Metallurgy Commons^™

A Review Of Gallium And Germanium Recovery From Industrial Solid Residues, Ernest V. Oteng, Marthias Silwamba, Lana Alagha, Alex Luyima

Mining Engineering Faculty Research & Creative Works

The global demand for critical elements such as gallium (Ga) and germanium (Ge), and the shift toward circular mining has accelerated the development of new extraction and recovery processing these metals from industrial solid residues. This transition is driven by a substantial surge in demand for advanced technologies and the depletion of primary ore. Consequently, industrial solid residues, particularly zinc processing residues, smelter slags, flue dusts, and coal fly ash, are emerging as viable alternative sources. These residues incorporate Ga and Ge through isomorphic substitution in phases such as ferrites, silicates, and glassy aluminosilicates, and are enriched by industrial processes, …

Thermo-Mechanical Behaviour Of Metal-Coated Optical Fibers For Distributed High-Temperature Sensing: From Laboratory Characterization To Industrial Case Validation, Koustav Dey, Rony Kumer Saha, Bohong Zhang, Laura Bartlett, Jeffrey D. Smith, Ronald J. O'Malley, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

Reliable distributed temperature sensing in high-temperature environments remains a significant challenge due to the thermal and mechanical limitations of conventional optical fibers. In particular, polymer-coated fibers degrade above ∼300 °C due to coating failure, mechanical fragility and hydrogen ingress. Metal-coated optical fibers offer a robust alternative for harsh environments such as Electric Arc Furnaces (EAFs), aerospace engines, nuclear systems, and oil and gas wells, owing to their superior mechanical strength and hermetic sealing. In this work, a first comprehensive experimental investigation of the thermo-mechanical behavior of metal-coated optical fibers for distributed high temperature sensing is presented over a wide temperature …

Comparative Lca Of Germanium Production From Coal Fly Ash Using Chlorinated Distillation And Solvent Extraction, Dennis Dadzie, Kwame Awuah-Offei, Michael Moats, Nasib Al Habib, Weston Hartzell

Mining Engineering Faculty Research & Creative Works

Germanium is increasingly important for high-tech applications, yet its supply chain is vulnerable, with production limited to a few countries. Although prior research has explored alternative techniques for extracting and recovering germanium, the literature lacks comparative life-cycle evidence that quantifies their environmental burdens and translates findings into actionable (policy) recommendations. This paper presents a cradle-to-gate life-cycle assessment that compares the environmental burdens of producing 1 kg of single-crystal germanium from coal fly ash via chlorinated distillation (CD) and solvent extraction (SX). Under the study's assumptions, CD has lower potential impacts in 15 of 19 impact categories, while both routes show …

Magnetic Field-Induced Transformation In Polycrystalline Ni2mnal Heusler Type Magnetic Shape Memory Alloy, Choji J. Daches, Joseph W. Newkirk, Mario Buchely, Laura N. Bartlett

Materials Science and Engineering Faculty Research & Creative Works

The martensitic and magnetic transformations, as well as the mechanical properties, of Ni₂MnAl alloys in as-cast (AC) and heat-treated (HT) conditions were investigated. Magnetic-field-induced strain was evaluated via magnetostriction, with reversible strains of 0.14% and 0.2% achieved in the martensitic phase at 2 K for the AC and HT alloys, respectively. Transformation temperatures and Curie temperatures were determined under constant applied magnetic field, revealing that γ-phase inclusions in the AC microstructure suppress antiferromagnetic domain response, yielding a lower magnetization (∼8.4 emu g⁻¹) compared to the HT alloy (∼13.4 emu g⁻¹). Both alloys exhibited hysteretic behavior in the martensitic state and …

Effect Of Allocation And Allocation Avoidance Methods On Life-Cycle Impact Results For Tellurium Production From Copper Anode Slimes, Ioanna Paschalidou, Kwame Awuah-Offei, Michael Moats

