Materials Science and Engineering Commons^™

Germanium And Gallium: Evaluating Their Potential In Coal Ash, Ari Campanaro

World of Coal Ash Proceedings

Germanium (Ge) and gallium (Ga) have been classified as critical minerals by the Department of the Interior due to their unique properties and security risk to the supply chain. Recent restrictions on Ge and Ga imports have exacerbated the need for domestic Ge and Ga from resources such as coal ash, the largest source of industrial waste in the U.S. Understanding the abundance and modes of occurrence of Ge/Ga in a specific fly ash source is essential to evaluate its feasibility as a Ge/Ga resource. Microbeam Technologies, Inc (MTI) is evaluating fly ash resources from coal combustion and gasification systems …

Novel Use Of Ped-Xrf For Identification Of Ccr In Fill Units And Comingled Media, Charla Barnes, Harris Byers, Eric Hageman

World of Coal Ash Proceedings

The EPA CCR Legacy Rule requires utilities to identify any areas of land on which noncontainerized accumulation of CCR is received, is placed, or is otherwise managed. While performing preliminary delineation efforts for implementation of the Legacy Rule, it has become apparent that not all encountered materials are easily identified through visual means. Depending on unit location, previous uses of the land underlying the potential CCR Management Units, and the type of native soils present, there may be uncertainty if an encountered material is CCR, native soil, or another non-CCR material. In cases where the color/texture of CCR fill is …

Tuning Boilers To Reduce Carbon In Fly Ash - Making Salable Ash, Rod Hatt

World of Coal Ash Proceedings

This paper will describe various coal quality and combustion improvement facts and methods. Impact of fuel parameters like calorific value, ash, HGI, and volatile will be briefly covered. The main focus of this paper is on pulverizer performance and balancing combustion to lower carbon in fly ash. Pulverizers operating with larger than design coal particles tend to create an unbalanced pipe to pipe coal flow. This results in zones of low excess O2, even if average O2 settings are maintained. Impact on coal size and pipe balance of classifier settings and primary air flow will be covered. The importance of …

Evaluation Of Bottom Ash For Beneficial Use, Danielle Sylvia Cofelice, Thomas Haskins

World of Coal Ash Proceedings

Historically, bottom ash has been beneficially used as a drainage layer within the final cover system for a coal combustion residual (CCR) landfill, positioned above the linear low-density polyethylene liner and below the protective soil cover and topsoil layers. This sustainable approach not only diverts bottom ash from waste management streams but also conserves natural resources by replacing the need for virgin materials, resulting in significant cost savings for ratepayers. To support the continued use of bottom ash in this application, an environmental assessment was completed. The assessment included sampling of bottom ash, an alternative drainage layer composed of virgin …

Fifteen Years, 450 Acres: Inside The Tva Gallatin Ash Pond Closure, Brian Egan, Shane Harris

World of Coal Ash Proceedings

This presentation is focused on the TVA Gallatin Ash Pond Complex Closure. The project team embarked on a major coal ash pond remediation effort in 2023, targeting a 450-acre site with operations expected to continue over a 15-year period. The long-term and massive scope of this dig and haul project required the design and construction of extensive supporting infrastructure, including haul roads suitable for large earthmoving equipment, major pipelines for process water rerouting, and a robust water treatment facility. Key components of the work include maintaining slope stability, conducting comprehensive air quality monitoring, and ensuring high standards for coal ash …

Liquefaction Susceptibility And Brittleness Of Coal Ash - A State Parameter Approach, Suafa'i Manson, Benoit Wentzinger, Scott Lines

World of Coal Ash Proceedings

Limited data exists on the liquefaction susceptibility of combined fly ash and bottom ash deposits. Their low plasticity and settling density pose a risk of liquefaction under certain triggers. The liquefaction potential is linked to the in-situ state, defining its shearing behaviour as dilative or contractive based on relative density and effective confining stress. This can be assessed using the state parameter (Ψ) concept from critical state soil mechanics theory. This paper presents findings from a follow-up to our 2021 study, which used cone penetration test (CPT) based methods to estimate the in-situ state parameter and perform liquefaction susceptibility screening. …

Carbon-Negative Supplementary Cementitious Materials Produced From High-Calcium Coal Ashes, Hongyan Ma

