Innovative and sustainable strategies of urban mining

openLa gestione di un’enorme quantità di rifiuti da apparecchiature elettriche ed elettroniche (RAEE), rappresenta un problema rilevante per la nostra società, poichè rischi per l’ambiente e la salute umana, legati ad una scorretta gestione, sono combinati con la perdita di materiali valorizzabili. Questo lavoro ha per oggetto lo sviluppo di processi sostenibili per il recupero di metalli di valore dai RAEE: in particolare, è stata effettuata un’indagine in laboratorio mirata all’estrazione, da schermi a cristalli liquidi, di indio, un metallo recentemente classificato dalla Commissione Europea tra i “critical raw materials”. La sperimentazione ha permesso l’ottimizzazione di un processo con rese di recupero di indio superiori al 90%, basato su operazioni idrometallurgiche. E’ stato studiato inoltre il processo dal punto di vista della sua sostenibilità ambientale, confrontandone l’impatto con quello degli attuali sistemi di gestione degli schermi a cristalli liquidi . La valutazione ha evidenziato che il ciclo di gestione delle acque di processo e pre-trattamenti fisici del pannello finalizzati alla concentrazione del metallo, rappresentano dei fattori chiave per la sostenibilità ambientale del processo. Il lavoro è stato svolto nel contesto di un progetto finanziato dalla Commissione Europea nell’ambito del 7FP, denominato HydroWEEE. Tale progetto aveva per obiettivo la realizzazione di un impianto mobile, con caratteristiche flessibili per il recupero di metalli da diversi RAEE: indio da TV/monitor a cristalli liquidi, ittrio da lampade e tubi catodici, rame oro e argento da circuiti stampati, cobalto da batterie litio-ione. L’attività di ricerca è stata anche finalizzata a valutare la sostenibilità ambientale dei vari processi realizzati nell’impianto mobile, evidenziandone un generale vantaggio (tra il 20 e l’80%) rispetto alla produzione primaria dei metalli. La valutazione dei rischi per i lavoratori nell’impianto mobile conclude lo studio.The management of a huge quantity of waste from electric and electronic equipment (WEEE) represents a critical issue for the modern society. The negative environmental and health effects due to the improperly management are combined with the loss of valuable materials. The present work focused on the recovery of metals from WEEE with particular attention to indium from end-of-life liquid crystal displays (LCD). The experimental section allowed the optimization of a process that includes an acid leaching characterized by an innovative cross-current design, followed by a cementation with zinc powder. Considering the satisfying efficiencies obtained on the lab scale, higher than 90%, the whole process was studied from an environmental point of view comparing its emissions with those produced by the current management strategies (disposal in landfilling sites, incineration and traditional recycling). A life cycle assessment (LCA) of the different scenarios proved the significant advantage of recycling ways. Moreover, the traditional recycling resulted to be the most favorable, due for both the relevant water consumption of the innovative treatment and to the low indium content in the LCD. Nevertheless, a simple water recirculation system, combined with a physical indium upgrading in the waste, make the innovative option the best choice. The simple design of the optimized process allows its implementation in a mobile plant, built within the European project, HydroWEEE. The plant mobility prevents the impacts due to the waste transport, that contributes to the 30-40% of the currently treatments. Furthermore, this advantage is combined with the possibility to treat several WEEE for the recovery of different metals. The sustainability of this approach was proved by a LCA that highlighted the positive effect also in the comparison with the primary production, with a benefit between 20 and 80%. Last, but not least, the risk for workers in the real mobile plant was assessed.SCIENZE DELLA VITA E DELL'AMBIENTEAmato, AlessiaAmato, Alessi

