Sustainable Dismantling and Recycling of Metallic Aerostructures

Executive Summary:

The SENTRY Project comprised the dismantling, recycling and environmental assessment of the End of Life (EoL) phase of the “B2 Demonstrator” panels, a subcomponent of “low weight metallic fuselage section”, which has been manufactured within the Eco-Design for Airframe (EDA) activity in the Clean Sky (CS) programme. The SENTRY Project has assessed the current EoL management practices, based mainly on a size reduction step, where the output is a mix of the alloys included in the panel, a drying step of the metal scraps to remove the moisture and a remelting process to produce secondary raw materials.

The proposed new EoL procedures have been tested with a panel dismantling experiment at AELS facility, an accredited EoL aircraft manager, where parts have been identified, separated, sorted and shredded in order to satisfy input specifications of metal smelters that recycle them. The separated metallic fractions (once decoated and dried) have been processed in a bench scale melting facility and the produced metallic alloys characterised in order to validate their close loop recycling as better alternative than the downgrading practice. During dismantling and recycling activities, materials and energy flows, emissions and waste generation have been inventoried in order to complete the Life Cycle Assessment (LCA) of the EoL of the “B2 Demonstrator” panels that have been compared with the one of a reference panel. The final results have been the definition of the new EoL schemes for the “B2 Demonstrator” panels manufactured by Dassault Aviation (Panel B) and IAI (Panel A). The assessment of the environmental aspects related to the new EoL scenarios has allowed the identification of those activities with a strong environmental impact and the definition of ecodesign solutions to optimize potential reuse/recycling of metallic materials.

Within the SENTRY Project, a new EoL scenario, able to recover high quality aluminium alloys by promoting proper and efficient sorting techniques that avoid the down-cycling, has been defined and demonstrated. Considering the results of the chemical assays completed on the recovered aluminium alloys and the validation from Constellium, as global aluminium products manufacturer, it can be stated that they exhibit a maximum reuse potential since, due to the absence of contamination, they can be considered as first quality materials and therefore directly introduced again in the aeronautic sector.

In particular and focusing in the chemical composition results, it is shown that in all the cases the recovered aluminium alloys fulfil the specifications, containing percentages of the most critical elements below the maximum limits (Si

From the environmental point of view, when the market value of recyclable scraps relative to primary material was considered in the LCA, determining the product-specific degree of quality loss and the appropriate EoL credit, the impacts derived from the new EoL scenario were, in almost all impact categories, lower than the impacts derived from the current EoL. However, in a holistic approach, overall impacts throughout the entire life cycle of a product must be considered, meaning that impacts arising in the manufacturing, use and EoL phases should be regarded.

Finally, it is essential to add that all collected data from B2 Demonstrator and Reference Panels have been exchanged with the EDA Activity to be incorporated in the EDA LCA database, contributing thus with valuable and detailed LCA data on aeronautic components that can be applicable for the analysis of other parts.