Centrifugal granulation characteristics of molten blast furnace slag and performance of the granulated particles

Abstract

Molten blast furnace (BF) slag is almost the last high-temperature liquid waste heat resource that has not been recycled in iron and steel making industry. Aiming at heat recovery of BF slag, dry granulation techniques have been proposed, among which centrifugal granulation technique is the most promising one. However, the immaturity of the centrifugal granulation technique limits its industrialization. Well understanding of the centrifugal granulation characteristics of molten BF slag is the immediate need for advancing this technique. In present work, the visualization experiments were carried out on the centrifugal granulation of molten BF slag. The influences of operation conditions on the granulation characteristics were discussed. Furthermore, for the purpose of potential commercial application of the granulated slag particles, the performance of the obtained particles including vitreous content, grindability and hydration activity were tested. The results showed that the particle size was strongly dominated by the granulator rotating speed and the mass flow rate of molten BF slag. Moreover, the obtained particles had a high vitreous content which cost nearly the same grinding work in comparison with water quenching BF slag, but the compressive strength test of mortar mixture showed slightly lower hydration activity for centrifugal granulated BF slag particles.