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About this book

Every sector faces unique challenges in the transition to sustainability. Across each, materials will play a key role. That will depend on novel materials and processes, but these will only be effective with a solid understanding of the trends in the market. For each respective sector, the papers in this collection will explore the trends and drivers toward sustainability, the enabling materials technologies and challenges, and the tools to evaluate their implications.

Major sections in REWAS 2019 include:

Disruptive Material Manufacturing: Scaling and Systems Challenges

Education and Workforce Development

Rethinking Production

Secondary and Byproduct Sources of Materials, Minerals, and Metals

Table of Contents


REWAS 2019: Disruptive Material Manufacturing—Scaling and Systems Challenges


From Recycled Machining Waste to Useful Powders for Metal Additive Manufacturing

To fulfill the growing demand for alternative and sustainable feedstock production for metal additive manufacturing, a novel dual-stage ball milling strategy was proposed to effectively convert recycled stainless-steel machining chips to powder with desirable characteristics for metal additive manufacturing. A theoretical analysis was performed to evaluate the impact of ball size on the chips-to-powder evolution and the consequent powder morphology. To verify the viability of using the ball milled powder created from machining chips in metal additive manufacturing, single tracks have been successfully deposited via laser engineered net shaping deposition and compared to the single tracks made from gas atomized powder using identical deposition conditions. The microstructures of these single tracks exhibited adequate adhesion to the substrate, a uniform melt pool geometry, continuity, and minimal splatter. Minimal differences in grain structure were observed between the single tracks made from ball milled powder and those made from gas atomized powder.

Blake Fullenwider, Parnian Kiani, Julie M. Schoenung, Kaka Ma

Recycling in Supply Chains for Tomorrow’s Low-Carbon Industries

Metal production and recycling technology changes are urgently needed to confront multiple simultaneous grand challenges in society. Energy production and distribution and transportation are undergoing disruptive transformations, and industry will follow. Unlike prior disruptions, such as the Internet and biotech, this will up-end material and energy flows around the planet. Due to both heightened awareness of climate impacts and plunging costs of sustainable technology, fossil energy and metals technologies which took 250 years to reach planet-wide industrial ubiquity must be swept aside and replaced in 2–3 decades. This talk will present energy industry scenarios and discuss new supply chains which will need to emerge in order to support these scenarios, the role which recycling must play in order to make these new supply chains themselves sustainable, and the timescales in which these changes need to happen, in order to meet targets for preventing large-scale climate disruption.

Adam C. Powell

The Role of Manufacturing Variability on Environmental Impact

Additive manufacturing (AM) especially metal additive manufacturing (MAM) is expected to disrupt many industries. Besides being very flexible and allowing bespoke parts with little to no setup time, AM technology is able to fabricate parts with geometries which were previously impossible to create. This allows for dramatically better designs by making the product lighter or more efficient. However, despite these numerous and significant benefits, the uptake of functional additive manufactured parts is slow. A major barrier to expedited uptake of this technology is process control. It is not certain what the most important process parameters or the ideal process windows are and how this changes for different process/material combinations. As of yet, there is not a set process to certify an AM part or process. This makes quality assurance prohibitively longwinded and expensive. Furthermore, to ensure safety under such uncertain conditions, a high safety factor and therefore thicker parts must be used. As a result, uncertainty is also tied to increased material consumption and therefore higher environmental impact. We need to better understand the nature of variability in AM in order to alleviate some of these problems. This manuscript presents several examples of the influence of variability in manufacturing and its potential impact on environmental performance.

Alexander van Grootel, Jiyoun Chang, Elsa Olivetti

Manufacturing Materials Optimization Research at The REMADE Institute

Manufacturing accounts for about 25% of the energy consumption in the United States. To help reduce the energy consumption and emissions, the US Department of Energy (DOE) has supported “The REMADE Institute”, a public–private partnership launched in 2017. The objective of REMADE is to increase manufacturing energy efficiency and reduce embodied energy in materials (metals, polymers, electronic waste, and fibers). This talk provides an overview of REMADE’s five nodes and the objective of its Manufacturing Materials Optimization (MMO) node.

Pradeep Rohatgi, Alan A. Luo, Magdi Azer

Sustainable Nitrogen-Based Fertilizer Production from Sun, Air, and Water

In the DüSol research project, the technology of sustainable fertilizer production is developed and demonstrated on the basis of solar thermal redox cycle processes. The focus is on the unexplored step of solar thermal air separation for the production of nitrogen. For this reaction, corresponding materials are identified by thermodynamic calculations and qualified and optimized on a laboratory scale. In combination with material development, a prototype reactor is designed based on computer-aided calculation tools. In a test campaign in the new high-performance simulator for concentrated solar radiation SynLight at the Technology Center in Jülich, this reactor is being tested and the solar thermal nitrogen production demonstrated. These experimental works go hand in hand with the overall process simulation and optimization, which lead to a comprehensive economic analysis.

Dorottya Guban, Martin Roeb, Josua Vieten, Hanna Krüger, Stephan Petersen, Klaus Hack, Tatjana Jantzen, Martin Habermehl, Markus Hufschmidt

REWAS 2019: Education and Workforce Development


Sustainability as a Lens for Traditional Material Science Curriculums

The theoretical and methodological foundations of the sciences and technologies are essential to the removal of barriers to achieving sustainable systems. The teachings of these concepts still lie in traditional academic disciplines such as engineering, science, and mathematics. This structure can often manifest significant barriers to progress in tackling challenging sustainability issues due to an absence of a multifaceted, interdisciplinary, systems approach. This work will explore approaches for using current sustainability issues and problems to introduce both systems thinking and traditional material science discipline specific learning objectives to the classroom. Specific examples will be illustrated for a diverse set of courses and curriculum. Results show such an approach can improve recruitment and retention results in addition to improved teaching outcomes.

Gabrielle Gaustad

Corrosion Education for Materials Life Extension: Pathway to Improvement in Resource Productivity

Materials are nonrenewal resources that are created through an “unnatural” process. In addition to resource recovery and recycling of valuable materials to achieve sustainability, simple methods to extend the life of materials enhance the resource productivity. The natural process of corrosion tries to reverse the process of material extraction causing enormous loss of energy and impacts the environment. Corrosion costs the U.S. over $300 billion per year and also produces significant safety hazards. Corrosion control is, therefore, important to enhance the life of engineering metals and materials, which is also the focus of many government regulatory agencies such as the EPA, DOT, and OPS. Corrosion protection technology utilizes metallurgy, material chemistry, and physics as well as electricity to prevent or control corrosion degradation and therefore, the education of corrosion science and engineering is directly linked to improving material life. Education in corrosion control applies these sciences to control the chemical and mechanical aspects that are involved in the deterioration of properties. This paper will address the educational aspects of corrosion technology that allow resource productivity improvement of materials.

