Super-clear alkali lime low-iron ultra-white float glass and its preparation process

Abstract

The application discloses a kind of super-transparency soda lime low-iron ultra-white float glass and its preparation process, belong to ultra-white float glass technical field.Its technical scheme is: including mix and broken glass, broken glass is 18-25% of the total mass of mix, mix includes the following weight percentage components: quartz sand 56-62%, alumina 1.5-3.5%, soda lime 3-6%, potassium feldspar 4-6%, calcite 4-6%, dolomite 6-8%, soda ash 13-16%, barium sulfate 0.5-1.5%, boric anhydride 0.15-0.35%, sodium sulfate 0.7-1%, sodium fluoride 1-2% and NaSb (OH) 6 0.5-2%.The ultra-white glass prepared by the application can be various deep processing like other high-quality float glass, has superior physical, mechanical, optical properties, has less apparent defect and high transparency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultra-white float glass, in particular to an ultra-transparent soda lime low-iron ultra-white float glass and a preparation process thereof. BACKGROUND

[0002] The ultra-white glass has the basic property of ultra-white transparency, is a new high-grade glass variety with high quality and multiple functions, and has higher transmittance than ordinary glass. The ultra-white glass has less impurities in raw materials, strict process control and fine process conditions in the preparation process, so that the ultra-white glass is more uniform than ordinary glass, has excellent physical, mechanical and optical properties beyond ordinary glass, and can be deep processed like ordinary glass. Due to high technical content and excellent quality, the ultra-white glass is often applied to high-end markets. Due to the ultra-high transmittance of the ultra-white glass, the ultra-white glass can be applied to high-end scientific and technological products, electronic products, high-grade car glass and solar cell industries.

[0003] The color of the ultra-white glass is mainly caused by iron oxide. Iron in the glass is Fe 2+ and Fe 3+ , Fe 2+ makes the glass blue and blue-green, Fe 3+ has a semi-full state of 3d orbit, so the coloring ability is very weak, making the glass become light yellow-green or yellow, the coloring ability of Fe 2+ is several tens times of that of Fe 3+ , and the color of the glass is determined by the balance state of Fe 2+ and Fe 3+ . The existing ultra-white glass has low transmittance, and the ultra-white glass is more prone to mildew than ordinary glass, which is the result of the exchange of alkali metal ions R + with external ions. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art, provide an ultra-transparent soda lime low-iron ultra-white float glass and a preparation process thereof, and the prepared ultra-white glass can be deep processed like other high-quality float glass, has excellent physical, mechanical and optical properties, and has fewer apparent defects and high transparency.

[0005] The technical scheme of the present application is as follows:

[0006] In one aspect, the present application provides a super-clear soda-lime low-iron ultra-white float glass, comprising batch materials and cullet, the cullet being 18-25% of the total mass of the batch materials, the batch materials comprising the following components in percentage by weight: quartz sand 56-62%, alumina 1.5-3.5%, soda lime 3-6%, potassium feldspar 4-6%, calcite 4-6%, dolomite 6-8%, soda ash 13-16%, barium sulfate 0.5-1.5%, boron trioxide 0.15-0.35%, sodium sulfate 0.7-1%, sodium fluoride 1-2%, and NaSb(OH)6 0.5-2%.

[0007] Preferably, comprising batch materials and cullet, the cullet being 22% of the total mass of the batch materials, the batch materials comprising the following components in percentage by weight: quartz sand 59%, alumina 1.8%, soda lime 4%, potassium feldspar 5%, calcite 5.5%, dolomite 7%, soda ash 14%, barium sulfate 0.6%, boron trioxide 0.2%, sodium sulfate 0.9%, sodium fluoride 1.2%, NaSb(OH)6 0.8%.

