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

Abstract

The invention belongs to the technical field of glass preparation, and particularly relates to ultra-white and ultra-thick float glass and a preparation method thereof. The ultra-white and ultra-thick float glass is prepared from the following raw materials: quartz sand, dodecacalcium heptaaluminate, titanium oxide whiskers, lanthanum hexaboride, barite, lithium hydroxide, Ca3 (SbO4) 2, Mg2SnO4, zinc selenite and neodymium oxide. According to the ultra-white and ultra-thick float glass, quartz sand, dodecacalcium heptaaluminate, titanium oxide whiskers, lanthanum hexaboride, barite and lithium hydroxide are used as main raw materials to construct a compact glass network structure, the mechanical performance of the ultra-white and ultra-thick float glass is ensured, a mixture of Ca3 (SbO4) 2, Mg2SnO4, zinc selenite and neodymium oxide is used as a clarification decolorizing agent, and the ultra-white and ultra-thick float glass is obtained. And the light transmittance of the prepared ultra-white and ultra-thick float glass is ensured. Therefore, the synergistic effect of the raw materials ensures that the prepared glass has very good bending strength and light transmittance.

Description

Technical Field

[0001] The present invention belongs to the technical field of glass preparation, and particularly relates to an 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 glass liquid continuously flows onto the surface of molten metal tin while controlling the flow rate of the glass liquid. Under the combined action of gravity, surface tension, buoyancy and pulling force of the tin liquid, a glass ribbon with a certain equilibrium thickness is formed. During the process of the glass ribbon advancing, it gradually cools and solidifies, and finally is pulled out from the outlet end of the tin bath and then enters the annealing furnace. The equilibrium thickness is about 6 mm. To produce thick glass with a thickness greater than the equilibrium thickness, the reverse-assisted direct drawing method or the retaining wall method is usually adopted. However, for the production method of ultra-thick float glass with a thickness of 19 mm or more, it is difficult to obtain finished products with the same performance as those of the finished products with the equilibrium thickness in most cases.

[0003] Ultra-white glass has the basic characteristics of ultra-white transparency and is a new type of high-quality and multi-functional high-grade glass variety with a higher light transmittance than ordinary glass. Due to less impurities in the raw materials and strict process control and refined process conditions in the preparation process, ultra-white glass is more uniform than ordinary glass and has excellent physical, mechanical and optical properties that exceed those of ordinary glass. At the same time, it can be processed in various ways like ordinary glass. Because ultra-white glass has an extremely high light transmittance, it can be applied to industries such as high-end technology products, electronic products, high-grade car glass, and solar cells.

[0004] For ordinary basic glass batches, the light transmittance of ultra-white float glass mainly depends on impurities such as total iron content. Since sulfur and iron impurities are inevitably introduced during the raw material and glass production processes, and the combination of sulfur and iron in the glass will form iron sulfide (usually referring to iron sulfide or polysulfide), it will affect the optical property - visible light transmittance of float glass.

[0005] The light absorption of ultra-white float glass is caused by three aspects: the intrinsic absorption of the glass structure, the absorption of impurities contained in the float glass, and the absorption of atomic defect color centers. For float glass in the visible light to near-infrared wavelength range, the absorption of impurities is the main one. The impurities are introduced into the float glass by coloring elements such as iron, titanium, nickel, and chromium in the raw materials of the float glass, refractory materials eroded during the melting process, sulfur, vanadium, iron, etc. in the fuel of the melting furnace, and iron and alloys in equipment during forming and processing. Generally, iron elements exist in two ionic states in float glass, 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, measured 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: The preparation method of Mg2SnO4 is as follows: MgO and SnO2 are weighed in a molar ratio of 2:1, put into a grinding jar, add ethanol as a grinding aid, and ball-mill for 40 minutes; the uniformly mixed material is placed in a ventilated place to dry, 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.

[0009] The preparation method of Ca3(SbO4)2 is as follows: Sb2S3 and Ca(OH)2 are weighed in a molar ratio of 1:3, put into a grinding jar, add ethanol as a grinding aid, and ball-mill for 30 minutes; the uniformly mixed material is placed in a ventilated place to dry, 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.

[0010] Preferably, the ultra-white and ultra-thick float glass described in the present invention is composed of the following raw materials, 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.

[0011] The method for preparing the ultra-clear and ultra-thick float glass of the present invention comprises 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 according to certain weight proportions to obtain a batch material; (2) Add the batch material into a kiln for melting to obtain molten glass; (3) Feed the molten and clarified glass liquid into a float glass tin bath at a temperature of 980 - 1000 °C through a runner for forming, and linearly draw it thinner by using three-stage decelerated traction; (4) Feed the formed glass into an annealing kiln for step annealing to obtain ultra-clear and ultra-thick float glass.