Innovative and sustainable strategies of urban mining

La gestione di un’enorme quantità di rifiuti da apparecchiature elettriche ed elettroniche (RAEE), rappresenta un problema rilevante per la nostra società, poichè rischi per l’ambiente e la salute umana, legati ad una scorretta gestione, sono combinati con la perdita di materiali valorizzabili. Questo lavoro ha per oggetto lo sviluppo di processi sostenibili per il recupero di metalli di valore dai RAEE: in particolare, è stata effettuata un’indagine in laboratorio mirata all’estrazione, da schermi a cristalli liquidi, di indio, un metallo recentemente classificato dalla Commissione Europea tra i “critical raw materials”. La sperimentazione ha permesso l’ottimizzazione di un processo con rese di recupero di indio superiori al 90%, basato su operazioni idrometallurgiche. E’ stato studiato inoltre il processo dal punto di vista della sua sostenibilità ambientale, confrontandone l’impatto con quello degli attuali sistemi di gestione degli schermi a cristalli liquidi . La valutazione ha evidenziato che il ciclo di gestione delle acque di processo e pre-trattamenti fisici del pannello finalizzati alla concentrazione del metallo, rappresentano dei fattori chiave per la sostenibilità ambientale del processo. Il lavoro è stato svolto nel contesto di un progetto finanziato dalla Commissione Europea nell’ambito del 7FP, denominato HydroWEEE. Tale progetto aveva per obiettivo la realizzazione di un impianto mobile, con caratteristiche flessibili per il recupero di metalli da diversi RAEE: indio da TV/monitor a cristalli liquidi, ittrio da lampade e tubi catodici, rame oro e argento da circuiti stampati, cobalto da batterie litio-ione. L’attività di ricerca è stata anche finalizzata a valutare la sostenibilità ambientale dei vari processi realizzati nell’impianto mobile, evidenziandone un generale vantaggio (tra il 20 e l’80%) rispetto alla produzione primaria dei metalli. La valutazione dei rischi per i lavoratori nell’impianto mobile conclude lo studio.The management of a huge quantity of waste from electric and electronic equipment (WEEE) represents a critical issue for the modern society. The negative environmental and health effects due to the improperly management are combined with the loss of valuable materials. The present work focused on the recovery of metals from WEEE with particular attention to indium from end-of-life liquid crystal displays (LCD). The experimental section allowed the optimization of a process that includes an acid leaching characterized by an innovative cross-current design, followed by a cementation with zinc powder. Considering the satisfying efficiencies obtained on the lab scale, higher than 90%, the whole process was studied from an environmental point of view comparing its emissions with those produced by the current management strategies (disposal in landfilling sites, incineration and traditional recycling). A life cycle assessment (LCA) of the different scenarios proved the significant advantage of recycling ways. Moreover, the traditional recycling resulted to be the most favorable, due for both the relevant water consumption of the innovative treatment and to the low indium content in the LCD. Nevertheless, a simple water recirculation system, combined with a physical indium upgrading in the waste, make the innovative option the best choice. The simple design of the optimized process allows its implementation in a mobile plant, built within the European project, HydroWEEE. The plant mobility prevents the impacts due to the waste transport, that contributes to the 30-40% of the currently treatments. Furthermore, this advantage is combined with the possibility to treat several WEEE for the recovery of different metals. The sustainability of this approach was proved by a LCA that highlighted the positive effect also in the comparison with the primary production, with a benefit between 20 and 80%. Last, but not least, the risk for workers in the real mobile plant was assessed

Value recovery from Waste Electrical and Electronic Equipment (WEEE): A potential opportunity towards a circular economy for end-of-life Mobile Phones