[0008] Quartz sand is one of the main raw materials for float glass, and the chemical composition and particle size composition of quartz sand have an important influence on the product quality of float glass. The main component of quartz sand is SiO2, followed by a small amount of Al2O3 and a trace amount of iron oxide (Fe2O3). SiO2 is the main oxide for forming float glass, and it forms an irregular continuous network with silicon-oxygen tetrahedral structural units as the "skeleton" of the glass, which can impart a series of excellent properties to the glass, increase the viscosity of the glass, and improve the thermal stability and chemical stability of the glass. The density and thermal expansion coefficient of the glass decrease with increasing SiO2 content. If the SiO2 content is too high, it will lead to high melting point and high viscosity of the glass, making it difficult to melt, clarify and homogenize the glass, and increasing energy consumption.

[0009] After adding a small amount of Al2O3, it can capture the oxygen provided by soda lime to form [AlO4] tetrahedra, which can replace [SiO4] tetrahedra in the glass to form a unified three-dimensional network structure, which can reduce the crystallization tendency and crystallization rate of the glass, reduce the expansion coefficient of the glass, and improve the viscosity, surface tension, chemical stability and mechanical strength of the glass. Al2O3 has a greater effect on increasing the viscosity of the glass than SiO2. With the increase of Al2O3 content, the viscosity and surface tension of the glass increase, which not only slows down the melting speed of the glass, prolongs the clarification time, but also is not conducive to homogenization, which is easy to form glass rods and lines on the surface of the glass sheet. Moreover, it is not conducive to the flattening, polishing and thinning of the glass liquid in the tin bath. Therefore, the content of Al2O3 in the glass composition should be strictly controlled.

[0010] Soda lime, also known as sodium lime, is mainly composed of calcium oxide and calcium hydroxide. Due to its high hardness and high melting point, the addition of a proper amount of soda lime in the formula can enhance its bending strength and chemical stability; soda lime has the characteristics of high refractive index and low scattering rate, which can improve the optical transparency of glass to a certain extent, making the glass more transparent; the relatively large molar mass of soda lime can make the molecular arrangement of the glass more compact, thereby increasing the density of the glass. In addition, soda lime and sodium fluoride complement each other, and the reaction of sodium fluoride with soda lime will generate calcium fluoride and sodium hydroxide, and calcium fluoride is an additive that can enhance the hardness of glass, because of its special structure, calcium fluoride can form crystal fibers in glass, which can enhance the hardness of glass and improve its wear resistance and corrosion resistance. Calcium fluoride can stimulate the growth of fibers in glass, making it more flexible and elastic, which helps to prevent cracks and breakage of glass.

[0011] Potassium feldspar, as a glass base raw material, contains a lot of R2O (mainly K2O and Na2O), and the melting process of potassium feldspar into glass is relatively slow, and the crystallization ability is small, which can prevent the formation of crystals during the glass formation process and affect normal production or glass defects. Potassium feldspar has good chemical stability and can act as a fluxing agent when co-melting with ultra-pure sand and silicates, and can be used as a fluxing agent to reduce the firing temperature and save costs.

[0012] Calcite is a calcareous mineral, and its main component is CaCO3. The preparation of glass requires heating silicate mineral raw materials to a high temperature state to melt them into glass. In this process, the addition of a certain amount of calcite can increase the viscosity and consistency of the glass melt, which is more conducive to the forming and processing of glass. Calcite can form a complex by reacting with silicate mineral raw materials, and the CaO and MgO components can form a melt with SiO2, and the viscosity of this melt is high. Calcite can also reduce the expansion coefficient of glass, improve the chemical stability and durability of glass. The ultra-white glass of the present application controls the color of the glass through a proper amount of iron oxide in the raw materials, and calcite can inhibit the generation of bubbles and impurities, improve the transparency of the glass and the quality of the glass.

[0013] Dolomite is a carbonate mineral, the main components are CaO, MgO and a small amount of silicon, aluminum, iron, titanium and other impurities. Dolomite added to glass can fill the small gaps inside the glass, enhance the density and hardness of the glass; at the same time, the hardness of dolomite is relatively high, so that the dolomite particles added to the glass play a role in enhancing the strength and wear resistance of the glass; dolomite has a high melting point and thermal stability, adding it to the glass can improve the thermal conductivity of the glass, making the glass more resistant to high temperature; the refractive index of dolomite is close to that of the glass matrix, so that the light propagates between the two almost without refraction or reflection. Therefore, adding an appropriate amount of dolomite can reduce the reflection and scattering of light on the surface of the glass, improve the transparency of the glass and the transmission efficiency of light; dolomite has good acid and alkali resistance, can neutralize acidic substances in the glass, and increase the corrosion resistance of the glass.

