Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B3/00—Charging the melting furnaces
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B3/00—Charging the melting furnaces
  • C03B3/02—Charging the melting furnaces combined with preheating, premelting or pretreating the glass-making ingredients, pellets or cullet
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C1/00—Ingredients generally applicable to manufacture of glasses, glazes, or vitreous enamels
  • C03C1/02—Pretreated ingredients
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
  • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
  • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
  • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
  • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
  • C03C3/087—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal containing calcium oxide, e.g. common sheet or container glass
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
  • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
  • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium

Definitions

• the present invention relates to a method for producing a molten glass and a method for producing a glass article, in particular, a method for producing an aluminosilicate glass and a method for producing a glass article.
• alkali aluminosilicate glass is used for a cover glass of a liquid crystal display device or the like because strength is required.
• such glass is required to have high chemical resistance and durability, low bubbles in the glass, high homogeneity, and high flatness, but the above-mentioned quality in the production of alkali aluminosilicate glass Is known to be more difficult than in the production of soda lime glass.
• the glass melting step it is possible to improve the quality of glass articles and improve productivity by dissolving silica sand, which is the least soluble in the glass raw material composition, into the molten glass uniformly and quickly. It is important.
• a suspended matter layer (so-called scum layer or bubble layer) may be formed on the molten glass liquid surface due to a dissolution delay due to a difference in solubility of oxides contained in the glass raw material composition. is there.
• the “floating material layer” is mainly composed of heterogeneous molten glass and bubbles, but the specific gravity of the heterogeneous molten glass is lower than that of the molten glass and its viscosity is high. A floating layer is formed on the surface layer.
• the molten glass located under the float layer is used to inhibit heat input from the upper combustion space, which is a heat source for melting the glass raw material composition.
• the temperature rise is insufficient, and a time difference occurs between the melting of the glass material that is difficult to melt and the glass material that is easily melted.
• a time difference occurs in melting, that is, when melting delay occurs in a part of the glass raw material, it becomes easier to form a heterogeneous molten glass having a specific gravity different from the composition of the target glass article, and is included in the glass raw material powder.
• the present invention has been made in view of the above circumstances, and by reducing the melting delay of the glass raw material and reducing the formation of a suspended layer on the surface of the molten glass in the melting furnace, it has excellent homogeneity and is contained in the glass. It aims at providing the manufacturing method of the molten glass which can manufacture efficiently the glass article with few bubbles, and the manufacturing method of a glass article.
• the present inventors investigated and examined the suspended matter layer formed on the molten glass liquid surface, and found that not only undissolved silica sand but also a large amount of undissolved aluminum oxide remained. Furthermore, the present inventors have found that by using silica sand having a large particle size distribution and using aluminum oxide having a specific particle structure, it is possible to simultaneously reduce the dissolution delay of silica sand and aluminum oxide.
• the glass component is represented by an oxide such as SiO 2 or Al 2 O 3 .
• the content (glass composition) of each component with respect to the entire glass is expressed as a mole percentage based on the oxide.
• a method for producing a molten glass having the following glass composition by melting a glass raw material composition containing silica sand, aluminum oxide and an alkali metal source, wherein the silica sand has a D90 of 450 ⁇ m or more and 600 ⁇ m or less, and The difference between D90 and D10 is 350 ⁇ m or more, and the aluminum oxide has a D90 of 200 ⁇ m or less and a pore volume distribution in the pore diameter range of 0.004 to 5 ⁇ m as measured by mercury porosimetry with a pore diameter of 0.00.
