty-Six Years Of Research, Larry G. Twidwell

Metallurgical & Materials Engineering

No abstract provided.

L.G. Twidwell Fifty-Six Years Of Research A Summary, Larry G. Twidwell

Metallurgical & Materials Engineering

Larry G. Twidwell, D.Sc. is Emeritus Professor in the Department of Metallurgical and Materials Engineering at Montana Technological University. He has fifty-six years of experience in teaching and directing research in Metallurgical and Materials Engineering at Montana Tech. Twidwell and his graduate students and coworkers have conducted research emphasizing extractive metallurgy and the application of extractive metallurgical engineering to the treatment of metallurgical wastes, process waters and byproducts. Four books, seventy-seven M.Sc. theses, one-hundred-thirty refereed publications and one hundred-eight national and international presentations have resulted from their research efforts. Twidwell has received several outstanding teacher/researcher awards during his tenure at …

Selective Leaching Of Rare Earth Elements From Complex Rare Earth Ore Using Deep Eutectic Solvents, Frank Agyemang, Mehran Saddat, Zainab Nasrullah, Richard Ladouceur

Metallurgical & Materials Engineering

Rare earth elements (REEs) are valuable for various modern technological applications, including metallurgy, machine building, radio electronics, instrument engineering, nuclear engineering, and manufacturing. The extraction and separation of rare earth elements (REEs) from their complex ores is challenging due to their distinct physical and chemical properties, contributing to their market scarcity. At present, REE recovery utilizes traditional pyro- or hydrometallurgical processes. The overall process in the recovery and separation of individual elements from complex REE systems suffers from high energy demands and the use of many hazardous chemicals that negatively impact the environment. With the growing trend toward a circular …

Surface Chemistry And Adsorption Mechanism Of Orfom® D8 For Cu Depression In Cu-Mo Flotation, Patrick Jeff Mensah

Graduate Theses & Non-Theses

In traditional chalcopyrite-molybdenite (Cu-Mo) flotation separation systems, inorganic depressants such as NaSH and NaCN are used to selectively depress chalcopyrite making it more hydrophilic so molybdenite can be floated and recovered. NaSH and NaCN are highly toxic, have high explosion potential, strong odor, and readily oxidize in air resulting in a high consumption rates. To control oxidation, nitrogen gas, and Nokes reagent are both necessary, making the process even more expensive. In addressing these challenges, attention is fast shifting to disodium carboxymethyl trithiocarbonate (Orfom® D8), a novel organic depressant designed to replace conventional inorganic depressants because it does not easily …

Optimizing The Physical Properties Of Biochar For Co2 Adsorption Using Resonant Vibrations, Amirhosein Riahi, Richard Ladouceur

Mining Engineering

Among various Carbon Capture and Sequestration (CCS) technologies, significant emphasis has been placed on biochar as an effective post-combustion CO2 capture method. Biochar demonstrates potential as a technically effective method for stabilizing carbon. However, the efficacy of CCS based on adsorption phenomenon depends on factors such as the CO2 uptake of the adsorbent, kinetic rates, and cyclic adsorption. The study shows that Low-Frequency High Amplitude (LFHA) resonant vibratory mixing improves the physical characteristics and adsorption properties of hemp biochar. According to the results of an analysis of variance (ANOVA), increasing both the mass of biochar and the intensity of resonant …

Electrical Resistance Tomography Measurements In Column Flotation Of Pure Hydrophobic And Hydrophilic Systems, Vimeipha Vilayphone

Graduate Theses & Non-Theses

Column flotation was phenomenologically investigated with Electrical Resistance Tomography (ERT) as an uninterrupted instrument to measure gas holdup. Two-phase tests were performed to use the measurements for examining gas dispersion. Results were found to duplicate the findings in a previous thesis. With confidence attained in experimental procedures, three-phase tests were then performed to compare gas holdup with hydrophobic and hydrophilic solids. Hydrophobic solids included talc as well as dolomite with dodecyl amine (DDA) collector. Hydrophilic solids included dolomite as well as talc with carboxymethyl cellulose (CMC) depressant. Variables throughout the research included frother concentration and sparger size. Results showed gas …