[0014] Soda ash has many functions in glass, it can lower the melting point of glass, improve the transparency of glass, adjust the chemical properties of glass and improve the processing performance of glass. In the glass manufacturing process, reasonable use of soda ash can improve the quality and production efficiency of glass, and also can reduce the pollution to the environment.

[0015] Soda ash is an alkaline substance, its chemical formula is Na2CO3, it can react with SiO2 in glass to form sodium silicate (Na2SiO3). The melting point of Na2SiO3 is lower than that of SiO2, so adding soda ash can lower the melting point of glass, making it easier to melt and shape; the transparency of glass is related to the impurity content in it. Soda ash can react with impurities in glass to convert them into volatile gases or substances dissolved in glass, thereby reducing the impurity content in glass and improving the transparency of glass; adding an appropriate amount of soda ash can make the glass have high impact resistance and heat resistance; the addition of soda ash can make the surface of the glass soft, so that the glass has good processing performance, easy to cut, polish, etc.

[0016] Barium sulfate in glass can be used to improve the performance of glass products and adjust the cost; it can improve the flowability of the forming process, promote sintering, and improve the mechanical properties; it can also lower the melting temperature, improve the clarification effect, and reduce the generation of bubbles.

[0017] Barium sulfate decomposition produces O2 and SO2, which plays an important role in the growth and dissolution of bubbles; the solubility of SO2 is related to the alkali content of the melt, the oxygen partial pressure in the gas phase and the melt temperature, and increases significantly with the increase of Na2O content. In the Na2O-CaO-SiO2 glass system of the application, the maximum temperature of the melt absorbing SO2 to form sulfate is close to 1200℃, the temperature range for absorbing SO2 is 900-1200℃, and when the temperature is >1200℃, the sulfate content decreases due to thermal decomposition, and when the temperature is >1300℃, the sulfate decomposition is complete. The dissolution rate of pure O2 and SO2 gas is slow, but when they exist together, they combine to form SO3, which enters the glass network and is easily dissolved.

[0018] Boric anhydride has a preservative effect, can enhance the transmittance of glass to ultraviolet light, and improve the transparency and heat resistance of glass. Boric anhydride contains boric oxide, which is a substance that forms a glass network structure, can reduce the viscosity of glass without affecting the linear expansion coefficient and chemical stability of glass, making the glass more stable. It can be used as a solvent, an aid and a strengthening additive to change the physical and chemical properties of glass, so it is widely used in the manufacture of optical glass.

[0019] Sodium sulfate is one of the important raw materials for glass manufacturing, which is a white crystal with the chemical formula NA2SO4. In the glass production process, sodium sulfate is mainly used to adjust the viscosity and flowability of glass, thereby improving the formability and production efficiency of glass. Sodium sulfate can also be used as a glass component mixing agent to adjust the chemical composition and properties of glass, improve the transparency, impact resistance and heat resistance of glass. At the same time, sodium sulfate can also adjust the oxidation resistance of glass. In the glass production process, due to high temperature and the presence of O2, glass is easily affected by oxidation, which can cause color change, bubbles and other defects in glass, and reduce its quality. As a reducing agent, sodium sulfate can react with O2 to reduce the degree of oxidation of glass, improve its oxidation resistance, and make it more stable and durable.

[0020] Sodium fluoride can promote the uniform distribution of sodium ions and fluorine ions at high temperatures, improve the hardness of glass, and make it less prone to scratching and wear. F - It also plays a role in preventing light scattering, thereby increasing the transparency of glass. Sodium fluoride reacts with SiO2 raw materials in the application: 6NaF+SiO2=Na2SiF6+2Na2O, and the generated Na2SiF6 can convert Fe2O3 and FeO in the impurity elements in the raw materials of dolomite and potassium feldspar into FeF3. FeF3 is volatilized at high temperature to generate bubbles, thereby improving the whiteness and transmittance of glass.

