Abstract: Al₂O₃-Cr₂O₃-ZrO₂ bricks are widely used as lining material in hazardous waste incinerators because of their excellent slag corrosion resistance. However, toxic water-soluble Cr(VI) may be formed during the preparation and service of Al₂O₃-Cr₂O₃-ZrO₂ bricks, and the related research work has not been reported. In present study, two kinds of Al₂O₃-Cr₂O₃-ZrO₂ bricks were prepared using monoclinic zirconia and zircon as zirconia sources. The corrosion behavior of the bricks in four kinds of hazardous waste incinerator slags and the content of Cr(VI) in the bricks before and after slag corrosion were studied. The results show that zircon decomposes into monoclinic zirconia and amorphous silica at high temperatures, which promotes the formation of highly chemical stable (Al,Cr)₂O₃ solid solution and improves the densification as well as corrosion resistance of the Al₂O₃-Cr₂O₃-ZrO₂ bricks. Furthermore, the formed silica can reduce Cr(VI) compound, which lowers the content of Cr(VI) in Al₂O₃-Cr₂O₃-ZrO₂ bricks. The content of Cr(VI) in the penetration layer of Al₂O₃-Cr₂O₃-ZrO₂ bricks is closely related to the composition of slag. There is higher Cr(VI) content in the penetration layer after being corroded by the slag with high alkaline oxide content, while Cr(VI) content in the origin and penetration layer of Al₂O₃-Cr₂O₃-ZrO₂ bricks with zircon is lower than the EU limit standard in the four kinds of slag.

Key words: Al₂O₃-Cr₂O₃-ZrO₂ brick, zircon, slag corrosion resistance, Cr(VI), Cr₂O₃ containing refractory