Symposium ES14—Materials Circular Economy for Urban Sustainability

As materials scientists, researchers and engineers, we are responsible for the substances that go into our products, as well as those in our synthesis and manufacturing processes. Many of these substances kill and cause disease, others gobble energy when refined and used, still others are in limited supply yet we casually throw them away. We need to do better - much better. This five-person panel discussion will allow the ES13 Symposium Organizers to share provocative insight into both the challenges and solutions associated with making materials experts better guardians of our world.

Panelists:
Carol Handwerker
Bill Olson
Alan Rae
Julie Schoenung
Ashley White

Metals recovery from electronic product recycling is currently focused on high-volume metals that are easily recoverable and on low-volume, high-value precious metals. Current and future electronics will increasingly contain small quantities of materials which are not currently recovered in today’s recycling infrastructure. Trends toward miniaturization, product dematerialization, and increasing materials heterogeneity create increasing challenges with respect to materials recovery, and the financial viability of electronics recycling generally.
In particular, the project examined whether conditions exist in the electronics and recycling industries to develop a voluntary, community-based solution involving adaptive governance systems to self-manage used electronics as common pool resources. This concept was inspired by the work of Dr. Eleanor Ostrom (2009 Nobel Laureate in Economics). It was concluded that the necessary conditions do exist, and that the time was right to take the next steps.
Therefore, iNEMI (the International Electronics Manufacturing Initiative) undertook a collaborative project to examine the role its members could play in increasing materials recovery, while promoting sustainable electronics. The main take-home message from the project was that the situation is bad and getting worse if we consider materials recovery as the only option for end-of-use (EoU) electronics. As a result of that project, a new iNEMI project was then launched to focus on value recovery from hard disk drives (HDDs), including multiple existing and possible future dimensions of an EoU system that could improve its effectiveness, financial viability, and sustainability. The dimensions examined ranged from reuse and remanufacturing of HDDS to reuse of components, transformation of components for use in other applications, and recycling of critical materials as well as commodity materials being lost under the existing recycling paradigm.
The project aims to study and implement a proof of concept of the necessary conditions and issues involved to develop a voluntary, community-based solution involving adaptive governance systems to self-manage common pool resources. Though the focus is on the reuse and recovery of spinning media (Hard Disk Drives) and rare earth magnets, the principles can be applied to any used electronic product.
It includes,
Identifying Criteria for Enabling Reuse of used, functioning HDDs and of components from used, non-functioning HDDs
Identifying Criteria for Enabling Reuse of HDD components in HDD applications – both direct and indirect for metal components, disks, magnetics, motors, head, PWBs etc.
Identifying Criteria for Enabling Reuse of magnets in non-HDD applications
Developing economic and logistics estimates for cases studies
Establishing necessary Design principles for the system for value recovery
Conducting a Demonstration project on HDD recovery to validate the principles identified
Benchmarking the current reuse and recovery (direct, indirect) and barriers with stakeholder input
Identifying the Leverage Points, mapping the supply chain, and identifying key gaps for developing a circular economy including each value recovery pathway for HDDs

A review of existing recyclability and reusability metrics revealed that the industry has limited means of practically assessing circular economic value (recyclability, reusability, reparability and refurbish-ability) of an ICT product. Current mass-based metrics, in their most simplistic form, are deficient. Product designers control material and design choices which affect downstream end-of-life costs, while the market controls the materials that are recovered. Yet, no metric or guidance links these attributes together.
The iNEMI Reuse and Recycling Metrics Project team has been developing a practical means for assessing the circular economic value of an Information and Communication Technology (ICT) product with the focus on incorporating score factors that assign reasonable impact value to product design features along with the ability to recover (whole products, parts) and return value (from reuse, recycling and/or energy recovery) back to the market. Included in this scoring factor are highlighted aspects that are within the product designer’s control such as material choice and ease of liberation of components and materials and those aspects outside the product designer’s control such as the availability of recovery for reuse/recycling technologies in the markets where the product is placed. The metric assigns a reasonable impact value based on the design and a weighted recovery rate, which brings the actual results into the traditional mass-based metrics. The project is developing an assessment tool for the ability to disassemble a product for repair and recovery of whole product, components and parts.
The resulting system assesses the economic feasibility and physical practicality to separate and liberate the parts, components and materials from ICT type products when whole product reuse is not possible. The assessment is divided into three tiers; material choice, ease of liberation, and the available recycling technology. Regional factors have also been researched and incorporated in the assessment criteria. Additionally, the team reviewed the hierarchy of recovery, which impacts the ease of returning value to the market: repair and reuse, parts harvesting, material recovery, or energy recovery/landfill.
ICT stakeholders, including product designers, manufacturers, customers, recyclers, governmental authorities, and environmental advocates can use this means to assess the relative impact of product design choices early in the product life cycle. This will benefit both the industry and the environment to achieve sustainability. The intention for the metric is to identify gaps that prevent return to market value by highlighting the most impactful action(s) needed to close the gaps, and to inform product designers and manufacturers of the end-of-life impacts of their decisions.