Process Intensification For Rare Earth Elements Adsorption By Resonant Vibratory Mixing, Oluwatosin Adebayo, Richard Ladouceur, Zainab Nasrullah

Graduate Theses & Non-Theses

The adsorption capacity for six rare earth elements (Lanthanum, Terbium, Neodymium, Dysprosium, Praseodymium, and Holmium) by biochar produced from hemp feedstock was investigated. An innovative approach to enhancing the adsorption of rare earth elements using biochar was studied and investigates the potential of resonant vibratory mixing (RVM) as a process intensification method compared to conventional mechanical mixing for the adsorption process. Hemp hurds as source of biomass was pyrolyzed to produce biochar at a temperature of 4500C for 60 minutes. The biochar was characterized by FTIR (Fourier Transform Infra-red), SEM (Scanning Electron Microscopy), Surpass 3 Electrokinetic solid surface analyzer, and …

A Guide To Fifty Years Of Research At Montana Tech: Part 3-Decontamination Of Ratioactively Contaminated Steel By Melt Refining/Slagging Processing, Larry G. Twidwell, Samuel A. Worcester

Metallurgy

This presentation includes a discussion of the research conducted at Montana Tech in the Department of Metallurgical and Materials Engineering. The discussion is focused on Decontamination of Radioactively Contaminated Steel by Melt Refining/Slagging. This presentation is based on the research of Master of Science graduate students, industrial and academic colleagues, at the Montana College of Mineral Science and Technology (which morphed to Montana Tech [1977], then to Montana Tech of The University of Montana [2000], then to Montana Technological University [2019]). The referenced work of each of the graduate students in this presentation is gratefully acknowledged. The following summary presentation …

A Guide To Fifty Years Of Research At Montana Tech: Part 2 The Treatment Of Electroplating And Electromachining Metal Hydroxide Sludge For The Recovery Of Metal Values [See Also Part 1), Larry G. Twidwell

Metallurgy

ABSTRACT and FORWARD

The treatment and recovery of metal species from hydrometallurgical solutions and wastewater solids has been and continues to be an important research topic. This presentation includes a guide to the literature with a summary discussion of the research conducted at Montana Tech in the Department of Metallurgical and Materials Engineering during the 1984-2001 period. A previous presentation (Part 1) focused on the removal of arsenic, selenium, and other species by hydrometallurgical processes and the formation of environmentally stable disposable products. This guide is available at the reference presented above.

This following presentation (Part 2) is based on …

A Guide To Fifty Years Of Research At Montana Tech: Part 1-The Treatment Of Arsenic, Selenium, Thallium, Metal Bearing Solutions And Waste Solids, Larry G. Twidwell

Metallurgy

ABSTRACT and FORWARD

The removal of arsenic, selenium, and metal species from hydrometallurgical solutions and wastewaters has been and continues to be an important research topic. This presentation includes a discussion of the research conducted at Montana Tech in the Department of Metallurgical and Materials Engineering during the past fifty years. The discussion is focused on removal of arsenic by co-precipitation with Fe(III) and Fe(II), co-precipitation with Fe(III) and Al(III), reduction using elemental iron; the removal of selenium by elemental iron and catalysed iron; and the removal of cadmium, copper, nickel, zinc by co-precipitation with Fe(III) and Al(III).

This presentation …

Timeline - History Of The Metallurgy / Mineral Processing Programs (1900-2022), Jerome Downey, Larry G. Twidwell

Metallurgy

No abstract provided.

History Of The Metallurgy / Mineral Processing Programs (1900-2022), Jerome Downey, Larry G. Twidwell

Metallurgy

No abstract provided.

