An air-based automated material recycling system for postconsumer footwear products

AbstractThe worldwide consumption of footwear is estimated to be in excess of 20billion pairs of shoes per year. To date very little work has been done to develop material recycling solutions for mixed footwear products. In fact less than 5% of end-of-life shoes are being recycled, with most being disposed of in landfill sites around the globe. One of the primary reasons is that most modern footwear products contain a complex mixture of leather, rubber, textile, polymers and metallic materials, that makes it difficult to perform complete separation and reclamation of material streams in an economically sustainable manner. This paper discusses the development of an economically feasible automated material recycling process for mixed postconsumer footwear waste. Central to this process are bespoke air-based separation technologies that separate granulated shoe particles based upon the difference in size and weight. Experimental studies with three different types of postconsumer footwear products show that it is possible to reclaim four usable material streams; leathers, textiles, foams and rubbers. For each of the reclaimed materials there are a variety of applications such as surfacing materials, insulation boards and underlay products