The recycling of waste electrical and electronic equipment (WEEE) has been a great challenge for the recycling industry in the last decades. Predictions on the future volume of such waste shows that it will rapidly increase during the coming years (Baldé et al., 2015). Some of the waste fractions derived from WEEE are considered to be hazardous, since they contain toxic compounds restricted by the Directive of EU (2002) for Hazardous substances in WEEE. Therefore, the scientific community are focusing on finding alternative processes in order to minimise their environmental impacts and eliminate the risk of human exposure during recycling.
Previous studies have investigated several processes for recycling of WEEE in terms of materials or energy. Pyrolysis is one of the alternatives which combines both energy and partially materials recovery through its production of oil and gas. Moreover, the solid residue, which contains high percentage of metals in non-oxidised form can be recovered through hydrometallurgical process.
The current study investigates the decomposition of three representative WEEE fractions, collected at a recycling plant located in Sweden focusing on feedstock recycling. The experiments are performed in a thermogravimetric analyser (TGA) in order to evaluate their decomposition behaviour. Furthermore, pyrolysis experiments have been performed at different temperatures (300-700 oC) in order to correlate the pyrolysis products with the choice of temperature. Through these experiments a kinetic study has been performed aiming to design a process that can maximize the production of specific organic compounds while minimizing the evolution of brominated compounds, which are usually present in the oil (Evangelopoulos 2015).
Tests were also performed in a semi industrial continuous pilot plant designed to treat 1kg of WEEE per hour. The experiments examine the possibility of releasing less brominated compounds according to the different tested temperature conditions. Moreover, the properties of the oils obtained by the process was also investigated experimentally in order to conclude to the application of this as a new material for feedstock recycling or for energy purposes. Finally, the results shows a route that should be followed for implementing pyrolysis in order to minimize the material and energy loses in the concept of circular economy towards a more sustainable way of recycling the WEEE.

In light of growing demand and pollution versus a finite amount of resources, electronic waste recycling is a way towards material circularity. Due to the complex composition of end of life products and the physical characteristics of the materials, it becomes more difficult to recover pure metals form the waste stream. Especially rare metals, which, although abundant in the earth’s crust, only occur in low concentrations, are a sought after commodity as they are important for the economy and are found in numerous products. New recycling technologies not only face technical difficulties but also need to overcome challenges of feasibility in both economic and environmental aspects. An assessment regarding environmental impacts and economic factors at the early development stages of such technologies is necessary to ensure a successful establishment.
Bioleaching has been specifically applied in copper recovery since the 16^th century and is now also used to win metals such as zinc, gold or cobalt. Using this hydrometallurgical approach for the recovery of by-metals such as indium is an innovative approach in the first development stages. Indium-rich material such as electronic waste is leached in a bioreactor as opposed to the environmentally risky heap leaching. The beneficiation process of indium from electronic waste can be classified into four steps. In a first step, the material is crushed and comminuted. The fines are then fed into a bioreactor, where bioleaching takes place in multiple stages. The third and fourth steps are the solvent extraction and subsequent recovery of the target metal from the solution. In a combined process, indium rich tailings and primary ores could also be added in the reactor to ensure a stable input and independence of the amount of end-of-life products.
The novel existent technology of using bioleaching as a hydrometallurgical process to win indium from electronic waste will be assessed exemplarily. This presentation will focus on preliminary results of batch trials in a lab scale bioreactor, whereby Indium was recovered from the electronic waste recycling process. Hereby Life Cycle Assessment is used to determine the ecological factors. Further, the environmental risks connected to this technology are summarized and put into perspective. LCA offers a standardized opportunity to determine the environmental impacts over the life cycle of a given product but can be applied to processes. The data is used to establish the feasibility of this recycling technology including both economic and ecologic parameters.

In the push for a more sustainable economy, fiber reinforced polymer composites (FRPCs) have proved an important component in implementing this vision. FRPCs have improved energy efficiencies in the transportation sector through the lightweighting of vehicles, such as aircraft and cars, and have enabled alternative energy technologies such as wind. The increasing use of FRPCs, however, has led to a corresponding increase in composite waste, such as production scrap from carbon fiber composite aircraft and accumulating end of life wind turbine blades. Up until the last half decade or so, no successful techniques for recycling these materials existed resulting in near 100% of all FRPCs being destined for landfill. Recent successes repurposing waste-to-energy pyrolysis technology, already developed for the processing of feedstocks like e-waste, have resulted in the emergence of a nascent recycled carbon fiber (rCF) industry. In these pyrolysis systems, polymer matrix materials are converted to energy while the reinforcing fiber is reclaimed for 2^nd generation (and beyond) composite production.
In this talk, research efforts to extend the success of rCF to the recycling of glass fiber reinforced composites (GFRCs) will be discussed. GFRCs comprise over 90% of all FRPC production; however, they also exhibit numerous technical challenges that have limited progress in their recovery. Emphasis will be placed on addressing glass fiber embrittlement incurred during pyrolysis processing and re-engineering fiber surface chemistry for redispersion in new polymer resins. Optimized recovery and postprocessing are essential for producing recycled glass fiber (rGF) of sufficient value that can economically support a rGF industry and begin closing the loop on FRPC materials writ large. Discussion will also include details from initial pilot plant scale pyrolysis trials completed in partnership with the Institute for Advanced Composites Manufacturing Innovation (IACMI) and the American Composites Manufacturers Association (ACMA).