The Light Metals Solidification Processing Group of the Institute for Structural and Engineering Materials, part of the National Institute of Advanced Industrial Science and Technology (AIST), has developed an extremely rapid method of separating steel wires from used tires by treating the tires with high frequency waves to induce heating. Estimates show that around 100 million used tires are discarded every year in Japan and used tire waste is increasing year by year around the world. As a result, there is a growing need for tire waste disposal methods. Tires include steel wires for additional strength and these wires have proved difficult to remove, limiting possible applications for used tires.

The AIST tested a number of methods to eliminate the wires, but cost was a major problem. In this latest research, a dielectric heating method was used on the steel wires, resulting in the areas mixed with the wires expanding like a balloon in a matter of seconds (Figure 1). A method was then discovered to easily remove the steel wires once the expanded areas had split (Figure 2). Further research is underway, in collaboration with a number of private companies, into methods to cut and granulate the tires after removal of the steel wires. Research is also being done on reuse of the used tire materials for applications such as sidewalk paving (Figure 3).

Figure 1

Figure 2

Figure 3