Technical Paper
formation, but also reducing risk of matrix washout. 2.5 – CMA application in fired carbon-free bricks
Like in alumina-spinel ladle castables also in alumina-spinel bricks the advantage of a CMA-addition was observed. A pressed alumina-spinel brick with a small addition of CMA showed superior performance in a ladle for clean steel production.
Another application field are Magnesia-Spinel bricks for rotary kilns for Portland cement production. Here, a coating on the brick surface is also key to maximize the service life of the bricks. Adding CMA to a M-MA brick can result in a small amount of in-situ formed high viscous liquid that can form at the brick surface by reaction with the kiln feed and impurities from fuels and alternative energy sources. Inside the brick CMA has the potential to form a small amount of liquid in the matrix that can absorb stress maxima and reduce risk of crack formation and propagation.
3 – SUMMARY
Fig. 19: Steel ladle slag zone with MgO-C bricks without (top) and with MagArmour addition (bottom)
Calcium Magnesium Aluminate, either introduced as binder into monolithics and/or as aggregate or additive to monolithics and bricks has shown multiple positive performance aspects in a large range of products and applications. In monolithics a CMA-based bond results in higher corrosion and penetration resistance. Applied as aggregates in monolithics a lower material requirement for a given lining design can be achieved. Added in small quantities to carbon bonded bricks for steel ladles and to bricks for OPC kilns, a protective surface layer can form in-situ.
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Fig. 20: Steel ladle metal zone with MgO-C bricks without (left) and with MagArmour (right)
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