Study of the induration phenomena in single pellet to traveling grate furnace

Abstract

The process for pelletizing iron ore fines is an important operation unit for producing high quality of raw materials for the subsequent reduction processes such as blast furnace or direct reduction. The process essentially involves production of green pellets and induration on a traveling grate furnace to promote inner partial melt and agglomeration that confers adequate physical and metallurgical properties. This work focuses on the phenomena that occur in the firing step aiming the construction of a mathematical model that describes each phase and chemical species. The model was formulated based on transport equations able to predict the evolution of the temperature profile inside the pellet for each zone on the induration furnace. It was taken into account coupled phenomena of momentum, energy and mass transfer between gas and particles within the agglomerates. The finite volume method was used to discretize the transport equations of momentum, mass and energy describing the behavior of a pellet in an industrial traveling grate furnace. Model results are shown for the temperature profile along the pellet radius during the residence time inside the furnace. In this context, in the present work i a tool was developed to optimize the thermal profile in the induration furnace and hence control the mechanical strength of the agglomerate.