Abstract: Based on the optimization of bottom tuyere configuration in water model experiment, asymmetric bottom tuyere configuration layout was used in the 100 t combined-blowing converter of Sanming Iron and Steel Co. Then, bottom blowing process and bottom tuyere maintenance were optimized for start-up, heating-up and whole campaign of the converter and maintenance modes of bottom tuyeres of the converter and bottom blowing intensity at different stages and different bottom thickness were determined. Influence of end-point temperature, converter life and bottom blowing intensity on [%C]•[%O] at end-point was investigated. The investigation results showed that [%C]•[%O] at end-point is between 0.002 63—0.002 72, on average 0.002 67, in the earlier stage of the converter campaign and at 1 620—1 635 ℃. Bottom lining thickness of the converter during whole campaign could be kept 600—750 mm, which ensured stirring effect of bottom gas and [%C]•[%O] at end-point was kept 0.002 6—0.003 0. [%C]•[%O] at end-point rose with increase in end-point temperature under the same bottom blowing, about 0.000 03 rising on each 10 ℃ up in temperature. Contents of carbon, phosphorus and sulfur decreased, while content of residual manganese increased, with increase in intensity of pure bottom post-stirring.

Key words: top and bottom combined blown converter, [%C]?[%O] at end-point, asymmetrical bottom tuyere configuration, bottom gas blowing mode, maintenance of bottom tuyeres