Waste electrical and electronic equipment (WEEE) is one of the fastest growing solid waste streams worldwide and, if not treated properly, presents serious health and environmental issues as well as extensive loss of strategic metals. The dramatic increase in the consumption of raw materials over recent decades to meet consumer demand has led to an imbalance in supply and demand, and a potential threat to the continued supply of critical metals. WEEE is a resource-rich source with many of the metals embedded in its composition listed as critical by the European Commission; extraction of these metals from WEEE, to mitigate their threat to supply, is imperative. Using end-of-life mobile phones (EoL-MPs), fast-moving consumer electronics, representative of the value embedded in WEEE, as a case study, a full characterisation of metallic and non-metallic fractions within a mobile phone confirms the presence of up to 71 elements, with many of the strategic and critical metals found in higher concentrations than in their natural ores. Exploiting the unique properties of ionic liquids (ILs), chosen for their selectivity as potential extractants, [Bmim]HSO4 for copper, Cyphos 101 for gold, Cyphos 101 and Aliquat 336 for indium, and [Hbet][Tf2N] for REEs, processes were developed using model test systems to determine optimal parameters to achieve recovery. These developed processes were then applied to treat as-received multigenerational EoL-MP components (printed circuit boards, screens, speakers, etc.), with metals of almost 99% purity recovered, for conversion to products of commercial value. Moreover, the benefit of recycling the ILs as extractants multiple times, without impacting their integrity or efficiency, is realised. This research demonstrates the potential to unlock value from this waste stream that can be exploited in other WEEE streams, as a step towards balancing the criticality of supply and demand of metals that are under threat.Open Acces

Resource Use and Water Implications of Material Consumption in Consumer Electronics

Rapid technological innovation has introduced a broad spectrum of materials in the consumer electronics sector. Consumption of these materials increases the demand for water and potentially discharge contaminants into the water resources across their life cycle, exacerbating freshwater scarcity and pollution. These water impacts have not yet been fully studied, as most literature on consumer electronics focuses on supply chain energy, carbon footprint, or end of life management. Evaluating water impacts requires data on material content, life cycle water consumption and emissions at spatial level, and availability of impact assessment models that connects life cycle data to water impacts. Data on these aspects are available at varied degrees for different materials used in the electronics. This research created data on materials used in consumer electronics and studied implications on water resources for two major material categories - metals and plastics. Bill of materials (BOMs) data were created for 95 unique consumer electronic products that contain information on mass of major materials and components. Then, life cycle water impacts associated with extraction and production of metals found in consumer electronics are evaluated to identify material hotspots for future improvement. Water impacts were analyzed for individual metals and then for the representative metal profile of case study products (smartphones and laptop computers). Finally, profile of polymers and additives in the e-waste is created to understand linkage to water impacts as well to evaluate implications to establishing e-plastics circular systems. Results indicate that, on the individual material level, precious metals have the highest water impacts in their supply chain. Water scarcity impact is mainly because of water consumed directly for mining operations and indirectly for energy production, and water degradation attributed to metal emissions during mine tailings management. The geographical region where metal production happens is also a contributing factor to water impacts, as water stress varies spatially. Therefore, sourcing metals from regions with lower water stress is an opportunity to reduce supply chain water impacts. At product level, precious metals have the highest contribution per smartphone, whereas aluminum has the highest contribution per laptop. Product design changes, such as use of recycled metal or using a low impact metal are observed to reduce water impacts. Further, e-waste shows a diverse mix of polymers and additives, including flame retardants, pigments, and heavy metals that can potentially pollute water resources if released. As a result, transition to circular systems is important to keep the plastics from entering the environment. To enable this transition, multistakeholder engagement in the electronics sector is required to make an informed decisions in product design, policy planning and material recovery infrastructure

Power and limitations of electrophoretic separations in proteomics strategies

Proteomics can be defined as the large-scale analysis of proteins. Due to the complexity of biological systems, it is required to concatenate various separation techniques prior to mass spectrometry. These techniques, dealing with proteins or peptides, can rely on chromatography or electrophoresis. In this review, the electrophoretic techniques are under scrutiny. Their principles are recalled, and their applications for peptide and protein separations are presented and critically discussed. In addition, the features that are specific to gel electrophoresis and that interplay with mass spectrometry (i.e., protein detection after electrophoresis, and the process leading from a gel piece to a solution of peptides) are also discussed

