Designing and Assessment of a Dry Based Physical Separator for Recovery of Metal Fractions from Used Tyres

Sustainable resource recovery and recycling forms an integral part of a developed and developing economy. Energy hunger and record hike in fuel prices coupled with market competition in the cement industry has provided many opportunities for the application of alternative fuels from waste materials. Scrap tires as an alternative fuel is gaining grounds in comparison with coal and furnace oil due to its low price and nearly parallel heating value (i-e 7200 8300 kcal/kg) coupled with the ease of its availability and currently low prices. Scape tyres used as a fuel not only give heat energy but also reduces tonnage of waste produced. To get the continuous feed of TDF, tyres are shredded before combustion which results in combustible (e. g. Rubber) and non-combustible (steel wires) products. Many solutions are in use to separate the non-combustible steel wires such as the use of magnetic separator however varying size of the steel wires and that of the polymeric combustible material makes it difficult to achieve the complete separation. This is mainly due to the wire entanglement and trapping of combustible material as well as clinging of small sized particles in both separation phases, resulting in poor separation efficiency. This results in loss of combustible material as well as produces a low quality steel for metal recyclers. In this work a dry separation method with no pre and post treatment is proposed. Experiments carried out at different operating condition resulted in determination of optimum reduced particle size of 4.0mm for the feed material which gave the maximum separation efficiency of 73.6 % when the particle bed height was set at 60mm with the partition gap opening of 05mm. These optimum conditions resulted in enhancing the purity of the steel wire which is intended to generate good revenues and a valuable source of raw materials for the local steel industry.