Extract the Metals and Reprocess the Rubber : Tyres – A Waste Industry Headache or Newfound Hero?
They’re still considered by many as a problematic waste stream that is economically unviable to process. But the changing commodity landscape and the advancement of technology means the resource potential of old tyres can now really come to the fore. Gary Moore, tyre shredding specialist at UNTHA, elaborates…
With a reported 1.5 billion products reaching their end of life globally, every year – and a worrying 60% of these said to be landfilled, stockpiled, illegally dumped or ‘lost’ from the resource chain – tyres represent a notorious problem for the waste management industry. The impact that the unscrupulous handling of these redundant materials has on the environment, is also vast – not least when stockpile fires break out unexpectedly or are deliberately started to solve the mounting waste issue.
But the complex make-up of tyre products and a lack of engineering advancement in this specific area of waste handling, means that for several years they have been considered economically unviable to process. But profit is not a dirty word, and firms should not be afraid of striving to make money from their operations, especially if they are to be commercially sustainable.
In the eyes of many – even those who want to support the drive to achieve a circular economy – end-of-life tyres are simply a waste headache. But fast forward to 2020 and they could just become an industry hero.
The impact of COVID-19
The COVID-19 pandemic has contributed to newfound difficulties across the resource sector overall, with valuable recyclables now in short supply. Previously difficult waste streams – including tyres – are therefore being re-evaluated for their resource potential.
Highly sought-after steel, for instance, remains ‘locked’ within tyres, unless the products are shredded, and the composite materials liberated for segregation. And even the rubber itself is now deemed to be rich in potential.
In fact, devise a carefully-designed tyre processing line and it is possible to extract the metal for resale andtransform the rubber into a homogenous product that can be used for road base, tip cover, landscaping and playground safety surfaces. Any residual material can be utilised in energy recovery processes including thermal desorption, to produce fuel oils and clean gas for electricity generation, plus a burn-efficient tyre derived fuel (TDF) for the cement industry.
Some savvy operators are already way ahead of the curve, of course, and did not need the Coronavirus outbreak to highlight the opportunities associated with intelligent tyre processing. For these forward-thinking firms, all eyes are now on maximising the margins from their plants.
The wealth in ‘waste’
Processing tyres for recycling and energy recovery sounds like a complex task, and of course sophisticated machinery must lie at the heart of such an operation. But as is often the case, thanks to engineering advancements, ultra-clever technology can in fact be very simple to run. And, acknowledging the long-standing difficulties associated with making money from this once-deemed-unshreddable waste stream, tyre processing systems are now also designed with profitability in mind. In fact, many waste handlers have achieved a payback period as short as 18 months.
Key to maximising the wealth in this waste stream, is the design of a processing line that can produce a contaminant-free, homogenous output, in a single pass. This reduces the capital investment required to build the system. If the technology is flexible and can be easily reconfigured to handle different input materials – including standard car or passenger tyres, through to more rugged truck and OTR tyres, and more – the investment is further protected. And if different output specifications ranging from 30-400mm can be satisfied, depending on end user requirements, routes to market should open up too, to minimise risk.
The technology must be engineered to withstand the pressures of this tough, bulky waste stream, of course, and a slow-running machine with high torque should ideally be sought. This will also ensure minimal wear and long service intervals, which maintains plant uptime and keeps maintenance costs low, without any detriment to throughputs. A capacity of 8-10 tonnes per hour should be comfortably achievable, with operator safety always protected.
What’s next?
Acknowledgement of the resource potential in tyres is only going to grow, and quickly. In fact, a product that has long proven troublesome for many, could soon emerge as a widely recognised and important piece of the environmental jigsaw.
Various external factors such as the state of the commodity landscape – as well as operators’ own appetite to process end-of-life tyres – means a number of rubber specialists now have the opportunity to develop not just cradle to grave systems for this ‘waste’ stream, but a completely closed loop business model.
And that’s when things will get really exciting…