Multi-lifecycle assessment of cathode ray tubes

Over the past few years environmental issues and concerns have become more and more important, as they become a common part of most people\u27s personal experience. In these regards, the electronics industry is facing substantial problems in terms of end-of-life management of its products, televisions and monitors in particular. The building blocks of this industry are usually viewed as relatively clean . However, manufacturing by-products of the electronics industry and the disposition of electronics are becoming increasingly important technical, financial, and environmental issues. Within the context of the above issues, environmentally responsible disposal of Cathode Ray Tubes (CRT\u27s), which is still the prominent display of choice for both the television and the computer monitor, is regarded as a major concern, due to the high amount of lead in the CRT glass. A considerable proportion of the environmental effects of a CRT is related to its lifecycle and also to the lifecycle of its materials. And hence to analyze and assess the environmental impact of the raw materials used in a CRT during its complete lifecycle, the method of Multi-Lifecycle Assessment (MLCA) is adopted in this research and thesis. A generic process modeling structure for manufacture of materials is developed to conduct a full inventory analysis, in terms of mass balance, energy balance and environmental performance. The demanufacturing aspect of televisions is also addressed. The disassembly process is studied and different disassembly levels are analyzed using the reverse fishbone diagram technique. Considering three different end-fate objectives for recovering the subassemblies, components, and materials in the television, a cost effectiveness analysis is also performed to compare end-fate objectives and determine the scenario yielding the highest value for disassembling televisions. The major contributions and results obtained from this research are as follows: A database for eco-profile of commonly used materials namely, steel, aluminum, copper, lead, and leaded-glass, is generated by conducting LCI of these materials. Environmental burden for the lifecycle of CRT from raw materials extraction to production is calculated. The demanufacturing study conducted suggested that, for profitable and economical operation of a disassembly process, the procedure and level of disassembly, the time required for disassembly, and the current market value of recovered materials, are important and dependent on each other. The demanufacturer has to make a trade-off between these issues and thus try to efficiently and effectively manage the entire demanufacturing operation

The behavior of tellurium during copper ore processing at the American Smelting and Refining Company (Tucson, AZ)