World of Coal Ash Proceedings

High-calcium coal ashes, traditionally considered challenging for use in blended cements, offer unique opportunities for the development of carbon-negative supplementary cementitious materials (SCMs). This study explores innovative processing and carbonation strategies to transform high-calcium ashes into reactive binders that not only reduce clinker demand but also permanently sequester CO2. Through multiple optimized and enhanced carbon mineralization pathways, the treated ashes exhibit enhanced pozzolanic performance, durability, and compatibility with Portland cement systems. Life-cycle analysis confirms that the dual benefits of CO2 capture and clinker displacement yield a net carbon-negative profile, advancing both decarbonization of cement production and sustainable coal ash management.

Evaluating And Managing Ccr Variability At An Active Beneficial Use Clean Closure Site, John Garten, Bob Baker, Lee Lenhart

World of Coal Ash Proceedings

The basin is a 132-acre (534,200 square meter) coal combustion residual (CCR) disposal impoundment that has been undergoing closure-by-removal since 2021, with CCRs harvested for use in concrete manufacturing. Excavated CCRs are processed on-site through initial drying and screening before being routed through a thermal beneficiation process. Despite an extensive pre-closure CCR characterization program, pockets of material encountered in 2025 caused significant off-specification issues for the beneficiation feedstock that required immediate corrective action. To address this, a supplemental surveying, sampling, and on-site testing program was implemented to obtain additional grainsize and Loss on Ignition (LOI) data for active and upcoming …

Identifying And Controlling Landfill Construction Impacts To Stormwater Flow Paths, Kory Anstead

World of Coal Ash Proceedings

This presentation will examine the engineering challenges and lessons learned associated with construction impacts and altered stormwater flow paths in the vicinity of a Sediment Pond adjacent to a newly constructed landfill. During construction activities, the sediment basin liner experienced multiple instances of flotation. Early corrective measures were implemented as quick fixes; however, these proved ineffective and ultimately necessitated more comprehensive solutions once the underlying causes were better understood. The presentation will begin with an analysis of the initial liner flotation events, focusing on the conditions that led to the problem, the immediate responses, and the eventual engineered solution. It …

Three Use Cases For Interferometric Synthetic Aperture Radar (Insar) For Coal Ash Combustion (Ccr) Pond Closure Projects, Zach Boucias

World of Coal Ash Proceedings

Interferometric Synthetic Aperture Radar (InSAR) is a satellite-based radar system that uses electromagnetic pulses and advanced post-processing software to detect ground subsidence across large areas with millimetric precision. This paper has two primary objectives: (1) to outline the advantages and limitations of InSAR and (2) to present three specific use cases for InSAR in connection with coal combustion residual (CCR) pond closures. InSAR offers key advantages over traditional monitoring methods: remote monitoring without field intervention, full-surface coverage, all-weather and day/night operation, and high precision. InSAR also has limitations in connection with rapidly changing surface conditions, and the presence of water …

Harvesting Rare Earths From Coal Ash Using An Ionic Liquid, Laura Stoy

World of Coal Ash Proceedings

This presentation highlights a promising early-stage pathway for transforming coal fly ash from a long-term liability into a source of both critical minerals and construction materials. The speaker describes a recyclable ionic-liquid process that, at bench scale, demonstrates selective recovery of rare earth elements (REEs) from a wide range of U.S. fly ashes under mild conditions while preserving the treated solids for potential use as supplementary cementitious materials (SCMs). Attendees gain insight into why this chemistry is attracting attention: it avoids full acid digestion, shows strong preference for REEs over bulk metals, and enables repeated solvent reuse in a closed …

Testing Of Accelerated Pozzolanic Activity Of Fly Ash, Anne Oberlink, Tom Robl, Bob Jewell, Haley Johnson

World of Coal Ash Proceedings

The determination of the pozzolanic reaction in fly ash by ASTM strength activity index has been shown to be problematic, frequently producing false positives. The use of Wenner probe resistivity has been demonstrated to be rapid, simple and non-destructive method, producing no false positives. However, using this method and confirming it with other techniques finds that the reaction itself is slow with a dilatancy of 28 days or more before the measurements become discriminatory, a major drawback to this method. This study used high-temperature, high humidity curing of OPC-based mortars with various fly ash sources to determine how pozzolanic activity …

