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AN UPDATE ON ALUMINIUM ’ S RECYCLABILITY
NIGEL HEADFORD - CAB CHIEF EXECUTIVE
Aluminium is a fundamental component of our daily environment , greatly impacting our modern way of life . Its significance is evident in transportation , construction , and packaging , making it difficult to imagine modern day life without it . The International Aluminium Institute ( IAI ) indicates that global yearly demand for aluminium is now over 100 million tonnes of semi-fabricated materials , predominantly in sheet and extrusion formats . This demand is fulfilled by more than 65 million tonnes of primary aluminium , over 20 million tonnes from recycled post-consumer scrap , and more than 15 million tonnes from pre-consumer scrap .
Since aluminium ’ s commercialisation in the 1880s with the advent of the Hall- Héroult process , aluminium ’ s recyclability has been well documented . In fact , it has always been encouraged as the material is valued highly with its ability to be virtually 100 % recycled . With the advent of portable handheld XRF analysers ( X-Ray Fluorescence ) the ability to identify the various aluminium alloys outside the laboratory now allows easier recycling of various alloys back into their original grades .
There are currently eight ‘ series ’ of ‘ grades ’ used to identify the different types of aluminium alloy available . An alloy is created by mixing other types of materials into the pure aluminium to offer desirable features such as greater strength or a higher melting temperature . These ‘ mixes ’ are recognised as ‘ series ’ or ‘ grades ’ of aluminium that offer different properties , each having a specific application and use .
Grades are identified using four-digit numbers with the first number denoting the ‘ series ’ or ‘ grade ’ which also indicates the primary alloying elements . This grading system is known as the International ‘ Alloy Designation System ’. Extrusion grade aluminium used in fenestration is normally a 6061 or 6063 grade of alloy both of which use magnesium and silicon as the alloying elements to create magnesium silicide .
Quickly identifying the alloy enables a closed loop recycling opportunity where there is no loss of quality through cross contamination with other alloys . This has been something that CAB have been pioneering for some time with their own ‘ Closed Loop Recycling Scheme ’ where members report their recycling amounts within the scheme .
Several recyclers and members of CAB now utilise a modern separation process for aluminium fenestration products where thermal breaks and hardware are removed , resulting in a ‘ clean ’ aluminium alloy presented in a chipped form for easy handling and transport . This chipped alloy is then shipped directly to a re-melter where the recycled aluminium is formed back into billet or logs for the extrusion process . So , from aluminium extruded windows back into 6061 or 6063
extrusions which are very likely to be used as fenestration profiles once again .
Whilst the aluminium industry is working hard to achieve an 80 % reduction in greenhouse gas emissions in the production of prime aluminium , the industry is also expecting that the yearly demand for primary aluminium will increase by up to 40 % by 2050 .
A great deal of work has already been done in primary aluminium production , where carbon embodiment has been significantly reduced . According to a 2020 white paper , ‘ Low-carbon Aluminium , Solution for Sustainable Construction & Renovation ’, primary aluminium from China , which has been as high as 20 CO2e / t ( carbon dioxide emissions equivalent per tonne of aluminium ), drops to an average global production output of primary aluminium of 16.7 CO2e / t . ‘ Lowcarbon ’ primary aluminium in 2020 on average is reported as releasing 6.67 CO2e / per tonne of aluminium .
Today , while ‘ low carbon ’ primary aluminium is not formally defined , a carbon footprint of less than 4 CO2e / t is a common reference , representing the very lowest achievable with currently available technologies . This carbon footprint is often referred to as ‘ Cradle to Gate ’. The
46 NOVEMBER 2024 CLEARVIEW-UK . COM