Frozen rubber pays dividends for Sharjah

A recycling plant in the emirate that uses cryogenics to turn piles of rubber into useful material has been valued at $40m.

A handful of the powdered rubber that is produced after old tyres have been recycled.

SHARJAH // Storing old vehicle tyres is a growing problem in the UAE, but the solution could be a recycling triumph and big business. The UAE's first plant capable of turning old tyres into useful products is opening in Sharjah. The facility, worth US$40million (Dh146.9m), has a formidable task - the emirate's stockpile, by the Sajaa landfill, is estimated to contain eight million tyres.

More than a million more old tyres are generated in the emirate each year, said Samer Kamal, the managing director of Bee'ah, a public-private company responsible for managing Sharjah's waste. But Mr Kamal said he is unfazed by the pile. The new factory is expected to begin operating in a week or two, he said. The facility should be at full production by autumn. "This would mean we will have a capacity to deal with two-and-a- half to three million used tyres per year," he said.

Reducing the huge stockpile has several environmental benefits. "Tyres are flammable; having them sit outside in the desert means they could burn, and if they burn the environmental impact can be significant," said Mr Kamal. "In addition, we do not want to take up desert space unnecessarily." Rather than sitting in a landfill for hundreds of years, old tyres can be turned into new products, he said. Applications include playground and sports-area flooring, landscaping and even roads. While conventional tyre recycling uses shredders to chop the material into small pieces, at the Sharjah facility a more advanced approach is applied.

In what experts refer to as a cryogenic process, shredded tyres are frozen with liquid nitrogen and then broken down into even smaller pieces. "They become very brittle, like glass," said Jim Anderson, the chief executive of RTI Cryogenics, the company which is fitting the Sharjah facility with the equipment to carry out the recycling operation. The process starts with shredding the tyres in a machine that can chop about 800 units per hour. From there, the material travels to a hopper feeder and into the cryogenic system.

"The long tube there is the freeze chamber," said Mr Anderson, pointing to a rectangular tank about 17 metres long. Nitrogen is normally in the form of gas, but turns into liquid when it reaches temperatures below -196°C. When shredded tyre is fed into the freeze chamber, it is mixed with nitrogen and reaches -100°C, which makes it very brittle. From there, the material drops into three hammer mills, each with a 200-horsepower motor, where it is smashed to tiny pieces.

Tyres contain fibre and steel, and separating these materials from the rubber involves further processing. The mixture drops into a rotating screen, which traps fibre on top and isolates the rubber and steel at the bottom of the screen. Finally, the steel is separated via a powerful magnet. What's left is recycled rubber, which is stored in five tanks of various sizes, depending on how finely ground it is. This, said Mr Anderson, in turn determines the use that the recycled product is put to.

Finely-ground rubber goes into a machine right next to the tanks, which produces flat hexagonal bricks. These can be used in play and sport areas. Mr Kamal said that Bee'ah has already reached agreement with the Shajah Municipality to use the product in recreational areas in the emirate. "Crumb rubber can be used to make hundreds of products," he said, explaining that other uses include mulch, which is utilised in landscaping instead of sand, gravel or wood, as well as moulded rubber products.

"The really big one is asphalt rubber," said Mr Kamal. "We have a design that involves putting 20 per cent rubber in the top surface layer of roads," he said. Mr Kamal and Mr Anderson said that using rubber in road surfaces increases the lifespan of the roads and makes them quieter and cheaper to maintain. Bee'ah will be building a small stretch of test road to demonstrate the advantages to municipal officials.

Large tyre dumps are an issue not only in Sharjah. Dubai also has a stockpile of eight million, while millions more are lying around in Abu Dhabi and Al Ain. Plans have been announced to build facilities in Dubai and Abu Dhabi, but few details have yet to be made available. [e-mail]