The authors previously found that tin was concentrated in iron dust in the pilot experiments of smelting reduction with a large amount of slag. In order to apply this phenomenon to the scrap melting process, 1 kg and 5 ton scale experiments were performed to clarify the mechanism of tin removal and to improve the tin concentration into iron dust.
It was found that tin could be removed from scrap efficiently in a scrap melting process with a thick layer of slag. In this method, a high evaporation rate of tin can be achieved by using the high temperature of hot spot with oxygen top blowing. From the experimental studies and theoretical analyses, it was supposed that most of tin vaporized as SnS. The vapor of SnS could be highly concentrated in dust by suppressing bubble burst dust. Therefore, in order to improve the tin removal ratio, it is of great importance to separate oxygen jet from metal bath to suppress bubble burst dust.
It was also found that the tin concentration ratio remarkably increased when pulvirized coke was blasted to the hot spot. It might be possible to improve the tin concentration ratio by means of local centent of sulfur near the hot spot.
