Efficiency assessment of bag filters for removal of dust and heavy metals from emissions of electric arc furnaces

Industrial processes release a range of gaseous and particulate pollutants containing heavy metals into the air. Lack of enough attention to the design، installation، repair and maintenance of gas and dust filtration systems in industries، is one of reasons of increasing the emissions of these pollutants. Hereon، the steel making processes is one of emission sources of heavy metals. According to the importance of this issue، in this study، the efficiency of IASCo''s bag filters in removal of particles and metals emitted from EAFs was investigated. A total of 20 samples of emitted particulates from EAF furnaces by systematic method were simultaneously harvested in various melting from before and after the bag filter system and using standard method “EPA Method 1” and “EPA Method5” and with TCR-Tecora device. The concentration of heavy metals Pb، Cd، Cr and Ni in the original and control samples was determined with using Varian SpectrAA 100/200 device and ISO 9855 method. The results showed that the concentration of dust in the flue exhaust is lower than the standard rate. Also، according to the obtained results، the efficiency average of bag filters in removal of dust from EAFs، was 99. 58 percent. The results of survey of the bag filter efficiency in the removal of metals in dust form، showed different efficiencies for various metals. Thus، in this study the efficiency of the filters in removing metals respectively from highest to lowest was Ni، Cr، Pb and Cd with values ​​96. 3، 95. 9، 95. 4 and 84. 6 percent.