A novel approach to the disposal and recycling of plastics – the so-called "cryo recycling" – has been developed by Prof. Harry Rosin, director of the hygiene institute in Dortmund (Hygiene-Institut, Hövelstr. 8, D-44137 Dortmund) in cooperation with more than 50 engineers. The advantages of this approach could be economic as well as ecological, its inventors say. As operating costs amount to only about a fifth of the cost of ordinary rubbish incineration, recyclate might one day become as cheap as virgin material. In addition to preparing bottles, yogurt cups, pipes or carrier bags for recycling, the Dortmund method is said to be capable of shredding, crushing and separating old tyres, electronic scrap and composites in such a manner that the single-polymer raw materials won back can be reintroduced into the production cycle.

In contrast to the most popular method of treating mixed plastics wastes, the idea here is to freeze, rather than burn. Wastes are frozen at temperatures as low as -160 C, so that they become as "brittle as Christmas ornaments" and easy to crush. As the individual components expand at different temperatures, composites can be separated. While still frozen, the plastics can be pulverised and separated according to polymer, in some cases also according to colour. After succeeding in commercialising another of the Dortmund institute's inventions, the "eco fridge," which runs on a propane-butane mixture as an alternative to chlorofluorocarbons, the inventors of "cryo recycling" say they have found companies interested in forming a consortium to prepare the market for this new method of treating waste plastics. Watch future issues of Plasteurope.com for progress reports.