Fluid Dynamics Studies Related to Bottom Blown Copper Smelting Furnace Lang SHUI Master of Engineering
A thesis submitted for the degree of Doctor of Philosophy at The University of Queensland in 2016 School of Chemical Engineering
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.
The mixing behaviour in the single phase bath with single lance blowing was investigated in the first stage. Mixing time was used as the index of mass transfer efficiency in this cold model and was measured to examine the characteristics of the fluid dynamics in the bath. It was found that there is an effective stirring range within an area adjacent to the blowing lance, in which mixing time changes little with horizontal or vertical distance, while out of the range mixing time increases with increasing horizontal distance and the increment is much greater on the surface of the bath. Mixing time was found to decrease with increasing bath height and gas flowrate within the effective stirring range. However, the effective stirring range can be reduced with increasing the bath height. An empirical prediction of mixing time from gas flowrate and bath height was then established for horizontal bottom blown furnace with single phase bath. = 37.5 . .
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
1 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.