[0021] NaSb(OH)6 is a complex fining agent, and the antimony in it exists in a high valence form, which eliminates the need for low-valence Sb3+ Oxidation to high-valence Sb 5+ After the conditions are met, the high-valence oxidation decomposes the antimony oxide to release oxygen, which saves the amount of soda ash, reduces the reduction and volatilization loss of soda ash. In addition, the oxygen release temperature of NaSb(OH)6 is >1050℃, so the oxygen release is at the bottom of the glass liquid, and the clarification of the glass liquid is complete, which is very beneficial to the homogenization of the glass. The coloring effect of divalent iron is 10 times that of trivalent iron, and iron exists in the form of compound or element in the batch. After the glass liquid is formed, iron exists in the form of ion and is easily oxidized. Therefore, high-temperature oxygen release has a good inhibitory effect on the coloring of glass iron, which is extremely beneficial to the light transmittance of the ultra-white glass. When NaSb(OH)6 is used as a glass clarifying agent, its principle is that at a temperature of 1000-1200℃, Sb2O3 is oxidized by the released oxygen (Sb2O3→Sb2O5); when the temperature reaches 1300℃ or above, O2 is released (Sb2O5→Sb2O3), thereby playing a clarifying role; during the cooling process, Sb2O3 changes to Sb2O5 again, thereby absorbing and removing O2 bubbles.

[0022] The cullet, also known as the clinker, is an indispensable raw material for glass production. The addition of the cullet can improve the melting rate, help clarification and homogenization. The melting of the batch is mainly the melting of SiO2, and with the increase of the amount of the cullet, the melting time of the batch is correspondingly shortened, and the melting speed is improved; when the amount of the cullet is appropriate, the fluxing effect of the cullet can reduce the viscosity of the glass melt, shorten the clarification and homogenization time. The addition of the cullet is beneficial to saving energy and prolonging the service life of the kiln. While saving soda ash, increasing the amount of the cullet can also greatly save fuel. However, the amount of the cullet added depends on the composition of the glass, and for soda-lime-silica glass, the amount of the cullet should not be too much, otherwise the glass will become brittle and the mechanical strength will be reduced.

[0023] On the other hand, the present application also provides a preparation process of the above-mentioned ultra-clear soda-lime glass with low iron and ultra-white float glass, which comprises mixing the batch and the cullet, melting the mixture into a glass liquid in a kiln, and the heating process is as follows: first, heating at a temperature increasing rate of 2℃ / min to 300℃, and then heating at a temperature increasing rate of 5℃ / min to 1500-1650℃, and keeping the temperature for 150-180min; then, the glass liquid flows into a flow channel to form a glass ribbon, and then cools to room temperature after annealing.

[0024] Preferably, the annealing temperature is 520-580℃, and the annealing time is 60-90min.

[0025] The melting of the glass is a process of melting qualified and high-quality batch at high temperature to form a clarified, uniform and finally suitable glass liquid for forming. The melting of the glass is a very complex physical and chemical change process, and the glass raw materials complete the silicate formation, glass formation, glass liquid clarification, glass liquid homogenization and glass liquid cooling stages in the melting furnace.

[0026] The forming process of float glass production is completed in a tin bath into which protective gas (N2 and H2) is introduced. The high-temperature molten glass liquid continuously flows from a pool furnace and floats on the surface of tin liquid with a relatively large specific gravity. Under the action of gravity and surface tension, the glass liquid spreads and flattens on the tin liquid surface to form a glass ribbon with flat upper and lower surfaces and parallel to each other, which is drawn to the tail of the tin bath, polished, thinned, hardened, cooled, and annealed, and then introduced into a roller table. The rollers of the roller table rotate to draw the glass ribbon out of the tin bath and into an annealing furnace for annealing, and then the glass is cut.

[0027] In the case where the glass liquid is only balanced by gravity and surface tension, a free thickness of 6-7 mm of the glass ribbon can be formed on the tin liquid surface. When the glass is drawn slightly smaller than the balanced thickness, only the drawing speed needs to be appropriately increased to generate a certain tension on the glass ribbon. The tension stretches the glass ribbon in the longitudinal direction, and the thickness gradually decreases, and the width also shrinks accordingly, so that a glass of 5-6 mm can be more easily produced.