Innovative Analysis Of Groundwater Data For Scalable, Defensible, And Predictive Compliance, Shannon Zahuranec

World of Coal Ash Proceedings

Groundwater monitoring networks at coal combustion residual (CCR) facilities now yield dataset volumes that routinely exceed the capacity of traditional, univariate interpretation. This presentation introduces a scalable multivariate and machine learning (ML) framework that prioritizes understanding data structure before predictive models are applied. The workflow applies Principal Component Analysis and other multivariate statistics to groundwater datasets, to illustrate how unsupervised learning can rapidly reveal dominant sources and controls on impacted and unimpacted groundwater quality. The talk frames multivariate analysis as a practical portfolio management tool, emphasizing inference categories rather than concentrations or site identifiers. Fleet-scale multivariate screening offers strategic advantages …

Subsurface Delineation Of Coal Combustion Residuals Using Multiple Geophysical Methods, Eric Hageman, Adam Rak, Thomas Jordan, Kate Mckinley

World of Coal Ash Proceedings

Geophysical techniques provide alternative methods of Coal Combustion Residual (CCR) delineation and characterization to supplement more invasive boring programs used for beneficial reuse planning. A demonstration project was designed to characterize the electromagnetic and seismic stratigraphy of CCR material and test the effectiveness of three geophysical techniques: Electrical Resistivity Imaging (ERI), Transient Electromagnetic (TEM) induction, and Multi-channel Analysis of Surface Wave (MASW). The demonstration project was completed at a dry-stack CCR unit containing a variety of CCR ash, gypsum, and thin layers of drainage aggregate (limestone). During a single-day deployment, several geophysical survey tests were conducted in specific areas of …

Benefits Of Geophysical Imaging For Coal Combustion Residuals Management Unit Delineation, Gabriel Herbert

World of Coal Ash Proceedings

Gabriel J. Hebert1, Gregory B. Byer1, Margaret Gentile1 1Arcadis U.S., Inc., 2839 Paces Ferry Road SE, Suite 1000, Atlanta, GA 30339 KEYWORDS: geophysical imaging, delineation, CCRMU ABSTRACT Under the 2024 Legacy CCR Rule detailed in 40 CFR Part 257, Section 75, all electric utility companies with a known legacy coal combustion residuals (CCR) surface impoundment are required to conduct a facility evaluation to identify the location, dimensions, and volumes of CCR placed and remaining on site and to assess structural stability. At a minimum, the presence or absence of CCR management units (CCRMUs) must be documented through a desktop records …

Evaluating The Properties Of Ohio Ponded Fly Ash For Reliable Use In Concrete Mixtures, Ayah Suliman

World of Coal Ash Proceedings

Concrete producers are under pressure to reduce the carbon footprint of concrete while maintaining a reliable supply of supplementary cementitious materials. Meanwhile, U.S. coal production in 2023 declined to less than half of its 2008 peak, significantly reducing the availability of fresh ASTM C618 compliant fly ash. At the same time Ohio contains more than 145 million cubic yards of coal combustion residuals stored in ponds, representing a large and underutilized source of potential fly ash for concrete applications. This study evaluates the suitability of harvested Ohio ponded fly ash for use in concrete through practical and specification-driven testing aligned …

Basin Ash Harvesting At The Brunner Island Station, Kyle Flynn

World of Coal Ash Proceedings

Tribo-electrostatic separation has been used for the commercial beneficiation of coal combustion fly ash to produce a low carbon product for use as a cement replacement in concrete for over twenty-five years. With 24 separators in 18 coal-fired power plants and cement plants across the world, ST Equipment & Technology LLC’s (STET) patented electrostatic separator has been used to produce over 25 million tons of low carbon product that has been recycled for use in concrete or cement production. STET has developed and commercialized a new process for beneficiation of reclaimed fly ash from landfills and ponds that utilizes fly …

