Comprehensive Study of Flow and Chemical Reactions in a Submerged Lance Copper Smelting Furnace
The submerged lance smelting furnace (SLS) for copper smelting has been developed and used by Dongying Fangyuan Nonferrous Metals Co., Ltd. The process of this furnace is to remove iron from the copper concentrate. The technology has shown many advantages, such as high oxygen enrichment, good feeding adaptability, short process time, high SO2 content, and auto-thermal operation. During the copper smelting process, the raw material is charged from the top of the furnace and falls into the high temperature bath and melt. The oxygen enriched gas is injected at the bottom of the furnace and reacts with the melt to continuously produce the copper matte and slag. The matte and the slag will separate from each other due to the density differences and drain out respectively from each tap-hole. The high grade matte (High Cu content) is the final product of this furnace and is used to do further converting and refining. The study of the flow behavior inside the furnace is important inside the metallurgical vessel. The mixing behavior between gas and liquid is determined by the flow, which is directly related to the reaction rate. The chemical reactions inside the furnace also need to be further investigated. The full-scale model was used to simulate the gas liquid flow inside the furnace under the iso-thermal condition. The VOF model was used to capture the sharp interface between gas and liquid. The numerical model was further validated with the water model experiment. The baseline case was established based on the real process. The flow pattern in the submerged lance smelting furnace indicated rapid flow development and strong turbulent interactions between the gas and liquid phases. The optimization of the key structure parameters were conducted, and it shows that the lance diameter 55mm, lance inclined angle 10°, 25°, 600m lance interval and 1500mm bath depth cases are respectively the best flow field in each of the parametric studies. The non-free surface model was used to study the reacting flow inside the furnace in order to save computational cost. The Euler-Lagrangin model was used to simulate the gas-liquid reaction. The baseline case was validated with the measurement data. The parametric study about the bath temperature, inlet gas oxygen mass fraction and feeding capacity were conducted. The results show that the high bath temperature and high oxygen mass fraction can improve the Cu content in the matte. In addition, as the feeding capacity increases, the gas injection rate should also be adjusted accordingly.
Zhou, Purdue University.
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