Abstract
Slag splashing, which is a new technology to increase converter lining life, has achieved significant economic and environmental results. Via a converter model of Steelmaking Plant no. 3 of An-Shan Iron and Steel Group Corp., physical model experimental research on slag splashing was carried out. The effects of top blowing parameters, bottom stirring parameters, slag properties and lance structure on slag splashing are discussed. The optimum slag amount is 11% under the experimental conditions investigated. The secondary nozzles of the lance have a detrimental effect on slag splashing. The nozzle angle of the lance has a significant effect: the 12° lance obviously achieves much better results than the 14·5° lance. Bottom stirring is not only beneficial, but also can effectively control overslag of the furnace bottom and increase the life of bottom tuyeres. It is also advantageous to increase the bottom stirring gas flow appropriately. When the optimum lance height from the physical model is applied in plant, the lance height must be modified. The modification factor is 0·85-0·95. The modification factor should be smaller for higher viscosity slag and greater for lower viscosity slag. There is a gestation time for slag splashing. In the gestation time, the temperature of the slag is decreased and the viscosity of the slag is increased; at the same time, the slag foams dramatically. The gestation time is 1/4-1/2 of the total slag splashing time. The results of the physical model have already been applied to plant operation. At Steelmaking Plant no. 3 of An-Shan Iron and Steel Group Corp., slag splashing has increased the average lining life of a converter from 1472 to 8915 heats, and steel yield has risen from 3·13 to 4·00 Mton/year with an annual economic benefit of about US$3·4. This would provide a theoretical basis for the extension and application of slag splashing.
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