The relining of the new blast furnace 4 at the Donawitz site will result in many improvements over the next eight to ten years.
Production wears down the refractory material that lines a blast furnace and the deformed hearth has to be replaced or relined every eight to ten years. The blast furnace that was relined in the summer of 2012 was in operation from October 5, 2002 until July 1, 2012, and smelted around 6 million tons of pig iron during this period – the highest production volume during a furnace campaign ever reached at the Donawitz site. A furnace campaign is the time a blast furnace is in operation between relinings.
The relining of blast furnace 4 was accompanied by several technological innovations: The new bell-less top saves on reducing agents (= lowers the coke consumption). This means significantly less carbon dioxide production, which is better for the environment. The refractory material in the lower area of the hearth was also improved. The latest, highly thermally conductive materials were used. This is expected to bring a major improvement that will extend the furnace campaign. A new drilling and tufting machine was also installed. This machine has higher contact pressures, is more ergonomic to use and easier to maintain. The newly relined hot-blast stove with a state-of-the-art lining helps further reduce carbon dioxide emissions.