Extracting Rees From Refuse Pile Coal, Howard Mcclintic

World of Coal Ash Proceedings

Concurrent Technologies Corporation (CTC) has a patented high temperature electric arc furnace (EAF) technology that reaches 4000-degree centigrade temperature(s). Such high temperatures are sufficient to extract each of the seventeen rare earth elements (REEs) from coal fly ash to ultimately manufacture diverse magnets. Neodymium iron boron magnets (NdFeB) are the strongest magnets produced, heretofore almost exclusively by the Chinese. For national security reasons, CTC has become part of the domestic supply chain, as an alternate to China. Scaling is the next hurdle, since our demonstration unit is operational. Nationwide, coal is decreasingly used as a fuel for generating electricity. However, …

Adaptive Design And Execution In Ccr Pond Closure: A Case Study Of Technical And Regulatory Innovation, Jay Mokotoff, Angie Casbon-Scheller

World of Coal Ash Proceedings

Closure by removal (CbR) of CCR impoundments presents complex challenges, particularly when unique hydrogeologic conditions exist. This presentation highlights the advance planning and ongoing closure of a Midwestern utility’s East Ash Pond (EAP), a relatively small facility with highly atypical characteristics. To comply with the CCR Rule, sluicing to the EAP ceased while the generating unit remained operational. Fly ash handling was converted to a dry system for beneficial reuse; however, wet sluicing of bottom ash continued. To avoid constructing a new regulated CCR impoundment, an innovative geotextile tube containment area (GTCA) was designed and implemented to capture bottom ash …

Evolution Of Instrumentation Use For Ccr Unit Decision Making, Nick Mcclung, Victoria Bierwirth, Matt Bishop

World of Coal Ash Proceedings

Over the past decades, the power industry’s instrumentation needs and requirements have shifted to meet industry standards and regulations. In the early 2010s, piezometers and slope inclinometers were the primary types of instrumentation used to evaluate the stability of a CCR Unit. Some of the piezometers and slope inclinometers installed are still in use today to evaluate long-term stability for operations and closure. Since this time, additional instrument types were selected for installation including observation wells and temporary wells to further understand phreatic conditions within the CCR Unit. As utilities are faced with closures including removal of free liquids, data …

Recycling 3d Printing Waste In The Binghamton University Makerlab, Kevin Tejera

Library Research Scholars Program Spring 2026

3D printing is an important part of many university makerspaces. However, it comes with negative environmental consequences, including polylactic acid (PLA) filament waste. Currently, the MakerLab at Binghamton University has no closed-loop recycling system, leading to large quantities of used filament being sent to landfills, where it contributes to greenhouse gases and microplastic production.

This research project looks at the feasibility of an in-house PLA filament recycling program by examining the mechanical recycling process, cost/equipment needs, contamination issues, available space, and the effect of repeated recycling on the filament. An economic analysis will be completed through a break-even analysis and …

Temperature And Environmental Implications On Ti3c2cl2 Mxene Degradation Process, Yang Yang

McKelvey School of Engineering Graduate Student Theses & Dissertations

MXenes, a rapidly emerging class of two-dimensional transition metal carbides and nitrides, have attracted considerable attention owing to their exceptional electrical, mechanical, and chemical properties. However, the inherent thinness of their atomic structure and the reactivity of their functional groups render MXenes susceptible to environmental degradation, whereby the lattice integrity is compromised and desirable material functionalities are dimin- ished. In this work, ex situ electron microscopy characterisation is performed on Ti₃C₂Cl₂ MXene specimens subjected to controlled gas environments — nitrogen gas (N₂) and air — at annealing temperatures of 200°C and 600°C, with …

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 …

Lunar Manufacturing Systems And The Role Of Additive Recycling Technologies, Camille A. Newman

Honors Theses

Renewed international interest in sustained lunar exploration has created a growing demand for technologies to support long-duration space exploration. Part of the recent Artemis missions and the Moon to Mars initiative is to improve key mission capabilities and fill critical gaps necessary to sustain lunar habitation. Waste management, recycling systems, and manufacturing systems have been identified as critical technologies that need further development before a sustained mission is possible. This thesis explores the feasibility of an additive manufacturing and recycling system designed to process plastic waste generated during extended lunar habitation. Initial research focused on existing manufacturing and recycling technologies …

Lunar Manufacturing Systems And The Role Of Additive Recycling Technologies, Camille A. Newman

