Mass Transfer in B. O. H. Metal Bath

Abstract

¹⁹⁸ Au sealed in a steel capsule was introduced into the center of metal bath in 130t B. O. H. F. In order to investigate the mass transfer in metal bath, steel samples were taken at 5 doors every 2 minutes after ¹⁹⁸ Au addition, and to examine the uniformity between 1st and 2nd ladle, samples were taken from tap gutter during tapping, and from several moulds during teeming of these 2 ladles.
The mass transfer in metal bath seemed to be caused mainly by turbulent diffution and additionally by forced flow with combustion flame.
The time required to get nearly homogeneous ¹⁹⁸Au concentration-defined as the time in which mean square deviation of radioactivities at 5 doors from steady value reaches within 10 pct.-was 10 or 17 minutes in the case of boiling, 10 or 14 minutes in reboiling, 21 or 23 minutes in blocking. Furthermore, in the case of blocking, mixing rate was slowed down at 6 and 10 minutes after¹⁹⁸. Au and alloy addition: These periods were recognized to correspond with the complete dissolution of alloy from both data on radioactivity and analysis. When ¹⁹⁸ Au was introduced in the end of metal bath (just below the burner) during boiling, it did not distribute homogeneously within 30 minutes.
When ¹⁹⁸ Au was introduced in the center of bath at 4 to 7 minutes before tap, concentration of ¹⁹⁸Au in 2nd ladle was 8 to 45 pct lower than that of 1st ladle in 4 of 5 cases.