Ultra-clear and ultra-thick float glass and preparation method thereof

Abstract

The present invention belongs to the field of glass preparation technology, and specifically relates to ultra-clear, ultra-thick float glass and its preparation method. The ultra-clear, ultra-thick float glass is composed of the following raw materials: quartz sand, calcium dodecyl heptaaluminate, titanium oxide whiskers, lanthanum hexaboride, barite, lithium hydroxide, Ca3(SbO4)2, Mg2SnO4, zinc selenite, and neodymium oxide. The ultra-clear, ultra-thick float glass of the present invention uses quartz sand, calcium dodecyl heptaaluminate, titanium oxide whiskers, lanthanum hexaboride, barite, and lithium hydroxide as the main raw materials to construct a dense glass network structure, ensuring the mechanical properties of the ultra-clear, ultra-thick float glass. A mixture of Ca3(SbO4)2, Mg2SnO4, zinc selenite, and neodymium oxide is used as a clarifying and decolorizing agent to ensure the light transmittance of the ultra-clear, ultra-thick float glass. The synergistic effect of the raw materials ensures that the prepared glass has excellent flexural strength and light transmittance.

Description

Technical Field

[0001] The invention belongs to the technical field of glass preparation, and specifically relates to ultra-white and ultra-thick float glass and a preparation method thereof. Background Art

[0002] The forming principle of float glass is that high-temperature molten glass continuously flows into a metallic tin bath while controlling its flow rate. Under the combined effects of gravity, surface tension, the buoyancy of the tin bath, and the pull of gravity, the molten glass forms a glass ribbon of a certain equilibrium thickness. As it flows, the glass ribbon gradually cools and solidifies before being pulled from the tin bath outlet and entering an annealing lehr. The equilibrium thickness is approximately 6mm. The production of thicker glass than the equilibrium thickness typically utilizes a reverse-assisted direct drawing method or a retaining wall method. However, most methods for producing ultra-thick float glass of 19mm and above struggle to achieve a finished product with the same performance as that of a finished product of the equilibrium thickness.

[0003] Ultra-clear glass, characterized by its exceptional clarity and transparency, is a high-quality, versatile, and new premium glass variety with a higher transmittance than ordinary glass. Due to its low impurity content in raw materials and the rigorous process control and refined manufacturing process, ultra-clear glass is more uniform than ordinary glass. It possesses superior physical, mechanical, and optical properties, while also amenable to the same extensive processing as ordinary glass. Due to its exceptionally high transmittance, ultra-clear glass is suitable for applications in high-end technology products, electronics, luxury car glass, solar cells, and other industries.

[0004] The transmittance of ultra-clear float glass, as opposed to ordinary base glass, is primarily determined by impurities such as total iron content. Sulfur and iron are inevitably introduced into the raw materials and during the glass production process. The combination of sulfur and iron in the glass forms iron sulfides (usually iron sulfide or iron polysulfide), which affect the optical properties of float glass—visible light transmittance.

[0005] Ultra-clear float glass absorbs light due to three factors: intrinsic absorption of the glass structure, absorption of impurities in the float glass, and absorption of atomic defect color centers. For float glass in the visible to near-infrared band, absorption by impurities is the main factor. Impurities are introduced into the glass by coloring elements such as iron, titanium, nickel, and chromium brought into the float glass raw materials, refractory materials corroded during the melting process, sulfur, vanadium, iron in the melting furnace fuel, and iron and alloys in the molding and processing equipment. Generally speaking, iron in float glass has two ionic states, namely Fe 3+ and Fe 2+ , because Fe 3+There are two absorption bands, one at 380-390nm and the other at 440-450nm. However, the iron element in the float glass production process cannot exist in only one ionic form, and the reducing tin bath of float glass further increases the difficulty of its production control.

[0006] Therefore, exploring a production method for ultra-white and ultra-thick float glass has become a technical problem that needs to be solved urgently. Summary of the Invention

[0007] The ultra-white and ultra-thick float glass of the present invention is composed of the following raw materials, calculated by weight: 100 parts of quartz sand, 7.5-8.5 parts of dodecaluminate heptaaluminate, 0.4-0.6 parts of titanium oxide whiskers, 0.3-0.5 parts of lanthanum hexaboride, 4.0-5.0 parts of barite, 1.8-2.0 parts of lithium hydroxide, 0.07-0.09 parts of Ca3(SbO4)2, 0.18-0.20 parts of Mg2SnO4, 0.03-0.05 parts of zinc selenite, and 0.02-0.04 parts of neodymium oxide.