Treatment Of Arsenic-Bearing Minerals And Fixation Of Recovered Arsenic Products: An Updated Review, Larry G. Twidwell

Metallurgy

Mineral processing and extractive metallurgical operations have created and are creating appreciable arsenic bearing wastewater and waste solid products that have to be handled, treated for recycle, or treated for environmentally safe disposal. At present there are intense research and operational activities being conducted to provide the best viable processing procedures to ensure that the mineral processing and extractive metallurgical industries are profitable and environmentally secure. The focus of this presentation is on the element arsenic, even though many other deleterious elements may also be present in ores and concentrates. Numerous base metal resources contain arsenic bearing minerals, especially resources …

Synthesis And Stabilization Of Gold Nanoparticles From Chloride And Cyanide Systems, Kathryn Ariela Bozer

Graduate Theses & Non-Theses

Generating gold nanoparticles (AuNPs) from gold chloride solution by precipitating with compounds can be difficult due to the potentially required high temperatures. Tin chloride can be used to overcome this dilemma. The process that is known to make Purple of Cassius is a method where gold chloride and tin chloride solutions are mixed to form AuNPs and tin oxide precipitate. However, it is modified by adding hydrazine to resolubilize the tin oxide and provide a more stable solution for the AuNPs. A three-factor central composite experimentally designed model was created using Design Expert incorporating pH, temperature, and gold concentration as …

A Novel Method For Making Titanium Dioxide For Photocatalytic Applications, Gary Wilson

Graduate Theses & Non-Theses

Titanium dioxide possesses near-ideal properties for large-scale application as a photocatalyst. It is cheap and abundant, nontoxic, and environmentally safe. However, it still suffers from logistical problems preventing its application in industry: namely, rapid electron-hole recombination and inability to utilize visible light. For nearly five decades researchers in this booming field have made numerous attempts to address these problems, doping and combining titanium dioxide with a wide range of materials. A novel ambient-temperature approach to synthesis and doping/modification of anatase-form titanium dioxide was attempted using both oxygen-rich and oxygen deprived synthetic routes. Reactants were exposed to various wavelengths of ultraviolet …

Effect Of Frother Strength And Solids On Gas Dispersion In A Cavitation Sparger Measured By Electrical Resistance Tomography, Philip Holdsworth

Graduate Theses & Non-Theses

Gas dispersion in column flotation is critical for optimizing particle-bubble interaction and maximizing recovery. The effect of various flotation frothers on axial gas dispersion rates in a column flotation cell were measured using electrical resistance tomography (ERT). Tests included two-phase (gas-liquid) and three-phase (gas-liquid-solid) to determine the effect of mechanical parameters and the presence of solids on gas dispersion. Gas holdup can be measured using ERT and utilized in the determination of axial gas dispersion rate in the column. The ERT is constructed with two sensor planes making it possible to simultaneously capture gas holdup values at one cm and …

Investigation Of Surface Treatment And Density Separation For Selective Recycling Of Plastics, Adilbek Baigabelov

Graduate Theses & Non-Theses

Froth flotation has been a useful method for flotation separation of plastics. Teeter bed concentration may also be potentially employed to accomplish gravity-based separation of plastics from a mixture. This work investigates selective separation of six different types of plastics using a novel method by combining advanced gravity concentration and froth flotation techniques. Surface active reagents were used during flotation studies for modification of surface properties of certain plastics in order to enhance selectivity. Elutriation technology in a teeter bed separator was successfully employed to achieve gravity-based concentration of certain plastics. The novel flowsheet was shown to recover plastics of …

Surface Chemistry And Modelling Of Salicyl Hydroxamic Acid Adsorption At The Surface Of Rare Earth Oxides, Carbonates And Phosphates, Marc F. Sime

Graduate Theses & Non-Theses

The adsorption mechanism of salicyl hydroxamic acid (SHA, C7H7O3N) on rare earth minerals was investigated using two complementary methods: precipitation studies and modelling. Precipitation studies showed that SHA adsorption occurs through a displacement of the hydroxide ion at the surface in an ion exchange mechanism, leading to surface precipitation and/or chemisorption. Surface precipitation predominates in the light rare earth oxides (LREOs), while chemisorption predominates in the heavier REOs. Modelling revealed that adsorption of SHA on the REM surface is dependent upon the orientation of SHA on the surface as well as the distance between rare earth elements sites on the …

Comparison Of Salicyl Hydroxamate Adsorption On Rare Earth Phosphates To Oxides And Carbonates, Stephanie Trant

