New Additive Package for Microsilica Gel-bonded MgO Castables

Hong Peng, Bjørn Myhre

Elkem Silicon Materials, 4675 Kristiansand/Norway


Volume 5, Issue 4, Pages 83 - 88


The use of high-performance basic refractory castables is essential in state-of-the-art steel-making and clean steel production. However, self-flowing magnesia castables have not been widely used until now. A major challenge is that during the hydration process brucite is formed which causes volume expansion and subsequent cracking. The objective of this paper is to present a new Elkem specialty product (SioxX-Mag), which has been developed for gel-bonded MgO castables based on MgO-SiO2-H2O bond. It contributes to better workability and setting behaviour while hot-properties remain unchanged. When SioxX-Mag replaces other dispersants in MgO castables, self-flow is more than doubled in our test system. Using SioxXMag, cracking caused by brucite formation is suppressed and crackfree dried samples are made. It is also observed that the explosion resistance during firing has been significantly improved making fast firing feasible.


MgO castables, additives, self-flowing, microsilica, gel-bond


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