Dynamic Modelling of Molten Slag-Matte Interactions in an Industrial Flash Smelting Furnace Settler

Abstract

Depleting copper resources and advancing technologies have challenged industries to develop more viable, adaptable and cost efficient processes using also secondary raw materials in copper production. This study is targeting to that goal by dynamic modelling of flow and heat transfer coupled with chemical kinetics in an industrial scale flash smelting furnace settler using commercial CFD software ANSYS Fluent. First, different physical phenomena occurring inside the settler, for example, settling and separation of the matte/slag phases, and heat transfer between slag/matte phases and settler walls are studied. Secondly, reaction kinetics between matte and slag, and between slag/matte and settler walls, and impurity element distribution will be studied. This would also include phase changes phenomena due to these reactions and the flow of the reaction gases inside the settler. Settling of polydispersed droplets, their coagulation, breakage, and WEEE particle behavior are further targets of the modelling work.

Computational Approaches for Studying Slag–Matte Interactions in the Flash Smelting Furnace (FSF) Settler

“…The current investigation continued by adding the coalescence of droplets. Furthermore, instead of mono-sized droplets at the inlet, a mixture of different-sized droplets as reported in literature [33] were used for the inlet conditions, and the results from the full-scale settler were consistent with those reported earlier [6,7,10].…”

“…The conclusion drawn in these studies was that mostly droplets of 100 µm and below remained suspended in the slag phase, and that a higher tapping velocity and tap position close to the inlet disturbed the settling and entrapped the matte droplets. Similar conclusions were later drawn when using the Eulerian-Eulerian approach and transition state conditions while studying 100 µm, 300 µm, and 500 µm sized droplets individually [10]. The current investigation continued by adding the coalescence of droplets.…”

“…Similar trajectories have been reported in a study by Zhou et al [8]. Studies by Khan and Jokilaakso, and Jylhä and Jokilaakso show a funneling effect created by drag flows in the slag [9,10]. These drag flows were caused by settling matte droplets.…”

“…This poses a challenge for the validation of the full-scale model results as there are no possibilities for direct observations of the flow phenomena in the molten slag layer inside the settler. So far, the only option is to compare copper losses from the CFD model with industrial data [10].…”

“…This scaled-down settler geometry with similar slag and matte physical properties was modeled with CFD software as well. However, in addition to the previous research in this regard (single particle size of 500 µm) [10] and the CFD-DEM modeling part, in this CFD modeling the particle size distribution (PSD) scheme was also applied. The final selection and distribution of different droplets present in the initial mixture (PSD) were taken from the work of Jun 2018 [33], which is presented in Table 2.…”