[0012] Wherein: In step (2), the melting process is as follows: First, heat up at a rate of 3 °C / min to 830 - 850 °C and hold for 30 min, then heat up at a rate of 5 °C / min to 1030 - 1050 °C and hold for 60 min, then heat up at a rate of 2 °C / min to 1330 - 1350 °C and hold for 40 min, and finally heat up at a rate of 4 °C / min to 1560 - 1580 °C and hold for 240 min.

[0013] In step (3), the temperature of the first stage is 950 °C, the drawing speed is 160 m / h, the temperature of the second stage is 880 °C, the drawing speed is 100 m / h, the temperature of the third stage is 830 °C, the drawing speed is 60 m / h, the temperature of the fourth stage is 760 °C, and the drawing speed is 42 m / h.

[0014] In step (4), the step annealing is as follows: First, cool down at a rate of 2.5 °C / min to 570 - 580 °C and hold for 8 h, then cool down at a rate of 1.5 °C / min to 540 - 550 °C, cool down at a rate of 1.8 °C / min to 460 - 470 °C and hold for 2 h, cool down at a rate of 1.5 °C / min to 400 - 410 °C and hold for 8 h, cool down at a rate of 1.2 °C / min to 360 - 370 °C and hold for 12 h, cool down at a rate of 1.0 °C / min to 340 - 350 °C and hold for 24 h, cool down at a rate of 0.8 °C / min to 240 - 250 °C and hold for 12 h, cool down at a rate of 30 °C / h to 100 °C, and finally cool down naturally to room temperature.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) For the ultra-clear and ultra-thick float glass of the present invention, quartz sand, dodecacalcium heptaluminate, titanium oxide whiskers, lanthanum hexaboride, barite, and lithium hydroxide are used as 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 fining and decolorizing agent to ensure the light transmittance of the prepared ultra-clear and ultra-thick float glass. Thus, through the synergistic effect among the raw materials, the prepared glass has good flexural strength and light transmittance.

[0016] (2)The ultra-white and ultra-thick float glass of the present invention uses quartz sand, dodecacalcium heptaluminate, titanium oxide whiskers, lanthanum hexaboride, barite, and lithium hydroxide as the main raw materials. Among them, dodecacalcium heptaluminate 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, a calcium aluminosilicate intermediate phase is formed. At the same time, trivalent aluminum occupies the tetrahedral voids to form [AlO4] - tetrahedrons, which together with [SiO4] construct a dense network to improve the hardness of the glass; the titanium oxide whiskers play a role in inducing microcrack deflection and toughening. Lanthanum hexaboride decomposes at high temperature to generate La2O3@B nanoclusters, which are filled at the interface between TiO2 and the silicon-oxygen network, making the network denser. Thus, the synergistic effect of dodecacalcium heptaluminate, titanium oxide whiskers, and lanthanum hexaboride improves the mechanical strength of the glass. Barite decomposes at high temperature to generate barium oxide and sulfur trioxide. Sulfur trioxide further decomposes to generate sulfur dioxide and oxygen. Sulfur dioxide and oxygen play a physical clarification role, and the formation of barium oxide can reduce the high-temperature viscosity and improve the hardness of the glass; lithium hydroxide can reduce the melting temperature, shrink the glass network, and reduce the thermal expansion coefficient.

[0017] (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 fining and decolorizing agent. Ca3(SbO4)2 reacts with ferrous oxide at high temperature to generate ferric oxide, calcium oxide, antimony trioxide, and oxygen. Sb 5+ oxidizes the strongly coloring ion Fe 2+ to the weakly coloring Fe 3+ , significantly weakening the blue-green tone of the glass. The generated Sb2O3 can further cooperate with Se in zinc selenite to generate a colorless Sb-Se compound to neutralize the residual yellow color. At the same time, the released O2 forms bubble nuclei, which combine with the gas dissolved in the glass (such as SO2) to improve the light transmittance of the glass. The Mg2SnO4 powder decomposes at high temperature, and the decomposition temperature matches the glass melting temperature, generating magnesium oxide, tin dioxide, and oxygen. The oxygen therein forms microbubble nuclei, and during the upward floating process, it combines with the gas dissolved in the glass melt and brings it out of the melt. In addition, at the later stage of glass melting, the oxygen partial pressure decreases, promoting the partial reduction of SnO2 to produce gas and generating divalent tin with strong reducibility, which can reduce the coloring metal ions in the glass. In addition, the generated magnesium oxide can reduce the alkalinity of the glass, promote Fe 3+ to exist stably as [FeO4] - , thereby reducing the yellow color tone. 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 voids, and inhibit the change rate of the Si-O bond angle at high temperature. Zinc selenite decomposes in the high-temperature glass melt, releasing the strongly reducing substance Se 2- , reducing the coloring Fe 3+ to Fe 2+At the same time, the generated zinc oxide 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 color 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, reduces the concentration of oxygen vacancies, and increases the hardness of the glass. As a result, Ca3(SbO4)2, Mg2SnO4, zinc selenite, and neodymium oxide work synergistically to generate different decolorizing substances and gases to achieve clarification and decolorization.