[0008] in:

[0009] The preparation method of Mg2SnO4 is as follows: MgO and SnO2 are weighed according to a molar ratio of 2:1, placed in a grinding jar, ethanol is added as a grinding aid, and ball milling is performed for 40 minutes. The uniformly mixed material is placed in a ventilated place to dry, and the ethanol and moisture are removed to obtain a dry material. The dry material is kept at 1230°C for 3.5 hours to prepare Mg2SnO4.

[0010] The preparation method of Ca3(SbO4)2 is as follows: Sb2S3 and Ca(OH)2 are weighed in a molar ratio of 1:3, placed in a grinding jar, ethanol is added as a grinding aid, and ball milling is performed for 30 minutes. The evenly mixed material is placed in a ventilated place to dry, and the ethanol and moisture are removed to obtain a dry material. The dry material is calcined at 800°C for 5 hours to prepare Ca3(SbO4)2.

[0011] Preferably, the ultra-white and ultra-thick float glass described in the present invention is composed of the following raw materials, in parts by weight: 100 parts of quartz sand, 8.0 parts of dodecaluminate heptaaluminate, 0.5 parts of titanium oxide whiskers, 0.4 parts of lanthanum hexaboride, 4.5 parts of barite, 1.9 parts of lithium hydroxide, 0.08 parts of Ca3(SbO4)2, 0.19 parts of Mg2SnO4, 0.04 parts of zinc selenite, and 0.03 parts of neodymium oxide.

[0012] The method for preparing the ultra-clear and ultra-thick float glass of the present invention comprises the following steps:

[0013] (1) Quartz sand, calcium dodecaaluminate, titanium oxide whisker, lanthanum hexaboride, barite, lithium hydroxide, Ca3(SbO4)2, Mg2SnO4, zinc selenite and neodymium oxide are fully mixed in certain weight proportions to obtain a batch;

[0014] (2) Adding the batch material into the kiln and melting it to prepare glass liquid;

[0015] (3) The melted and clarified glass liquid is fed into the float glass tin bath at a temperature of 980-1000°C for forming, and linear thinning is performed using three-stage deceleration traction;

[0016] (4) The formed glass is placed in an annealing kiln for step annealing to produce ultra-white and ultra-thick float glass.

[0017] in:

[0018] The melting in step (2) is first heated to 830-850°C at a rate of 3°C / min and kept warm for 30 minutes, then heated to 1030-1050°C at a rate of 5°C / min and kept warm for 60 minutes, then heated to 1330-1350°C at a rate of 2°C / min and kept warm for 40 minutes, and finally heated to 1560-1580°C at a rate of 4°C / min and kept warm for 240 minutes.

[0019] In step (3), the temperature of the first section is 950°C, the pulling speed is 160 m / h, the temperature of the second section is 880°C, the pulling speed is 100 m / h, the temperature of the third section is 830°C, the pulling speed is 60 m / h, and the temperature of the fourth section is 760°C, the pulling speed is 42 m / h.

[0020] The step annealing in step (4) is first cooling to 570-580°C at a rate of 2.5°C / min and keeping warm for 8h, then cooling to 540-550°C at a rate of 1.5°C / min, cooling to 460-470°C at a rate of 1.8°C / min and keeping warm for 2h, cooling to 400-410°C at a rate of 1.5°C / min and keeping warm for 8h, cooling to 360-370°C at a rate of 1.2°C / min and keeping warm for 12h, cooling to 340-350°C at a rate of 1.0°C / min and keeping warm for 24h, cooling to 240-250°C at a rate of 0.8°C / min and keeping warm for 12h, cooling to 100°C at a rate of 30°C / h, and finally cooling naturally to room temperature.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The ultra-clear and ultra-thick float glass of the present invention uses quartz sand, calcium dodecaaluminate heptaaluminate, titanium oxide whiskers, lanthanum hexaboride, barite, and lithium hydroxide as the main raw materials to construct a dense glass network structure, ensuring the mechanical properties of the ultra-clear and ultra-thick float glass. A mixture of Ca3(SbO4)2, Mg2SnO4, zinc selenite, and neodymium oxide is used as a clarifying and decolorizing agent to ensure the light transmittance of the ultra-clear and ultra-thick float glass. As a result, the raw materials work synergistically to ensure that the prepared glass has excellent bending strength and light transmittance.