[0028] The purpose of glass annealing is to eliminate residual internal stress and optical inhomogeneity in the glass product, and to stabilize the structure inside the glass. The temperature range between the upper and lower limits of the glass annealing is an important stage of the glass annealing, and in this temperature range, the cooling of the glass product must be carried out at a slow speed to ensure the quality requirements of the glass annealing. Otherwise, problems such as asymmetric cooling of the upper and lower surfaces of the glass ribbon, transverse temperature inhomogeneity of the glass ribbon, and asymmetric distribution of the transverse temperature of the glass plate will occur. These problems will lead to edge tensile stress and longitudinal cracking, edge dropping and transverse cracking, upward bending and downward bending of the glass, etc. Therefore, a reasonable annealing schedule is of great significance to the glass forming.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] The ultra-white glass prepared by the present application can be subjected to various deep processing like other high-quality float glass, has superior physical, mechanical and optical properties, and has less apparent defects and high transparency. DETAILED DESCRIPTION

[0031] In order to enable the personnel in the technical field to better understand the technical solutions in the present application, the technical solutions of the present application will be clearly and completely described below in combination with the embodiments of the present application.

[0032] Examples 1-5 and Comparative Examples 1-5

[0033] The material formula of the 6 mm thick ultra-transparent soda-lime low-iron ultra-white float glass prepared in Examples 1-5 is shown in Table 1:

[0034] Table 1 Glass material formula of Examples 1-5

[0035] Component Example 1 Example 2 Example 3 Example 4 Example 5 Crushed glass wt.% 22 18 25 20 19 Batch wt.% 78 82 75 80 81 Total wt.% 100 100 100 100 100

[0036] The glass batch of Examples 1-5 is shown in Table 2:

[0037] Table 2 Glass batch of Examples 1-5

[0038] Component SiO2 Al2O3 CaO MgO K2O Na2O Fe2O3 Na2SO4 B2O3 Content wt.% 61.2 16.5 3.52 2.95 2.45 11.45 0.05 0.04 1.84

[0039] The glass batch of Examples 1-5 is shown in Table 2:

[0040] The glass batch of Examples 1-5 is shown in Table 2:

[0041] Table 3 Glass batch of Examples 1-5

[0042]

[0043] Table 4 Glass batch of Examples 1-5

[0044]

[0045] The glass batch of Examples 1-5 is shown in Table 2:

[0046] The glass batch of Examples 1-5 is shown in Table 2:

[0047] Table 5

[0048]

[0049]

[0050] The glass prepared in Examples 1-5 and Comparative Examples 1-5 was tested for performance, and each performance test method was as follows:

[0051] Visible light reflectance: The testing instrument was Shimadzu UV3600 ultraviolet visible near-infrared spectrophotometer, the tested sample was a single piece of glass with a thickness of 6 mm, and the percentage of light intensity that passed through the glass in the visible light spectrum 380-780 nm was measured.

[0052] Visible light transmittance: The test instrument was a Shimadzu UV3600 UV-Vis-NIR spectrophotometer. The test sample was a single piece of glass with a thickness of 6 mm. The percentage of the intensity of light reflected by the glass to the intensity of the incident light was measured in the visible spectrum range of 380-780 nm.

[0053] Ultraviolet transmittance: The test instrument was a Shimadzu UV3600 UV-Vis-NIR spectrophotometer. The test sample was a single piece of glass with a thickness of 6 mm. The percentage of ultraviolet light intensity transmitted through the glass to the incident light intensity was measured in the visible spectrum range of 280-380 nm.

[0054] Shading coefficient: The test instrument was a Shimadzu UV3600 UV-Vis-NIR spectrophotometer. The test sample was a single piece of glass with a thickness of 6mm. The ratio of total solar transmittance to solar radiation from a 3mm standard glass was measured.

[0055] Elastic modulus: The testing instrument is an elastic modulus tester, and the test sample is a single piece of glass with a thickness of 6 mm.

