Blast-furnace process as a source of anthropogenic mercury emissions

Abstract

The metallurgical industry is a major source of anthropogenic emissions of mercury, whose compounds have an adverse impact on the environment and human health. In the year 2017 in the European Union, the industry was responsible for nearly 13 % of mercury emissions, being their third largest source. In Poland the industry is the fourth largest source of emissions, accounting for approximately 3.6 % the total. There are several component processes in the steel production process. The first consists of the preparation of ferrous additive, mainly in the sintering process. The second consists of smelting of pig iron in a blast furnace and the last entails processing in a converter or arc furnace. The main source of mercury in the blast furnace process is the fuel (coal and coke). The largest stream of mercury leaves the furnace with the blast furnace gas, which contains 2.4 μg/m3 after cleaning. Mercury content in pig iron has always been below detection levels with respect to analysis methods used. Using balance investigation results and data available in literature, an emission index has been determined for the whole production cycle: 10.181 mg Hg/Mg of steel. This value consists of emissions generated in the following steps: preparation of sinter – 1.622 mg Hg/Mg of steel, coke production – 4.953 mg Hg/Mg of steel, combustion of blast furnace gas produced during the blast furnace process – 3.557 mg Hg/Mg of steel and pig iron processing – 0.050 mg Hg/Mg of steel. This research was financed from the AGH University of Science and Technology Research Subsidies no. 16.16.210.476 and 16.16.110.663.