Brajendra Mishra

Material-Oriented Product Development by QFD4Mat Material Selection Strategy Approach

Beyond the already published SpringerBrief of the author on Material Selection strategyMaterial Selection strategy titled “Material Selections by a Hybrid Multi-Criteria Approach”, US Springer, 2015, the QFD4Mat method is presented as it has been teaching to engineering students as material selection strategyMaterial selection strategy learning tool, as well as it has been adopting in big automotive sector industry that employs training and knowledge transfer. Structured on the classic quality function deployment approach, one key of success of QFD4Mat method is its open-source customizable platform by which any multidisciplinary teamwork with varying specialties and languages can actively participate to specific product development decision-making process, together with material specialists. The QFD4Mat method goes beyond usual Quality Function Deployment (shortly, QFD) technique by creation of two useful graphic analysis tools: (a) the material value curves for product and the Performance–Cost–Receptiveness (PCR) bubble maps, namely, two immediate infographic snapshots of the best product value material solution for the specific challenge.

Fabrizio D’Errico

REWAS 2019: Rethinking Production


Recycling Steel Manufacturing Wastewater Treatment Solid Wastes via In-process Separation with Dynamic Separators

In steel manufacturing, various solid wastes are generated in wastewater treatment. Iron, carbon, and fluxes (CaO and MgO) are the main beneficial components in these solid wastes for recycling in the ironmaking and steelmaking process. However, the wastewater treatment solid wastes often also contain some undesirable components. Separation of those unwanted components from the wastewater treatment solid wastes is a prerequisite to recycle the solid wastes safely, economically, and environmentally. In this contribution, producing clean wastewater treatment solid wastes via dynamic separation at ArcelorMittal is reviewed and discussed, and some case studies are presented.

Naiyang Ma

Tannic Acid—A Novel Intumescent Agent for Epoxy Systems

Tannic acid (TA) is a bio-based high molecular weight organic (HMWO), aromatic molecule. Although biologically sourced, TA currently pollutes industrial wastewater streams, and there is an industrial desire to find applications to downcycle this molecule. Epoxy thermosets have revolutionized many industries, but are too flammable to be used in many applications without additives which augment its flame retardancy (FR). Many flame retardants used in epoxy thermosets are synthesized from petroleum-based monomers leading to significant environmental impacts at the industrial scale. Various bio-based modifiers have been developed to improve the FR of the epoxy resin; however, increasing FR of the system without trade-offs with other properties has proven to be challenging. In this work, TA was incorporated into the thermoset. The molecule was found to increase the intumescence of the system without significant changes to the Tg and strength paving the way for biological intumescent agents to be used industrially.

Matthew Korey, Alexander Johnson, William Webb, John A. Howarter

Effect of CO Partial Pressure on Extraction of Alumina from Coal Fly Ash During Carbothermal Reduction Process

Comprehensive utilization of coal fly ashCoal fly ash (CFA) is a promising industry with great environmental protection and resource recycling. Alumina extraction from coal fly ash usually produces a large amount of silicon-containing waste, which would have adverse effects on the environment. In order to reduce the production of silicon-containing slag, a new process of carbothermal reduction is proposed. Owing to the generation of CO in solid phase reaction, it is necessary to study the effect of CO partial pressureCO Partial Pressure on the reaction. By changing argon gas flow rates, the effect of CO partial pressure on carbothermal reduction process is analyzed. Moreover, the experiments in vacuum furnace have been studied. The results show that the mullite phase in coal fly ashCoal fly ash (CFA) can be more easily decomposed with low CO partial pressureCO Partial Pressure at the same reduction temperature. This paper provides a new sight for the industrial application of alumina extraction from coal fly ash.

Yang Xue, Wenzhou Yu, Zhixiong You, Xuewei Lv

Removal of Sulfur from Copper Smelting Slag by CO2

In the process of extracting iron from copper slag, the iron obtained by reduction is difficult to use because of the high content of copper and sulfur. In this paper, the thermodynamics of CO2 desulphurization of slag is simulated using FactSage 7.1. In tube furnace, the desulfurization of copper slag was investigated by changing the temperature and flow rate of CO2. Thermodynamic simulation using FactSage 7.1 shows that increasing temperature and flow rate of CO2 can promote the removal of sulfur, and the desulfurization rate can reach up to 54.97%. The experiment shows that the removal trend of sulfur in the slag is the same as that of the thermodynamic calculation, and the maximum removal rate is 56.64%. The utilization rate of CO2 increasedUtilization rate of CO2 with the increase of temperature, but decreased with the increase of CO2 flow rate. Compared with air, CO2 is not easy to cause slag peroxidation.

Wang Yun, Zhu Rong, Hu Shaoyan, Wang Hongyang, Guo Yaguang

Sustainable Use of Precious and Rare Metals Through Biotechnological Recycling

We proposed using new biotechnologies to recycle platinum group metals (PGMs) and gold from the end of life wastes, which will lead to the sustainable use of precious and rare metals. When targeting leachate of spent automotive catalysts, the metal ion-reducing bacterium Shewanella algae was found to reduce and deposit aqueous PGMs ions (Pd(II), Pt(IV) and Rh(III)) as metallic particles within the bacterial cells at room temperature and pH 6 within 60 min, using formate as the electron donor. We also found that the baker’s yeast Saccharomyces cerevisiae can be applied as a biomaterial for adsorbing Au(III) ions from aqueous acidic solutions. When processing leachate of spent electronic components, S. cerevisiae cells were able to rapidly and selectively collect Au(III) ions from strongly acidic solutions. Unlike conventional hydrometallurgical methods, our proposed microbial methods enable the attractive and eco-friendly recovery of PGMs and gold from secondary sources.