[0018] (4) The method for preparing the 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 the ultra-thick glass through four-stage deceleration thinning, and eliminates the internal stress of the 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

[0019] The present invention is further described below with reference to the embodiments.

[0020] Example 1 The ultra-white and ultra-thick float glass described in Example 1 is composed of the following raw materials, measured by weight: 100 parts of quartz sand, 8.0 parts of calcium dodecaaluminate, 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.

[0021] in: The preparation method of Mg2SnO4 is as follows: MgO and SnO2 are weighed in a molar ratio of 2:1, put into a grinding jar, add ethanol as a grinding aid, and ball-mill for 40 minutes; the uniformly mixed material is placed in a ventilated place to dry, 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.

[0022] The preparation method of Ca3(SbO4)2 is as follows: Sb2S3 and Ca(OH)2 are weighed in a molar ratio of 1:3, put into a grinding jar, add ethanol as a grinding aid, and ball-mill for 30 minutes; the uniformly mixed material is placed in a ventilated place to dry, 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.

[0023] The method for preparing the ultra-clear and ultra-thick float glass described in Example 1 comprises 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 according to certain weight proportions to obtain a batch material; (2) Adding the batch materials into a kiln for melting to prepare molten glass; (3) The molten and clarified glass liquid enters the float glass tin bath at a flow channel with a temperature of 990°C for molding, 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.

[0024] in: The melting in step (2) is firstly heated to 840°C at a rate of 3°C / min and kept at that temperature for 30 min, then heated to 1040°C at a rate of 5°C / min and kept at that temperature for 60 min, then heated to 1340°C at a rate of 2°C / min and kept at that temperature for 40 min, and finally heated to 1570°C at a rate of 4°C / min and kept at that temperature for 240 min.

[0025] 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.

[0026] 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.

[0027] 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 proves its high whiteness.

[0028] Example 2 The ultra-white and ultra-thick float glass described in Example 2 is composed of the following raw materials, measured 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.

[0029] in: The preparation method of Mg2SnO4 is as follows: MgO and SnO2 are weighed in a molar ratio of 2:1, put into a grinding jar, add ethanol as a grinding aid, and ball-mill for 40 minutes; the uniformly mixed material is placed in a ventilated place to dry, 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.

[0030] The preparation method of Ca3(SbO4)2 is as follows: Sb2S3 and Ca(OH)2 are weighed in a molar ratio of 1:3, put into a grinding jar, add ethanol as a grinding aid, and ball-mill for 30 minutes; the uniformly mixed material is placed in a ventilated place to dry, 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.

[0031] The method for preparing the ultra-clear and ultra-thick float glass described in Example 2 comprises 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 according to certain weight proportions to obtain a batch material; (2) Adding the batch materials into a kiln for melting to prepare molten glass; (3) The molten and clarified glass liquid enters the float glass tin bath at a flow channel with a temperature of 1000°C for molding, 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.

[0032] in: In step (2), the melting process is as follows: first, the temperature is raised to 850 °C at a rate of 3 °C / min and held for 30 min, then it is raised to 1050 °C at a rate of 5 °C / min and held for 60 min, then it is raised to 1350 °C at a rate of 2 °C / min and held for 40 min, and finally it is raised to 1580 °C at a rate of 4 °C / min and held for 240 min.

[0033] In step (3), the temperature of the first stage is 950 °C, the drawing speed is 160 m / h, the temperature of the second stage is 880 °C, the drawing speed is 100 m / h, the temperature of the third stage is 830 °C, the drawing speed is 60 m / h, the temperature of the fourth stage is 760 °C, and the drawing speed is 42 m / h.