Mining Engineering Faculty Research & Creative Works

The global transition toward green energy has increased demand for metals and intensified the need for sustainable supply sources. Tellurium (Te), an essential metal for photovoltaics technology, is produced primarily as a by-product of copper refinery slimes treatment. This study conducts a life-cycle assessment (LCA) study of Te production to investigate the effect of environmental impact allocation choices on LCA results in multi-product metal systems. A cradle-to-gate LCA model of the Te product system was developed in SimaPro v9.5.0.1 software by combining industrial data, Ecoinvent v3.7.1 datasets, and literature information. Environmental impacts were quantified using the ReCiPe v1.04 Midpoint method …

Eliminating Barriers For The Implementation Of Automation In The Mining Industry, Sefiu O. Adewuyi, Kray Luxbacher, Kanagy David, Miller Ben, Miller Hugh, Michael Moats, Savit Mark

Materials Science and Engineering Faculty Research & Creative Works

The integration of new technologies into U.S. mining operations is necessary for achieving continuous improvement in worker health and safety, as well as improving operational efficiency, but many have questioned why uptake of autonomy in the U.S. mining industry has been slow compared to other nations. Despite extensive research on mining automation, there remains a critical gap in understanding and systematically identifying the barriers to its adoption within the U.S. mining industry and globally. To quantify these barriers, a workshop model of data collection was employed. A total of 708 invitations were extended to professionals to participate in nine different …

Wasting The Risk, Or Risking The Waste? Understanding The Trends Of Critical Raw Material Loss Into Waste Streams During Copper And Aluminium Processing, Ella Lausberg, Joël Brugger, Rahul Ram, John R. Owen, Deanna Kemp, Micheal S. Moats, Jonathan Hamisi, Vanessa N.L. Wong

Materials Science and Engineering Faculty Research & Creative Works

Many critical raw materials (CRM) necessary in the transition to carbon-neutral energy reside in the waste streams of mining projects, as they are by-products and often not recovered alongside the primary metal. This work aims to document (i) the loss and potential recovery of by-product metals during the host commodity processing and (ii) the consequences of non-recovery, via a multi-scale risk–reward analysis. The information on the deportment of by-product metals through processing circuits is crucial for treating them as a resource, without which they risk near-permanent loss when treated as 'waste'. We review the deportment of tellurium and selenium as …

Inclusion Engineering Through Deoxidation Practice Optimization For Enhanced Mechanical Properties Of Cast Cr-Ni-Mo Steel, Kingsley T. Amatanweze, Viraj A. Athavale, Simon Lekakh, Ronald J. O'Malley, Laura N. Bartlett

Materials Science and Engineering Faculty Research & Creative Works

Deoxidation is an integral part of steelmaking, as it determines steel castability, cleanliness, and porosity levels of the final product. Steel quality is critical to its performance and can be sabotaged by impurities such as non-metallic inclusions and porosity. This study investigates the effects of four distinct deoxidation practices, using Al, Al-Ca, Zr-Ca, and Mn-Si respectively, on tensile strength, tensile ductility and impact toughness of a Cr-Ni-Mo steel. These deoxidation reactions were modeled on a commercially available thermodynamic software and possible inclusion product phases were predicted. The casting samples were studied on a scanning electron microscope (SEM) utilizing energy dispersive …

Post-Calcium Treatment Evolution Of Alumina (Al2o3) Inclusions Morphology, Naziru I. Fuseini, Ronald J. O'Malley, Todd P. Sander, Jeffrey D. Smith, Haiming Wen, Laura N. Bartlett

Materials Science and Engineering Faculty Research & Creative Works

The post-calcium morphological evolution of Al₂O₃ inclusions formed under high-oxygen supersaturation (~1000 ppm) was investigated through time-resolved sampling and quenching of aluminum-killed, calcium-treated steel. SEM-EDS analysis revealed the formation of angular two-phase CaO·Al₂O₃–CaS inclusions within 1 minute, gradually transforming into spherical liquid 12CaO·7Al₂O₃ and CaO·Al₂O₃ with a thin CaS layer around it. The 3D morphology of the CaS phase of the complex CaO·Al₂O₃–CaS inclusions observed at 1 minute appeared as a cone-cap attached to the partially modified CaO·Al₂O₃. This …

Comparative Evaluation Of Gating Systems In Femnal Castings, K. Balasubramanian, Laura Bartlett, M. Xu

