| 摘要 |
PURPOSE:To make cluster strength zero and achieve higher productivity by setting the horizontal radius of the furnace body after the intermediate region of reducibility 50% or more within the specified range in the shaft furnace which reduces iron ore at temperatures above 900 deg.C. CONSTITUTION:In the shaft furnace which reduces iron ore at a high temperature above 900 deg.C at which clutsering becomes of problem, the horizontal radius R(cm) of the furnace body after the intermediate region of reducibility 50% or more is set within the range shown by the formula (T; reducing gas blowing temperature deg.C). For example, the double cylindrical shaft furnace 1 is constituted by the double cylinders of an inner barrel 2 of 30m in overall height and 7.6m in diameter and an outer barrel 3 of a diameter 10m and the piling pressure in the hydraulic radius R1.2m, 50-70% reduction region becomes about 1kg/cm<2> or less. As a result of this, if the pressure in the furnace is maintained at 1kg/cm<2> or less, the shrinkage rate of iron ore may be kept within about 15% and the strength of cluster is made substantially zero, whereby the phenomena such as hanging are eliminated. |