• a method for producing molten glass wherein the volume ratio of 1 to 5 ⁇ m is 60% or more.
• a volume ratio of the pore diameter of 0.1 to 5 ⁇ m of the aluminum oxide is 70% or more.
• Glass composition (oxide basis): SiO 2 content 50-75 mol%, Al 2 O 3 content 5-20 mol%, B 2 O 3 content 0-20 mol%, Li 2
• the total content of O, Na 2 O, and K 2 O is 5 to 25 mol%, and the total content of MgO, CaO, SrO, and BaO is 0 to 20 mol%.
• the melting delay of the glass raw material can be reduced, and the formation of a floating layer on the surface of the molten glass in the melting furnace can be reduced.
• the method for producing a glass article of the present invention it is possible to efficiently produce a glass article with reduced melting delay of the glass raw material, excellent homogeneity, and few bubbles in the glass.
• the “particle diameter”, “pore volume distribution of aluminum oxide by mercury intrusion method”, and “ratio of the solid area of aluminum oxide” are measured as follows.
• D50 is an average particle diameter represented by a 50% diameter in the integrated fraction.
• D50 of the glass raw material is a 50% diameter in a volume-based integrated fraction obtained by measuring the particle diameter by a laser diffraction method.
• D90 is a 90% diameter in a volume-based integrated fraction obtained by particle diameter measurement by a laser diffraction method.
• D10 is a 10% diameter in a volume-based integrated fraction obtained by particle diameter measurement by a laser diffraction method.
• the ratio of the integrated value of the pore volume in the range of the pore diameter of 0.1 to 5 ⁇ m to the integrated value of the pore volume in the range of the pore diameter of 0.004 to 5 ⁇ m was determined, and “the pore diameter of 0.1 to The ratio of the volume of 5 ⁇ m ”.
• Sample amount about 0.3 to 0.4 g.
• Pretreatment Heat treatment at 150 ° C. for 1 hour in a dryer.
• Mercury contact angle 140 deg.
• Mercury surface tension 480 dyn / cm.
• a reflection electron image of aluminum oxide is taken with an electron probe microanalyzer (EPMA).
• EPMA electron probe microanalyzer
• a square or rectangle that is inscribed in the particle image and that has the largest area is defined as an area measurement area.
• the area measurement area is image-processed to obtain a binary image.
• the ratio of the area of the high-luminance region (white portion) in the area measurement area to the area (100%) of the area measurement area is obtained and is defined as “solid area ratio (unit:%)”.
• “Ratio of solid part area” is obtained for 100 randomly selected particles, and the average value obtained by dividing the total by 100 is referred to as “average value of solid part area ratio (unit:%)”. To do. Further, a particle having a “solid portion area ratio” of 70% or less is referred to as a “particle including a non-solid portion”. “Ratio of solid part area” is obtained for 100 randomly selected particles, and the percentage of “particles containing non-solid part” out of the 100 particles is “including non-solid part”. Particle ratio (unit:%) ”. [Photographing conditions of reflected electron image by EPMA] Voltage: 15 kV. Current: 9.2 nA. Contrast: 3200. Brightness: 30-40. Process time: 6.55 seconds.
• Image size 1280 ⁇ 960 pixels. Magnification: 500 times.
• Image processing software WinRoof Ver. 6.1.
• Binarization processing Automatic binarization processing by the peak valley method. Threshold: 31-255.
• Area for measuring the area of the high-luminance region a square or rectangle that is inscribed in one particle and has the maximum area.
• the method for producing molten glass of the present invention is a method for producing a molten glass having a specific glass composition by melting a glass raw material composition containing a silicon source, an aluminum source and an alkali metal source.
• the silicon source is a compound that becomes SiO 2 upon melting.
• the aluminum source is a compound that becomes Al 2 O 3 by melting.
• the silicon source includes silica sand, and the aluminum source includes aluminum oxide.
• D90 is 450 ⁇ m or more and 600 ⁇ m or less, and the difference between D90 and D10 is 350 ⁇ m or more. That is, the silica sand contains large particles having a particle diameter of 450 ⁇ m or more and has a wide particle size distribution. By using the silica sand having such a particle size distribution, the melting delay of the glass raw material composition at the time of melting can be reduced well.
