Mercury emission from sintering process in the iron and steel industry of China

Iron and steel production is one of the most significant anthropogenic sources of atmospheric mercury emission. However, there is little information about this source in China. In this study, we focused on three typical Chinese sintering furnace processes. Mercury in flue gas was sampled using the EPA Method 30B and Ontario Hydro Method, and solid samples were also analyzed. We found that 1.12–4.66% of mercury input in sintering furnace processes was emitted into the atmosphere. The total mercury concentrations in the sintering furnace flue gas were 17.773, 31.765 and 18.275μg/m3; the major mercury species was oxidized form, which accounted for 73.4–94.7% of the total mercury. The mercury concentrations in the stack flue gas were 0.373, 0.533 and 0.465μg/m3, while its removal efficiencies by air pollution control devices (APCDs) were 97.5%, 81.1% and 96.8%, and its emission factors were 2.49, 2.71 and 1.28mg/t sinter. The main mercury inputs were iron ore, coal, coke and lime, where the iron ore input was 74.84–92.22% of the total mercury quantity. Moreover, mercury was distributed in fly ash (19.22–81.54%), gypsum (13.29–46.00%), iron ore sinter (0–11.45%), and flue gas (1.12–4.66%). An approximate mercury mass balance could be obtained from various samples in this study. [Display omitted] •The distribution of mercury during the sintering process was evaluated.•Mercury from sintering process is mainly emitted in oxidized form.•Over 80% mercury removal efficiencies were reached by air pollution control devices.•Emission factors range from 1.28 to 2.71mgHg/t sinter.