Materials Science and Engineering Faculty Research & Creative Works

To understand the efficiency of gating systems, four systems, namely AFS styled pressurized system, AFS styled non-pressurized system, naturally pressurized system with a side riser and a naturally pressurized system with a top riser, were studied. The naturally pressurized systems were provided with overflows which collected the incoming metal swirl while the pressurized and non-pressurized systems had runner wells. Parameters like velocity of metal flow, air entrapment, microporosity and Niyama criterion were considered, and a design was developed with a common pouring basin using solidification software. Two molds were 3D printed using carbonitride sand, and steel of composition Fe-29Mn-8.2Al-0.91C-0.88Si-0.49Mo was …

Multiphysics Modeling Of Melt Pool Dynamics And Powder Bed Stability In Lpbf Of Inconel 718 For A Circular Cavity, Nayan Pundhir, Oluwapelumi O. Adejumo, Kumbla Chandrashekhara, Joseph W. Newkirk, Heath Misak, Cesar Ortiz Rios

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser powder bed fusion (LPBF) is a metal additive manufacturing process in which a concentrated laser beam selectively melts successive powder layers to fabricate components. Final part quality is highly sensitive to process parameters such as hatch spacing, powder bed density, laser power, and scanning speed. In this study, a computational fluid dynamics model employing discrete element method has been developed in FLOW-3D to simulate LPBF of Inconel 718. The modeled powder bed incorporates particle size distribution data obtained from scanning electron microscopy and is evaluated for single-layer, single-track deposition over a circular cavity. The model captured melt pool dynamics …

A Combined Stochastic And Physical Framework For Alloys And Metal Casting Processes Modeling, Simon N. Lekakh, Oleg Neroslavsky

Materials Science and Engineering Faculty Research & Creative Works

High temperature metal casting processes have dualistic nature and conceptually consist of two parts of distinct processes: the first type is deterministic, strictly obeying the physical law, while the second type is stochastic. Therefore, the metal casting processes are not precisely predictable, and deterministic considerations cannot provide exact outcomes. To solve this problem, the combined stochastic and deterministic framework was suggested. The local processes were described using deterministic models for several parameter arrangements, while the distribution of these arrangements on macro level was calculated using stochastic approaches. The approach was used for cast alloy design, investment casting process optimization, and …

Thermal Transformations And Mechanical Properties Of All-D-Metal Mn2fecu Heusler-Type Shape Memory Alloy, Choji J. Daches, Joseph W. Newkirk, Mario Buchely

Materials Science and Engineering Faculty Research & Creative Works

All-d-metal Heusler alloys are emerging functional materials in which magnetic ordering, lattice distortion, and mechanical behavior are strongly coupled through d–d electronic interactions. This study systematically investigates the structural, thermal, magnetic, and mechanical properties of Mn₂FeCu synthesized within a Heusler-type compositional framework. SEM/EDS revealed a dual-phase FCC-based microstructure consisting of Mn–Fe–rich and Mn–Cu–rich domains, while XRD confirmed FCC symmetry with compositional partitioning rather than full L2₁ ordering. Differential scanning calorimetry identified partial melting of the Cu-rich phase near ~ 900 °C. Dilatometry showed a thermoelastic FCC → FCT transformation at ~ 770–780 °C with a recoverable strain of ~ 0.067%. …

Design Of Novel Gating Systems For Steel Castings, K. Balasubramanian, Laura Bartlett, M. Xu

Materials Science and Engineering Faculty Research & Creative Works

Gating systems play an important role in determining the quality and mechanical properties of castings. To understand the efficiency of gating systems, four systems, namely pressurized system, non-pressurized system, naturally pressurized system with a side riser and a naturally pressurized system with a top riser, were studied. The naturally pressurized systems were provided with overflows which collected the incoming metal swirl. Parameters like velocity of metal flow, air entrapment, microporosity and Niyama criterion were considered, and a design was developed with a common pouring basin. 8630 alloy was poured into two molds using a teapot ladle. The inclusion analysis revealed …

The Effects Of Mold Flux Contamination On Oxide Scale Formation And Hydro-Descaling Efficiency During Steel Processing, Tochukwu Princewill Ojiako, Richard Osei, Mario Buchely, Haiming Wen, Simon Lekakh, Ronald O'Malley

