| 摘要 |
PROBLEM TO BE SOLVED: To improve the wear resistance, namely hot strength, of a burned magnesia-chrome brick mainly used in an AOD oven by adding fine Al2 O3 powder having a specific average particle diameter or smaller to a semi- rebonded type magnesia-chrome brick containing electrofused magnesia-chrome clinker in a specific amount. SOLUTION: The Al2 O3 component most increases its strength among additives added to the semi-rebonded type magnesia-chrome brick consisting mainly of the electrofused magnesia-chrome clinker. Since the Al2 O3 component easily forms a low melting point compound together with CaO component contained in a slag, an effect by the addition of a slight amount of the Al2 O3 component is necessary, and the hot flexural strength increases with the increase of the addition amount. The peak addition amounts of the additives are however different each other in response to burning conditions and the reactions of the additives with other components in the brick, and the smaller the diameter of each additive is, in the smaller amount the effect is obtained. The fine Al2 O3 powder having an average particle diameter of <=5 μm is added in an amount of 1-5 wt.% to the semi-rebonded type magnesia-chrome brick containing >=60 wt.% of the electrofused magnesia-chrome clinker. |