[0023] (2) The ultra-white and ultra-thick float glass of the present invention uses quartz sand, calcium dodecanol, titanium oxide whiskers, lanthanum hexaboride, barite and lithium hydroxide as main raw materials. Among them, calcium dodecanol undergoes a decomposition reaction in the low-temperature melting stage, releasing active oxygen free radicals to efficiently crack the silicon-oxygen network. In the high-temperature homogenization stage, it forms a calcite mesophase, and trivalent aluminum occupies the tetrahedral voids to form [AlO4] - Tetrahedrons, together with [SiO4], form a dense network, enhancing the hardness of the glass. Titanium oxide whiskers act to induce microcrack deflection and toughening. Lanthanum hexaboride decomposes at high temperatures to form La2O3@B nanoclusters, which fill the interface between the TiO2 and silicon-oxygen network, densifying the network. Thus, dodecaluminate heptaaluminate, titanium oxide whiskers, and lanthanum hexaboride work synergistically to enhance the mechanical strength of the glass. Barite decomposes at high temperatures to form barium oxide and sulfur trioxide, which further decomposes into sulfur dioxide and oxygen. These two gases act as physical clarifiers, while the formation of barium oxide reduces high-temperature viscosity and increases the hardness of the glass. Lithium hydroxide lowers the melting temperature, shrinks the glass network, and reduces the thermal expansion coefficient.

[0024] (3) The ultra-white and ultra-thick float glass of the present invention is added with a mixture of Ca3(SbO4)2, Mg2SnO4, zinc selenite and neodymium oxide as a clarifying and decolorizing agent. Ca3(SbO4)2 reacts with ferrous oxide at high temperature to produce ferric oxide, calcium oxide, antimony trioxide and oxygen. Sb 5+ The strong coloring ion Fe 2+ Oxidized to weakly colored Fe 3+, significantly reducing the blue-green hue of the glass. The generated Sb2O3 can further cooperate with Se in zinc selenite to generate colorless Sb-Se compounds, neutralizing the residual yellow. At the same time, the released O2 forms bubble nuclei, which merge with the gases dissolved in the glass (such as SO2) to improve the light transmittance of the glass. Mg2SnO4 powder decomposes at high temperatures, and the decomposition temperature matches the glass melting temperature to generate magnesium oxide, tin dioxide and oxygen. The oxygen forms microbubble nuclei, which merge with the gases dissolved in the glass liquid during the floating process and carry them out of the melt. In addition, in the later stage of glass melting, the oxygen partial pressure decreases, which promotes the partial reduction of SnO2 to produce gas. The divalent tin produced at the same time has strong reducing properties and can reduce the color-causing metal ions in the glass. In addition, the generated magnesium oxide can reduce the alkalinity of the glass and promote Fe 3+ [FeO4] - Stable presence, thereby reducing the yellow hue, at the same time, the presence of magnesium oxide can reduce the thermal expansion coefficient of the glass, play a role in filling the network gap, and inhibit the rate of change of the Si-O bond angle at high temperature. Zinc selenite decomposes in high temperature glass melt, releasing a strong reducing substance Se 2- , the color-causing Fe 3+ Reduction to Fe 2+ At the same time, the zinc oxide generated can reduce the O / Si ratio of the glass, thereby inhibiting the hydrolysis of iron ions. 2+ As an intermediate ion, it strengthens the Si-O network and reduces the coloration of oxygen vacancy defects. 3+ The 4f electron transition of ions has a strong absorption peak in the visible light region (580–600 nm), which just covers the iron impurities (Fe 2+ / Fe 3 + ) produces a yellow-green hue. In addition, Nd 3+ The ion field is strong, and as a network intermediate, it fills the gaps in the silicon-oxygen network, reducing the oxygen vacancy concentration and increasing the hardness of the glass. As a result, the synergistic effect between Ca3(SbO4)2, Mg2SnO4, zinc selenite, and neodymium oxide produces different decolorizing substances and gases to achieve clarification and decolorization.