[0056] Flexural strength: The mechanical strength of glass is measured by flexural strength. A KJJ300-1 electric flexural strength tester is used. Maximum load: 300N, accuracy: 1%, sample size: 50mm×4mm×2.5mm, fine grinding of the sides and both ends.

[0057] Glass density: The density of the glass sample was measured using Archimedes' principle. The medium was distilled water. The mass of the sample was measured using a density balance. Small glass samples without defects such as bubbles and streaks were selected. The samples were cleaned with anhydrous ethanol and dried. The data were then measured and obtained.

[0058] Linear expansion coefficient: The experimental measurement was conducted using a NETZSCH DIL402PC linear expansion analyzer at temperatures ranging from 25 to 300℃.

[0059] Chemical properties: Glass is subject to corrosion from water, acids, and alkalis during use. The glass's resistance to these corrosive substances is called its chemical stability; the stronger the glass's resistance to corrosion, the better its chemical stability. Water resistance is tested using the powder method, while acid and alkali resistance is tested using the surface method.

[0060] Water resistance: The method specified in GB / T6584-1997 (Particle test method and classification of water resistance of glass at 98℃) was adopted. 2g of glass powder with a particle size of 300-500um was heated with 50mL of water in a boiling water bath for 2h. The precipitated alkali was titrated with hydrochloric acid at a concentration of 0.1mol / L, using methyl red as an indicator. The water resistance grade was determined based on the acid consumption. The water resistance grades are classified as shown in Table 6.

[0061] Table 6 Water resistance classification

[0062]

[0063] Acid resistance: The glass was cut into two test pieces of an easily measurable shape with a total surface area of 10-15 cm 2 The tested glass surface was boiled in 20% hydrochloric acid (HCl concentration = 6 mol / L) for 6 h, and the weight loss of the glass was determined in mg / 100 cm 2 The glass was classified into 4 acid resistance grades according to the average value, and the acid resistance classification is shown in Table 7:

[0064] Table 7 Acid resistance classification

[0065] Acid resistance rating H1 H2 H3 H4 Glass weight loss (mg / 100 cm 2 ) 0-0.7 0.7-1.5 1.5-15 ＞15 Designation High acid resistance Medium acid resistance Low acid resistance High acid attack

[0066] Alkali resistance: The glass was cut into two test pieces of an easily measurable shape with a total surface area of 10-15 cm 2 The tested glass surface was boiled in a mixed solution of NaOH (1 mol / L) and NaCO3 (0.5 mol / L) with equal volume for 3 h, and the weight loss of the glass was determined in mg / 100 cm 2 The glass was classified into 3 alkali resistance grades according to the average value, and the alkali resistance classification is shown in Table 8:

[0067] Table 8 Alkali resistance classification

[0068] Alkali resistance rating A1 A2 A3 Glass weight loss (mg / 100 cm 2 )]]> 0-75 75-175 ＞75 Designation Low alkali attack Medium alkali attack High alkali attack

[0069] Punctiform defects (bubbles): The maximum core size of the punctiform defects was measured by a reading microscope with a grading value of 0.01 mm according to JB / T 2369, and the punctiform defect size is shown in Table 9:

[0070] Table 9 Punctiform defect size

[0071]

[0072] The performance test results of the 6 mm thick super alkali lime low iron ultra-white float glass prepared in Examples 1-5 and Comparative Examples 1-5 are shown in Tables 10-11:

[0073] Table 10 Performance test results of the glass prepared in Examples 1-5

[0074]

[0075] Table 11 shows the performance test results of the glass prepared in Comparative Example 1-5

[0076]

[0077]

[0078] As can be seen from Table 11, the mechanical properties and chemical properties of the glass prepared in Comparative Example 1 are greatly reduced compared with Example 1, mainly because the soda lime and sodium fluoride complement each other, and the reaction between the two generates calcium fluoride. The special structure of calcium fluoride enables it to form crystal fibers in the glass, which can enhance the hardness of the glass and improve the wear resistance and corrosion resistance of the glass.

