Behavior of Alkalis and Zinc in Blast Furnace and Their Influences on the Furnace Operation

At Chiba No. 1 blast furnace, fine materials condensed from the gas phase were sampled by the use of a vertical probe inserted into the furnace from the top. After the sampling the materials were examined by chemical analysis and X-ray diffraction. On the basis of the examination the in-furnace circulations of zinc, alkalis and their compounds were discussed through thermodynamic calculation. The results of the dissection survey of blown-out furnace could be well explained by the calculation result based on the measurement. An important role of the circulating materials, especially zinc and its compounds, in the formation of scaffold and inactive zone near the wall also was pointed out.