Blast furnace burden softening and melting phenomena - Melting onset in acid and basic fluxed pellets

The cohesive zone, where ferrous burden materials soften and melt, greatly affects the performance of the blast furnace. Minimizing the size and lowering the position of the cohesive zone will improve productivity and decrease the coke rate. The present paper is part of a research program in progress designed to better understand the softening and melting phenomena. The liquid onset in the oxide core is one of the mechanisms that lead to the loss of mechanical strength in ferrous burden materials. Experiments were conducted to visualize the onset of liquid in the oxide core of pellets using the Confocal Scanning Laser Microscope. The results show that the initial liquid appears at temperatures relatively lower than expected in the dolomite fluxed pellet as well as in the acid pellet.