[0025] (4) The method for preparing ultra-white and ultra-thick float glass of the present invention optimizes the densification of the network structure through four-stage gradient melting, achieves stable forming of ultra-thick glass through four-stage deceleration thinning, and eliminates internal stress of ultra-thick glass through seven-stage step annealing. The synergistic effect between the process steps ensures the stable performance of the prepared ultra-white and ultra-thick glass. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the examples.

[0027] Example 1

[0028] The ultra-white and ultra-thick float glass described in Example 1 is composed of the following raw materials, in parts by weight: 100 parts of quartz sand, 8.0 parts of dodecaluminate heptaaluminate, 0.5 parts of titanium oxide whiskers, 0.4 parts of lanthanum hexaboride, 4.5 parts of barite, 1.9 parts of lithium hydroxide, 0.08 parts of Ca3(SbO4)2, 0.19 parts of Mg2SnO4, 0.04 parts of zinc selenite, and 0.03 parts of neodymium oxide.

[0029] in:

[0030] The preparation method of Mg2SnO4 is as follows: MgO and SnO2 are weighed according to a molar ratio of 2:1, placed in a grinding jar, ethanol is added as a grinding aid, and ball milling is performed for 40 minutes. The uniformly mixed material is placed in a ventilated place to dry, and the ethanol and moisture are removed to obtain a dry material. The dry material is kept at 1230°C for 3.5 hours to prepare Mg2SnO4.

[0031] The preparation method of Ca3(SbO4)2 is as follows: Sb2S3 and Ca(OH)2 are weighed in a molar ratio of 1:3, placed in a grinding jar, ethanol is added as a grinding aid, and ball milling is performed for 30 minutes. The evenly mixed material is placed in a ventilated place to dry, and the ethanol and moisture are removed to obtain a dry material. The dry material is calcined at 800°C for 5 hours to prepare Ca3(SbO4)2.

[0032] The method for preparing the ultra-clear and ultra-thick float glass described in Example 1 comprises the following steps:

[0033] (1) Quartz sand, calcium dodecaaluminate, titanium oxide whisker, lanthanum hexaboride, barite, lithium hydroxide, Ca3(SbO4)2, Mg2SnO4, zinc selenite and neodymium oxide are fully mixed in certain weight proportions to obtain a batch;

[0034] (2) Adding the batch material into the kiln and melting it to prepare glass liquid;

[0035] (3) The melted and clarified glass liquid is fed into the float glass tin bath at a temperature of 990°C for forming, and linear thinning is performed using three-stage deceleration traction;

[0036] (4) The formed glass is placed in an annealing kiln for step annealing to produce ultra-white and ultra-thick float glass.

[0037] in:

[0038] The melting in step (2) is first heated to 840°C at a rate of 3°C / min and kept warm for 30 minutes, then heated to 1040°C at a rate of 5°C / min and kept warm for 60 minutes, then heated to 1340°C at a rate of 2°C / min and kept warm for 40 minutes, and finally heated to 1570°C at a rate of 4°C / min and kept warm for 240 minutes.

[0039] In step (3), the temperature of the first section is 950°C, the pulling speed is 160 m / h, the temperature of the second section is 880°C, the pulling speed is 100 m / h, the temperature of the third section is 830°C, the pulling speed is 60 m / h, and the temperature of the fourth section is 760°C, the pulling speed is 42 m / h.

[0040] The step annealing in step (4) is first cooling to 575°C at a rate of 2.5°C / min and keeping warm for 8h, then cooling to 545°C at a rate of 1.5°C / min, cooling to 465°C at a rate of 1.8°C / min and keeping warm for 2h, cooling to 405°C at a rate of 1.5°C / min and keeping warm for 8h, cooling to 365°C at a rate of 1.2°C / min and keeping warm for 12h, cooling to 345°C at a rate of 1.0°C / min and keeping warm for 24h, cooling to 245°C at a rate of 0.8°C / min and keeping warm for 12h, cooling to 100°C at a rate of 30°C / h, and finally cooling naturally to room temperature.