Materials Science and Engineering Faculty Research & Creative Works

Oxide scale formation during thin-slab continuous casting has a complex structure, which is influenced by mold flux contamination, that modifies interfacial reactions during solidification, subsequent reheating, and descaling. While individual aspects of the oxidation behavior of carbon steel have been previously examined, the synergetic effects of mold flux contamination during continuous casting and subsequent reheating on scale modification and the efficiency of hydraulic descaling remain inadequately studied. This study quantitatively examines the effect of flux composition on oxide scale evolution, adhesion, and hydraulic removal in low-carbon steel under simulated industrial conditions. Slab samples with as-cast, cleaned, and flux-coated surfaces were …

Critical Parameters Controlling Oxide Scale Formation And Hydro-Descaling Efficiency During Steelmaking, Tochukwu Princewill Ojiako

Doctoral Dissertations

In modern steelmaking, cast slabs are exposed to high-temperature oxidizing environments during secondary cooling, reheating, and hot rolling, resulting in the formation of multilayer oxide scales on the steel surface. These scales interact with mold-flux residues originating from the casting process (CC). The morphology, chemistry, and adhesion of oxide scale strongly influence its removability during high-pressure hydraulic descaling and ultimately determine the surface quality of hot-rolled products. However, the mechanistic relationship between oxide scale evolution, scale-steel interfacial structure, and hydraulic descaling performance remains poorly understood.

This dissertation investigates oxide scale formation, modification, and removal in low-carbon thin-slab steels produced by …

N-Radii Approach For Multi-Scale Characterization Of Graphite Shape In Cast Iron, Simon N. Lekakh, Laura Bartlett

Materials Science and Engineering Faculty Research & Creative Works

Knowledge of multi-scale particle macro-shape and micro-surface topology is critical in many technical disciplines. Specifically, quality assessment of the shape of the graphite phase in cast irons is essential for day-to-day metal casting operations. Common methods for evaluating particle macro-shape have several drawbacks, often resulting in underestimation of sharp corners and surface texture. In this article, a method based on plotting n-radii from the center of mass to the perimeter and computing multi-scale topological characteristics is described and tested. Parametric tests, involving variations in the number of n-radii and image resolution, were performed to optimize the test parameters. The method …

Modeling Of Transformation Temperatures In Cast Martensitic Stainless Steels-Ca6nm: Effects Of Composition, Heating Rate, And Grain Size, Ugochukwu Agbedo, Mario Buchely, Laura Bartlett, Caelan Kennedy

Materials Science and Engineering Faculty Research & Creative Works

Accurate prediction of the critical transformation temperatures Ac1 and Ac3 is one of the essential factors in the heat treatment of CA6NM cast martensitic stainless steel. In this study, the influence of alloy composition, heating rate, and prior austenite grain size on the critical temperatures was quantified using dilatometric measurements and statistical modeling. Six heat treatment conditions produced prior austenite grain sizes ranging from ~75 to 247 µm. Experimental results showed that grain size variations produced only minor changes in Ac1 and Ac3, indicating a weak dependence of transformation temperatures on prior austenite grain size within the investigated range. In …

Multiphysics Simulation And Experimental Validation Of Phase Transformation And Hardness In Jominy End-Quenched Low-Alloy Steels, J. S. Alabi, E. Heidari, M. F. Buchely, K. Chandrashekhara, S. N. Lekakh, R. J. O'Malley, V. A. Athavale, A. Kumar

Materials Science and Engineering Faculty Research & Creative Works

High-volume industrial continuous hot-rolled steel heat treatment processes involve sophisticated multi-phase modeling. The performance of a given process can be optimized by coupling phase transformation kinetics with the cooling conditions of the process. This study develops a multiphysics model to simulate an intensive quenching process for steel, which is inherently transient and highly dependent on numerous parameters. The simulated object was a Jominy end-quenched specimen geometry using two commercial steels, AISI 4130 and AISI 4140, with the goal of transferring a verified methodology to the heat treatment process for industrial heavy-section products (bars, slabs). The simulation employs thermal, mechanical, and …