[0034] In step (4), the step annealing is as follows: first, the temperature is lowered to 580 °C at a rate of 2.5 °C / min and held for 8 h, then it is lowered to 550 °C at a rate of 1.5 °C / min, then it is lowered to 470 °C at a rate of 1.8 °C / min and held for 2 h, then it is lowered to 410 °C at a rate of 1.5 °C / min and held for 8 h, then it is lowered to 370 °C at a rate of 1.2 °C / min and held for 12 h, then it is lowered to 350 °C at a rate of 1.0 °C / min and held for 24 h, then it is lowered to 250 °C at a rate of 0.8 °C / min and held for 12 h, then it is lowered to 100 °C at a rate of 30 °C / h, and finally it is naturally cooled to room temperature.

[0035] The ultra-white and ultra-thick float glass prepared in Example 2 has a thickness of 19.2 mm, a flexural strength of 130 MPa, and a light transmittance of 93.0%. Its high light transmittance proves its high whiteness.

[0036] Example 3 The ultra-white and ultra-thick float glass described in this Example 3 is composed of the following raw materials in parts by weight: 100 parts of quartz sand, 8.5 parts of dodecacalcium heptaluminate, 0.4 part of titanium oxide whiskers, 0.3 part of lanthanum hexaboride, 4.0 parts of barite, 2.0 parts of lithium hydroxide, 0.09 part of Ca3(SbO4)2, 0.20 part of Mg2SnO4, 0.03 part of zinc selenite, and 0.02 part of neodymium oxide.

[0037] Among them: The preparation method of Mg2SnO4 is to weigh MgO and SnO2 according to a molar ratio of 2:1, put them into a grinding jar, add ethanol as a grinding aid, and ball-mill and mix for 40 min. Place the uniformly mixed material in a ventilated place to dry, remove ethanol and moisture to obtain a dry product, and hold the dry product at 1230 °C for 3.5 h to prepare Mg2SnO4.

[0038] The preparation method of Ca3(SbO4)2 is as follows: Sb2S3 and Ca(OH)2 are weighed in a molar ratio of 1:3, put into a grinding jar, add ethanol as a grinding aid, and ball-mill for 30 minutes; the uniformly mixed material is placed in a ventilated place to dry, 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.

[0039] The method for preparing the ultra-clear and ultra-thick float glass described in Example 3 comprises 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 according to certain weight proportions to obtain a batch material; (2) Adding the batch materials into a kiln for melting to prepare molten glass; (3) The molten and clarified glass liquid enters the float glass tin bath at a flow channel with a temperature of 980°C for molding, 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.

[0040] in: The melting in step (2) is firstly heated to 830°C at a rate of 3°C / min and kept at that temperature for 30 min, then heated to 1030°C at a rate of 5°C / min and kept at that temperature for 60 min, then heated to 1330°C at a rate of 2°C / min and kept at that temperature for 40 min, and finally heated to 1560°C at a rate of 4°C / min and kept at that temperature for 240 min.

[0041] 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.

[0042] 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.

[0043] The thickness of the ultra-white and ultra-thick float glass prepared in Example 3 is 19.1 mm, the flexural strength is 132 MPa, and the light transmittance is 93.1%. The high light transmittance proves its high whiteness.

[0044] Comparative Example 1 The preparation method of the ultra-white and ultra-thick float glass described in this Comparative Example 1 is the same as that in Example 1. The only difference lies in the raw material composition. The ultra-white and ultra-thick float glass described in this Comparative Example 1 is composed of the following raw materials in parts by weight: 100 parts of quartz sand, 8.0 parts of dodecacalcium heptaluminate, 0.5 part of titanium oxide whiskers, 0.4 part of lanthanum hexaboride, 4.5 parts of barite, 1.9 parts of lithium hydroxide, 0.19 part of Mg2SnO4, 0.04 part of zinc selenite, and 0.03 part of neodymium oxide.

[0045] The thickness of the ultra-white and ultra-thick float glass prepared in Comparative Example 1 is 19.0 mm, the flexural strength is 110 MPa, and the light transmittance is 87.8%.

[0046] Comparative Example 2 The preparation method of the ultra-white and ultra-thick float glass described in this Comparative Example 2 is the same as that in Example 1. The only difference lies in the raw material composition. The ultra-white and ultra-thick float glass described in this Comparative Example 2 is composed of the following raw materials in parts by weight: 100 parts of quartz sand, 8.0 parts of dodecacalcium heptaluminate, 0.5 part of titanium oxide whiskers, 0.4 part of lanthanum hexaboride, 4.5 parts of barite, 1.9 parts of lithium hydroxide, 0.08 part of Ca3(SbO4)2, 0.04 part of zinc selenite, and 0.03 part of neodymium oxide.