[0041] The ultra-white and ultra-thick float glass prepared in Example 1 has a thickness of 19.0 mm, a bending strength of 133 MPa, and a light transmittance of 93.3%. Its high light transmittance indicates its high whiteness.

[0042] Example 2

[0043] The ultra-white and ultra-thick float glass described in Example 2 is composed of the following raw materials, in parts by weight: 100 parts of quartz sand, 7.5 parts of dodecaluminate heptaaluminate, 0.6 parts of titanium oxide whiskers, 0.5 parts of lanthanum hexaboride, 5.0 parts of barite, 1.8 parts of lithium hydroxide, 0.07 parts of Ca3(SbO4)2, 0.18 parts of Mg2SnO4, 0.05 parts of zinc selenite, and 0.04 parts of neodymium oxide.

[0044] in:

[0045] The preparation method of Mg2SnO4 is as follows: MgO and SnO2 are weighed according to a molar ratio of 2:1, placed in a grinding jar, ethanol is added as a grinding aid, and ball milling is performed for 40 minutes. The uniformly mixed material is placed in a ventilated place to dry, and the ethanol and moisture are removed to obtain a dry material. The dry material is kept at 1230°C for 3.5 hours to prepare Mg2SnO4.

[0046] The preparation method of Ca3(SbO4)2 is as follows: Sb2S3 and Ca(OH)2 are weighed in a molar ratio of 1:3, placed in a grinding jar, ethanol is added as a grinding aid, and ball milling is performed for 30 minutes. The evenly mixed material is placed in a ventilated place to dry, and the ethanol and moisture are removed to obtain a dry material. The dry material is calcined at 800°C for 5 hours to prepare Ca3(SbO4)2.

[0047] The method for preparing the ultra-clear and ultra-thick float glass described in Example 2 comprises the following steps:

[0048] (1) Quartz sand, calcium dodecaaluminate, titanium oxide whisker, lanthanum hexaboride, barite, lithium hydroxide, Ca3(SbO4)2, Mg2SnO4, zinc selenite and neodymium oxide are fully mixed in certain weight proportions to obtain a batch;

[0049] (2) Adding the batch material into the kiln and melting it to prepare glass liquid;

[0050] (3) The melted and clarified glass liquid is fed into the float glass tin bath at a temperature of 1000°C for forming, and linear thinning is performed using three-stage deceleration traction;

[0051] (4) The formed glass is placed in an annealing kiln for step annealing to produce ultra-white and ultra-thick float glass.

[0052] in:

[0053] The melting in step (2) is first heated to 850°C at a rate of 3°C / min and kept warm for 30 minutes, then heated to 1050°C at a rate of 5°C / min and kept warm for 60 minutes, then heated to 1350°C at a rate of 2°C / min and kept warm for 40 minutes, and finally heated to 1580°C at a rate of 4°C / min and kept warm for 240 minutes.

[0054] In step (3), the temperature of the first section is 950°C, the pulling speed is 160 m / h, the temperature of the second section is 880°C, the pulling speed is 100 m / h, the temperature of the third section is 830°C, the pulling speed is 60 m / h, and the temperature of the fourth section is 760°C, the pulling speed is 42 m / h.

[0055] The step annealing in step (4) is first cooling to 580°C at a rate of 2.5°C / min and keeping warm for 8h, then cooling to 550°C at a rate of 1.5°C / min, cooling to 470°C at a rate of 1.8°C / min and keeping warm for 2h, cooling to 410°C at a rate of 1.5°C / min and keeping warm for 8h, cooling to 370°C at a rate of 1.2°C / min and keeping warm for 12h, cooling to 350°C at a rate of 1.0°C / min and keeping warm for 24h, cooling to 250°C at a rate of 0.8°C / min and keeping warm for 12h, cooling to 100°C at a rate of 30°C / h, and finally cooling naturally to room temperature.

