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JP-7857314-B2 - Refractory products containing high-content zirconia

JP7857314B2JP 7857314 B2JP7857314 B2JP 7857314B2JP-7857314-B2

Inventors

  • カボディ，イザベル
  • ベスパ，ピエリック

Assignees

  • サン－ゴバン サントル ド レシェルシュ エ デテュド ユーロペアン

Dates

Publication Date
20260512
Application Date
20220407
Priority Date
20210407

Claims (16)

  1. A molten cast refractory product, in terms of weight percentage relative to the oxide, with respect to a total of 100%, ZrO₂ : Amount to complete up to 100% HfO₂ : <5% SiO 2 : 8.0% to 11.0% Al 2 O 3 : 4.0% to 6.5% Na 2 O + K 2 O + B 2 O 3 : 0.40% to 1.30% B2O3 : < 0.60% Y2O3 : < 1.0% Fe2O3 + TiO2 : < 0.60% Other species: <1.0% Includes, Here, the SiO₂ /( Na₂O + K₂O + B₂O₃ ) ratio is 19.0 or less . The molten cast refractory product wherein the Al₂O₃ content is 5.1% or more, and the SiO₂ content is 8.5% or more.
  2. 83.0% < ZrO₂ + HfO₂ <88.0%; and/or, 8.4% < SiO₂ <10.6%; and/or, 3.9% < Al₂O₃ < 6.1%; and/or, Na₂O + K₂O + B₂O₃ ≤ 1.00 %; and/or, 0.40% < Na₂O + K₂O ; and/or, B2O3 < 0.50%; and/or, Y2O3 <0.40%; and / or, Fe₂O₃ + TiO₂ <0.40%; and / or, The SiO₂ /( Na₂O + K₂O + B₂O₃ ) ratio is between 10.0 and 19.0 . The fire-resistant product according to claim 1.
  3. 83.5% < ZrO₂ + HfO₂ <87.0%; and/or, 8.5% < SiO₂ <10.5%; and/or, 4.0% < Al₂O₃ < 6.0%; and/or, 0.50% < Na₂O + K₂O ; and/or, B2O3 < 0.45%; and/or, The SiO₂ /( Na₂O + K₂O + B₂O₃ ) ratio is between 12.0 and 18.0 . The fire-resistant product according to claim 2.
  4. The fire-resistant product according to claim 1 , wherein 8.5% ≤ SiO₂.
  5. In terms of weight percentage relative to the oxide, SiO 2 : 8.5% to 11.0% Al2O3 : 4.0 % to 6.0% Na 2 O + K 2 O: 0.50% to 1.00% B 2 O 3 : 0.00% to 0.40% A fire-resistant product according to claim 1 , including the above.
  6. In terms of weight percentage relative to the oxide, SiO 2 : 8.5 % to 10.5% Al 2 O 3 : 4.4% to 5.5% Na 2 O + K 2 O: 0.55% to 0.95% B 2 O 3 : 0.00% to 0.30% A fire-resistant product according to claim 5, including the above.
  7. A refractory product according to any one of claims 1 to 6 , wherein the SiO₂ / Al₂O₃ ratio is greater than 1.2 and less than 2.6, and/or the Al₂O₃ /( Na₂O + K₂O ) ratio is less than 8.5.
  8. A fire-resistant product according to any one of claims 1 to 6 , wherein Al₂O₃ < 5.1%.
  9. The SiO₂ content is less than 10% and greater than 8.1%, and The Al₂O₃ content is less than 5.0% and greater than 4.0%. The fire-resistant product according to claim 8.
  10. The SiO₂ content is less than 8.7% and greater than 8.3%, and The Al₂O₃ content is less than 4.7% and greater than 4.3%. The fire-resistant product according to claim 9.
  11. A refractory product according to any one of claims 1 to 6 , wherein Al₂O₃ ≥ 5.1 % and the SiO₂ / ( Na₂O + K₂O + B₂O₃ ) ratio is 10.0 or more.
  12. A refractory product according to any one of claims 1 to 6 , wherein the weight content of free corundum or corundum in the form of a corundum/zirconia eutectic is less than 5%.
  13. A glass furnace comprising a block made from a refractory product according to any one of claims 1 to 6 .
  14. The glass furnace according to claim 13, wherein the block is arranged in a tank and the weight content ratio of SiO₂ /( Na₂O + K₂O + B₂O₃ ) is greater than 10.0.
  15. The glass furnace according to claim 13, wherein the block is positioned within the throat.
  16. The glass furnace according to claim 13, wherein the total dimensions of all the blocks exceed 150 mm.