[0079] Compared with Example 1, the optical properties, mechanical properties, chemical properties and glass density of the glass prepared in Comparative Example 2 are reduced, mainly because the soda lime has high hardness and high melting point, so adding an appropriate amount of soda lime can enhance its mechanical strength and chemical stability; soda lime has the characteristics of high refractive index and low scattering rate, which can improve the transparency of the glass to a certain extent; the molar mass of soda lime is relatively large, which can make the molecular arrangement of the glass more compact, thereby increasing the density of the glass.

[0080] Compared with Example 1, the mechanical properties and optical properties of the glass prepared in Comparative Example 3 are reduced, mainly because sodium fluoride can promote the uniform distribution of sodium ions and fluorine ions at high temperature, which can improve the hardness of the glass. Sodium fluoride reacts with SiO2 raw material in the present application: 6NaF+SiO2=Na2SiF6+2Na2O, and the generated Na2SiF6 can convert Fe2O3 and FeO in the impurity elements of dolomite and potassium feldspar in the raw material into FeF3. FeF3 is volatilized at high temperature to generate bubbles, which improves the transmittance of the glass.

[0081] Compared with Example 1, the optical properties of the glass prepared in Comparative Example 4 are reduced and the point defects are increased, mainly because sodium sulfate as a glass mixing agent can adjust the chemical composition and properties of the glass and improve the transparency of the glass; sodium sulfate as a reducing agent can react with O2 to reduce the oxidation degree of the glass and improve the antioxidant performance of the glass, thereby reducing the number of bubbles and point defects in the glass liquid.

[0082] Compared with Example 1, the optical properties of the glass prepared in Comparative Example 5 are reduced and the point defects are increased, mainly because antimony directly exists in the form of high valence, which saves the process of converting low valence Sb 3+ to high valence Sb 5+The sodium pyrosconescenting oxygen-releasing temperature is higher than 1050 DEG C, so the oxygen is released from the bottom of the glass liquid, the glass liquid is completely fined, and the homogenization of the glass is very favorable, and the optical performance of the glass is better and the apparent defects are less.

[0083] It can be seen from the above tests that the super-transparency soda-lime low-iron super-white float glass prepared by the application has excellent performance, and the performance index is better than similar glasses, so that the final produced super-white glass can be subjected to various deep processing like other high-quality float glass, has excellent physical, mechanical and optical performance, has less apparent defects and high transparency, and has good application prospect.

Claims

1. An ultra-clear soda-lime low-iron ultra-white float glass, characterized in that, The batch material and the cullet, the cullet being 18-25% of the total mass of the batch material, comprise the following components in percentage by weight: quartz sand 56-62%, alumina 1.5-3.5%, soda lime 3-6%, potassium feldspar 4-6%, calcite 4-6%, dolomite 6-8%, soda ash 13-16%, barium sulfate 0.5-1.5%, boron trioxide 0.15-0.35%, sodium sulfate 0.7-1%, sodium fluoride 1-2%, and NaSb(OH)6 0.5-2%; The preparation process of the super-transparency soda lime low-iron ultra-white float glass, the batch material and the cullet are mixed, and the mixture is heated and melted into a glass liquid in a kiln, and the heating process is as follows: first, the temperature is raised to 300℃ at a rate of 2℃ / min, and then the temperature is raised to 1500-1650℃ at a rate of 5℃ / min, and the temperature is kept for 150-180min; then the glass liquid flows into a flow channel to form a glass ribbon, and then the glass ribbon is cooled to room temperature after annealing.

2. The ultra-clear soda-lime low-iron ultra-white float glass according to claim 1, wherein, The batch material and the cullet, the cullet being 22% of the total mass of the batch material, comprise the following components in percentage by weight: quartz sand 59%, alumina 1.8%, soda lime 4%, potassium feldspar 5%, calcite 5.5%, dolomite 7%, soda ash 14%, barium sulfate 0.6%, boron trioxide 0.2%, sodium sulfate 0.9%, sodium fluoride 1.2%, and NaSb(OH)6 0.8%.

3. The ultra-clear soda-lime low-iron ultra-white float glass according to claim 1, wherein, The annealing temperature is 520-580℃, and the annealing time is 60-90min.

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