Flight Dynamics and Sensible Heat Recovery of Granulated Blast Furnace Slag

As a valuable byproduct of iron-making process, blast furnace slag contains tremendous amount of sensible heat. Granulation of blast furnace slag is the first step for its heat recovery. Due to environmental and energy issues, dry centrifugal granulation has received a considerable amount of attention. However, the flight dynamics of blast furnace slag, which is of great importance for size design of blast furnace slag granulator and heat recovery device, has been seldom reported. A granulation experiment and a heat exchange experiment were developed in this work to study the mechanisms of both flight dynamics and sensible heat recovery of blast furnace slag. It is shown that the linear velocity of the outer edge of rotary cup is bigger than the escape velocity of slag escaping from the outer edge of rotary cup. The flight distance correlates positively with either the rotation speed or the rotary cup diameter. For a constant slag cooling capacity, a negative correlation was found between air feed ratio and slag layer height. And the heat recovery efficiency has the trend of first increase and then decline with the continuously increasing slag layer height.