Norizoh Saitoh, Toshiyuki Nomura, Yasuhiro Konishi

Control of Leachate Contamination from Mine Wastes Through an Appropriate Operating Practice

Mine wastes pose a significant environmental risk. Natural waters in areas that have a long history of mining tend to be polluted by release of metals resulting in environmental issues such as acid mine drainage.Acid mine drainage (AMD) Interventions to mitigate such risks can be part of the operating practice and need not be assigned to the post-mining era. In this study, the leachability potential of slag at a smelter slag dump of a former mine site was assessed using the modified Ontario leachate extraction procedure (MOLEP)Modified Ontario Leachate Extraction Procedure (MOLEP) and other regulatory leachate quality criteria. Results showed that the release of contaminants (Cu, Co, Pb, Zn, As, Fe and Cd) can be maintained within industry-regulated standard limits mainly by adopting a smelter operating practice that produces a slag composition with adequate self-neutralising capacity.

Kenneth Sichone

REWAS 2019: Rethinking Production: Poster Session


Degradation of Ore Collector with Photooxidation UV/H2O2 and Photo-Fenton

Several types of surfactantsSurfactant have been used in mineral process flotationFlotation . Studies appoint an environmental danger potential for some surfactants due to its persistent pollutant characteristic. Oxidation techniques, such as photo-FentonPhoto-Fenton , are better for surfactants degradation than conventional treatments. The aim of this work is to study the influence of reagent concentrations in the photo-Fenton reaction to degrade a surfactantSurfactant used on mineral flotationFlotation . Experiments were conducted in 3L UV reactor with approximately 260 ppm surfactant solution, 10, 15, 22, 33, and 45 mM H2O2 and 1.4, 1.9, 2.2, 28, 80.13, 83, and 84.4 Fe2+/H2O2 molar rate. From this result, different pHPH ranges are available showing the 2.5–3 obtained best result. Samples were taken every 20 min in total of 2 h. The degradation was measured through analysis of total organic carbon. Preliminary results indicated that 1.4 molar rate is more efficient showing 70% of degradation when compared to another concentration.

Isabela F. B. Alves, Marcela P. Baltazar, Jorge A. S. Tenório, Denise C. Romano

Influence of Metallic Impurities on Solvent Extraction of Cobalt and Nickel from a Laterite Waste Liquor

Limonite is the surface zone of lateritic ore and it was considered an ore waste. However, because of the demand, limonite is now considered an important resource of nickel and cobalt. The presence of impurities in the ore such as magnesium, manganese, and chromium makes it difficult for the recovery of nickel and cobalt. The separation of nickel and cobalt can be done by solvent extraction technique using Cyanex 272Cyanex 272 as the extractant. In order to study the extraction of cobalt and nickel from a solution containing chromium, magnesium, and manganese, the pHPH range between 3.5 and 5.5 was investigated. However, precipitation of chromium, magnesium, manganese, and nickel was observed at pH 5.5. By increasing the pHPH value, the extraction of cobalt, magnesium, manganese, and chromium was increased. Nickel was not extracted during the study. It was not possible to obtain a solution containing only nickel or cobalt without the presence of the other metals in solution.

Paula Aliprandini, Mónica M. Jiménez Correa, Jorge A. Soares Tenório, Denise Crocce Romano Espinosa

Iron Recovery from Nickel Slag by Aluminum Dross: Viscosity Evolution in Different Periods

Nickel slag can be recycled as one of the excellent secondary sources due to valuable iron resource. Slag viscosity during iron recovery from nickel slag by aluminum dross was studied from 1773 to 1873 K, and the viscosity evolution in different periods was systemically discussed. Experimental results showed that slag viscosity increased suddenly after “FeO”/(“FeO” + Al2O3) ratio lower than 0.53, signifying the transition of dominant role from “FeO” to Al2O3. Structure investigation by Raman spectra showed the center of curves transferred to higher shift, which indicated the formation of many more complicated structural units during the reduction process. Furthermore, the increasing units ratio (Q2 + Q3)/(Q0 + Q1) in [SiO4]-tetrahedra showed a good agreement with the variation of apparent activation energy.

Guangzong Zhang, Nan Wang, Min Chen, Ying Wang, Hui Li

Isolation of Cyanide-Degrading Bacteria from Cassava-Processing Effluent

Cyanidation is a widely used process for gold leaching where cyanide-containing solutions are used to extract metals from ores. However, cyanidation produces toxic wastes that must be treated prior to discharge to the environment. In this context, cyanide biodegradation has appeared as an environmental friendly and alternative technology. In this study, cyanide-degrading bacteria was isolated from cassava-processingCassava-processing effluents containing 300 ppm of free cyanide using a selective media with cyanide and glycerol. From the effluent, four isolated strains and one consortium were obtained and were tested to degrade cyanide in alkaline medium containing 150 mg L−1 free cyanide and 0.5 g L−1 scratch for 72 h in orbital agitation. Two strains and the consortium showed the biggest difference from negative control degrading 27–30% of free cyanide in solution proving their potential use in cyanide treatment. Finally, microscopy analysis showed rod-shaped cells in selected samples and classified isolated strains as gram negative and the consortium as gram positive.

Amzy Tania Vallenas-Arévalo, Carlos Gonzalo Alvarez Rosario, Marcela dos Passos Galluzi Baltazar, Denise Crocce Romano Espinosa, Jorge Alberto Soares Tenório

REWAS 2019: Secondary and Byproduct Sources of Materials, Minerals, and Metals: Secondary and Byproduct Beneficial Use


Introducing the Extraordinary Leuven Cement: Raw Materials, Process, Performance, and First Real-Life Applications

The development of alternative cementitious binders has been primarily fueled by the need to reduce the environmental footprint of Ordinary Portland Cement (OPC). It would be reasonable to expect though that these new binders to come should be on one hand better in terms of environmental footprint, and on the other hand, at least comparable in terms of performance and availability to society. The latter, in engineering terms, translates into a production process that is relatively easy to erect, technically and financially, and robust during operation. Moreover, the binder itself should be composed of abundant elements so as to empower construction and growth for all. The most abundant elements in earth’s crust are oxygen, silicon, aluminum, iron, calcium, and sodium. Assuming a high-temperature process is employed, then the parent minerals where these elements are present are of little interest: they will all melt, and by adjusting the chemistry and the cooling conditions, the solidified product will be the glass precursor to be used as the main component in the cementitious binder thereafter. In the work herein, we present our approach to meet all the above. We try to translate intentions (i.e., develop a binder of low environmental footprint and abundant to all) into actions (i.e., develop and test the process and the materials), respecting the obvious boundaries of the system (i.e., thermodynamics).The work is structured around the production process of this new binder. It starts with an overview of the different steps (i.e., unit operations) and continues with in-depth presentation of raw materials, firing conditions, milling, additives, (…), concluding to the two lines of binders that have been developed over the past years, one with OPC (blended) and the other one without. In addition to OPC, these formulations can also integrate other materials, namely, ground granulated blast furnace slag, fly ash, calcined clays, and more, thus, resemble to a great extent the family of blended cements in the market today. The data communicated refer to work conducted at both laboratory and pilot-plant scale, and extend from the atomic structure of these new binders to mortar formulations and ultrahigh strength concrete.The name of this new binder is Extraordinary Leuven Cement. It is abbreviated as ELCE, suggesting that “elce”, an obsolete form of “else”, i.e., something different is a possibility even for one of the most massively used materials today.

