Simulation of the pyrometallurgical recovery of technology elements in the TSL (top submerged lance) smelting of lead
The circular economy paradigm offers a realizable way of turning the present industrial model from a linear to a restorative and regenerative one. Nevertheless, this paradigm has its intrinsic limitations: thermodynamics defines the boundary conditions for material losses during recycling. In order to close the circular economy system and minimize the losses, especially in the case of WEEE metals, it is crucial to optimize the pyrometallurgical and hydrometallurgical process routes utilized to recover and/or refine these valuable metals. Lead is an important carrier metal: its extractive metallurgy allows for the recovery of many important technology elements (*). In this work, we present the development and application of a thermochemically-based process model to assess the behavior of indium, silver, germanium, tellurium and copper in the smelting of lead concentrates combined with secondary materials. The model is based on the connected local equilibria method and combines equilibrium thermodynamic calculations with a flow-sheeting approach to describe the movement of material in the TSL smelter. Through the usage of the model, the distribution ratios of the technology elements among the different phases are determined, what is a fundamental condition for the realization of the subsequent refining steps. It is shown how the variation of process parameters and feed composition affects the process outputs of the model simulations. This is an important step towards the process simulation of the pyrometallurgical recycling route of strategic metals.