Aluminium for RFID Tags – A Life Cycle Perspective
Traditional RFID tags
Radio frequency identification (RFID) tags are growing in popularity in a variety of supply chains including the fashion industry (1) and the packaging industry (2) to name a few. The technology can be used in simplifying the end of life processes of different products by allowing the storage on information such as traceability of raw material inputs of the product as well as any associated manufacturing history. Further understanding of the environmental impact of the manufacture of the tags themselves is necessary to achieve a low environmental footprint for their production.
An RFID tag is constructed from a silicon chip bonded to conductive tracks that link to an antenna. This is all formed on a substrate that is laminated into a sealable, flexible label-like device. Aluminium is commonly used as a raw material in forming the antennae and conductive tracks of RFID tags. The process of manufacture includes lamination of a polyester or paper film and aluminium foil followed by removal of excess aluminium by a wet etching. Additional face paper is then used to convert the inlay to a tag, together with release paper and label adhesive (1). This process produces waste at each step and highlights the need for biobased raw material alternatives. This article reviews the global status of aluminium and highlights the reasons exploration of new materials for the manufacture of RFID tags is beneficial.
Sustainable development and LCA
To fully assess the environmental footprint of traditional RFID tags, sustainable development principles have to be applied. Sustainable development is about matching short and long term needs, and to do that, a life cycle perspective has to be employed. The consideration of the life cycle perspective can be supported with measurement and decision-making tools such as life cycle assessments (LCAs). An LCA analyses the life cycle of a product, often using a cradle to grave approach meaning that each phase of a product is looked at from raw materials, processing, packaging, distribution, product use and product disposal. Each of these phases will have an impact on the environment. An LCA can be used as an objective method to define and quantify the environmental impacts of each phase of the life cycle and increase awareness so that environmentally friendly decisions can be made at every stage of the life cycle of a product or service.
An LCA follows ISO10040/ ISO14044, an internationally recognised framework developed by the International Organisation for Standardisation (ISO) (2). There are four key stages: goal and scope definition, inventory analysis, impact assessment and interpretation. An important note is that LCA is an iterative process and is revisited to accommodate changes in study goals and data availability. It is intended that LCA studies on project REFORM (pRinted Electronics FOR the circular econoMy) will influence the way products are designed, manufactured, distributed, consumed and disposed of and it is important that the studies cover all of these aspects to avoid environmental impacts being unintentionally shifted to elsewhere within the life cycle. LCAs inform holistically on more environmental impacts other than carbon footprint and hence provide insights on impacts that represent planetary boundaries.
Aluminium as a raw material for RFID tags
Aluminium is the second most popular metal used globally and the production of the material is a carbon intensive process producing about 16.6 tonnes of CO2e per tonne of aluminium. Greenhouse gas emissions generated during production present a sustainability challenge for aluminium and any subsequent products to which it is a raw material input. With electrolysis as the primary extraction method, production relies heavily on electricity and the use of renewable energy can have a significant positive impact on the environmental footprint of primary aluminium production from bauxite. Primary aluminium produced in Europe has a lower carbon footprint than globally produced aluminium because of decarbonising efforts within the European energy sector which have led to renewable energy shares in their grid mixes. Despite high production and recycling of aluminium in Europe, around 30% of aluminium is still imported from outside Europe and this means that a large number of products still have an inherently large carbon footprint from aluminium produced using fossil based electricity (3). This inherently increases scope 3 emissions for any companies using imported aluminium as they have to take on any carbon emitted from the production of their input materials when producing carbon accounting reports. As an example, aluminium produced in China using coal-based electricity has a carbon footprint three times higher than European products (4).
Aluminium foil is a raw material used in the production of traditional RFID tags. One of the main sources of environmental burden involves the use of aluminium in the manufacturing stage of RFID tags production (5). Chemical etching of aluminium provides a challenge after a tag has been used and is about to be recycled. Elimination of this process will allow the complete recycling of aluminium residues and result in significant carbon footprint reduction (6). The production of the aluminium foil itself has a significant contribution to the environmental burden of the full life cycle of RFID tags. An assessment of aluminium as a raw material in terms of its production, global supply chain and environmental impact is a useful exercise in order to create a baseline for understanding the benefits of moving to more sustainable alternatives for raw materials (4).
The mining process for the material also affects land use as an environmental impact indicator as this affects biodiversity. The mining processes are primarily open pit which requires large land zones. The mines are also often near indigenous lands or tropical forests and this has also been a large contributor to the deforestation of the Brazilian Amazon for example. Other sources of environmental burden during the mining of bauxite include water and electricity use. From a social sustainability perspective, the leading suppliers of bauxite are based in countries with low governance standards and poor social indicators such as percentages of child labour, fragile state, conflict risk and Human Development index.
Aluminium is also widely recycled. Recycled aluminium covers one third of aluminium metal supply and two thirds of all aluminium produced in the EU currently. The use of aluminium in products requires ease of access for recycling to support circularity of the material (4). Where the product or packaging has a tag attached to it, it is important for either the product or packaging to be recyclable or for the tag to be easily detachable.
The future of RFID tag manufacture
To support the circularity of RFID tags, it is important for sustainable design thinking to be incorporated innovatively and inherently at the early stages of the design process. This in turn will result in products with a lower environmental footprint that support sustainability goals. The REFORM project is aimed at improving printed electronics manufacturing enabling the fabrication of products that cater for a more sustainable future. The project aims to accelerate and guide the development of a new European green functional electronics supply chain. It seeks to use eco-design principles to ensure that functional electronics can be produced that meet multiple application requirements for technological performance and compliance, while also meeting societal and environmental needs for sustainability. REFORM will achieve this by developing environmentally benign electronic ‘building blocks’ focusing on green, bio-derived adhesives, conductive inks and flexible substrates. These will be integrated into industry-led functional electronics systems and supported by innovations in conformance testing and material recovery methods.
References
(1) Voipio, V., Korpela, J., Elfvengren, K. 2021. Environmental RFID: measuring the relevance in the fashion industry. International journal of fashion design, technology and education. Available at: https://lutpub.lut.fi/bitstream/handle/10024/162924/voipio_et_al_environmental_rfid_postprint.pdf?sequence=1 (Accessed: 08 May 2024).
(2) ISO - International Organization for Standardization (2014). ISO 14044:2006. [online] ISO. Available at: https://www.iso.org/standard/38498.html.
(3) Fostering the production of sustainable aluminium in Europe. (2020). Available at: https://european-aluminium.eu/wp-content/uploads/2022/08/2020-07-29-european-aluminium_fostering-the-production-of-sustainable-aluminium-1-1.pdf [Accessed 18 Jun. 2024].
(4) Georgitzikis K., Mancini L., d’Elia E., Vidal-Legaz B. 2021. Sustainability aspects of Bauxite and Aluminium: Climate change, Environmental, Socio-Economic and Circular Economy considerations. Available at: https://rmis.jrc.ec.europa.eu/uploads/library/jrc125390_sustainability_profile_bauxite__aluminium_online.pdf (Accessed: 08 May 2024).
(5) Gehring, F., Prenzel, T.M. and Albrecht, S., 2019. Environmental impacts and implications of RFID tags. Available at: https://publica.fraunhofer.de/entities/publication/bcc151d9-7fbd-4152-a85b-bebbb18cdac8/details (Accessed: 08 May 2024).
(6) Comprehensive green tag program promises truly sustainable RFID products. 2019. Avery Dennison. Available at: https://rfid.averydennison.com/en/home/news-insights/insights/sustainability-comprehensive-green-tag-program-promises-truly-sustainable-rfid-products.html (Accessed: 08 May 2024).
