Heat-transfer considerations in the bath smelting of composite organic and ferrous wastes

Prediction of the heating behaviour of composite pellets smelted in single-vessel bath smelting reactors is complicated by simultaneous multiple reactions within the pellets and a lack of knowledge of relevant heattransfer data. Limited heat-transfer analysis has been performed for the smelting of composite organic and ferrous wastes. The smelting process was modelled in two stages—a falling-pellet–gas region and an in-slag smelting region. The temperature profile generated within the composite pellet in the falling-pellet–gas region was determined by use of an exact solution for transient heating and a computer program was written to solve two-phase, moving-boundary, heat-transfer equations to determine the smelting time in the in-slag smelting region. Modelling established that significant volumes of the composite pellet are heated to reaction temperatures in the falling-pellet–gas region and that formation of a slag immersion crust is unlikely. Smelting times predicted by the heat-transfer model were validated experimentally.