The production of ceramic materials from end-of-life tires respects the waste management hierarchy that ENEA summarizes in this pyramid
Did you know you can get them ceramic materials of various types (pads for disc brakes, heating elements for ovens, elements of microelectronics…) starting from exhausted tires? The system was developed by ENEA and meets the need to dispose of 'inconvenient' waste with a process that is not only economically sustainable but also profitable.
A perfect match. On the one hand there is a sector of ceramic materials in constant growth but held back by two limits: the cost of raw materials and that of synthesis processes. On the other hand, there are more than 300 million end-of-life tires produced every year in EU countries, and even more in North America, Asia and the Middle East.
It is true that end-of-life tires are collected through authorized channels (there are special consortia for the disposal of tires) and that energy can be obtained from them through heat treatment (especially pyrolysis), but the problem of the economic sustainability of the process remains. The ability to transform into ceramic materials the char (solid waste) resulting from the heat treatment of tires has opened up new possibilities.
Waste disposal is an economic rather than a technological problem. Almost any type of waste can be disposed of by transforming it into something else with heat treatment technologies, pyrolysis (heat treatment in the absence of oxygen) and gasification (heat treatment in the absence of an oxidizing agent or in the presence of steam). Three things result from the heat treatment: gaseous matter, liquid matter and solid matter (char).
The point is that in order to make waste heat treatments economically and environmentally sustainable, the three resulting ones must have a possibility of use and therefore also an economic value. With gas you can produce energy through combustion and here we are enough. The problems are the liquid fraction and even more the solid fraction. If the latter ended up in landfills (in the case of tires, the char is 40% of the weight of the starting material), heat treatment would not make sense. If, however, it can be used to produce ceramic materials the speech changes completely.
What the ENEA researchers have done, with a research that has been awarded among excellence, is to take the carbothermic reactions used to produce the ceramic materials and adapt them to waste heat treatment processes. In this way they have developed a heat treatment and synthesis process capable of producing both energy (from gas) and ceramic material, using char as a starting material.
From this process of heat treatment of used tires, a char composed of silicon carbide is obtained, an element which, due to its characteristics, can be used for the production of ceramic materials high-end: from shuttles shielding plates to automobile engines, from gas turbines to furnace resistors, to microelectronics elements. And more: sandpaper and abrasives, cutting tools, brake pads and disc brakes for performance cars, catalyst mounts and more.