Estimation of Metal Flow in the Hearth and the Hearth Brick Protection Mechanism in Chiba No.6 Blast Furnace

摘要

Chiba No.6 blast furnace was blown out after theworld record of service life, twenty years and nine months.During the blowing out operation, tracer was injected from theNo.23 tuyere. Further, metal, coke and slag in the lower part ofthe furnace were gathered and analysed to investigate the metalflow at the hearth bottom, and the protection mechanism of thehearth brick. As a result, a stable solidified layer of hot metalformed during most of the operation period has played a keyrole to prevent the hearth brick wear. The formation of thesolidified layer is explained by the stagnant metal flow which iscaused by the "low permeability zone".