Emission Characteristics and Chemical Compositions of both Filterable and Condensable Fine Particulate from Steel Plants

ABSTRACT

Steel production is an important source of particulate matter emission. In this study, both filterable and condensable fine particulate (PM_2.5) emissions from an electric arc furnace (EAF) and four integrated iron and steel plants were measured. Chemical compositions including water soluble ions and metal elements of these two types of PM_2.5 were analyzed. The results show that filterable PM_2.5 concentrations emitted from sintering, coke making, blast furnace, basic oxygen furnace (BOF) and EAF are 1.01, 0.37, 0.16, 0.15 and 0.28 mg/Nm³, respectively. Sintering has the highest filterable PM_2.5 emission concentrations. Condensable PM_2.5 concentrations emitted from the above processes are 65.3, 89.7, 3.84, 1.32 and 2.02 mg/Nm³, respectively, which are much higher than filterable PM_2.5. K, Fe, Pb and Zn concentrations are high in filterable PM_2.5 for sintering process, which is attributed to the feedstocks of recycled materials. High sulfur content of the feedstocks results in high concentrations of SO₄^2– for all the test plants. In addition to Fe, the emissions of Pb, Zn and Sn are high for EAF, which is due to the complexity of the recycled steel feedstock for EAF. SO₄^2– is the highest emission ion for sinter process and coke making. For blast furnace, BOF and EAF, however, Na⁺, K⁺ and Cl^– are the predominated ions. For metal elements, concentrations of Na and K are highest for all the plants, which might be caused by their high potential of vaporization.