Yiannis Pontikes

Ferroalloy Production from Spent Petroleum Catalysts by Reductive Smelting and Selective Oxidation Processes

Solid spent catalysts from the hydroprocessing units of petroleum refining industries contain valuable metals of V, Ni, and Mo in appreciable concentration together with a significant amount of sulfur in an alumina supporting material. A recycling process for this resource has been developed and commercialized by reductive smelting and selective oxidation processes to recover these metals in the form of ferroalloys. The carbon saturated Fe–V–Ni–Mo melt recovered from the reductive smelting was oxidized to separate vanadium into a slag which can be processed for Fe–V alloy production. Then Fe–V and Fe–Ni–Mo alloys were successfully manufactured with high recovery ratios of over 90% and 95%, respectively.

Jong-Jin Pak, Do-Hyeong Kim, Min-Kyu Paek, Yong-Dae Kim

Reactivity of Crystalline Slags in Alkaline Solution

Slags with varied amorphous and crystalline content, typical of iron and steel production, are generally underutilized. One promising reuse pathway for these wastes is chemical activation, producing alternatives to conventional building materials with lower embodied energy. The formation of a hardened binder is dependent on the slag mineralogy and, specifically, the reactivity of relevant phases. Reactivity can be understood by monitoring elemental dissolution rates through inductively coupled plasma (ICP-OES) analysis. Post-dissolution ICP analysis of activating solution and spectroscopic analysis of remaining solids was performed on several highly crystalline slags and on relevant synthetic minerals to track changes in chemical and phase composition. Amorphous and ionic phases have been observed as more reactive than other crystalline phases. This work aims to inform future studies on waste blending in alkali-activated systems, a promising avenue for valorization of industrial wastes with varied physicochemical properties. To this end, dissolution tests with varied initial Si, Al, and Ca concentrations in activating solution were also performed.

Brian Traynor, Hugo Uvegi, Piyush Chaunsali, Elsa Olivetti

Extraction of Zinc, Silver and Indium via Vaporization from Jarosite Residue

Based on technological reasons or in case of indium, which has gained its importance only in recent decades, metals such as zinc, indium and silver can be found in the residues or by-productsBy-products of the corresponding industry like the iron precipitate—jarosite—from primary zinc production. As a result of low zinc and lead contents, targeted economic recycling of this material has to take into account also the present minor elements, such as indium and silver. In this context, a pyrometallurgical process is investigated which recovers zinc, indium and silver simultaneously as a dust product and the iron as an alloy. The reductive vaporization process is realized by the addition of a second residue, the electric arc furnace dust, acting as a chlorine carrier. Therefore, the paper describes the investigated process development and the achieved recovery rates for the main metals zinc, indium and silver.

Stefan Steinlechner, Jürgen Antrekowitsch

Efficient Utilization of Zinc-, Lead- and Copper-Containing By-Products

Ores nowadays often show a higher complexity, containing different valuable metals as well as disturbing elements. In the state-of-the-art smelters, the majority of these elements end up as by-products. Treatment of such by-productsBy-products is in many cases not done and if processes exist, they often recover only one metal, leaving a lot of value in newly generated residues. New strategies have to be employed to allow more efficient utilization of these important raw materials. The paper describes developments in bath smelting processes allowing a simultaneous recovery of different metals in one step, generating valuable products and an inert slag which in best case enables utilization in the construction industry. The proposed system is described in detail for zinc-, lead- and copper-containing by-products. Especially economic considerations are explained, showing how different metals contribute to a feasible process and what are the critical factors that have to be considered.

Juergen Antrekowitsch, Stefan Steinlechner

Production of High-Purity Mo and Fe–Mo Alloys from Recycled Mo Oxide and Mill Scale Through Hydrogen Reduction

The present study handled an economic and clean route for the synthesis of pure Mo and Fe–Mo alloys through utilization of waste materials such as spent acid containing Mo and mill scale removed from the surface of steel slabs. The Mo oxide, MoO3, wasMoO3 successfully synthesized from the spent acid by ammonia gas neutralization method and reduced under hydrogen atmosphere to produce a high-purity Mo powder. The optimum condition for the spherical shape and uniform particle size of Mo powder was determined. In addition, the recycled MoO3 fromMoO3 the spent acid was mixed with mill scale as an iron oxide source to produce Fe–Mo alloyFe–Mo alloy by the hydrogen reduction. Based on the thermogravimetric analysis, the reduction rate of the mixed MoO3MoO3 and mill scale was measured at 700–1100 °C. The Arrhenius equation with the approved mathematical formulations for the heterogeneous gas–solid reaction was applied to calculate the activation energy (Ea) values and determine the rate controlling mechanisms.

Min-Kyu Paek, Do-Hyeong Kim, Daniel Lindberg, Jong-Jin Pak

Alkali Elution of Various Mineralogical Phases in Steelmaking Slag

To suppress alkaline elution from steelmaking slag, the dissolution behaviors of mineralogical phases in slag need to be studied. In this paper, primary crystal phases (CaO·SiO2, CaO·SiO2·FeO, and CaO·SiO2·2MgO) of CaO–SiO2–FeOx and CaO–SiO2–MgO systems were synthesized, and their dissolution behaviors and the change in pHPH were investigated. The results showed that CaO·SiO2 caused the increase in pHPH by the dissolution of alkali. Therefore, the alkali elution from steelmaking slag is caused by not only free CaO and 2CaO·SiO2 but also CaO·SiO2. Then, slags corresponding to actual steelmaking composition in the system CaO–SiO2–FeOx and CaO–SiO2–MgO systems were synthesized and their dissolution behaviors were observed. The result showed that the pHPH values after the dissolution of every slag were lower than that of CaCO3, even though water soluble phases were contained in slag. Therefore, alkali elution from slag containing soluble phases can be suppressed when the mass fractions of these phases in slag are low enough.

