Salzgitter Flachstahl GmbH, Salzgitter, Germany:

Pethke J., Dr. Eng., General Manager, Ironmaking Work

Mirkovic T., Dr. Eng., Head of Blast Furnace B Ironmaking

Hille V., Dr. Eng., Head of Projectmanagement Ironmaking

Paul Wurth Refractory & Engineering GmbH, Mainz Kastel, Germany:

Hebel R., Mag. Eng., Concultant, rudolf.hebel@paulwurth.com

The current campaign of Salzgitter Flachstahl’s blast furnace B (BF-B) started in 2004. One year later, blast furnace A was refurbished. The hearth of BF-B was relined with small, hot pressed carbon bricks, while the hearth of BF-A was bricked with large carbon blocks glued together. The goal of this new composite lining method is to avoid or at least substantially to reduce the brittle zone that forms in the carbon blocks of the hearth. During the current campaign, the hearth lining of BF-B, consisted of mortared, small, hot-pressed carbon bricks formed a natural protective skull. The interim report describes different wear progress mechanisms of the heart lining and focuses on certain aspects relative to lining design and progress of refractory wear as observed during the time of low hot metal production, mandated by the 2008–2009 recession. The following shall be noted after 5.5 and 6.5 years of operation of the blast furnaces A and B, respectively: (a) blast furnace B has very little wear in the undisturbed hearth area; (b) blast furnace B shows premature wear in both reinforced tap hole zones; (c) blast furnace A shows to date less wear in the hearth than predicted; (d) both furnaces are approaching the ideal bowl shape wear pattern; (e) over a period of three years, heat resistance measurements and computations at blast furnace B revealed the necessity to apply grouting procedures to the hearth wall in order to re-establish physical contact between the small, mortared carbon bricks and the furnace shell; (f) significant heat flux changes were observed in the individual bottom and hearth measuring sections of both furnaces; (g) a remarkable correlation between slag run-time and hearth wall temperature exists, there is a clear dependency between both parameters.