Honors Theses

Renewed international interest in sustained lunar exploration has created a growing demand for technologies to support long-duration space exploration. Part of the recent Artemis missions and the Moon to Mars initiative is to improve key mission capabilities and fill critical gaps necessary to sustain lunar habitation. Waste management, recycling systems, and manufacturing systems have been identified as critical technologies that need further development before a sustained mission is possible. This thesis explores the feasibility of an additive manufacturing and recycling system designed to process plastic waste generated during extended lunar habitation. Initial research focused on existing manufacturing and recycling technologies …

Coal Ash-Derived Aluminosilicate Precursors: A Chemical Engineering Approach To Geopolymer Characterization, Hafiz Abdul Basit, Abdullah Bashir, Abdur Raafey

World of Coal Ash Proceedings

The chemical and microstructural evaluation of coal-derived aluminosilicate precursors is critical for understanding their suitability in advanced construction material systems. In this study, a characterization of Class F fly ash, ground granulated blast furnace slag (GGBFS), and Silica Fumes (SF) was conducted to elucidate their morphological and elemental features. Scanning Electron Microscopy (SEM) was used to assess particle morphology and surface characteristics (porosity, particle diameter, particle geometry), and Energy-Dispersive X-ray Spectroscopy (EDS) to determine elemental composition and distribution. The analysis revealed distinct morphological and compositional differences among the precursors, including spherical fly ash particles, calcium-rich slag phases, and ultra-fine silica …

State Permitting Program Update, Jessica Reiss

World of Coal Ash Proceedings

State Permitting Program Update Jessica L. Reiss, Barnes & Thornburg LLP, 11 South Meridian Street, Indianapolis, IN 46204 KEYWORDS: states, permitting, permit program, rulemaking ABSTRACT At the end of 2016, the United States Congress authorized states to establish permit programs for coal combustion residuals (CCR) surface impoundments and landfills.[1] Since then, several states have established such programs, and the United States Environmental Protection Agency (U.S. EPA) has approved programs for Oklahoma,[2] Georgia,[3] Texas,[4] and North Dakota,[5] proposed approval for Wyoming,[6] and denied approval for Alabama.[7] Other states, such as Indiana,[8] are actively working through the state rulemaking process and plan …

Zero-Waste And High-Value Valorization Of Coal Combustion Residues Via Critical Minerals Recovery And Cementitious Materials Production, Hongyan Ma

World of Coal Ash Proceedings

Coal combustion residues (CCRs) pose significant environmental and disposal challenges, yet they also represent an untapped resource rich in aluminosilicates and critical minerals. This work presents a zero-waste, high-value valorization pathway that integrates critical mineral recovery with the production of cementitious materials. Advanced separation and extraction techniques are employed to recover strategically important elements such as gallium and rare earths, while the mineral-rich residues are simultaneously processed into supplementary cementitious materials (SCMs) for blended cements and concretes. This integrated approach not only offsets the environmental burden of CCR disposal but also supports domestic supply chains of critical minerals and reduces …

Revolutionizing Closure Systems: The Performance Advantages Of Structured Geomembranes, Scott Perugia

World of Coal Ash Proceedings

Coal combustion residual (CCR) containment facilities have traditionally been closed using methods that have changed little over several decades, but structured geomembranes are now reshaping closure design by improving slope stability, increasing interface friction, enhancing drainage, and providing long-term durability. Two systems are emerging as leading solutions: a structured geomembrane paired with a geotextile and vegetative cover, and a structured geomembrane paired with engineered turf. This presentation compares these approaches using field performance data, laboratory testing, and lessons learned, with emphasis on key factors such as infiltration control, drainage efficiency, slope stability, constructability, and regulatory compliance. The engineered turf system …

Developing Concentrated Brines / Salt Slurries For Disposal Of Coal Ash Wastewaters., Lance Edling

World of Coal Ash Proceedings

If coal ash wastewater is not fully concentrated to the greatest extent possible, then this results in greater disposal volumes and costs. However, concentrating a wastewater stream high in scaling compounds can be difficult. Membranes are prone to scale and Vacom thermal systems are higher in operating cost. This presentation will discuss the need to minimize disposal volumes by concentrating wastewater that is readily prone to scale and foul. The discussion will present past project examples of waste streams that were concentrated until salt crystals formed and the method used to minimize fouling and scaling during the concentration process. In …