Thesis (M.S.) University of Alaska Fairbanks, 2016Essentially all tellurium (Te), an element used in solar panels and other high technology devices, is recovered as a byproduct of copper mining. Recent increases in demand have sparked questions of long-term supplies of Te (crustal abundance ~3 μg∙kg-1). As part of a larger study investigating Te resources, this project examines the behavior of Te during Cu ore mining, smelting, and refining at the American Smelting and Refining Company (Tucson, AZ) as a first step toward optimizing Te recovery. Mass balance calculations estimate that only 4 ± 1% of the Te in the ore reports to the Cu anodes, while 60 ± 30%, 0.8 ± 0.2% and 5.8 ± 0.4% is lost in the tailings, slag, and dust, respectively. The uncertainties reported are the standard deviation of analytical measurements, but due to heterogeneity of Te distribution in the ore, the actual uncertainty is likely higher. Microprobe data shows that Te in the concentrate is mainly present as telluride minerals, but substitution into sulfides most likely also occurs. X-ray fluorescence (XRF) mapping showed that Te is collocated with S in the raw anode slimes, pressed anode slimes, and doré furnace soda slag. X-ray absorption spectroscopy (XAS) was used to examine Te speciation in anode slimes. It was found that Te oxidizes during the Cu ore smelting process, with 44% Te4+ in the flash furnace SO₂ filter. Te also showed 32% Te4+ in the raw and pressed anode slimes. The doré furnace soda slag and dust filter showed the most oxidation of Te at 57% Te4+ and 60% Te6+ respectively. These results indicate several points in the extraction process that could be examined further to determine if additional Te might be recovered from the overall process.Chapter 1 Introduction -- 1.1. What is Tellurium? -- 1.2. Tellurium End Uses and Market -- 1.3. Global Supply of Tellurium -- 1.4. Tellurium Scarcity and Criticality -- 1.5. Current Copper Extraction Process -- 1.5.1. Copper Mining -- 1.5.2. Copper Smelting -- 1.5.3. Copper Refining -- 1.6. Tellurium Byproduct Recovery -- 1.6.1. Mineralogy of Tellurium in Ore Deposits -- 1.6.2. Behavior of Tellurium during Copper Concentration -- 1.6.3. Behavior and Mineralogy of Tellurium in Copper Anodes and Anode Slimes -- 1.6.4. Extraction of Tellurium as a Copper Byproduct -- 1.7. Research Objectives -- Chapter 2. Site Description -- 2.1. The Mines -- 2.2. The Smelter -- 2.3. The Refinery -- Chapter 3. Methods -- 3.1. Sample and Standard Collection, Preparation, and Preservation -- 3.2. Elemental Analysis -- 3.2.1. Inductively Coupled Plasma Mass Spectrometry -- 3.2.1.1. Method Development of Sodium Peroxide Sinter -- 3.2.1.2. Sample Preparation for ICP-MS -- 3.2.1.3. ICP-MS Elemental Analysis -- 3.2.2. Wavelength Dispersive X-Ray Fluorescence -- 3.2.2.1. Sample Preparation and Analysis of WD-XRF -- 3.3. Mass Balance Calculations -- 3.4. X-Ray Absorption Spectroscopy -- 3.4.1. Bulk S XAS -- 3.4.1.1. Bulk S XAS Collection -- 3.4.1.2. S XAS Data Analysis -- 3.4.1.3. S Linear Combination Fitting -- 3.4.2. Bulk Te XAS -- 3.4.2.1. Bulk Te XAS Collection -- 3.4.2.2. Te XAS Data Analysis -- 3.4.2.3. Te Linear Combination Fitting -- 3.5. Microfocused X-Ray Fluorescence Map Collection and Analysis -- 3.5.1. Experimental Conditions -- 3.5.2. Map Analysis -- 3.6. Electron Microprobe Analysis -- 3.6.1. Experimental Conditions -- Chapter 4. Results -- 4.1. Method Development and Verification -- 4.2. Elemental Analysis of Samples -- 4.3. Mass Balance -- 4.4. X-Ray Absorption Spectroscopy -- 4.4.1. Sulfur -- 4.4.2. Tellurium -- 4.5. Micro-focused X-Ray Maps -- 4.6. Electron Microprobe Analysis -- Chapter 5. Discussion -- 5.1. Mass Balance -- 5.2. Mine -- 5.3. Smelter -- 5.4. Refinery -- Chapter 6. Conclusions -- 6.1. Future Directions -- References

Sustainability Implications of Consumer Electronics Adoption in the United States

High rates of technological innovation and consumer adoption in the consumer electronics sector has led to increasing concerns about the potential implications on resource consumption and waste generation. Despite growing public and policy attention on recycling as a strategy to curb resource demand and waste management impacts, less than 50 percent of end-of-life electronics are recovered for recycling in the U.S. A critical barrier to sustainable management of electronics is the lack of data and tools to proactively estimate consumption and waste flows, to create solutions that respond to the dynamic nature of this product sector. For sustainable solutions to keep pace with the rapid rate of innovation, they must be informed by comprehensive and proactive research, that not only quantifies material flows in electronics but also investigates associated economic, environmental and social implications. This dissertation aims to fill this knowledge gap through three interconnected lines of inquiry. First, a baseline material footprint analysis is conducted to retroactively estimate the material consumption and waste generation associated with household electronic product consumption in the U.S. from 1990 until present. Results from this analysis contradict the long-standing assumption that e-waste is a rapidly growing waste stream in the U.S. In fact, the net material footprint of electronics has begun to decline, mainly due to consumers phasing out large Cathode Ray Tube TVs in favor of lighter flat panel technologies. While the analysis shows decline in potential e-waste toxicity from traditional hazards like lead and mercury, it also raises new issues of concern for e-waste management. Notably, results show high resource potential in the emerging e-waste stream with new opportunities to recover scarce metals not currently recycled. Second, a predictive material flow model based on historic product adoption behavior was developed, to enable future forecasts of resource and waste flows so that stakeholders can create proactive – rather than reactive – solutions. Adoption forecasts for emerging technologies show increasingly fast windows of product innovation and uptake. In other words, new electronics are likely to have rapid uptake in the market but may be quickly replaced by subsequent product innovations. The forecasts also suggest that waste flows for mature products like CRTs, desktops, monitors and flat panel TVs will continue to be a major issue for the short term, with declining contribution to the U.S. e-waste stream in the future. Material flow estimations predict increasing prevalence of critical materials in e-waste underscoring a need to shift e-waste management mechanisms from ‘mass’ to ‘materials’, or in other words, from an emphasis on ‘waste diversion’ to a new focus on ‘resource retention’. Finally, a comprehensive set of sustainability metrics were created and applied to assess the economic, environmental and social impacts for the wide spectrum of materials used in electronics. Material metrics help identify key material hotspots and prioritize new solutions for reducing resource demand and waste management challenges. This dissertation contributes novel data and modeling tools that can aid stakeholders across the electronics industry in making informed decisions in product design, policy planning and material recovery in electronics

