Fluid dynamics studies related to bottom blown copper smelting furnace

Abstract

The bottom blown copper smelting furnace is a novel technology developed by Dongying Fangyuan Nonferrous Metals Co. Ltd. China. Since it started in 2008, many advantages have been reported from industrial practice, such as high volume specific smelting capacity, low copper loss, autogenous smelting, adaptive to feeds, low temperature operation and so on. Most of those features are relevant to the fluid dynamics of the molten bath in the furnace. However, the detailed behaviour of molten bath in the bottom blown reactor still is not comprehensively understood.To understand the behaviour of molten bath in this newly established furnace, a 1/12 lab scale cold model was constructed according to the principles of similarity. In this physical model, water was used to simulate the liquid matte, compressed air was used to simulate oxygen enriched air blowing and its flowrate was adjusted accordingly. Silicone oils with different viscosities were used to simulate the molten slag layer of various viscosities. In the present study, several features of the bottom blown bath behaviour were investigated by using this physical model. In addition to single phase mixing behaviour study, multiphase bath mixing behaviour was also studied to further investigate the mass transfer in the presence of top layer. Single lance blowing was used and experimental variables including water height, gas flowrate, oil layer height and oil 2 viscosity were adjusted to investigate the impact of each on mixing. It was found that the mixing time decreases with water height and gas flowrate in a greater rate than that of single phase system, while it is increasing with oil layer height and oil viscosity, where the rate with oil layer height is much greater. An overall empirical relationship with these variables was developed as following, and it showed a good prediction of mixing time under different conditions.The correlation was then generalised to a model-independent format for wider use:Three different types of surface waves were studied in the single phase bath with single lance blowing. The 1 st asymmetric standing wave was found the most significant type among the three because it leads the entire bath to swing laterally. The 1 st asymmetric standing wave was found to take place only at certain combination of bath height and gas flowrate, which is summarised in two sub-boundaries in terms of bath depth, gas flowrate and blowing lance angle.Sub-boundary 1 = 0.036. .Sub-boundary 2 = 0.63. .The measured amplitudes at several conditions show that tapping end amplitude increases with flowrate and bath height, and when the 1 st symmetric standing wave is taking place, the amplitude is remarkably increased. The frequency of the 1 st asymmetric standing wave does not change with flowrate or blowing angle, but slightly increases with bath height.The longitudinal wave exists on bath surface when the combination of bath height and gas flowrate is out of the critical occurrence boundary. To study the behaviour of the longitudinal wave, the model ...

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“…Therefore, their behaviour have to be experimentally studied for developing accurate UDFs. CFD is also a critical tool in developing real time process advisors (Jansson et al 2016) that will be based on digitalised metallurgical knowledge both from industrial practises (Zhou and Chen 2016; Zhou et al 2019) and experimental basic research.…”