Abstract

Iron tilting runner, one of the facilities of iron making, is employed on the casthouse floor to transfer the molten iron tapped from the blast furnace to torpedo ladles. In recent years, the performance of blast furnace has gradationally increased, resulting in high productivity and high iron temperatures. Thus, high expectations are placed on the refractory linings of tilting runners to maintain sufficient durability even under stringent operational conditions. The severe wear at the impact zone results in downtime for repairs or new linings. Even though used universally as linings for runners and tilting runners in iron industry, cement black castables suffer from several drawbacks especially during the drying step and show some extent for harsh conditions, high temperatures, resulting in lower performance of the working lining. Over the past years, investigations on sol/gel castables have been carried out aiming to reduce the drying times, cracking and explosion and improve hot properties such as hot modulus of rupture. Nevertheless, nanostructured bonded materials show inherent drawbacks including the poor green mechanical strength and the sensitiveness due to ambient conditions and/or ageing. In order to overcome these problems and suit combinations of all requirements, a novel cement free binding system, inspired and reproducing fundamental features of zeolites, has been developed. First and foremost, the paper tackles the key properties of zeolites structure. The effect of this novel free cement bonding system on rheological properties, setting and green strength development kinetic as well as hot properties of vibratable Al2O3-SiC-C castables in comparison with cement based castable and sol/gel castable will be addressed over a second phase. According to the outcomes, the new cement free black castable reveals a high and rapid development of green mechanical strength during curing, providing installers time saving and ensuring safe demolding and mechanical operations. As for hot physical properties, the non-cement castable shows high hot modulus of rupture, resulting in a better resistance to the iron stream impact limiting therefore the risk of breakthrough. The new binding system enables Al2O3-SiC-C castables to offer better performance than ultra-low cement castables or sol/gel bonded castables regarding commissioning and running time when blast furnace operations become more severe and/or when wear lining sets stringent requirements on refractories, especially in the iron stream impact zones.