[0056] The ultra-white and ultra-thick float glass prepared in Example 2 has a thickness of 19.2 mm, a bending strength of 130 MPa, and a light transmittance of 93.0%. Its high light transmittance demonstrates its high whiteness.

[0057] Example 3

[0058] The ultra-white and ultra-thick float glass described in Example 3 is composed of the following raw materials, in parts by weight: 100 parts of quartz sand, 8.5 parts of dodecaluminate heptaaluminate, 0.4 parts of titanium oxide whiskers, 0.3 parts of lanthanum hexaboride, 4.0 parts of barite, 2.0 parts of lithium hydroxide, 0.09 parts of Ca3(SbO4)2, 0.20 parts of Mg2SnO4, 0.03 parts of zinc selenite, and 0.02 parts of neodymium oxide.

[0059] in:

[0060] The preparation method of Mg2SnO4 is as follows: MgO and SnO2 are weighed according to a molar ratio of 2:1, placed in a grinding jar, ethanol is added as a grinding aid, and ball milling is performed for 40 minutes. The uniformly mixed material is placed in a ventilated place to dry, and the ethanol and moisture are removed to obtain a dry material. The dry material is kept at 1230°C for 3.5 hours to prepare Mg2SnO4.

[0061] The preparation method of Ca3(SbO4)2 is as follows: Sb2S3 and Ca(OH)2 are weighed in a molar ratio of 1:3, placed in a grinding jar, ethanol is added as a grinding aid, and ball milling is performed for 30 minutes. The evenly mixed material is placed in a ventilated place to dry, and the ethanol and moisture are removed to obtain a dry material. The dry material is calcined at 800°C for 5 hours to prepare Ca3(SbO4)2.

[0062] The method for preparing the ultra-clear and ultra-thick float glass described in Example 3 comprises the following steps:

[0063] (1) Quartz sand, calcium dodecaaluminate, titanium oxide whisker, lanthanum hexaboride, barite, lithium hydroxide, Ca3(SbO4)2, Mg2SnO4, zinc selenite and neodymium oxide are fully mixed in certain weight proportions to obtain a batch;

[0064] (2) Adding the batch material into the kiln and melting it to prepare glass liquid;

[0065] (3) The melted and clarified glass liquid is fed into the float glass tin bath at a temperature of 980°C for forming, and linear thinning is performed using three-stage deceleration traction;

[0066] (4) The formed glass is placed in an annealing kiln for step annealing to produce ultra-white and ultra-thick float glass.

[0067] in:

[0068] The melting in step (2) is first heated to 830°C at a rate of 3°C / min and kept warm for 30 minutes, then heated to 1030°C at a rate of 5°C / min and kept warm for 60 minutes, then heated to 1330°C at a rate of 2°C / min and kept warm for 40 minutes, and finally heated to 1560°C at a rate of 4°C / min and kept warm for 240 minutes.

[0069] In step (3), the temperature of the first section is 950°C, the pulling speed is 160 m / h, the temperature of the second section is 880°C, the pulling speed is 100 m / h, the temperature of the third section is 830°C, the pulling speed is 60 m / h, and the temperature of the fourth section is 760°C, the pulling speed is 42 m / h.

[0070] The step annealing in step (4) is first cooling to 570°C at a rate of 2.5°C / min and keeping warm for 8h, then cooling to 540°C at a rate of 1.5°C / min, cooling to 460°C at a rate of 1.8°C / min and keeping warm for 2h, cooling to 400°C at a rate of 1.5°C / min and keeping warm for 8h, cooling to 360°C at a rate of 1.2°C / min and keeping warm for 12h, cooling to 340°C at a rate of 1.0°C / min and keeping warm for 24h, cooling to 240°C at a rate of 0.8°C / min and keeping warm for 12h, cooling to 100°C at a rate of 30°C / h, and finally cooling naturally to room temperature.

[0071] The ultra-white and ultra-thick float glass prepared in Example 3 has a thickness of 19.1 mm, a bending strength of 132 MPa, and a light transmittance of 93.1%. Its high light transmittance demonstrates its high whiteness.

