Dynamic model of a TSL furnace, developed with SimuSageTMsoftware

A dynamic model was developed in SimuSageTM, of a Top Submerged Lance (TSL) furnace in a lead smelting application. The objectives of the model are to create a tool for process control and optimisation, and to describe the complex metallurgical process which results from increasingly complex feed materials (from primary and secondary sources). Thermodynamic equilibrium models, e.g. created from FactSage, can be used to estimate the distributions of elements between phases. Likewise, laboratory equilibrium measurements for many elements are available. However, a dynamic model is required to address the fact that mass transfer processes are probably controlling smelting processes, especially in the TSL where evaporation of volatile elements should be taken into account. SimuSageTM is a flowsheet software package dedicated to modelling metallurgical processes by the Connected Local Equilibria method. Equilibrium compositions in process nodes are calculated by means of a Gibbs Energy Minimisation (GEM) approach and material can flow between these nodes by streams. In our model, the furnace is divided into a number of zones, e.g. a slag zone, metal zone etc. These zones are represented by nodes in a flowsheet, with mass flow between the nodes. Therefore, the chemistry in the reactor nodes is modelled by the GEM, while the mass transfer is handled by flow between the zones. It is thus possible to model the furnace without solving a large number of rate parameters for individual elements.