We Want Your Scrap!

Victoria Gate

by Phil Slinger – CAB Chief Executive

We all have the ability to play our part in ‘greening-up’ our lives to help us all to achieve some form of carbon neutrality by the middle of this century. Recycling more, reducing our waste, insulating our homes and adopting renewable technologies are some of the things we can do on a personal level. Every little thing helps but many of us can also influence much larger carbon savings with decisions we make in construction.

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The modern world we live in relies heavily on products made from aluminium, from food wrappers to planes, you are never far away from something containing aluminium. With aluminium being the third most abundant element in the Earth’s crust, and the most abundant metal here at 8% by volume, we are not going to run out of this material anytime soon. Bauxite ore which contains the aluminium in oxide forms, tends to be found close to the surface of the earth and is relatively easy to mine, but it does take quite a bit of energy to extract the ‘primary’ aluminium, which can then be mixed with other elements to form alloys for various usages.

A lot of work has been done to reduce the carbon emissions when producing primary aluminium, and reducing carbon emissions can equate with saving energy costs. Ways to achieve such reductions include technological improvements in the processes and the adoption of renewable energy sources such as the use of hydroelectricity. According to a 2020 white paper, ‘Low-carbon Aluminium, Solution for Sustainable Construction & Renovation’, primary aluminium from China can be as high as 20kg CO2e (carbon dioxide emissions equivalent) per kg of aluminium; for average global production of primary aluminium this figure drops to 16.7kg CO2e per kg. A ‘low-carbon’ primary, currently is on average just 6.67kg CO2e per kg. According to the white paper the Carbon Trust is currently targeting 8kg CO2e for all primary aluminium, and reviewing the Carbon Trust’s own report ‘The Case for Low-carbon Primary Aluminium Labelling’ they suggest that just 4kg CO2e is possible to achieve. The key here is that the global figure for primary production will continue to fall in the next few years, but that’s just part of the story.

Aluminium became a commercial commodity in the 1880’s when the ‘Hall-Heroult’ process was invented. Of all the aluminium produced since 1880, it is estimated that 75% is still in use today. Aluminium is virtually 100% recyclable and takes just 5% of the original energy needed to produce primary aluminium to recycle it for future use. Adding recycled aluminium back into primary aluminium allows the industry to reduce emissions further into what is known as ‘low-carbon’ aluminium, which can be 4kg CO2e per kg or less, so let’s just specify ‘low-carbon’ aluminium, right?

Beside the fact that there are not enough production plants offering low-carbon primary at the moment, we cannot get our hands on enough scrap aluminium as it is in very short supply. Aluminium, a victim of its own success, is lasting ever longer in its ‘use’ phase, meaning even less scrap is available for recycling! As a result, scrap aluminium carries a very good premium, almost as high as primary, but there is a further complication when it comes to recycling.

Aluminium is almost always used as an ‘alloy,’ it is mixed with other elements to offer characteristics best suited to the application. Alloy grade 6063 for example is a typical alloy used for fenestration extrusion and includes measured elements such as magnesium (about 0.7% by weight) and silicon (about 0.4% by weight) to offer a good balance of characteristics, including for extrusion and long life of applied finishes. There are many grades of aluminium and if we just bunch them all together when we recycle them, we can end up with low-grade scrap. Whilst this scrap can be used, it cannot easily go back into a specific grade of alloy.

This is where ‘closed loop’ recycling can offer huge benefits for the Fenestration Industry and the wider Construction Industry. If we take just fenestration extrusion scrap, products that have completed their ‘in-use’ phase, known as ‘post-consumer scrap’, grade 6063 for example, and keep it separate from other alloys, it can more easily be put back into extrusion grade 6063 aluminium. With careful process control, it is possible to include at least 75% of post-consumer aluminium scrap into wrought alloys, significantly reducing the amount of energy required to create the material. Globally, in 2019 according to the International Aluminium Institute, approximately one fifth of all aluminium put to a new use was post-consumer scrap. Importantly, as an industry we should be concentration on the near 100% recyclability of the metal we are specifying at its end of live, as simply put, we cannot all specify ‘low-carbon’ aluminium for our projects right now – there is not enough scrap to go round!

Two years ago, the Council for Aluminium in Building set up its own Closed Loop Recycling Scheme, encouraging members to recycle more in a closed loop where possible and to know where their production and post-consumer aluminium scrap was going. Research prior to the scheme being set up showed that the UK often exported aluminium scrap and that the scrap could end up in relatively low-grade applications such as in engine blocks or other forms of casting. As a reader so far, you will realise that by exporting or losing this resource from the UK does not make economic sense.

One member of CAB, Alutrade, an aluminium recycler based in the Midlands, can identify the grade of alloy in scrap aluminium and separate all other materials from post-consumer scrap. Other materials include metallic handles and screws, and plastics such as gaskets and thermal breaks. The result of their scrap processing is a ‘chipped’ aluminium of a single grade, which can easily be used to make new ‘billet’ or ‘logs’ which are used in the extrusion process. Ensuring the recycled material remains in the UK supports the UK’s ambition to supply more ’low-carbon’ aluminium for construction specifications.

CAB encourages all of its members to support the initiative, which costs nothing to join. CAB also encourages other companies who handle fenestration aluminium to join the Association and support the CAB Closed-Loop Recycling Scheme.

The Association continually supports the fenestration, facade and building envelope products supply chain, with staff on hand at the CAB offices to answer any technical or market related questions. Information is regularly updated on the CAB website at www.c-a-b.org.uk. For Association Membership enquiries, or should you wish to attend the next members’ meeting as a guest of CAB, please contact Jessica Dean at the CAB offices by email jessica.dean@c-a-b.org.uk or telephone 01453 828851.