Characterization of dust from blast furnace cast house de-dusting
C. Lanzerstorfer - Characterization of dust from blast furnace cast house de-dusting - ENVIRONMENTAL TECHNOLOGY, Vol. 38, No. 19, 2017, pp. 2440-2446
During casting of liquid iron and slag a considerable amount of dust is emitted into the cast house of a blast furnace. Usually, this dust is extracted via exhaust hoods and subsequently separated from the ventilation air. In most blast furnaces the cast house dust is recycled. In this study a sample of cast house dust was split by air classification into five size fractions which were then analysed. Micrographs showed that the dominating particle type in all size fractions is that of single spherical-shaped particles. However, some irregular-shaped particles were also found and in the finest size fraction also some agglomerates were present. Almost spherical particles consisted of Fe and O, while highly irregular-shaped particles consisted of C. Edged particles of a compact shape typically consisted of Fe and O and some additional elements like Ca, Mg, Al or Mn. The most abundant element was Fe, followed by Ca and C. These elements were distributed relatively uniformly in the size fractions. As, Cd, Cu, K, Pb, S, Sb and Zn were enriched significantly in the fine size fractions, while Al, Ba, Mg, Mn, Sr, Ti and V were enriched in the coarse size fractions. For the recycling of cast house dust, treatment by air classification would be an effective method for reducing the amount of Zn recycled. By separating a small fraction of fines (about 10%-20%) a reduction of the mass of Zn in the coarse dust recycled in the range of 40%-55% would be possible.