Chemistry Of Inclusions By Size In Three Primary Copper Anodes, Charles Campbell, Michael Moats

Materials Science and Engineering Faculty Research & Creative Works

Three copper anodes from different commercial electro refineries were characterized to measure inclusion chemistry, size (diameter), and morphology. An automated scanning electron microscope (SEM) paired with energy-dispersive X-ray spectroscopy (EDS) was used to examine hundreds of inclusions near the mold and set sides of each anode. The investigation revealed that in the two anodes with less impurities (99.65% Cu and 99.75% Cu), many of the inclusions were Cu2O with an average diameter of 2 microns. The greater impurity anode (99.05% Cu, 4076 ppm Pb, 1939 ppm As, 635 ppm Bi) contained significant numbers of complex oxide inclusions, averaging 4.6 microns …

Selective Nickel Leaching And Preparation Of Battery-Grade Nickel Carbonate From Copper-Rich Industrial Intermediate, Janaka Jayamini Wijenayake, Michael S. Moats, Lloyd Masuzyo Mseteka, Lana Alagha

Materials Science and Engineering Faculty Research & Creative Works

The rising demand for electric vehicles (EVs) has driven a significant increase in nickel consumption, a critical element in EV battery production. An industrially viable hydrometallurgical process was developed for the selective recovery of nickel from a copper-rich industrial intermediate, containing approximately 70 wt.% Cu and 6 wt.% Ni, predominantly as sulfides alongside minor impurities. Approximately 90% of nickel was selectively extracted via single-stage atmospheric pressure leaching using HCl and H2O2 at 95 °C for 12 h, with the majority of copper retained in the leach residue, which can be utilized as a valuable feedstock for copper smelters. The selectivity …

Tensile Performance Sensitivity To Variations Of Standard 17-4 Ph Heat Treatments On Lpbf-Produced Material, Ben Brown, Cory Read, Joseph Newkirk, Frank Liou

Materials Science and Engineering Faculty Research & Creative Works

Standard heat treatments for metals of a particular composition are typically designed with the assumption of a conventional starting microstructure, such as that produced by casting or wrought processing. When applied to metals fabricated by Laser Powder Bed Fusion (LPBF) metal additive manufacturing (AM), these heat treatments can produce inconsistent performance due to the unique as-built microstructures. This study investigates how modifications to standard heat treatments for 17-4 PH steel influence the microstructure and mechanical properties of LPBF-fabricated material. Specimens were produced and subjected to varying solutionizing and homogenizing treatments followed by standard aging treatments. Microstructures were characterized using optical …

Physical Characterization Of Copper Anode Slimes, Carter Glynn, Michael S. Moats

Miners Solving for Tomorrow Research Conference

No abstract provided.

Intelligent Turning Cyber-Physical Systems Modeling Using Sysml, Prithbey Raj Dey, David Lee Enke, Mario F. Buchely

Engineering Management and Systems Engineering Faculty Research & Creative Works

Cyber-Physical Systems (CPS) support industrial automation that incorporates people, hardware, signal, computation, and control using networking to achieve desired results. The complex automated CPS design demands a standard and comprehensive approach to appropriately identify the system requirements, define the architecture, and model the relationships among the software and hardware components. Systems Modeling Language (SysML) provides the capability for a comprehensive modeling to capture the desired design requirements in the systems architecture. SysML enables performance estimation of the model by analyzing constraints while identifying interactions among the components through various behavioral diagrams. In this paper, SysML is applied to the design …

Impurity Behavior In Cast Copper Anodes: Implications For Electrorefining In A Circular Economy, Agustin Morales-Aragon, Daniel Sánchez-Rodas, Guillermo Ríos, Michael S. Moats

Materials Science and Engineering Faculty Research & Creative Works

The behavior of impurities in cast copper was investigated to simulate production with increased utilization of secondary sources within the framework of a circular economy. The incorporation of impurities, particularly Ni, Sn, and Sb, from recycled Cu may significantly impact the electrorefining process. In this study, commercial anodes were doped with Ni, Sn, and Sb concentrations of 2500–6500 g/t, 300–900 g/t, and 450–950 g/t, respectively. Anode concentrations of Pb and Bi were maintained at 1000 g/t and 350 g/t, respectively. As concentrations were examined at two levels, 860 or 1700 g/t, depending on the commercial anode used to create the …

