In this present work, a computational fluid dynamics (CFD) model is devised to study and understand the flow hydrodynamics and chemical reactions occurring between the liquid molten concentrate containing cassiterite and gas phase containing hydrogen. 

This study is motivated by the goal for CO2-neutral production and recovery of valuable non-ferrous metals, e.g. copper, tin and zinc. The metallurgical industry is facing major challenges in transforming existing processes in terms of substitution of fossil fuels, considering costs and safety of plant operation and maintaining product quality. [1] Hydrogen is considered as a promising substituent to fossil fuels as reducing agent in high-temperature metallurgical applications, like smelting in top-submerged-lance (TSL) processes. [2] However, replacing traditional systems with hydrogen has a major influence on the process itself. Hence, numerical models enable a more detailed understanding of hydrodynamics between gas and slag phase as well as thermochemical interactions at the reactive interphase.  

In order to study the effect of hydrogen, a CFD model has been developed according to an experimental setup. [3] In the experiment a lance was introduced into the molten cassiterite though which a mixture of hydrogen and argon is injected into the molten concentrate. A one-fluid approach has been used to understand the interactions and track the interface between the gas and slag phase. Simulations have been carried out to investigate the influence of varying interphase reaction rates and gas flow rates on the flow hydrodynamics and the reduction performance.