Effect of Gahnite on Properties of High Alumina Castable.

In this paper, gahnite (ZnAl₂ O₄) was prepared with solid phase reaction by ZnO and Al₂ O₃ as raw materials. The micro-structure change of ZnAl2 O4 was researched when ZnO/Al₂ O₃ molar ratios were 1.0 : 0. 9, 1.0 : 1.0 and 1.0: 1.1, respectively. In addition, the effect of ZnAl₂ O₄ on properties of high alumina castables were studied. The results show that when the molar ratio of ZnO to Al₂ O₃ is 1.0: 0.9, due to the excessive ZnO, it volatilizes because of the removal of O^2- to produce liquid phase, and the surface of ZnAl₂ O₄ particles is microporous structure. When the molar ratio of ZnO and Al₂ O₃ is 1.0: 1.0 (standard molar ratio), the surface of ZnAl₂ O₄ particles with standard molar ratio is smooth. The lattice strain value (0.085 86) of standard molar ratio ZnAl₂ O₄ is the smallest, which can capture more manganese ions and iron ions in steel slag. When the molar ratio of ZnO to Al₂ O₃ is 1.0: 1.1, the surface of ZnAl₂ O₄ particles is rough. The high alumina castable with standard molar ratio ZnAl₂ O₄ has denser structure, highest strength and best slag resistance. [ABSTRACT FROM AUTHOR]