Understanding of Bath Surface Wave in Bottom Blown Copper Smelting Furnace
- PDF / 1,410,148 Bytes
- 10 Pages / 593.972 x 792 pts Page_size
- 96 Downloads / 193 Views
INTRODUCTION
GAS bottom injection has been widely applied in metallurgical processes, such as steelmaking converter and ladle refining. The injection creates gas-liquid two-phase plume zone above the orifice and the rising of the plume drives recirculation of liquid in the vessel. This circulating flow of liquid phase enhances the mixing and chemical reactions in the liquid greatly.[1,2] Meanwhile, the rising plume is able to set up bath sloshing motion in upright cylindrical container or standing waves in Peirce-Smith converter. It was reported that the liquid in the container is violently agitated which brings powerful mixing in bath at the presence of sloshing or standing waves. On the other hand, spitting, splashing, and refractory abrasion were also found corresponded to this phenomenon.[3–12] One of the earliest reports of this phenomenon was given by Thomas,[3] who studied the relationship between bath sloshing motion and its influence on the ejection of molten metal in steelmaking converter. The author also noticed abrasion of the refractory material with presence of this phenomenon. Later researchers[4–6] found in water model that the sloshing of bath was created by rotating of gas plume which only occurs when the gas flowrate is above a critical value. It was also found that this rotation wave is determined by gas flowrate, bath depth, and nozzle configuration. LANG SHUI, Ph.D. Student, XIAODONG MA, Postdoctoral Research Fellow, ANH V. NGUYEN, Professor, and BAOJUN ZHAO, Fangyuan Fellow, are with the The University of Queensland, Brisbane, Australia. Contact e-mail: [email protected] ZHIXIANG CUI, President, is with the Dongying Fangyuan Nonferrous Metals Co., Ltd., Dongying, China. M. AKBAR RHAMDHANI, Associate Professor, is with Swinburne University of Technology, Melbourne, Australia. Manuscript submitted on August 31, 2015. METALLURGICAL AND MATERIALS TRANSACTIONS B
Schwarz[7,8] proposed a mechanism of the bath sloshing motion. According to this mechanism, the sloshing motion is occurring when the buoyancy force on bubbles which are displaced from the center line as a result of the oscillation is sufficient to sustain the oscillation. A mathematical model of this mechanism was also developed to predict period and amplitude of the sloshing motion. Xie and Oeters[9,10] studied wave motion quantitatively in water/air ladle model and Wood’s metal/nitrogen ladle. They investigated the critical condition of oscillation occurrence, and used simple pendulum model to predict period and amplitude of bath oscillation. Iguchi[11,12] classified sloshing motion of bath in upright cylindrical container into two types by ratio of bath depth over diameter, and then gave four sub-boundaries of its occurrence condition. Similar bath sloshing was also reported in horizontal cylindrical containers like copper Peirce-Smith converter. In such vessels, the geometry of bath is different from steelmaking ladles and the gas injection is not absolutely from bottom but with some offset angles, instead. Different geometries of container and off
Data Loading...
