‘Incomparable’ – HungaroJet's process for producing a superior rubber powder
The use of recycled tyre rubber in the production of new tyres hasn’t really taken off yet, and a main reason for this is because the rubber powder produced by traditional recycling methods doesn’t always reach the level of purity required by new tyre makers – indeed, the European Tyre & Rubber Manufacturers’ Association opines that “while in the EU around 39 per cent of material from end of life tyres is recovered [this includes rubber, but also steel and fabric], recycled materials cannot be used as a substitute for natural rubber in new tyres because of technical limitations.” But now a firm in Hungary claims to have perfected a process that removes every last trace of steel from the rubber powder, thereby overcoming this limitation. Speaking with Tyres & Accessories during February’s Tire Technology Expo in Germany, Gábor Kostyál, CEO of HungaroJet Ltd., described the technology involved and how it can benefit the tyre and rubber industry.
“No other technology comparable to ours exists,” states Kostyál. “It removes rubber from whole tyres without the need to shred them first. Our powder has no steel content at all – current technologies always have a residual amount, even cryogenic techniques have some steel particles.” To prove his argument, Kostyál holds up a section of still-intact steel cord, completely denuded of rubber. “We can demonstrate where the steel is – and it’s not in our powder.”
The active rubber polymer powder produced through the HungaroJet technique is called GUMjet, and the process involved in its creation can be described at a very basic level as an ultra-high pressure waterjet milling technology. No prior shredding is required before the tyres are processed, and the technique allows for the various tyre components to be dealt with separately. “A second benefit compared with conventional techniques is that our system has a unique method of separating the tread from the sidewall and inner liner,” Kostyál explains. “We had to create three separate machines for peeling off the rubber. The first machine deals exclusively with the tread, the second with the sidewall and the third with the inner liner.”
The procedure, Kostyál elaborates, starts with washing: “We use water purified through reverse osmosis technology – this is recycled and not lost in the process.” Then the first machine peels off the tread. The steel cord remains, as a whole, minus the rubber. Next the sidewalls are cut off into two rings, and these go into a separate machine for milling. After this, the remaining inner liner rubber is peeled off.
The process was developed by Hungarojet’s engineers. “They approached us with the idea in 2008; some of the company’s experts have been working on it for about ten years at an experimental level,” shares Kostyál, adding that HungaroJet then set up a plant near Budapest in order to show “that the idea can be commercially viable.” In 2008 HungaroJet’s technology was awarded a prize at the Lyon-based Pollutec show the largest European Recycling Exhibition. At present this plant can produce 1,000 tonnes of rubber powder per year, a quantity obtained from 1,300 tonnes of tyres. Admittedly, this is a small commercial output, and the CEO says that the 300 or so tonnes of steel cord remaining after the process are taken away by steel collectors.
When asked about the cost of producing GUMjet, Gábor Kostyál notes that the process used in its manufacture is more expensive than conventional methods, but creates a higher value product. “No particle above 1mm is present – we don’t use knives or direct mechanical energy, therefore our energy consumption is higher. On the other hand, we don’t need to exchange knives and therefore make savings with this.” And when elaborating on the quality of GUMjet, Kostyál explains that “the structure of the powder produced is better; the morphology of every piece of dust is fundamentally different from those produced through cryogenic processes. They have a much higher surface-to-mass ratio. The difference is very clear when looking at the results through an electron microscope.”
This difference may be verifiable through such an inspection, however winning over sceptics is not as easy as presenting them with a microscope. Kostyál shares that although Continental has been endorsing HungaroJet’s products, the Hungarian firm must still turn around manufacturer resistance against the idea of using recycled rubber in new tyres; he sees this as the company’s most important task. “They are very cautious and don’t necessarily believe the test figures – they test and re-test. Therefore we need to repeatedly demonstrate the chemical purity and cleanliness of our product. This is very heavy work for us.” Nevertheless, the CEO believes the tyre industry “has the potential to become our number one customer.”
In addition to proving product quality, a goal for HungaroJet is to see GUMjet produced in economically viable quantities. Gábor Kostyál says plans to create new factories and a production system are already laid out, and currently HungaroJet is looking for local partners around the world. “We’ve already created some commercial partnerships and we aim to establish a plant that is five to eight times bigger than the current plant – that will give us the right economy of scale.” One partner present with Gábor Kostyál and György Moldován at the Tire Technology Expo was Lothar Günzel, director of Gum Germany, who represents the Hungarian firm in that particular market.
An additional priority is product development. “Further developing our product is what we love the most,” shares Kostyál. “This is taking several directions: First, we’re opening up a new, end of line product market, such as for PCR, OTR tyres and the milling of factory rejects. And then we’re also implementing further advances in energy reduction and automation – the cheaper, faster, more efficient utilisation of water and energy in our process. As well as this, together with tyre and non-tyre customers we are looking into different applications for our. We’re working with a Hungarian firm on a rubber bitumen product, and we are also exploring thermoplastic elastomers as an intelligent filler. Furthermore, the area of coatings is one we’ve yet to explore, but we believe potential exists there.”
As a company that’s been in the business for less than five years, it could be said that HungaroJet is still in the early stages of its evolution. Recognition for the Hungarian company is growing, however. In addition to attracting Continental’s attention, HungaroJet’s innovation was recently acknowledged by its nomination for an ‘Environmental Achievement of the Year’ award at this year’s Tire Technology Expo awards. Although the award went to the brand new, US-based Bridgestone Americas Technical Center, Kostyál said HungaroJet was honoured to be nominated alongside great, globally-active competitors. The company’s nomination together with Bridgestone, Continental and Hankook is also recognition of the potential the HungaroJet process and the GUMjet end product holds.