Improvements in the operation of blast furnaces, particularly for the purpose of reducing the ore softening zone

摘要

700,508. Blast furnace processes. BESCH P. N. Sep. 15, 1950, No. 22713/50. Class 72 [Also in Group XII] The operation of blast furnaces is improved by insufflating, at the periphery and below the belly of the furnace, a fluid capable of reacting endothermically with the coke at a point where the ascending gas temperature is between 1520‹C. and 1580‹C. to form an endothermic peripheral screen so that the zone in which the materials become plastic is removed from the walls and an annular zone of a temperature below that at which the charge becomes plastic is formed,. The fluid may be carbon dioxide, limekiln gas, burnt gas from furnaces, water, water vapour, or steam. The insufflation tuyeres may be arranged in the bosh, but it is preferred to increase the height of the well and arrange the tuyeres below the small diameter of the bosh. As shown, the well g2 has at its upper end an inwardly sloping truncated portion h leading to a collar i of smaller diameter than the well and forming the lower end of the bosh, and the insufflating tuyeres are arranged in the planes b, c, d, e below the truncated portion. The plastic zone is shown at 1e. The temperature of the charge emerging from the peripheral thermal screen should be between 1000‹C. and 1050‹C.