Recycling of rubber waste

The most important use of rubber in tonnage amount is for tires and inner tubes. All tires of automobiles, trucks, buses, airplanes etc., are made from rubber due to its unique properties. Rubber is related to thermo-plastic-elastic materials and is turned to thermosetting on vulcanization during manufacturing of rubber products or tires. This occurs as a result of the formation of three-dimensional structure due to the presence of the so-called vulcanizing system in rubber mixes. In this case, it is difficult to recycle rubber waste or refuse using the general methods used for thermoplastic materials. Thus, recycling of rubber waste is very important problem as such waste is not biodegradable and has its negative impact on environment. Besides, the recycled rubber should be considered as a source of new material with economic impact. In Egypt, the main producers of rubber tires are the Transportation and Engineering Company (TRENCO) and FAROS. These two companies that are based in Alexandria have different types of rubber. The amount of rubber waste in these companies is about 1500 t per year, beside the worn-out (old tires). It is established that the rubber waste in the companies is coming from different processing stages and through different operation units. Consequently, the waste may be green, scorched and vulcanized rubber. Also the waste may contain rayon or nylon fibers. This waste would be subjected to different methods of treatment such as hydrolysis, mechano-chemical reactions, or reclamation. The vulcanized waste must be grounded before any treatment. The present work aims at the recycling of rubber scrap via grinding, and identifying utilization methods that may be effective in solving the rubber scrap problem. These methods were reclamation, surface modification, use of rubber powder in asphalt paving, or as extender, or to produce filler to reduce the cost.