[0072] Comparative Example 1

[0073] The preparation method of the ultra-clear, extra-thick float glass described in Comparative Example 1 is the same as that of Example 1, the only difference being the raw material composition. The ultra-clear, extra-thick float glass described in Comparative Example 1 is composed of the following raw materials, in parts by weight: 100 parts of quartz sand, 8.0 parts of dodecaluminate heptaaluminate, 0.5 parts of titanium oxide whiskers, 0.4 parts of lanthanum hexaboride, 4.5 parts of barite, 1.9 parts of lithium hydroxide, 0.19 parts of Mg2SnO4, 0.04 parts of zinc selenite, and 0.03 parts of neodymium oxide.

[0074] The ultra-clear and ultra-thick float glass prepared in Comparative Example 1 has a thickness of 19.0 mm, a bending strength of 110 MPa, and a light transmittance of 87.8%.

[0075] Comparative Example 2

[0076] The preparation method of the ultra-clear, extra-thick float glass described in Comparative Example 2 is the same as that of Example 1, except that the raw material composition is different. The ultra-clear, extra-thick float glass described in Comparative Example 2 is composed of the following raw materials, in parts by weight: 100 parts of quartz sand, 8.0 parts of dodecaluminate heptaaluminate, 0.5 parts of titanium oxide whiskers, 0.4 parts of lanthanum hexaboride, 4.5 parts of barite, 1.9 parts of lithium hydroxide, 0.08 parts of Ca3(SbO4)2, 0.04 parts of zinc selenite, and 0.03 parts of neodymium oxide.

[0077] The ultra-clear and ultra-thick float glass prepared in Comparative Example 2 has a thickness of 19.0 mm, a bending strength of 105 MPa, and a light transmittance of 87.4%.

[0078] Comparative Example 3

[0079] The preparation method of the ultra-clear, extra-thick float glass described in Comparative Example 3 is the same as that of Example 1, except that the raw material composition is different. The ultra-clear, extra-thick float glass described in Comparative Example 3 is composed of the following raw materials, in parts by weight: 100 parts of quartz sand, 8.0 parts of dodecaluminate heptaaluminate, 0.5 parts of titanium oxide whiskers, 0.4 parts of lanthanum hexaboride, 4.5 parts of barite, 1.9 parts of lithium hydroxide, 0.08 parts of Ca₃(SbO₄)₂, 0.19 parts of Mg₂SnO₄, and 0.03 parts of neodymium oxide.

[0080] The ultra-clear and ultra-thick float glass prepared in Comparative Example 3 has a thickness of 19.0 mm, a bending strength of 114 MPa, and a light transmittance of 88.0%.

[0081] Comparative Example 4

[0082] The preparation method of the ultra-clear, extra-thick float glass described in Comparative Example 4 is the same as that of Example 1, except that the raw material composition is different. The ultra-clear, extra-thick float glass described in Comparative Example 4 is composed of the following raw materials, in parts by weight: 100 parts of quartz sand, 8.0 parts of dodecaluminate heptaaluminate, 0.5 parts of titanium oxide whiskers, 0.4 parts of lanthanum hexaboride, 4.5 parts of barite, 1.9 parts of lithium hydroxide, 0.08 parts of Ca₃(SbO₄)₂, 0.19 parts of Mg₂SnO₄, and 0.04 parts of zinc selenite.

[0083] The ultra-clear and ultra-thick float glass prepared in Comparative Example 4 has a thickness of 19.0 mm, a bending strength of 118 MPa, and a light transmittance of 88.5%.

[0084] The flexural strength and light transmittance of the ultra-white and ultra-thick float glass prepared in Examples 1-3 are much higher than those in Comparative Examples 1-4. In Comparative Examples 1-4, the flexural strength or light transmittance of the prepared glass is significantly reduced due to the absence of any one of Ca3(SbO4)2, Mg2SnO4, zinc selenite and neodymium oxide.

Claims

1. An ultra-clear and ultra-thick float glass, characterized by: The invention is composed of the following raw materials in parts by weight: 100 parts of quartz sand, 7.5-8.5 parts of dodecaluminate heptaaluminate, 0.4-0.6 parts of titanium oxide whiskers, 0.3-0.5 parts of lanthanum hexaboride, 4.0-5.0 parts of barite, 1.8-2.0 parts of lithium hydroxide, 0.07-0.09 parts of Ca3(SbO4)2, 0.18-0.20 parts of Mg2SnO4, 0.03-0.05 parts of zinc selenite, and 0.02-0.04 parts of neodymium oxide.

