Recycling of aluminium - a disussion of approaches

The aluminium bodywork of the new Jaguar XJ consists of 45-50% recycled material. And the aim is to increase this proportion. In a project supported by the UK government, Jaguar Land Rover is seeking to increase the recycled metal content (RMC) to 75%.

Aluminium scrap is in demand

These days when the aim is to employ as much "used material" as possible in the construction of even luxury limousines, it's no longer possible to ignore the issue of sustainability when it comes to product marketing. Companies in the aluminium industry are increasingly asked by customers about the recycled metal content (RMC) of their products. The ideal here would be "environmentally friendly" aluminium foil or aluminium sheet made from 100% recycled aluminium. However, the motivation often stems less from environmental considerations than from the desire to use the recycled content simply as an advertising ploy .

When Adrian Tautscher, Project Manager for the Jaguar Realcar Project, reported on the company's ambitious targets for increasing the RMC at last year's International Aluminium Recycling Congress of the Organisation of European Aluminium Refiners and Remelters (OEA), he received cautious praise as well as some fairly disparaging comments.

"I've got some bad news for you," commented Patrick de Schrynmakers, General Secretary of the European Aluminium Association (EAA), "we cannot 'mine' aluminium scrap at will , the supply of scrap is limited." According to de Schrynmakers, almost three-quarters of the supply of secondary aluminium is already being employed by the automotive industry, leaving very little potential for increased use.

Aluminium energy bank

Recycling is one of the key arguments used to justify the immense energy consumption that goes into extracting primary aluminium. The metal can be used over and over again without significant losses. Plus, the processing of recycled aluminium requires only 5% of the energy needed for the primary production process. The lifecycle assessment of aluminium as a material improves with each reuse cycle. The energy used for aluminium production is an investment in the future, which is why aluminium is sometimes referred to as an "energy bank".

However, the concept of RMC is a thorn in the flesh of the aluminium industry – and for good reason. According to Stefan Glimm, Managing Director of GDA, the concept of recycled metal content is "attention-grabbing greenwashing without a long-term sustainability factor" – in other words, an over-simplified response to a complex problem. Glimm, who has described RMC as the "Trojan Horse for the aluminium industry", states: "The RMC approach gives no incentive to further close the material loop nor to take responsibility for the recyclability of a product." It actually tends to result in a counterproductive incentive to produce more scrap in order to artificially increase the RMC.

The RMC – a zero-sum game

Because of its high market value, available aluminium scrap is rarely just left unused, it is normally recycled as quickly as possible. However, since there is not enough aluminium scrap available to meet demand, increasing the RMC in one product would only lead to its decrease in another – a zero-sum game for the environment. Even worse, because it diverts the flow of scrap, the RMC concept may, in addition to distorting market prices, also lead to longer transportation distances, which would actually increase the environmental impact.

"To improve the sustainability of aluminium further still, it makes much more sense to optimise the collection and recovery of aluminium products at the end of their useful lives," states Glimm. Only by considering the entire lifecycle of an aluminium product – from manufacture, through its useful phase to disposal and recycling – is it possible to determine its actual environmental footprint. Only a complete analysis of the material flows – cradle-to-cradle – can properly do justice to a metal that is not consumed but can be continually reused. The "end-of-life" approach therefore finds wide acceptance in the aluminium industry.

Still room for improvement

The Jaguar Land Rover team is also well aware of the complexity of the issue. It is not following a simple RMC approach and analyses the scrap flows in a completely holistic manner. In addition to the general optimisation of material cycles, the team is also looking for opportunities to recycle severely contaminated scrap for demanding applications.

For instance, Jaguar Land Rover is testing a number of innovations, including the melt-conditioning process developed by Brunel University. In this process the liquid metal is subjected to major shearing forces, which creates a finer grain structure and therefore better characteristics. The project has shown that there is still a significant amount of potential in the efficient recycling of scrap. The opportunities for further developing "urban mining" are far from exhausted.