Nonferrous metal flue gas purification based on high-temperature electrostatic precipitation

Abstract The removal of fly ash from nonferrous metals industry at high temperatures in electrostatic precipitators (ESPs) has attracted wide attention in reducing the industrial pollution. In this study, the removal characteristics of copper smelting (ash A) and nickel smelting fly ash (ash B) under regular and circulating flue gas conditions were investigated through a high-temperature wire-plate ESP. The two kinds of ash have various resistivity ranges at different temperatures, resulting in better removal of ash B than ash A at relatively low temperatures, whereas the opposite result was obtained at 573 K and 673 K. Besides, under the circulating flue gas condition, the number percentage of large particles was decreased while small particles ascended as the increase of the residence time. After sufficient residence time, the particle mass concentration would reach a stable value under 10 mg/m3. Furthermore, the removal characteristics of the two ash under the barbed electrode (DE2) compared with the round rod electrode (DE1) was also conducted. Results indicated DE2 owned a higher removal efficiency for both ash at high temperature no matter under which condition. Combining the electrode optimization by DE2 and the action of circulating flue gas, the ultimate collection efficiency of ash A and ash B could reach 95.65 % and 95.12 % at 673 K.