Study on slagging in a waste-heat recovery boiler associated with a bottom-blown metal smelting furnace

Bottom-blown smelting furnace is an efficient and environmentally friendly technology, and is known for the high adaptability to complex resources and high recovery of valuable metals. Its associated waste-heat recovery boiler (WHRB) cools the fume for cleansing and recovers heat for conserving energy. It is still considered as a developing technology and more studies are required to enhance the connection with the furnace to increase its operation safety and the operation rate. In this study, the WHRB associated with a bottom-blown smelting furnace was examined using experimental and numerical methods to solve its slagging, low-temperature corrosion, and air or fume leakage problems. The slagging mechanism was determined by detecting the characteristics of the slag. The improved hood of the WHRB was designed to control the air and fume leakage for solving the slagging problem. An optimal construction of the radiation cavity was realized using a numerical method to improve the flow pattern and temperature fields. This in turn can prevent molten slag formation and enhance the heat transfer performance of the WHRB. The operating rate of the smelting system was increased from 89.3% to 92.5%. The results can aid in developing green and highly efficient processes in the metallurgical industry.