Saint-gobain Centre De Recherches Et D'etudes Europeen

Ludovic Massard

Michel Gaubil

Isabelle Cabodi

The invention relates to a process for manufacturing a refractory product, comprising the following successive steps: a) mixing of raw materials so as to form a suitable feedstock so that the block obtained in step d) comprises more than 85% of ZrO, b) melting of said feedstock until a molten material is obtained, c) optionally, casting said molten material, d) cooling of the molten material to solidification in the form of a block, e) optionally, heat treatment, process comprising a compression operation in which a compression pressure of greater than 0.2 MPa is applied to at least one portion of the outer surface of the block obtained in step d), the compression operation beginning at a temperature above the temperature at which, in said block, tetragonal zirconia is converted to monoclinic zirconia or 'phase transformation temperature', and ending at a temperature below said phase transformation temperature.

Refractory product having a high content of zirconia

Fused cast refractory product comprising in percentages by weight on the basis of the oxides and for a total of 100%, &#x2014;ZrO; balance to 100%, &#x2014;HfO: &#x3c;5% SiO: 2% to 10%; &#x2014;YO: 0.4% to 2.0%; &#x2014;CaO: 4.0% to 8.0%; &#x2014;BO+NaO+KO: 0.4% to 3.0% &#x2014;AlO: 0.3% to 2.0%; &#x2014;PO: &#x3c;0.05%; &#x2014;FeO+TiO: &#x3c;0.55%; &#x2014;other species: &#x3c;1.5%. Application in glass melting furnaces.

A fused refractory product having the following average chemical composition, in % by weight on the basis of oxides and for a total of 100%: ZrO: 30-50%; SiO: 8-16%; AlO: balance to 100%; YO&#x2267;50/ZrOand YO&#x2266;5%; NaO+KO+BO&#x2267;0.2% and SiO/(NaO+KO+BO)&#x2267;5&#xd7;YO; CaO: &#x2266;0.5%; and other oxide species: &#x2266;1.5%.

Refractory block and glass furnace

A fused and cast refractory product containing, in weight percentages on the basis of the oxides and for a total of 100%:

Refractory product having high zirconia content

Fused and cast refractory product including on oxides basis in percent by weight and for a total of 100%: ZrO+HfOcomplement to 100%; 3.5% to 6.0% SiO; 0.7% to 1.5% AlO; 0.10% to 0.43% NaO+KO; 0.05% to 0.80% BO; less than 0.4% CaO+SrO+MgO+ZnO; less than 0.05% PO; less than 0.55% FeO+TiO; less than 1.5% other species. The ratio of percentages by weight of AlO/(NaO+KO) being greater than or equal to 3.5 and the ratio of percentages by weight of BO/(NaO+KO) being between 0.3 and 2.5.

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Monteux, France

Ludovic Massard