2. The ultra-clear and ultra-thick float glass according to claim 1, characterized in that: The preparation method of Mg2SnO4 is as follows: MgO and SnO2 are weighed according to a molar ratio of 2:1, placed in a grinding jar, ethanol is added as a grinding aid, and ball milling is performed for 40 minutes. The uniformly mixed material is placed in a ventilated place to dry, and the ethanol and moisture are removed to obtain a dry material. The dry material is kept at 1230°C for 3.5 hours to prepare Mg2SnO4.

3. The ultra-clear and ultra-thick float glass according to claim 1, characterized in that: The preparation method of Ca3(SbO4)2 is as follows: Sb2S3 and Ca(OH)2 are weighed in a molar ratio of 1:3, placed in a grinding jar, ethanol is added as a grinding aid, and ball milling is performed for 30 minutes. The evenly mixed material is placed in a ventilated place to dry, and the ethanol and moisture are removed to obtain a dry material. The dry material is calcined at 800°C for 5 hours to prepare Ca3(SbO4)2.

4. The ultra-clear and ultra-thick float glass according to claim 1, characterized in that: The invention is composed of the following raw materials in parts by weight: 100 parts of quartz sand, 8.0 parts of dodecaluminate heptaaluminate, 0.5 parts of titanium oxide whiskers, 0.4 parts of lanthanum hexaboride, 4.5 parts of barite, 1.9 parts of lithium hydroxide, 0.08 parts of Ca3(SbO4)2, 0.19 parts of Mg2SnO4, 0.04 parts of zinc selenite, and 0.03 parts of neodymium oxide.

5. A method for preparing the ultra-clear and ultra-thick float glass according to claim 1, characterized in that: It consists of the following steps: (1) Quartz sand, calcium dodecaaluminate, titanium oxide whisker, lanthanum hexaboride, barite, lithium hydroxide, Ca3(SbO4)2, Mg2SnO4, zinc selenite and neodymium oxide are fully mixed in certain weight proportions to obtain a batch; (2) Adding the batch material into the kiln and melting it to prepare glass liquid; (3) The melted and clarified glass liquid is fed into the float glass tin bath at a temperature of 980-1000°C for forming, and linear thinning is performed using three-stage deceleration traction; (4) The formed glass is placed in an annealing kiln for step annealing to produce ultra-white and ultra-thick float glass.

6. The method for preparing ultra-clear and ultra-thick float glass according to claim 5, wherein: The melting in step (2) is first heated to 830-850°C at a rate of 3°C / min and kept warm for 30 minutes, then heated to 1030-1050°C at a rate of 5°C / min and kept warm for 60 minutes, then heated to 1330-1350°C at a rate of 2°C / min and kept warm for 40 minutes, and finally heated to 1560-1580°C at a rate of 4°C / min and kept warm for 240 minutes.

7. The method for preparing ultra-clear and ultra-thick float glass according to claim 5, wherein: In step (3), the temperature of the first section is 950°C, the pulling speed is 160 m / h, the temperature of the second section is 880°C, the pulling speed is 100 m / h, the temperature of the third section is 830°C, the pulling speed is 60 m / h, and the temperature of the fourth section is 760°C, the pulling speed is 42 m / h.

8. The method for preparing ultra-clear and ultra-thick float glass according to claim 5, wherein: The step annealing in step (4) is first cooling to 570-580°C at a rate of 2.5°C / min and keeping warm for 8h, then cooling to 540-550°C at a rate of 1.5°C / min, cooling to 460-470°C at a rate of 1.8°C / min and keeping warm for 2h, cooling to 400-410°C at a rate of 1.5°C / min and keeping warm for 8h, cooling to 360-370°C at a rate of 1.2°C / min and keeping warm for 12h, cooling to 340-350°C at a rate of 1.0°C / min and keeping warm for 24h, cooling to 240-250°C at a rate of 0.8°C / min and keeping warm for 12h, cooling to 100°C at a rate of 30°C / h, and finally cooling naturally to room temperature.