| abstract |
The invention relates to a molten cast refractory product comprising, in weight percentages on the basis of the oxides and relative to a total of 100% of the oxides:n ZrO 2 +Hf 2 O is the remainder making up 100%, 4.5%<SiO 2 <6.0%, 0.80%≦Al 2 O 3 <1.10%, 0.3%<B 2 O 3 <1.5%, Ta 2 O 5 +Nb 2 O 5 <0.15%, Na 2 O+K 2 O<0.1%, K 2 O<0.04%, CaO+SrO+MgO+ZnO+BaO<0.4%, P 2 O 5 <0.05%, Fe 2 O 3 +TiO 2 <0.55%, and other oxide species <1.5%,n nthe “A/B” ratio of the Al 2 O 3 /B 2 O 3 contents by weight being between 0.75 and 1.6. The invention can be applied to glass melting furnaces. |