Experimental study of rotating dry slag granulation unit: Operating regimes, particle size analysis and scale up

Abstract

Blast furnace slag is a high-value by-product of the iron and steel industry. It leaves the plant at a very high temperature and possesses a large quantity of high-grade energy. One of the promising methods to extract this energy is dry slag granulation. In this study, the effectiveness of dry slag granulation was studied using a mixture of rosin and paraffin wax as an analogue for blast furnace slag. The effects of various parameters such as rotational speed of the disc, diameter of the disc and flow rate of the molten liquid have been studied. Different ranges of operating conditions in terms of non-dimensional numbers for fiber formation and particle formation were determined. This helps us determine the operating conditions under which particle formation is ensured. The study shows that with an increase in the rotational speed or disc diameter the average particle diameter decreases whereas with an increase in the flow rate the average particle diameter increases. The design of a granulation unit for a commercial plant utilizing the data from lab scale experiments is discussed.