• D90 is preferably 470 ⁇ m or more, and more preferably 490 ⁇ m or more.
• the upper limit of D90 is preferably 550 ⁇ m or less, and more preferably 500 ⁇ m or less in terms of reducing the melting delay of silica sand.
• D10 is preferably 90 ⁇ m or less, and more preferably 80 ⁇ m or less.
• the difference between D90 and D10 of silica sand is more preferably 400 ⁇ m or more, and further preferably 420 ⁇ m or more. In this invention, you may use 1 or more types of well-known silicon sources other than silica sand in the range which does not impair the effect of this invention.
• the aluminum oxide in the glass raw material composition satisfies the following (a). Further, in addition to (a), the following (b) or (c) is preferably satisfied. However, in aluminum oxide, what satisfies the following (a) usually satisfies both the following (b) and the following (c).
• the following (a) represents the particle structure of the aluminum oxide used in the present invention in terms of pore distribution, and the following (b) and (c) represent the particle structure as a feature in the reflected electron image of the particle. It is.
• D90 is 200 micrometers or less, and the average value of the ratio of the solid area in the binary image of the reflected electron image of particles is 70% or less.
• the ratio (number%) of “particles containing non-solid parts” whose D90 is 200 ⁇ m or less and the ratio of the solid part area in the binary image of the reflected electron image of the particles is 70% or less. ) Is 70% or more.
• D90 of aluminum oxide is preferably 150 ⁇ m or less, more preferably 100 ⁇ m or less, further preferably 90 ⁇ m or less, and particularly preferably 85 ⁇ m or less. In this invention, you may use 1 or more types of well-known aluminum sources other than an aluminum oxide in the range which does not impair the effect of this invention.
• the volume ratio of the pore diameter of 0.1 to 5 ⁇ m is preferably 70% or more, more preferably 80% or more, and still more preferably 90% or more, because the dissolution delay of aluminum oxide is reduced.
• the average value of the ratio of the solid part area of the aluminum oxide particles is preferably 60% or less, more preferably 50% or less, and more preferably 45% or less because the dissolution delay of aluminum oxide is reduced. Further preferred.
• the lower limit of the average value of the ratio of the solid part area can be set as appropriate, but the volume (volume) of aluminum oxide increases as the ratio of the solid part decreases. For this reason, it is preferable to set it as the range which can be conveyed with respect to the target glass composition and can supply easily. Practically, 15% or more is preferable, and 20% or more is more preferable.
• the ratio (number%) of the “particles containing non-solid parts” to aluminum oxide is more preferably 90% or more. Moreover, all the aluminum oxides except the aluminum oxide inevitably contained in other raw materials may be “particles containing non-solid portions”.
• the alkali metal in the present invention refers to Na, K, and Li.
• the alkali metal source is a compound that becomes Na 2 O, K 2 O, Li 2 O by melting.
• Examples of the alkali metal source include alkali metal carbonates, sulfates, nitrates, oxides, hydroxides, chlorides, and fluorides. These may be used alone or in combination of two or more.
• the particle diameter is not specifically limited, A well-known alkali metal source can be used.
• alkali metal carbonates are preferably sodium carbonate, potassium carbonate, lithium carbonate and the like, and sodium carbonate (soda ash) is particularly suitable in terms of ease of handling.
• the glass raw material composition can contain an alkaline earth metal source in addition to the above components.
• the alkaline earth metal in this specification refers to Mg, Ca, Ba, and Sr.
• the alkaline earth metal source is a compound that forms MgO, CaO, BaO, SrO by melting.
• Examples of the alkaline earth metal source include carbonates, sulfates, nitrates, oxides, hydroxides, chlorides, and fluorides of alkaline earth metals. These may be used alone or in combination of two or more.
• the particle diameter is not particularly limited, and a known alkaline earth metal source can be used. Also, composite carbonates such as dolomite and composite oxides such as calcined dolomite can be used.
• the glass raw material composition may contain a boron source.
• boron source examples include boric acid, boric oxide (B 2 O 3 ), and colemanite. These may be used alone or in combination of two or more.
• boric acid examples include orthoboric acid (H 3 BO 3 ), metaboric acid (HBO 2 ), and tetraboric acid (H 2 B 4 O 7 ).