Fully Solution Processed PEDOT:PSS and Silver Nanowire Semi-Transparent Electrodes for Thin Film Solar Cells

Building integrated photovoltaics (BIPV), such as semitransparent organic solar cells (OSC) for power generating windows, is a promising method for implementing renewable energy under the looming threat of depleting fossil fuels. OSC require a solution processed transparent electrode to be cost effective; but typically employ a nonsolution processed indium tin oxide (ITO) transparent electrode. PEDOT:PSS and silver nanowire transparent electrodes have emerged as a promising alternative to ITO and are solution processed compatible. However, PEDOT:PSS requires a strong acid treatment, which is incompatible with high throughput solution processed fabrication techniques. Silver nanowires suffer from a short lifetime when subject to electrical stress. The goals of this work were to fabricate a PEDOT:PSS electrodes without using strong acids, a silver nanowire electrode with a lifetime that can exceed 6000 hours of constant electrical stress, and use these two electrodes to fabricate a semitransparent OSC. Exploring optimal solvent blend additives in conjunction with solvent bend post treatments for PEDOT:PSS electrodes could provide an acid free method that results in comparable sheet resistance and transmittance of ITO electrodes. Silver nanowires fail under electrical stress due to sulfur corrosion and Joule heating (which melts and breaks apart electrical contact). A silver oxide layer coating the nanowires could hinder sulfur corrosion and help redistribute heat. Moreover, nanowires with thicker diameters could also exhibit higher heat tolerance and take longer to corrode. Four layer PEDOT:PSS electrodes with optimal solvent blend additives and post treatments were fabricated by spin coating. Silver nanowire electrodes of varying nanowire diameter with and without UV-ozone treatment were fabricated by spray coating and subject to electrical stress of 20 mA/cm2 constant current density. PEDOT:PSS electrodes exhibited a sheet resistance of 80 Ω/□ and average transmittance of 73%, which were too high and too low, respectively. Silver nanowire electrodes, on the other hand, were able to achieve sheet resistances below 50 Ω/□ while maintaining a direct transmittance above 80%. Silver nanowires electrodes with average nanowire diameters of 80 nm lasted 2 days longer with UV-ozone treatment than without; and silver nanowire electrodes with average nanowire diameters of 233 nm lasted for 6,312 hours, which met the 6000 hour goal. PEDOT:PSS transparent electrode needs to be improved where the sheet resistance is below 50 Ω/□ and transmittance above 80%. This could be achieved by adding silver nanoparticles (SNP) less than 40 nm in size, which would also have a plasmonic effect enabling the solar cell to absorb ultraviolet light. Then a fully solution processed semitransparent solar cell utilizing a PEDOT:PSS:SNP and silver nanowire transparent electrodes can be fabricated