| ‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘ KAWASAKI STEEL TECHNICAL REPORT No.5 ( May 1982 ) ‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘ |
| Development of Lime-based Powder Reagent for Injection Desulfurization of Hot Metal in Torpedo Car
Osamu Haida, Toshihiko Emi, Fumio Sudo, Sumio Yamada, Hajime Bada |
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Synopsis : Lime-based reagent with fine grain size and improved fluidity has been developed for hot metal desulfurization using the torpedo car (top) injection method. With the optimization of both the powder size and the C, CaF2 and CaCO3 contents in the reagent, lime reaction efficiency is improved far higher than the level reported in counterpart documents. This desulfurization method does not lead to resulfurization which usually occurs during the hot metal teeming into torpedo cars into which calcium carbide has been injected for desulfurization purposes. The effect of CaCO3 content in the reagent on ΕCaO and the absence of resulfurization is theoretically explained on the basis of uniform mixing time of hot metal in torpedo cars and the analysis of torpedo slags taken before and after the desulfurization. The high value ofΕCaO and the absence of resulfurization have contributed to lowering the unit consumption cost of the lime-based reagent to roughly one-half of that of carbide. Also, the choice of suitable lining material for torpedo cars (MgO-C for slag line and Al 2 O3-SiC for the remaining part) and an increased frequency of torpedo car utilization have reduced the lining cost for lime desulfurization to about 80% of that for the carbide desulfurization. The lime-based reagent replaced calcium carbide in August 1979 at the No.3 Steelmaking Shop at Chiba Works. |
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