• the glass raw material composition can contain compounds other than those known as glass raw materials as long as the effects of the present invention are not impaired.
• Examples of the compound other than the above include tin oxide, titanium oxide, zirconium oxide, zircon, cerium oxide, antimony oxide, iron oxide, cobalt oxide, chromium oxide, copper oxide, nickel oxide and the like. These may be used alone or in combination of two or more.
• a glass raw material composition is prepared by mixing glass raw materials such as a silicon source, an aluminum source and an alkali metal source so as to obtain a target glass composition.
• the glass composition of the glass raw material composition is adjusted so as to be substantially the same as the glass composition of the target molten glass, in terms of oxides, except for components that are easily volatilized during melting.
• the glass composition of the molten glass is the same as the glass composition of the glass article obtained by molding the molten glass. Moreover, you may mix the clarifier and the oxide which has a clarification effect
• the glass composition (on oxide basis) of the molten glass in the present invention has a SiO 2 content of 50 mol% or more, an Al 2 O 3 content of 5 mol% or more, and Li 2 O, Na 2 O, K 2.
• the total content of O is 5 mol% or more, and the total of these is 60 to 100 mol%.
• the ratio of silica sand / aluminum oxide in the glass raw material is preferably 2.5 or more, and more preferably 4 or more, in order to prevent undissolved aluminum oxide. Moreover, 15 or less are preferable and 12 or less are more preferable when preventing the undissolved residue of silica sand.
• the glass raw material composition can further contain at least one of boric acid and ZrO 2 in addition to silica sand, aluminum oxide, and an alkali metal source.
• a glass composition containing boric acid or ZrO 2 having a melting point greatly different from that of silica or alumina, for example, alkali aluminosilicate glass can prevent melting delay of raw materials and form a uniform molten glass.
• compositions (1) to (4) may be mentioned as preferred glass compositions (100 mol% in total) of the molten glass.
• Composition (1) 50 to 75 mol% of SiO 2 , 5 to 20 mol% of Al 2 O 3 , 0 to 20 mol% of B 2 O 3 , Li 2 O, Na 2 O, K 2 O 5 to 25 mol%, and the total of MgO, CaO, SrO and BaO is 0 to 20 mol%.
• Composition (2) 50 to 75 mol% of SiO 2 , 5 to 20 mol% of Al 2 O 3 , total of 5 to 25 mol% of Li 2 O, Na 2 O, K 2 O, MgO, CaO, SrO , BaO is 0 to 20 mol%, ZrO 2 , TiO 2 is 0 to 5 mol%, Fe 2 O 3 is 0 to 5 mol%, and Co 3 O 4 is 0 to 0 mol%. 5 mol%.
• Composition (3) SiO 2 is 50 to 75 mol%, Al 2 O 3 is 5 to 20 mol%, the total of Li 2 O, Na 2 O, and K 2 O is 5 to 25 mol%, and B 2 O 3 is 1 to 20 mol%, and the total of MgO, CaO, SrO and BaO is 0 to 25 mol%.
• Composition (4) SiO 2 is 50 to 75 mol%, Al 2 O 3 is 5 to 20 mol%, the total of Li 2 O, Na 2 O, and K 2 O is 5 to 25 mol%, and B 2 O 3 is 1-15 mol%, and MgO, CaO, SrO, the sum of the BaO 0 to 15 mol%, ZrO 2, the total of TiO 2 is 0 to 5 mol%, the content of Fe 2 O 3 is 0 to 5 mol% And the content of Co 3 O 4 is 0 to 5 mol%.
• the content of B 2 O 3 is preferably 0 to 6 mol%, more preferably 6 to 10 mol%.
• the ZrO 2 content is preferably 0 to 2 mol%, more preferably 2 to 5 mol%.
• the following composition (6) is mentioned as a preferable composition in the case of further containing boric acid and optionally ZrO 2 .
• Composition (6) SiO 2 is 50 to 75 mol%, Al 2 O 3 is 5 to 20 mol%, the total of Li 2 O, Na 2 O, and K 2 O is 1 to 15 mol%, and B 2 O 3 is 1-15 mol%, and MgO, CaO, SrO, the sum of the BaO 0 to 15 mol%, ZrO 2, the total of TiO 2 is 0 to 5 mol%, the content of Fe 2 O 3 is 0 to 5 mol% And the content of Co 3 O 4 is 0 to 5 mol%.
• the melting step for carrying out the method for producing molten glass of the present invention can be performed by a known method.
• the glass raw material composition is charged into a melting furnace and melted.
• a suspended matter layer is formed on the molten glass liquid surface in the melting furnace due to the delayed melting of the glass raw material composition. Insufficient heating and uneven heating are likely to occur due to heat being blocked by the suspended matter layer. For this reason, the effect by improving the meltability of a glass raw material composition by applying this invention is large.
• the melting furnace is not particularly limited, and may be a batch type or a continuous type.
• a glass raw material composition and, if necessary, a cullet having the same glass composition as that of the target molten glass is continuously charged into a melting furnace and heated to about 1600 to 1700 ° C. to be melted.