Zuoqiao Zhu, Xu Gao, Shigeru Ueda, Shin-ya Kitamura

Feasibility Assessment for Recycling Copper Slag as Ferrous By-Products in FINEX®: An Alternative Ironmaking Process

The oversupply of steel product has led the global steel industry to a significant decline in revenue and profit. To make things harder, increasing demand to reduce greenhouse gas emissions has intensified pressure on steelmakers. As an effort to make progress from economical and ecological perspectives, the ironmaking field is expanding the recycling of ferrous by-products. Copper slag has been widely recycled in the abrasive media, the pavement, and the cement industries. However, there was no successful activity of recycling copper slag in the steel industry. The FINEX process is known for the flexibility of recycling ferrous by-products. There are chances that the ferrous by-productsBy-products that cannot be recycled in the blast furnace due to inferior mechanical, thermal, and chemical properties can be recycled in the FINEX process. In the present study, the feasibility assessment of recycling copper slag in the FINEX process has been performed on an industrial pilot-scale.

Moo Eob Choi, Taehyeok Kim

Development of Electromagnetic Interference Materials from Metallurgical Wastes

In view of developing a sustainable metallurgical production, the potential of its slag and/or dusts as a secondary resource must be considered to avoid landfilling. Many products have been innovated such as cement, concrete, ceramics tiles, land reclaim, etc. High iron content industrial solid wastes from metallurgical process may be utilized in the making of electromagnetic shielding and absorbing materials due to the metal droplets and ferrite it contains. This article provides a proof-of-principle of a new high-value-added application for the high iron content industrial solid wastes as an admixture for enhancing electromagnetic interference (EMI) shielding with a potential for future improvement. These special materials are particularly needed for applications in underground vaults, electric power devices, telecommunication, anti-spying, etc.

Yong Fan

REWAS 2019: Plenary Session


Recycling of Critical Metals

In modern high-tech products, rare metals play an increasingly pivotal role. To support the development of a highly sustainable society, where valuable natural resources are not wasted and most materials are recycled, new efficient, environment-friendly recycling technologies for rare metals are required. The authors have developed environment-friendly recycling technologies that efficiently extract rare metals and precious metals from scrap without generating harmful waste solutions (waste liquids) and exhaust gases. These technologies include (1) a technique for converting contaminated titanium scrap, which is expected to increase in the future, into high-quality titanium feed material; (2) a technology for extracting and separating rare metals, such as rhenium, directly from end-of-life turbine blades used in aircraft and power stations without generating any waste aqueous solutions; and (3) a method for efficiently concentrating and separating platinum group metals in automobile catalytic converters without using harmful acids or other chemicals. These technologies will help establish an environment-friendly rare metal recycling system.

Toru H. Okabe, Takanari Ouchi

REWAS 2019: Secondary and Byproduct Sources of Materials, Minerals, and Metals: Electronics and Battery Recycling


Li-Cycle—A Case Study in Integrated Process Development

The resource recovery market has significant interest in new process development. One reason is that valuable materials for hi-tech applications are now present in sufficient quantities to warrant recycling efforts. Another is due to broad efforts on environment such as green chemistry and urban mining. However, many of these projects end in early development due to a lack of up-front integration on a broad range of issues such as experimental work, techno-economics, supply/demand, safety, regulatory landscape, and product quality. Using Li-Cycle, a Canadian lithium battery recycling company now engaged in process piloting, and as an example, this paper discusses the key barriers that companies developing new chemical or metallurgical processes face and how they can be overcome through an integrated approach. In the integrated approach, economic and market analyses commence as soon as possible in the project’s life. These are used to establish a clear process/project scope, define specifications for the process products, identify the key cost drivers to appropriately focus technical work, and ultimately provide an objective, effective, and efficient method to evaluate the merits of the project.

Boyd Davis, Kevin Watson, Alain Roy, Ajay Kochhar, Darcy Tait

Lithium-Ion Batteries, How to Generate Value Out of End of Life Mobile Units

The use of Lithium-Ion Batteries (LIB) increase every year. Warranty for LIB in vehicles is often about 7 years. Laptop LIBsSpent Lithium-Ion Batteries (LIBs) last less than half that time. Battery packs from both computers and vehicles can be used for stationary energy storage. After a second life used for energy storage, material recycling of especially Co and Li is important both from financial and resource perspective. In EU, there are about ten plants that with different technologies recycle mainly Co and Cu. Experiences from EU will be presented.

Christer Forsgren

Advances in Lithium-Ion Battery Electrolytes: Prospects and Challenges in Recycling

Lithium-ion batteries are already playing a key role in the move from fossil fuels towards clean and renewable energy systems. This is because variabilities in renewable energy grids need to be supported by very stable storage mechanisms (batteries). In electric vehicles, lithium-ion batteries are also very important and determine applicability on the target vehicle. At their end-of-life, substances contained in them make it impossible to be discarded in an uncontrolled way. Moreover, the batteries contain critical metals that need to be recovered. While there are currently numerous studies on recycling of the cathode materials, there is very scarce research on how electrolytes impact recycling. This research reviews and enumerates on the advances in lithium-ion batteryLithium-ion battery electrolytes in the context of recycling.

Joseph Hamuyuni, Fiseha Tesfaye

Increasing Lead Battery Performance Efficiency

An active research and development initiative in the secondary lead industry has produced a new lead alloy enabling lead batteries to function at 2× current performance standards. The need for this new lead is in response to elevated temperatures due to the new duty cycles common for rechargeable batteries. This innovation addresses the trace element impurity profile of secondary lead used in energy storage and enables improvement in cycle life, dynamic charge acceptance and capacity. Utilization of advanced structural characterization capabilities of the Advanced Photon Source at the Argonne National Laboratory has led to a fundamental reassessment of the mechanisms in Pb based batteries, driving the rate of technological improvement in this crucial and sustainable energy storage technology. The specific energy measurement of this new lead used in batteries reaches a level competitive with some lithium-ion batteryLithium-ion battery materials.

