Recycling. Recycling of Used Tires.

The present status on the production and waste treatment of used tires in Japan are summarized and the recent activities of research on the recycling of used tires are introduced.For recycling used tires, liquid-phase cracking was tried using various kinds of solvents under low pressure of N2-H2. Experiments were carried out using a 200ml autoclave with magnetic stirrer at 300-440°C, initial H2or N2pressure of 2.0-8.5 MPa, reaction time of 20-60 min with solvent to tire weight ratio of 1-2.5. When hydrogen donating solvent such as tetralin was used for cracking, almost all organic matter could be converted to light oil with very low sulfur content of 0.5 wt% by the reaction under low nitrogen pressure. Reaction residue can also be reused as carbon black for rubber manufacturing.