• cullet is glass waste discharged
• the glass article manufacturing method of the present invention is a method of manufacturing a glass article using the molten glass manufacturing method of the present invention.
• the molten glass obtained in the above-described melting step is molded into a target shape in the molding step, and then slowly cooled in the slow cooling step as necessary.
• a glass article is obtained by post-processing by a well-known method, such as cutting and grinding
• polishing polishing
• silica sand having a large particle size distribution is used, and a pore volume distribution of 0.14 to 5 ⁇ m in pore volume distribution with a pore diameter of 0.004 to 5 ⁇ m.
• aluminum oxide having a particle structure in which the volume ratio of 5 ⁇ m is increased the melting delay of silica sand and aluminum oxide can be reduced in the melting process of the glass raw material composition.
• a silica structure having a large particle size distribution is used, and a particle structure in which the ratio of the solid area in the binary image of the reflected electron image of the particle is small
• the melting delay of silica sand and aluminum oxide can be reduced during the melting process of the glass raw material composition.
• the above-mentioned suspended matter layer is composed of heterogeneous molten glass and bubbles.
• the heterogeneous molten glass has a higher concentration of SiO 2 and Al 2 O 3 than the molten glass of the target composition, and is produced by the fact that silica sand and aluminum oxide are delayed in melting from the other raw material compositions in the melting process of the glass raw material composition. Further, the dissolution rate of silica sand and aluminum oxide in the heterogeneous molten glass is inferior to those in the molten glass having the target composition.
• the ratio of silica sand and aluminum oxide, which have been once melted, tends to increase in the heterogeneous molten glass, and the time required until the melted silica sand and aluminum oxide are completely melted is further increased.
• the silica sand and the alkali metal source react rapidly to produce a low melting point reactant (xSiO 2 -yA 2 O (A represents an alkali metal).
• X and y represent reaction ratios)
• silica sand having a large particle size distribution when silica sand having a large particle size distribution is used, silica sand having a large particle diameter is relatively difficult to react, so that the ratio (x / y) of SiO 2 in the reaction product (xSiO 2 -yA 2 O) can be controlled low. For this reason, while keeping the viscosity of the reactant low, the reactivity with the aluminum oxide can be kept high by keeping the ratio (y / x) of A 2 O in the reactant high. Since aluminum oxide having the above specific particle structure dissolves well in such a reaction product, it is considered that the dissolution delay of aluminum oxide can be reduced.
• the melting delay of the silica sand can also be reduced. In this way, by reducing the melting delay of both silica sand and aluminum oxide, it is possible to reduce the formation of heterogeneous molten glass and the aggregation of silica sand and aluminum oxide that has been delayed.
• ⁇ Crucible bottom temperature and suspended layer thickness measurement method evaluation of melting delay of glass raw material composition
• Silica sand, aluminum oxide, an alkali metal source, and other raw materials were prepared to obtain a glass raw material composition so as to obtain an alkali aluminosilicate glass having a predetermined glass composition.
• the prepared glass raw material composition and cullet were mixed at a predetermined ratio, put into a crucible, and melted in the crucible. The temperature at the bottom of the crucible during glass melting was measured, and the degree of melting delay of silica sand or alumina oxide was compared.
• an alumina crucible (product name: SSA-S, manufactured by Nikkato Corporation, inner diameter 240 mm, height 245 mm) was used.
• a melting furnace in order to reproduce the heating state of the upper combustion space in which the molten glass is heated from above in a continuous melting furnace, a two-chamber type equipped with an operational crucible holder is equipped with a heater at the top of each furnace chamber. The large electric furnace provided was used.
• the side and bottom of the crucible were covered with a heat insulating board having a thickness of 20 cm or more to block heat input from the side and bottom to the glass raw material composition in the crucible.