Matthew Raiford, Timothy Ellis, Jagannathan Punjabkesar, Kelvin Naidoo, John Howes

Outotec Solutions for E-Scrap Processing

Scrap materials generated from End-of-Life electrical and electronic goods attract a great deal of attention both as a problem for society as well as an opportunity for new value creation through efficient recovery of the metals and energy content of such materials. Whilst the arisings of such materials appear to be ever increasing with growing affluence and decreasing product life cycle, processing of these secondary materials is faced with many challenges due to their complex and evolving nature. This paper discusses processing of complex scrap materials and how a combination of pyrometallurgy and hydrometallurgy can enable recovery of a wide range of valuable metals. Special attention is needed to address the environmental aspects of processing such materials and Outotec solutions are discussed with environmental performance as a key consideration. This is borne out by the successful experience on commercial projects in countries at the forefront of environmental and operating standards.

Stephen Hughes, Mikael Jåfs, Hannu Johto, Jan Stål, Janne Karonen

Rare Earth Magnet Recovery from Hard Drives by Preferential Degradation

Neodymium recycling by the mineral processing practice of liberation and separation of hard disk drives is envisioned and evaluated. Magnetic material is liberated from the hard drive, constructed mostly of malleable metals, by preferential degradation of the brittle magnet material. The process developed is shown to recover greater than ninety-five percent of the magnet material with a product grade of over 80% magnet material by mass. The process is designed to co-produce stainless steelStainless steel , aluminum, nickel alloy, carbon steel, and printed circuit board concentrates as contributors to the recycle value of hard drives.

Brandon Ott, D. Erik Spiller, Patrick R. Taylor

Selective Reduction and Separation of Europium from Mixed Rare-Earth Oxides Recovered from Waste Fluorescent Lamp Phosphors

Europium is vital to the production of high technology products. In recent years, the worldwide market for europium has been controlled by primary sources in China. However, recycling europium from waste fluorescents is a strategy to supply europium. Waste phosphor powder is recovered from recycled lamps and retorted, sieved, and leached to produce europium and yttrium rich concentrate. Europium is separated from yttrium by reducing Eu(III) to Eu(II) by selective reduction with zinc and precipitated as europium (II) sulfate from solution via sulfuric acid. After building upon previous work and removing unit operations, the optimized conditions for europium sulfate were determined. The effects of varying the entrance pHPH , quantity of sulfate, choice of inert gas, selective reduction time, and precipitation time were studied upon the final grade and recovery of europium (II) sulfate. The final purity of 93.84% of europium (II) sulfate with a recovery of 84.2% was obtained after using an entrance pHPH equal to 2.5, 5 times the stoichiometric ratio of sulfate, a 2 h precipitation time, and 30 min selective reduction time.

Mark L. Strauss, Brajendra Mishra, Gerard P. Martins

REWAS 2019: Secondary and Byproduct Sources of Materials, Minerals, and Metals: Circularity and Materials Availability


Circular Cities, E-Mobility and the Metals Industry—A World in Transition

The transition to a circular, sustainable society is well on its way. Cities are the place where this is happening bottom-up, supported top-down by the UN Sustainable Development Goals. E-mobilityClean (e-)mobility , circular economy and IoT are happening today. Circular cities integrate all aspects of life, connecting across people, economic actors, institutions and geographies. Circular cities are powered by renewable energy and responsible, sustainable materials; have closed resource cycles and are smart. The technical, industrial, economic, cultural and social systems meet, interact and challenge each other. The raw materials industry is an enabler of this transition in society. It provides materials, technologies and solutions. Concurrently, the industry itself needs to adapt to be an essential part of the transition to the future society. Using the e-mobilityClean (e-)mobility (batteries) value chain as example, recent and future developments in mobility and responsible material supply will be illustrated, including the impacts and challenges.

Christina Meskers, Mark Caffarey, Maurits Van Camp

The Role of Scrap Recycling in the USA for the Circular Economy: A Case Study of Copper Scrap Recycling

Recycled metals have become a significant source of supply, with a lower environmental impact than primary metals. Factors such as geography, trade regulations and economics on domestic recycling and international trade in scrap all influence the extent of recycling. The role of scrap recycling in the USA and its contribution to the Circular Economy with respect to metals is discussed. At one time, almost all the metal scrap arising in the USA was recycled and treated within the country. Since about the early 1980s, there has been a decline in the proportion of scrap metal recycled and treated in-country in the USA in favour, due to apparent cost benefits, of exporting to other countries such as China for treatment. It is considered that subsequently skills and technology in this area will require re-building to enable metal scrap to be efficiently treated at home using the best available technology. With the recent ban by China on certain metal imports, each country will now need to handle more of its own scrap metal. The opportunities in the USA as a consequence of this are discussed in the paper. The paper also describes the results of a case study for copper scrap recycling. As part of this, the technology, energy consumption and GHG emissions are examined in terms of the grade of scrap copperGrade of copper scrap for selected smelting process routes. It was found that the energy consumption in copper scrap recycling is far lower than that required to produce copper from as-mined ore, while at the same time, it is quite dependent on the grade of actual scrapGrade of copper scrap treated. It is concluded that enhanced copper recycling from secondary materials would be beneficial to the USA, driven by modern technologies as discussed in the paper, as well as encouraging policies from the regulators.

Phillip J. Mackey, V. Nubia Cardona, L. Reemeyer

Advancing the State of Prospective Materials Criticality Screening: Integrating Structural Commodity Market and Incentive Price Formation Insights

Broad, screening-style assessments of criticality highlight economically important materials facing significant threats to secure, sustainable supply. The studies identify many valuable metrics influencing the likelihood and impact of constraint; however, approaches to aggregating these metrics vary and lack unifying, causally grounded strategies. The present work seeks to advance the state of criticality screening by targeting this gap with structural commodity market insights. Grounded in the principle of price as indicative of economic scarcity, the model uses a small number of high-level metrics to drive changes in future incentive price (i.e., cost of opening new mines) by influencing structural markets elements in different ways (i.e., shape of long-run supply, demand, and incentive curves). Metrics like resource cover, ore grade loss, barriers to entry, secondary supply, end-use substitution and dematerialization rates, and all help to approximate changing supply–demand balance and inform criticality. The approach balances strengths of rapid, broad screening with insights of more detailed market modeling.

