Analysis of reasons for abnormal increase of hearth sidewall temperature of Jingtang No.2 blast furnace

The operation state of the hearth plays a critical role in the long service life of blast furnace. The abnormal temperature rise of the hearth sidewall of Shougang Jingtang No.2 blast furnace burst out from August 2017, which formed a threat to the normal production of blast furnace and operators′safety. The position coordinates of high-temperature points at hearth sidewall indicated that the direct cause of the abnormal temperature rise was the physical scour and chemical erosion resulted from the sharp circumferential flow of hot metal. The root of the abnormal temperature rise was explored further from the hot metal composition, the bottom temperature of blast furnace, tap hole depth and flow rate of hot metal, etc. The results showed that the deteriorating hearth activity was the primary cause. In addition, the high sulphur load and coke ash content, low final slag basicity and damaged cooling staves also made some contribution to the deteriorating hearth activity.