• the crucible bottom temperature was measured by the following procedure. First, the glass raw material composition and cullet were mixed at a predetermined ratio at room temperature and placed in a crucible. The total amount of the glass raw material composition and cullet was 2 kg in terms of glass mass.
• the crucible was accommodated in the first furnace chamber and heated under the above conditions, then transferred to the second furnace chamber, heated under the above conditions, and taken out from the second furnace chamber.
• the temperature of the outer surface of the bottom of the crucible was measured with a thermocouple, and the maximum temperature was recorded as the crucible bottom temperature.
• the higher the temperature at the bottom of the crucible the less the heat is blocked by the floating layer on the surface of the molten glass in the crucible, indicating that the temperature of the molten glass is efficiently increased by the heat from the heater.
• the crucible taken out from the second furnace chamber was gradually cooled to room temperature, and the molten glass in the crucible was solidified. After cooling and solidification, the side surface inside the crucible was observed, and the difference between the glass wet height and the glass surface height was recorded as the thickness of the suspended matter layer.
• Alkali metal source: Soda ash (1) (D50 400 ⁇ m).
• Magnesium source: Magnesium oxide (1) (D50 10 ⁇ m).
• Examples 1 and 2 are examples, and examples 3 to 5 are comparative examples.
• Silica sand, aluminum oxide, an alkali metal source, a magnesium source, and a fining agent shown in Table 3 were prepared so as to have the following glass composition (i) to obtain a glass raw material composition.
• the amount of fining agent added was 1.4 mol% with respect to the glass raw material composition.
• the crucible bottom temperature, the float layer thickness, and the number of bubbles were measured by the above method.
• the mass ratio of the glass raw material composition: cullet was 50:50. The results are shown in Table 3.
• the molar ratio of SiO 2 / Al 2 O 3 is 6.8.
• Examples 1 and 2 using silica sands A and B in which D90 is 450 ⁇ m or more and the difference between D90 and D10 is 350 ⁇ m or more have a crucible bottom temperature higher than those of Examples 3 to 5 using silica sands C to E. High, thin suspended layer thickness and few bubbles. It can be seen that the melting delay of the glass raw material has been reduced.
• Examples 6 to 8 are examples, and example 9 is a comparative example.
• Silica sand, aluminum oxide, an alkali metal source, a magnesium source, and a fining agent shown in Table 4 were prepared so as to have the glass composition (i), thereby obtaining a glass raw material composition.
• the amount of fining agent added is the same as in Example 1.
• the glass raw material composition of each example was evaluated for the melting delay of the glass raw material and the number of bubbles by the above-described method.
• the mass ratio of the glass raw material composition: cullet was 35:65. The results are shown in Table 4.
• the silica sand A is used, the D90 is 200 ⁇ m or less, the volume ratio of the pore diameter is 0.1 to 5 ⁇ m is 60% or more, and the average ratio of the solid area is 70% or less.
• Examples 6 to 8 using the alumina S to U used in this example use the alumina V in which the volume ratio of the pore diameter is 0.1 to 5 ⁇ m is 56% and the average ratio of the solid area is 75%.
• the bottom temperature of the crucible is high, the thickness of the suspended matter layer is thin, and the number of bubbles is small. It can be seen that the melting delay of the glass raw material has been reduced.
• the entire contents of the specification, claims and abstract of Japanese Patent Application No. 2016-221713 filed on Nov. 14, 2016 are incorporated herein as the disclosure of the specification of the present invention. It is.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Glass Compositions (AREA)
• Glass Melting And Manufacturing (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=62110684

Family Applications (1)

Country Status (5)

Families Citing this family (1)

Citations (5)

Family Cites Families (4)

• 2017
  • 2017-11-10 JP JP2018550272A patent/JP6981426B2/ja active Active
  • 2017-11-10 KR KR1020197013336A patent/KR102413987B1/ko active IP Right Grant
  • 2017-11-10 CN CN201780070329.7A patent/CN109952277B/zh active Active
  • 2017-11-10 WO PCT/JP2017/040513 patent/WO2018088503A1/ja active Application Filing
  • 2017-11-13 TW TW106139164A patent/TWI742195B/zh active

Patent Citations (5)

Also Published As

Similar Documents

Legal Events