Michele Bustamante, Tanguy Marion, Rich Roth

Mining Value from Waste Initiative: Towards a Low Carbon and Circular Economy

The concept of tailings reprocessing is not new. However, due to the complexities ranging from S&T to material handling to policy and regulations, reprocessing successes have been limited. Several factors have been identified by stakeholders as requirements for success, such as economic considerations, engineering challenges, and policy and regulatory implications. Innovation underlies each of these factors. One of the biggest challenges is to reduce the environmental liabilities associated with mining waste, for which the financial securities may not be sufficient to ensure adequate protection. The recovery of metal values from tailings is potentially attractive and economically viable, particularly when combined with a concomitant reduction in environmental liabilities. Recently, Natural Resources Canada embarked on a pan-Canadian effort entitled ‘Mining Value from Waste’ to develop tools, technologies, and policies to de-risk and accelerate demonstration and full-scale waste reprocessing/repurposing projects with the goal to reduce mine waste liability and environmental impact, while providing local and national value.

Janice Zinck, Bryan Tisch, Terry Cheng, Rory Cameron

Exploring Drivers of Copper Supply and Demand Using a Dynamic Market Simulation

Several authors have suggested that supplies for key non-renewable resources may soon cease to expand at the same rate as demand. Inevitably this would lead to some peak and then decline in production. This work describes the development and application of a fully dynamic model of the copper market. This model includes both a probabilistic simulator of future supply expansion based on published data on copper deposits and a novel model of copper demand that includes both short-term and long-term elasticity of demand—both due to self-price and aluminum price. Using this model in long-term simulations suggests significant copper reserve depletion would not be expected to occur in this century. The model predicts a time frame to significant depletion that is more than 50% further out in the future than previously reported results that did not include these effects.

Jingshu Zhang, Omar Swei, Richard Roth, Randolph Kirchain

Toward a Solid Waste Economy in Colombia: An Analysis with Respect to Other Leading Economies and Latin America

This investigation aims to analyze critically the historical situation, current, and potential trends of the main solid wastes in Colombia, not only from a detailed and internal point of view, but also in the Latin AmericanLatin America countries. To give a better context and understanding of the issue, some data is also studied in comparison with some leading economies worldwide. Most countries worldwide including Latin America still work with the linear economy model, where the wastes are not intended to be minimized, re-used, or considered in the initial design as is in the circular economy. To implement the circular economy, one of the major challenges in many countries is the quantification and thus reliable and verifiable data for waste, therefore being one of the main goals of the current investigation in Colombia, particularly focused in the main solid wastes. In addition, important clues have been found in relation with the waste, economy, population, gross internal product, regulation, and society practices. Results from the current investigation can be used for similar economies and for countries with comparative waste numbers to Colombia.

José J. Rúa-Restrepo, Gloria I. Echeverri, Henry A. Colorado

Cobalt Criticality and Availability in the Wake of Increased Electric Vehicle Demand: A Short-Term Scenario Analysis

Understanding cobalt criticality and availability is necessary as lithium-ion battery demand, particularly for electric vehicles, is projected to increase exponentially throughout the next decade. With these increases in demand, supply concentration and mining limitations could have a significant impact on cobalt-dependent firms, sectors, and emerging technologies. Increased recycling, cobalt refining capability, and possible substitution away from cobalt in high demand sectors form the basis of modeling scenarios; these scenarios are created to identify the implications of changes in the cobalt supply-demand balance to 2030. Based on these, cobalt faces a tight but not impossible short-term market, where recycling and additional cobalt sources should be pursued and will become increasingly important out to and past 2030.

Danielle Beatty, Xinkai Fu, Michele Bustamante, Gabrielle Gaustad, Callie Babbitt, Randolph Kirchain, Richard Roth, Elsa Olivetti

REWAS 2019: Secondary and Byproduct Sources of Materials, Minerals, and Metals: Poster Session


Distribution and Chemical Species of Chromium in the EAF Dust from Stainless Steel Plant

Electric Arc Furnace (EAF) dust generated in the production process of stainless steelStainless steel is a hazard to the environment and human health due to its large amounts of toxic substances, such as Cr(VI)Cr(VI) formation . Cr in the EAF dustEAF dust is mainly in the form of a residue according to sequential extraction procedure test, and only small amounts of Cr are mobility. Although the formation mechanism of the EAF dust has been gradually understood, the distribution and chemical species of CrCr distribution in EAF dust are rarely studied. In this paper, the distribution and chemical species of Cr in EAF dust were studied. The results show that Cr(III) and Cr(VI) are mainly present in the small particles. After sputtering about 140 s with Ar+ ion beam, the Cr(VI) on the surface of dust particles disappears, and the content of Cr(III) reaches 100%, indicating the Cr(VI) in the EAF dust comes from the oxidation of lower valent Cr-containing substances and enrich on the surface of the dust particles.

Zhi Li, Guojun Ma, Xiang Zhang

Effect of Coal Ratio on Preparation of Si–Ti–Fe Alloy by Carbothermic Reduction with Coal Fly Ash

With the development of electric power industry, the discharge of coal fly ashCoal fly ash (CFA) increases year by year. At present, one problem of coal fly ashCoal fly ash (CFA) is low-value utilization. The improper treatment of coal fly ash will also cause harm to air, water, and soil as well as human health. To test a process including high-value utilization and reduction of environmental pollution, a Si–Ti–Fe alloySi–Ti–Fe alloy was prepared in an intermediate frequency induction furnace by carbothermic reduction using coal fly ash as raw material. Coke was used as reducing agent. In this paper, the effect of coal ratio on metal recovery rate, composition, and microstructure was studied. The suitable coal ratio was proposed for future process development which could expand the utilization of coal fly ashCoal fly ash (CFA).

Kun Wang, Yan Liu, Song Qi, Jun Hao, Zhi-he Dou, Li-ping Niu, Ting-an Zhang

Effect of Contact Time on the Recovery of Metals from the Mining Effluent of Lateritic Nickel by Chelating Resin Dowex XUS43605

The generation of mining waste has been the subject of environmental, economic, and social concern. Thus, alternative and sustainable methods of metal treatment and recovery are desired. This paper focuses on the application of ion exchange technology for the recovery of metals from the mining effluent of lateritic nickel by chelating resin Dowex XUS43605. Chelating resin was chosen due to its ability to capture transition metals. 1 g of Dowex XUS43605 with 50 mL synthetic solution in 250 mL flask is shaken, in a speed of 200 rpm. The synthetic solution has nine types of metals, such as Al, Co, Cr, Cu, Fe3+, Mg, Mn, Ni, and Zn. Batch technique was employed to examine the effects of contact time (1–7 h) when solution was adjusted at pH 1.5 at 25 °C. The present work demonstrates that the chelating resin shows negligibly higher selectivity for copper ions compared to the other metals. The metal ions (Al, Co, Cr, Mg, Mn, and Zn) present in the solution were not adsorbed.

