Technical Paper
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Block surrounding tuyere
Ceramic wall
Carbon block
Ramming mix Figure 2: Saint-Gobain’s Ceramic Cup hearth design
• Chemical reactions and corrosion/erosion between refractory materials and melting iron and slags liquids.
• Thermo-mechanical stresses.
Inside the hearth, the fluid flow alone may cause wear to the refractory lining but a combination of this with particles abrasion and thermal stresses may cause inescapably more significant wear which could decrease drastically the campaign life [4].
In this paper, ceramic cup performances designed with both qualities (Coranit or Coranit Al) will be discussed through several examples:
• ArcelorMittal blast furnace number 4 in Dunkerque. • ArcelorMittal blast furnaces number 1 and 2 in Fos-sur-Mer. • ThyssenKrupp Steel Europe blast furnace number 2 in Duisburg.
For these blast furnaces, real field data were gathered and analysed to investigate the ceramic cup wear evolution throughout the BF campaign. Indeed, the global refractory wall wear is mapped thanks to the different sensors positioned on several blast furnace cross-sections.
The aim is to assess and better understand how the refractory lining wear profile has evolved over time in order to increase our knowledge and identify the next line of development for our forthcoming innovation strategy (quality material and hearth design).
METHODOLOGY USED TO COLLECT DATA DURING BF OPERATING
Hearth lining materials
All the blast furnaces studied are built with a Ceramic Cup design made up of several refractory layers (Figure 2):
- The ceramic bottom consisting of an upper layer of white ceramic materials, enjoying a high resistance to mechanical wear,
crack
occurrence and optimal jointing to limit liquid iron penetration/ solidification inside the lining while at the same time avoiding too high thermo-mechanical load.
- The tap-hole area, a critical zone where no clear philosophy for lining optimization on the material quality or design (brick, block, monolithics…) has emerged so far [5].
- The global refractory wall is designed with five different types of materials:
• A sacrificial layer of low quality brick generally made of fireclay, used to avoid significant thermal shock during start-up and the very first contact with molten iron.
• The ceramic wall made of Sialon bonded corundum bricks resistant to molten iron and slag and protecting the carbon behind from dissolution. Moreover, the 800°C-900°C isotherm is moved inside the ceramic, helping the cup extend the hearth lifetime [6]. Acting as
20 ENGINEER THE REFRACTORIES July 2017 Issue
Ceramic pad
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