关键词: 预合成CaZrO₃, 镁锆质耐火材料, CeO₂, 烧结性能, 抗渣性, 抗热震性

Abstract: In order to improve the properties of magnesia-zirconia refractories,the pre-synthesized CaZrO₃ (≤ 0.074 mm) with different CeO₂ extra-additions (0,1% and 2%,by mass) was firstly prepared using calcium carbonate,desilicated zirconia and CeO₂ as raw materials.Then,the pre-synthesized CaZrO₃ was mixed with fused magnesia (3-1,1-0.074 and ≤0.074 mm),and pressed into cylindrical and strip specimens under 250 MPa.The magnesia-zirconia refractories were prepared by heat treatment at 1 600 ℃ for 3 h.The effects of the pre-synthesized CaZrO₃ powder addition (10%,15% and 20%,by mass) on the properties of the materials were studied.The results show that:(1)a certain amount of CeO₂ forms a solid solution with ZrO₂,which makes ZrO₂ exist in the form of t-ZrO₂ at room temperature,stabilizes the crystal form of ZrO₂,and promotes the formation of CaZrO₃;(2)CeO₂ promotes sintering and is conducive to densification;the microcrack toughening caused by the difference on the thermal expansion coefficient between CaZrO₃,ZrO₂ and periclase improves the thermal shock resistance;the composite spinel and CaZrO₃ formed by the specimens and RH slag block pores and improve the slag resistance;(3)when adding 20% of the pre-synthesized CaZrO₃ with 1% CeO₂,the specimen has the optimal performance.

Key words: pre-synthesized CaZrO₃, magnesia-zirconia refractories, CeO₂, sintering properties, slag resistance, thermal shock resistance