A Dual Stream Model of Carbon Pickup based on Carbon Activity

Abstract

An improved model of carbon pickup (CPU) in cupolas was derived from a previous model. The improved model assumes that, upon melting, (1) the liquid iron and steel descend the cupola without intermixing (dual stream assumption) and (2) the instantaneous rate of change of carbon activity, a_c, is da_c/dt=k·(1-a_c), where k is a rate constant and 1 equals carbon activity in coke. The model involves a single temperature-dependent rate parameter which was determined from experimental data. The revised model accurately correlated CPU when the proportion of steel in the charge varied from 0–50%. The standard error was <0.10%C. Inputs to the model are the relative weights of the metallic charge constituents, their compositions, and tapped iron temperature. Outputs are the CPU for each charge metal and the overall CPU.