[0047] The thickness of the ultra-white and ultra-thick float glass prepared in Comparative Example 2 is 19.0 mm, the flexural strength is 105 MPa, and the light transmittance is 87.4%.

[0048] Comparative Example 3 The preparation method of the ultra-white and ultra-thick float glass described in this Comparative Example 3 is the same as that in Example 1. The only difference lies in the raw material composition. The ultra-white and ultra-thick float glass described in this Comparative Example 3 is composed of the following raw materials in parts by weight: 100 parts of quartz sand, 8.0 parts of dodecacalcium heptaluminate, 0.5 part of titanium oxide whiskers, 0.4 part of lanthanum hexaboride, 4.5 parts of barite, 1.9 parts of lithium hydroxide, 0.08 part of Ca3(SbO4)2, 0.19 part of Mg2SnO4, and 0.03 part of neodymium oxide.

[0049] The thickness of the ultra-white and ultra-thick float glass prepared in Comparative Example 3 is 19.0 mm, the flexural strength is 114 MPa, and the light transmittance is 88.0%.

[0050] Comparative Example 4 The preparation method of the extra-clear extra-thick float glass described in Comparative Example 4 is the same as that in Example 1, and the only difference lies in the raw material composition. The extra-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 dodecacalcium heptaluminate, 0.5 part of titanium oxide whiskers, 0.4 part of lanthanum hexaboride, 4.5 parts of barite, 1.9 parts of lithium hydroxide, 0.08 part of Ca3(SbO4)2, 0.19 part of Mg2SnO4, and 0.04 part of zinc selenite.

[0051] The thickness of the extra-clear extra-thick float glass prepared in Comparative Example 4 is 19.0 mm, the flexural strength is 118 MPa, and the light transmittance is 88.5%.

[0052] The flexural strength and light transmittance of the extra-clear extra-thick float glass prepared in Examples 1-3 are much higher than those in Comparative Examples 1-4. In Comparative Examples 1-4, the absence of any one of Ca3(SbO4)2, Mg2SnO4, zinc selenite, and neodymium oxide results in a significant decrease in the flexural strength or light transmittance of the prepared glass.

Claims

1. A super-white and super-thick float glass, characterized in that: 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 whisker, 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 in a molar ratio of 2:1, put into a grinding jar, add ethanol as a grinding aid, and ball-mill for 40 minutes; the uniformly mixed material is placed in a ventilated place to dry, 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-white and ultra-thick float glass according to claim 1, wherein: The preparation method of Ca3(SbO4)2 is as follows: Sb2S3 and Ca(OH)2 are weighed in a molar ratio of 1:3, put into a grinding jar, add ethanol as a grinding aid, and ball-mill for 30 minutes; the uniformly mixed material is placed in a ventilated place to dry, 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, wherein: The invention is composed of the following raw materials in parts by weight: 100 parts of quartz sand, 8.0 parts of calcium dodecaaluminate heptaaluminate, 0.5 parts of titanium oxide whisker, 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-white 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 according to certain weight proportions to obtain a batch material; (2) Adding the batch materials into a kiln for melting to prepare molten glass; (3) The molten and clarified glass liquid enters the float glass tin bath at a flow channel with a temperature of 980-1000°C for molding, 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 preparation method of the ultra-white and ultra-thick float glass according to claim 5, characterized in that: The melting in step (2) is first heated to 830-850°C at a rate of 3°C / min and kept warm for 30 min, then heated to 1030-1050°C at a rate of 5°C / min and kept warm for 60 min, then heated to 1330-1350°C at a rate of 2°C / min and kept warm for 40 min, and finally heated to 1560-1580°C at a rate of 4°C / min and kept warm for 240 min.

7. The preparation method of the ultra-white and ultra-thick float glass according to claim 5, characterized in that: 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 preparation method of the ultra-white and ultra-thick float glass according to claim 5, wherein: The step annealing described in step (4) is as follows: first, cool down at a rate of 2.5 °C / min to 570 - 580 °C and hold for 8 h, then cool down at a rate of 1.5 °C / min to 540 - 550 °C, cool down at a rate of 1.8 °C / min to 460 - 470 °C and hold for 2 h, cool down at a rate of 1.5 °C / min to 400 - 410 °C and hold for 8 h, cool down at a rate of 1.2 °C / min to 360 - 370 °C and hold for 12 h, cool down at a rate of 1.0 °C / min to 340 - 350 °C and hold for 24 h, cool down at a rate of 0.8 °C / min to 240 - 250 °C and hold for 12 h, cool down at a rate of 30 °C / h to 100 °C, and finally cool naturally to room temperature.