A novel separation process for recycling of post-consumer products

The use of automated product recycling based upon fragmentation and separation processes is rapidly increasing due to the high economic feasibility. Air-classifiers are key low-cost technologies employed in these processes; however their efficiency can be highly variable due to inhomogeneous particle sizes as separation largely relies upon the difference in particle terminal velocity. In this paper a pulsing air-column classifier is introduced in which particles are constantly accelerated and decelerated to provide higher separation efficiency regardless of particle sizes. Experimentation with inhomogeneous granulated leather, foam and rubber from footwear waste products demonstrates a separation improvement of 10–25% compared to existing technologies and ability to reclaim rubber with above 90% purity.