One of the most widely recycled packaging materials is steel, which can be used over and over again without losing its properties.
Globally, the recycling rate is 83% but it’s up to 90% in some countries. Even so, increasing the recycling rate to 95% in countries (most likely in the industrialised world) where steel stocks aren’t growing would cut the need for virgin steel production by two-thirds and carbon emissions by a similar amount, according to an analysis for the Energy Transitions Commission.
Peter Hodgson, manager for product sustainability at Tata Steel Europe, explains that there simply isn’t enough scrap globally to meet the demand for new steel, 35% of which is made from scrap, although that gap is expected to close to roughly 50% within a couple of decades. In the UK, Tata is the largest steel manufacturer, with a division dedicated to packaging materials. Its advances mean steel cans are 30% lighter than 20 years ago.
However, scrap steel has to be melted down, requiring hefty energy input to get to the temperatures required, and involving some loss of material.
Steel can also suffer from the same problem as plastics: being down-cycled into less valuable products, such as reinforcing bars used to strengthen concrete. Such down-cycling is partly due to contamination with other materials, such as copper.
According to one estimate, only 8% of the steel originally used in car manufacture gets re-used for the same purpose because of loss of quality. Research efforts are under way to tackle this. Tata Steel is pioneering a new energy-saving steel-making process, through an EU-backed project at its IJmuiden steelworks in the Netherlands. The HIsarna technology will also play a role in recycling, taking up to 50% scrap steel input, and, crucially, steel that is coated with zinc, from car bodies, for example. Potentially the zinc could be recovered and then reused in car making.
When the National Steel Innovation Centre gets off the ground in the UK next year it will look at the means to advance the circular economy in steel making, as well as the new steels that will be needed for more sustainable batteries for electric vehicles, and packaging.
“Some of our construction projects are developing demountable products,” says Hodgson. “Rather than a coarse demolition process that will reduce the value, if you make the structural components demountable, and deconstruct carefully then you have a whole bank of materials. But you need to have designed it that way.”
Analysis by researchers at Cambridge University suggest re-use is declining in the UK, but there are exceptions: much of the steel for south London’s BedZED eco-village arose from refurbishment work at Brighton railway station; several of the buildings developed for the London 2012 Olympics were designed for deconstruction, while the athletics stadium itself reused 2,500 tonnes of pipeline steel in the roof structure; and BAA leases a warehouse near Heathrow that was designed to be disassembled and reused.
IKEA’s newest UK store in Greenwich – billed as its most sustainable – recycled 99% of the building materials from a Sainsbury’s supermarket it demolished on the same site. The steel was re-used offsite. Ironically the Sainbsury’s building had been lauded as the UK’s most sustainable supermarket.
The WellMet 2050 project at the University of Cambridge concluded that by making the right design choices up to 75% of steel (and 50% of aluminium) in the UK could be reused, with negligible carbon emissions.
Tata Steel produced the materials for a distribution centre at Amsterdam’s Schiphol airport. To facilitate the re-use of the steel, the project partners developed a building material “passport”, containing the specifications of the steel used in the building.
As a building or a car gets to the end of its life, says Hodgson “you also need information on its composition, what it’s been through in its life that might affect its functionality in its second life.”
A recent EU-funded study looking at how to encourage steel re-use found quality, certification and traceability were frequently cited concerns, so efforts are under way to address these.
