Thermal conductivity of MgO-C refractory ceramics: Effects of pyrolytic liquid and pyrolytic carbon black obtained from waste tire

Abstract

In the present study, thermal conductivity and mechanical properties of MgO-C refractory ceramic bricks were investigated. Pyrolytic liquid and pyrolytic carbon black obtained from pyrolysis of waste tires were used as a resin and carbon source, respectively. The pyrolysis of the tires was conducted in a fixed bed reactor at the temperature of 500 °C with a 15 °C/min heating rate under nitrogen flow (0.5 lt/min). Before using in MgO-C refractory ceramic blends, pyrolytic products were purified with the acidic extraction methods which resulted in 61and 66 wt%. decreases in sulfur and ash contents in pyrolytic carbon, respectively. After this treatment of pyrolytic liquid, the sulfur content was reduced by 24 wt%. Eight different blends of MgO-C refractory ceramics consisting of different pyrolytic product contents were prepared, pressed, and tempered at 250 °C, and then characterized in terms of porosity, thermal conductivity, and density. The mechanical behavior of the samples was tested using a three-point bending test. Archimedes test was employed to determine the porosity and density. Surface properties of the bricks were analyzed by scanning electron microscopy (SEM). The obtained results were compared with a reference consisting of graphite and resin. The results revealed that mechanical and thermal properties of the developed bricks were highly sensitive to the porosity and the carbon source as well as the type of binder.