The emerging bottom blown copper smelting (SKS) technology has attracted growing interest since it came into production. To further reveal the agitation behavior inside the bath and optimize the variable parameters, CFD simulation was conducted on a scaled down SKS furnace model with different tuyere arrangements. The Multi-Fluid VOF model was used for the first time in SKS furnace simulation and the simulated results show good agreement with an experimental water model reported in the literature, in terms of plume shape and surface wave. It was found that a low velocity region would appear on the opposite side of the bubble plume and persisted for a long time. To enhance the agitation in the low velocity region and reduce the dead zone area, an arrangement with tuyeres installed at each side of the furnace was recommended. Results suggested that a smaller tuyere angle difference would help to strengthen the agitation in the system. However, further investigation indicated that the difference in tuyere angle between two rows of tuyeres should be limited within a certain range to balance the requirements of higher agitation efficiency and longer lining refractory lifespan.

Bath smelting and converting technologies for copper production have been improved, resulting in higher production efficiency and less polluting emissions. Reported studies on experimental and computational modeling approaches are reviewed in this paper, focusing on adjustable variables and flow details, for a thorough understanding of the complex flow phenomena of the high-temperature reactors used. Results from water models and Computational Fluid Dynamics (CFD) simulations indicate that the transport phenomena in different reactors should be analyzed separately, as flow behavior exhibits significant differences in different gas injecting regimes and furnace structures. Mixing behavior and further optimization for most furnaces are presented in this review, showing a considerable degree of agreement between experiments and computational simulations. In general, a deeper nozzle or tuyere level with a higher gas flow rate are factors in the majority of copper bath smelting and converting cases. However, the dynamic parameters cannot be infinitely increased, but should be maintained within an appropriate range to provide relatively high mixing efficiency while preventing refractory corrosion due to splashing. Research on detailed flow phenomena including bubbles and surface waves is relatively scarce. It is suggested that the most efficient reaction areas for furnaces in jetting and bubbling regimes are totally different, due to the differences in bubble behavior. Concerning the bath surface, the behavior of transversal standing waves and longitudinal waves has been preliminarily revealed using water models, suggesting that standing waves tend to disappear in particular ranges of bath height and gas flow rate.

There has been a great deal of focus on the optimization of tuyere arrangements in SKS bottom blown copper smelting furnaces since the last decade, as the improved furnace operation efficiency of SKS technology has potential that cannot be ignored. New –x + 0 + x deg tuyere arrangements with 14 tuyeres are proposed in this research paper. Using a previously verified numerical model, CFD tests on the velocity distribution and wall shear stress for scaled-down SKS furnace models were conducted, with a constant total volumetric gas flow rate, and different operating parameters and furnace cross-section geometries. The results indicate that, at a relatively low gas injection speed compared with the previously optimized tuyere arrangement, although the –x +0 +x deg tuyere arrangements are unable to supply enhanced agitation in the typical round furnaces, they achieve better performance in elliptical furnaces. At a comparatively higher gas injection speed, the – x + 0 + x deg tuyere arrangements can improve the agitation performance in a round furnace while maintaining an acceptable wall shear stress on the bottom and side wall. The agitation enhancement with the − x +0 +x deg tuyere arrangements can essentially be attributed to stronger interactions between bubble plumes and furnace side walls. To further exploit the advantages of the new tuyere arrangements, an optimized tuyere angle was confirmed by a full-scale furnace model simulation.

CFD simulation using a multi-fluid VOF model on scaled-down SKS furnace multiphase flow was conducted, targeting the agitation performance under conditions of different tuyere diameters and bath depths, at a constant total gas volumetric flow rate. The results indicate that an increased bath depth contributes to the lateral movements of the matte and air phased, significantly promoting the agitation at the far side of the plumes. The characteristic of a deep bath allows larger tuyere diameters operated at a lower gas injection speed, to achieve comparatively smaller low velocity regions and dead zones. In addition, the wall shear stress was found to correlate with the distribution of low-velocity regions. Since the selections of tuyere diameter and bath depth are of major importance in the optimizing of flow fields, the results from this simulation offer good references for the future operation and design of SKS furnaces and other similar industrial vessels.

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