Ligament Mode Disintegration of Liquid Film at the Rotary Disk Rim in Waste Heat Recovery Process of Molten Slag

Abstract

The blast furnace slag is rich in high-temperature waste heat, however, most of the slag sensible heat is wasted in the current “wet granulation” method. Dry granulation method based on rotary disk atomizer has received growing attention. However, the waste heat recovery efficiency of this method is mainly determined by the slag particle size. In this paper, a simple model is proposed to characterize the ligament mode disintegration of liquid slag film at the rotary disk rim. The results indicated that the ligament number increases with increasing rotational speed, slag density and slag tapping rate but decreases with increasing viscosity and surface tension. The Sauter mean diameter of the droplet increases with increasing viscosity and surface tension but decreases with increasing rotational speed and slag density. Compared with density and rotational speed, increasing of viscosity, surface tension and slag tapping rate results in slight increases of the Sauter mean diameters. The results in this paper can be applicable for characterizing the dry granulation of slag by rotary disk in the waste heat recovery process of molten slag in a wide range of operation condition.