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Substitute for natural product
| | A new recycling process now makes it possible to regain a high-grade secondary raw material from old tyres. The reprocessed rubber is practically the same as natural rubber.
By Kerstin Bendix
Sometimes, one single nail is all it takes. Car tyres may be able to take a lot of knocks but they are far from being unbreakable. A tear, an unbalanced wheel or a worn-out tread are only a few of the everyday problems that can lead to having to discard a car tyre. No matter what the reason for a tyre becoming unusable, the final result is a mountain of used rubber that has to be either dumped somewhere in the countryside or burnt. The remaining materials they contain are not usually recovered.
MeWa Maschinen- und Anlagenbau GmbH, a German company, has now developed a new recycling process for old tyres involving active fine grinding that produces a pure substitute raw material. This material can be used to mix in when manufacturing rubber.
Rubber products require the use of natural rubber as source material. Either natural rubber is used, which is often grown on plantations, or synthetic rubber, which is manufactured from a crude oil base. Both of these processes require a high amount of resources. Thus the use of old tyres could be helpful in saving resources.
photo:Pixelio
Old tyres
Recycling plants do already exist in which old tyres are shredded and the steel and textiles contained in them are separated. Certain types of reprocessing plant do produce a pure rubber granulate that, due to its material properties, can only be used in a limited way. It can, for instance, be used in the construction of sports centres, in moulded parts for road-building, as an additive for making asphalt or in the building industry.
The new recycling process from MeWa, however, is now said to have the ability to turn this granulate into a high-quality secondary raw material. According to MeWa, the process of actively fine-grinding old rubber is performed without the additional use of nitrogen and at ambient temperatures. The process produces a raw material that can be directly mixed with natural rubber in many applications and, depending on the requirement, can replace between 10 and 90 per cent of the rubber.
This means that the fine powder is suitable for use in a wide range of products because many applications needed on the market are made using approximately the same mixture of rubber that tyre manufacturers require.
After the recycling process is completed this new type of rubber powder is actively available to producers, according to the Geching-based company. The material created can be directly moulded to shape and pressed without having to add any adhesives. The manufacturing process only requires the corresponding pressure and temperature conditions.
Cheaper than natural rubber
According to MeWa, the rubber recovered through the recycling process is cheaper to produce than natural rubber. In contrast to granulate from other recycling processes, the end product does not consist of large pieces and is not at all different to the original rubber. The fine powder can also be recycled because it can be processed without the use of adhesives. The disadvantages of the type of granulate produced till now have meanwhile been eliminated.
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