Description

This invention relates to cast refractory products having a high zirconia content, and to glass furnaces containing such products. Glass furnaces typically contain a very large number of refractory products, arranged in various locations according to their properties. For each component of the furnace, the selected product must be durable enough to withstand a sufficiently long service life for the furnace without causing defects that render the glass unusable (which could reduce production yield). Fire-resistant blocks are classified into cast blocks and sintered blocks. In contrast to sintered blocks, cast blocks generally contain intergranular glass phases that bind the crystal grains together. Therefore, the problems arising from sintered and cast blocks, and the technical solutions employed to address them, are generally different. Consequently, compositions developed to create sintered blocks cannot, a priori, be directly used to create cast blocks, and vice versa. Cast blocks are often referred to as "electroformed" or "molten-cast," and to obtain them, a mixture of suitable raw materials is melted in an arc furnace or by any other suitable technique. The molten material is then conventionally poured into a mold and subsequently solidified. Generally, the resulting product is then subjected to a controlled cooling cycle to return to room temperature without crushing. This operation is called "annealing" by those skilled in the art. Cast blocks with very high zirconia content (VHZC), generally containing over 80% or even over 85% by weight of zirconia, are known. These cast blocks have gained a reputation for their excellent corrosion resistance and their ability to produce glass without discoloration or causing defects in the glass. European Patent Application Publication No. 403387 describes a molten cast product having a high zirconia content, containing, by weight percentage, 4% to 5% SiO₂ , about 1 % Al₂O₃ , 0.3% sodium oxide, and less than 0.05% P₂O₅ . French Patent Application Publication No. 2932475 describes a molten cast product having a high zirconia content, comprising, by weight percentage, 3.5 to 6.0% SiO₂ , 0.7 to 1.5% Al₂O₃ , 0.05 to 0.80% boron oxide B₂O₃ , 0.10 to 0.43% Na₂O + K₂O , and less than 0.55% Fe₂O₃ + TiO₂ . Conventionally, products with very high zirconia content are distinguished from alumina-zirconia-silica (AZS) castings, which have higher alumina content and lower ZrO2 content. In particular, AZS products conventionally contain less than 80% by weight of zirconia. AZS products also generally contain more than 10% or 30% of corundum (free corundum or corundum in the form of a corundum/zirconia eutectic), a phase that is generally not present in the VHZC product. French Patent Application Publication No. 2024526 essentially describes an AZS product for use in glass furnace tanks, stating that for products with an Al₂O₃ content considerably higher than the SiO₂ content, an Al₂O₃ content lower than the SiO₂ content makes it possible to limit the formation of cracks and stone. Cast blocks with very high zirconia content, such as ER1195, manufactured and sold by SEFPRO, are widely used in glass furnaces today. However, the need for even better quality glass and longer service lives for the furnaces, which involves being subjected to increasingly harsh conditions, means that refractory products with increasingly higher resistance to molten glass are required. The need for these refractory products is particularly important for certain specific zones in glass furnaces, such as blocks for glass furnace throats. Throat blocks, in contrast to tank blocks, are subjected to a specific environment. The throat blocks are located at the exit of the molten zone in a zone where the furnace cross-section is considerably narrower. In this zone, the interface between the molten glass and the refractory product is also horizontal, and the glass is placed beneath the lintel of the throat. This interface is reinforced by the elements of the refractory product forming the throat block, thereby generally increasing its density, and therefore, due to the specific orientation of the refractory product in this zone, gravity-induced settling is exacerbated. In this zone, only the refractory product is in contact with the molten glass, and therefore, any bubbles will form at the glass/refractory product interface (not glass/atmosphere as in the case of the tank). The presence of a gas (bubble)-molten glass-refractory product triple point causes accelerated corrosion. This particular type of corrosion, which rises to the throat level, is called "upward drilling." Furthermore, this zone is typically cooled by a water circuit or by blowing in air. Therefore, the temperature at the glass/refractory interface differs from the tank temperature, which can lead to behavioral differences that affect the corrosion rate. Thus, the corrosion is not of the same nature. Existing AZS or VHZC products have insuffici