Isadora Dias Perez, Jorge A. Soares Tenório, Denise C. Romano Espinosa

Experimental Study on Phosphorus Vaporization for Converter Slag by SiC Reduction

The phosphorus vaporizationPhosphorus vaporization experiment of converterConverter slag was carried out in laboratory with SiC as reducing agent. The results show that 2CaO·SiO2 and 3CaO·SiO2 are the main phases in the final slagFinal slag . After phosphorus vaporizationPhosphorus vaporization operation, the dendritic Fe phase and a large number of C phases were distributed in the phosphorus vaporization slag excepted the above phase. The experimental result shows that phosphorus vaporization rate decreased with increasing the basicity in the slag. Phosphorus vaporizationPhosphorus vaporization rate first increased and then decreased with increasing FeO in the slag and reached the maximum when the content of FeO was 20–25%. Phosphorus vaporization rate showed an upward trend with the increase of nitrogen flow rate and tended to be slow when the nitrogen flow rate was 0.4 m3/h. Phosphorus vaporization rate increased with increasing the reaction temperature, and the growth rate became gentle when the temperature was more than 1600 °C. Excessive addition of SiC will not obviously increase the phosphorus vaporization rate.

Y. K. Xue, S. H. Wang, D. G. Zhao, C. X. Li

Research on Thermogravimetric-Differential Scanning Calorimeter of Spent Lithium Iron Phosphate Batteries Cathode Plate

The recovery of spent lithium iron phosphate batteries (LFPBs) has significant meaning in resource recycling and environmental protection. In order to investigate the effect of thermal treatment on the spent LFPBsSpent LFPBs cathode plate, in this paper, the thermogravimetric-differential scanning calorimetry (TG-DSC) of spent LFPBsSpent LFPBs cathode plate is researched. TG-DSC results indicate that two stages of weight losses and a stage of weight gain appear during the heating process with a weight change of −3.7, +1.0, and −2.4%. DSC curve showed two endothermic peaks at 165.6, 657.5 °C and two exothermic peaks at 475.6, 532.2 °C. XRDX-Ray Powder Diffraction (XRD) results indicate that LiFePO4 is oxidized to Li3Fe2(PO4)3 and Fe2O3 during the heating process and the electrode material could be easily separated from aluminum foil due to the pyrolysis of the binder. SEM-EDSScanning Electron Microscopy Electron Dispersive Spectroscopy (SEM-EDS) results indicate that the agglomeration degree of cathode powders decreased after the TG-DSC test, the mole fraction of C and F decreased from 23.98 and 7.03% to 1.06 and 0.32%, which was due to the pyrolysis of binders and conductive additive.

Yafei Jie, Shenghai Yang, Yongming Chen, Zhiqiang Liu, Fang Hu, Nannan Liu, Yanqing Lai

Study of Precursor Preparation of Battery-Grade Lithium Iron Phosphate

In this paper, ferric sulfate was extracted from titanium white waste acid as the iron source of lithium iron phosphate precursor. The ferric sulfate obtained from titanium white waste acid, ammonium phosphate tribasic, and ammonia hydroxide were used as raw materials through liquid precipitation method to obtain iron phosphate as the precursor of lithium iron phosphate. Under the premise of ensuring the synthesis of FePO4·2H2O, the effects of the pHPH , synthesis temperature and reaction time on the particle size of the resulting product were investigated. The results showed that high purity amorphous FePO4·2H2O with a median diameter of 38.4 μm was acquired through the condition of pH = 2, T = 25 °C, and t = 12 h, which meets the requirements for preparation of lithium iron phosphate and realizes high value-added utilization of discarded resources.

Li-li Zhang, Wei-guang Zhang, Ting-an Zhang, Qiu-yue Zhao, Ying Zhang, Jing Liu, Kun Wang

Study on Vacuum Pyrolysis Process of Cathode Sheets from Spent Lithium-Ion Batteries

Spent lithium-ion batteries(LIBs)Spent Lithium-Ion Batteries (LIBs) contain lots of valuable metals such as nickel, cobalt, and lithium, together with organic solvents, binders, and other toxic materials. Therefore, recycling of spent LIBsSpent Lithium-Ion Batteries (LIBs) is of great importance for comprehensive resource recovery and environmental protection. In this study, vacuum pyrolysis was used to dispose of the cathode sheets of LIBsSpent Lithium-Ion Batteries (LIBs) . The effects of pyrolysis temperature and vacuum degree on the separation of cathode sheets and phase transitionPhase transition of valuable metal of cathode active powder were investigated in detail. The results showed that the effective separation of active powder and Al foil can be achieved under the optimized conditions of pyrolysis temperature of 600 °C and a vacuum degree of 1000 Pa, and the recovery rate of cathode active powder reached 98.04%. In the temperature range of 450–650 °C, with the increase of pyrolysis temperature, the XRDX-Ray Powder Diffraction (XRD) patterns of the cathode active powder showed that the characteristic peak of Li[NixCoyMn1-x-y]O2 gradually weakened and eventually disappeared.

Weilun Li, Shenghai Yang, Nannan Liu, Yongming Chen, Yan Xi, Shuai Li, Yafei Jie, Fang Hu

Waste Tire Rubber Powders Based Composite Materials

This investigation shows results for use of waste tire rubber powdered materials fabricated in composites by using polyurethane resin as a binder material. With this powders, processed at industrial scale for a recycling local company, rubber-based tiles were produced for several applications. The use of these materials is a solution that gives a valorization to the tires after use in many countries giving relief for an increasing problem worldwide with the tire use. Several concentrations and particle size distributions were investigated and tested. Tension and density tests were conducted in order to evaluate the flexible tiles for diverse applications. Scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and dynamic mechanical analyzer techniques were used to evaluate the microstructure of the samples. Weibull distribution analysis has been also included in order to analyze the variability of composite samples and thus characterize the manufacturing process at the industrial scale.

Carlos F. Revelo, Mauricio Correa, Claudio Aguilar, Henry A. Colorado


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