Shear waste

Efficient e-waste recycling technology on the anvil

By Monali Sharma
Published: Saturday 15 June 2002

 A solution to the mountains o (Credit: Basel Action Network)cleaner recycling of electronic waste is something the industry has been looking forward to for the last one decade. It might just have got lucky. Considering that in the us alone in 1988 5-7 million tonnes of e-waste was generated and that 50-80 per cent of it was exported to developing countries like India the breakthrough could be a real boon.

e-waste is toxic in nature, containing lead, beryllium, mercury and cadmium. The recycling methods adopted in countries like India include open burning of circuit boards or using acid strips, which are potentially harmful.

New Generation Plastic Inc (ngp), a us-based company has developed ultra high shearing (uhs) technology. Currently most of the recycling technologies involve sorting of waste as per type of polymer or colour and use of chemicals 'compatilisers'. These compatilisers are very expensive and make recycling an unviable option. The uhs technology has two advantages over existing technologies.

First, it can recycle a different assortment of wastes and secondly, it does not use any chemical additives. It is economical as well as environment- friendly. The technology is based on the principle of ultra shearing whereby a very high mechanical shear stress is generated to break chemical bonds of the different polymers and form a copolymer as bridge between different polymers.

Simply put, different plastics are fed into a specially designed shearing chamber with blades rotating at a very high speed. As the blades rotate, the mechanical stress generated is so high that it breaks the existing chemical bonds of plastic and pushes it beyond its limit of incompatibility to form new polymers. The product produced is a stabilised compound with superior quality than other processes not using chemical additives.

The uhs process is capable of recycling all kind of thermoplastics. The company has successfully tested this technology in blending various plastic waste streams from computer hardware in collaboration with Hewlett Packard post consumer pc dismantling Centre in France. Currently the company is in talks with department of Correze in West of France for construction of first industrial size computer scrap plant. It has already received or applied for patents in 59 countries, including a European patent granted in September 1998 for recycling purposes.

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