Chemical recovery is attractive but has limitations in flexible foam, the Europur report suggests (see story p20). To be effective, chemical recovery methods need a homogeneous input stream to deliver a useable recyclate. Acidolyisis is commercially available and converts polyurethane into a secondary polyol that can be re-used. But foam mattresses made with old formulations may contain additives and blowing agents which are grey or blacklisted. It would need extra processing to remove these. The application of acidolysis in flexible foam is also unfavourable in terms of the material balance. The report said that it takes one tonne of prime polyol to recover one tonne of end of life foam. "The resulting secondary polyol must be diluted with prime polyol by a factor of four to be fit for prime foam production." However, this discusses flexible foam only and the report adds that production from single market foaming plants could deliver a good homogenous input streams but these are limited in number. A third route could be gasification-which converts shredder residue into synthesis gas-a mixture of hydrogen, methane and carbon monoxide. The process has been around for a while and has been given a new twist by Ecoloop. This company is part of Xella a building materials group from Germany. The Ecoloop process uses air as the main reactant and lime as a catalyst and scavenger for potential pollutants such as halogens and dioxins. Ecoloop has a 32MW pilot plant at Ebingerode, Hannover, Germany which went into operation in the last quarter of 2012.
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