Graduate Theses & Non-Theses

Adsorption behavior of the anionic collector salicyl hydroxamic acid (SHA) on a group of selected rare earth phosphates (REPs) was studied by means of experimental methods and modeling software. These REPs were then compared to rare earth carbonates (RECs) and rare earth oxides (REOs) to develop a trend. A suite of rare earth elements (REE) were studied that included light (LREE) and middle (MREE). Results for heavy (HREE) were inferred. Synthetic phosphate, oxide and carbonate powders of the rare earth elements Lanthanum (La), Cerium (Ce), Europium (Eu) and Dysprosium (Dy) were tested for these studies. Dysprosium phosphate was the only …

Material Properties Of Laser Powder Bed Fusion Processed 316l Stainless Steel, Steven Keckler

Graduate Theses & Non-Theses

Laser powder bed fusion additive manufactured 316L stainless steel specimens were evaluated to establish a baseline for future research in determining an optimized energy density and build orientation. Test specimens were printed at various energy densities. At each energy density, tensile and fatigue specimens were printed at 0o (longitudinal), 45o, and 90o (transverse) orientation to the build plate. Tensile and high cycle fatigue tests were performed then representative fracture surfaces were analyzed. The apparent melt track and dendrite size were evaluated using grain analysis software. Static loading of the tensile specimens showed a marginal difference in UTS for specimens with …

Characterization Of Process Induced Defects In Laser Powder Bed Fusion Processed Alsi10mg Alloy, Edward Stugelmayer

Graduate Theses & Non-Theses

Additive manufacturing using laser powder bed fusion (AM-LPBF) methods have recently experienced rapid growth and development, having the potential to replace manufacturing by plastic deformation, precision machining, or casting. AM offers advantages such as the freedom to design highly complex geometries, time and cost savings through material usage efficiency and shortened production cycles, and the potential for improved mechanical properties. Process induced defects, however, result in degradation and scattering of mechanical properties and hinder the widespread adoption of AM-LPBF in industry. This investigation focuses on the effects of varying energy density and build orientation on the evolution of process induced …

Investigations Of Solid-State Sintering Behavior Of Binary Refractory Metal Oxide Systems, Maureen Chorney

Graduate Theses & Non-Theses

Refractory metals are commonly alloyed for improved corrosion resistance, thermal stability, and strength. In service, these alloys form highly stable oxides under mildly oxidizing conditions at relatively low temperatures. In order to recycle these materials, high temperature electrochemical processing is required to reduce the refractory metal oxides. To abet experimental evaluation of the electrochemical reduction process under development at the Idaho National Laboratory, binary mixtures of selected refractory metal oxide powders were sintered to produce cathode pellets, which could be suspended in the molten salt electrolyte during reduction experiments. Preparatory literature review revealed a paucity of published information relative to …

Evaluation Of Metallurgical And Mechanical Properties Of Alsi10mg Produced By Selective Laser Melting, Luke J. Suttey

Graduate Theses & Non-Theses

Selective laser melting (SLM) additive manufacturing (AM) of metal powders has long been a focus in the study of AM due to the possibility of weight reduction, complex shape formation, and production cost savings. Although applicable to a variety of metals SLM AM of the AlSi10Mg alloy was studied in an attempt to characterize the effect of processing parameter and build angle variation on the final microstructural, fractographic, and mechanical properties of parts produced without any thermal post-processing techniques. Research was conducted on five build angles (0°, 30°, 45°, 60°, and 90°), and three Global Energy Densities (GED) (37.15, 45.39, …

Adsorption Of Salicylhydroxamic Acid On Selected Rare Earth Oxides And Carbonates, Greer Galt

Graduate Theses & Non-Theses

Adsorption behavior of the anionic collector salicylhydroxamic acid (SHA) on a selected group of rare earth oxides (REOs) and carbonates (RECs) was studied via experimental methods and modelling software. Synthetic oxide and carbonate powders of the rare earth elements cerium (Ce), praseodymium (Pr), europium (Eu), and terbium (Tb) were tested for this research. Studies were conducted at different pH levels to analyze the kinetics of collector adsorption onto the oxide and carbonate surfaces in attempts to optimize recovery parameters for commercial flotation processes using SHA. In addition, thermodynamic software StabCal was implemented to compare theoretical adsorption behavior of collectors SHA …