| Abstract |
The first dynamic process model of a Top Submerged Lance (TSL) furnace based on a fundamental phase solution thermochemical basis is reported. This development is required to understand fully the role of TSL as an enabler of the circular economy, i.e., how well it brings materials back into the cycle. To achieve this understanding, the volume inside the furnace has been divided into six zones (bullion, bullion/slag interface, slag, bubble, splash, freeboard), gleaning from industrial experience and roughly guided by CFD studies by the authors. For each of these zones, local equilibrium is assumed. The model is implemented for lead smelting using SimuSage and has been benchmarked against reported production data. It is shown that the model can be used to optimize processing parameters: the process gas flow through the lance, to achieve a compromise between maximization of bullion production and process stability by avoiding the formation of matte phase. In a virtual experiment, a concentrate poorer in PbS is used and it is proposed how processing conditions should be modified to achieve a stable process and how the maximum achievable productivity changes. Finally, the model is applied to predict the partitioning of indium, as an important technology element from a typical recycling feed between the bullion, slag, and dust phases. It is observed that indium reports mainly to the slag phase during the smelting stage. |