Selective Surface Activation And Flotation Of Pyrite For The Recovery Of Tellurium From Sulfide Tailings, Mulenga Mutema Chibesa

Masters Theses

Copper sulfide tailings from past and present mining operations are important secondary sources of critical elements such as tellurium (Te), a key component in cadmium–telluride photovoltaic solar cells. Characterization of tailing streams from copper porphyry (CP) ore flotation revealed that Te-bearing minerals are predominantly hosted in pyrite, which is usually depressed and discarded. Enhancing pyrite recovery is therefore a critical first step toward concentrating Te minerals for downstream extraction. However, pyrite flotation is often hindered by hydrophilic surface complexes formed during prior processing. This research investigated selective flotation of Te-bearing pyrite from CP tailings using micro flotation and bench-scale flotation, …

Characterization And Leaching Feasibility Studies Of Copper Flue Dust For The Recovery Of Main And Trace Metals, Fardis Nakhaei, Marek Locmelis, Lana Alagha, Michael S. Moats, Carlos Eyzaguirre, Cory Smith

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Although copper smelter dust (CSD) is classified as hazardous waste, it also serves as a valuable secondary resource, offering potential for the recovery of critical elements. In this study, CSD samples were collected from the waste heat boiler (WHB) and electrostatic precipitator (ESP) units connected to the flash smelting furnace at a copper smelter. The representative samples were extensively characterized by particle size, and chemical and mineralogical analyses. Following sample characterization, leaching experiments were performed to evaluate the potential extraction of Cu, Fe, As, Zn, Pb, In, Ga, and Ge from the flue dusts. Distilled water, H2SO4, and HCl were …

Understanding Heterogeneous Nucleation In Iron Alloys From First Principles: A Review And Discussion, Semen Naumovich Lekakh

Materials Science and Engineering Faculty Research & Creative Works

Heterogeneous nucleation during solidification plays a key role in structure formation of different types of iron-based alloys, including steels and cast irons. A review summarizes the novel theoretical methods which were used to understand the nature of heterogeneous nucleation in iron-based alloys. An ab initio simulation of atomic adsorption was used to predict the activity of heterogeneous nuclei, and the thermodynamic methods were applied to design conditions for desired precipitate formation in the iron melts. A high-resolution TEM study of individual nucleus and statistics of nuclei family, obtained from an automated SEM/EDX analysis, illustrates a possibility to design processes of …

High-Temperature Performance Of Alloyed Cast Irons And Cr/Ni Austenitic Steels—An Overview And Discussion, Simon N. Lekakh, Mei Li, Larry Godlewski

Materials Science and Engineering Faculty Research & Creative Works

Fe-based cast alloys, including cast irons and steels, have been used in service at a wide range of mechanical and thermal load in oxidizing environment. Special alloying practices can be used to improve high temperature performance of Fe-based cast alloys in an oxidizing atmosphere. At elevated temperatures, alloying elements can produce a protective interface layer which prevents oxidant penetration into the metal matrix. However, a combination of thermo-mechanical loads along with surface oxidation can decrease the materials integrity by destroying the stable protected interface limiting the range of working parameters and lifetime performance of the material. This overview aims to …

The Effect Of Carbon Equivalent And Nodularity On Multi-Axial Casting Wall Movement During Spheroidal Graphite Iron Solidification And Cooling, Noah J. Brack, Mingzhi Xu, Jingjing Qing, Simon Lekakh

Materials Science and Engineering Faculty Research & Creative Works

Spheroidal graphite iron, also known as ductile iron, is an iron–carbon casting alloy used in industry for its good castability, balanced mechanical properties, and low cost. Ductile iron consists of round graphite nodules in an iron matrix. During solidification and cooling, ductile iron castings experience dynamic volume changes due to the precipitation of graphite nodules and formation of austenite. These dynamic volume changes can distort external casting surfaces, causing swell and shrinkage porosity. A novel apparatus was custom-built to capture the casting wall movement in real time along three axes. This study found that casting expansion increased with carbon equivalent …