Spinel Formation in Coreless Induction Furnace Linings


Spinel-forming refractories reduce penetration of metal and slags through a tightening of the lining resulting from the volume expansion associated with spinel formation. Sintered spinel is often added to reduce the overall volume increase that results. Tests were carried out to evaluate the difference in performance between spinel-forming and spinel-containing refractory mixes. Eight refractory linings, one pure magnesia three magnesia-base spinel-forming and four alumina-base spinel-containing dry vibratable mixes, were tested for 4 h in contact with a low-carbon, low-manganese steel in a coreless induction furnace at temperatures > 1600 C. Sample wear and penetration were then measured. For MgO-based mixes, wear was minimised using 20-30 wt% spinel formation, although further experiments are required to determine the optimal value. For Al2O3-based mixes, there appears to be an optimal ratio of spinel added to the spinel formed that minimised penetration and wear at the slag line. Sidewall accretion occurred, and the accretion was the highest for the mix with a ratio of spinel formed to spinel added near the optimum value. Therefore, to design an optimum refractory mix, the benefits of higher ratios of spinel added to reduce penetration and wear at the slag line will need to be balanced with the tendency to form accretions on the sidewalls of the furnace.


Materials Science and Engineering

Research Center/Lab(s)

Peaslee Steel Manufacturing Research Center

Keywords and Phrases

Aluminous Refractories; Coreless Induction Furnaces; Iron and Steel Making; Magnesite Refractories; Ultrasonic Testing

Document Type

Article - Conference proceedings

Document Version


File Type





© 2004 Canadian Institute of Mining, Metallurgy, and Petroleum, All rights reserved.

Publication Date

01 Aug 2004

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