At a time when resources are increasingly limited and the need to reduce waste, emissions and energy consumption is more urgent than ever, the aluminium industry is facing major challenges. The energy required to produce one tonne of aluminium from bauxite ore is equivalent to the annual consumption of an average-sized house. But there is hope. Recycled aluminium can secure the supply for the future - in a more sustainable way.
Lightweight, durable and corrosion resistant, aluminium is a material with endless possibilities and applications. Aluminium also has great recycling potential, which needs to be exploited given the energy-intensive production process.
"Recycling aluminium saves energy and reduces emissions, making it a sustainable alternative," says Johan Berglund, researcher and project manager for manufacturing processes at RISE.
Advanced sensor technology improves the recycling process
Although it is often said that aluminium can be recycled an unlimited number of times without its properties deteriorating, the reality is more complicated. Recycled aluminium is made from scrap - old products that have been melted down to be reused in new components. Although the aluminium itself does not change when it is melted down, the scrap can contain small amounts of impurities that affect the properties of the material.
"The aluminium recycling process must be kept as clean as possible so that different aluminium alloys are not mixed more than necessary. It is therefore important that the scrap is carefully sorted according to the properties of the aluminium alloys, which can be done with modern sensor technology," says Johan Berglund.
An effective way to recycle aluminium in a controlled way is to focus on a specific component of a specific alloy. A good example of this is companies that specialise in recycling aluminium wheels. Here the energy consumption is less than 1% of the energy required to produce new aluminium. It uses 100% post-consumer scrap, i.e. scrap from end users rather than industrial production.
Great potential for recycled aluminium
Another challenge with recycled aluminium is the contamination and undesirable substances that can increase as aluminium scrap circulates. For example, the iron content often increases, which reduces both the strength and corrosion resistance of aluminium.
"To address this, it is important to understand how recycled aluminium affects the properties of the material. It is therefore important to further develop methods for measuring and predicting the material's behaviour in different applications, something RISE is working hard on," says Anton Bjurenstedt, researcher at RISE.
Should we expect recycled aluminium to perform worse than virgin aluminium? Or is it possible to get material properties from recycled aluminium that meet expectations? The answer to this question can be found by comparing real test results with what is stated in the standards.
After a fatigue test on a die-cast component, it was concluded that the real life was 10 times longer than the calculated life.
"The result shows that there is more potential in recycled aluminium than what is stated in the standard or calculated. With good design and an optimised manufacturing process, there is potential to cast components that exceed expectations," says Anton Bjurenstedt.
With good design and an optimised manufacturing process, there is potential to cast components that exceed expectations
Recycled aluminium – a necessity
Using more recycled aluminium is not only an option but a necessity in our quest for a sustainable and resilient future. Embracing this change will not only reduce the environmental footprint but also pave the way for a more efficient and prosperous aluminium industry.
RISE offers a wide range of services and expertise to help you as a manufacturer to transition to a more sustainable production.As an independent research institute, RISE can support you throughout the entire process, from idea to development of prototypes and testing to practical implementation in production. A collaboration with RISE can involve both direct support in the form of one-off interventions tailored to your specific needs or based on a partnership in a research and innovation project.
