Recipe of glass capable of carbon emission and preparation method for glass capable of carbon emission

Abstract

The present invention belongs to the technical field of glass manufacturing. Provided are a recipe of glass capable of carbon emission and a preparation method for the glass capable of carbon emission. The recipe comprises the following raw material components in percentage by mass: 53-60% of quartz sand, 12-18% of wollastonite, 5-12% of albite, 0.5-2% of spodumene, and 15-20% of NaOH; on this basis, 2-5% of water and 5-10% of a silica sol binder are additionally added to ensure the humidity and good adhesive effect of a compounded material. The raw materials are fully mixed and then fed to an extrusion molding machine, the pressure in the extrusion molding machine is controlled to be 50-150 MPa, and extrusion is performed to form spherical or flake-shaped pellets having a diameter of 5-15 mm; and the granulated and molded pellets of the compounded material are then preheated to 500°C and put into a kiln for melting to obtain glass capable of carbon emission. The preparation method can improve the utilization rate of the compounded material, shorten the melting time, reduce the melting temperature, improve the quality of glass melting, reduce the unit energy consumption, and reduce the carbon emission.

Description

A carbonized glass formula and preparation method thereof

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on January 10, 2024, with application number CN202410036184.0 and invention name “A decarbonized glass formula and its preparation method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application belongs to the field of glass manufacturing technology, and specifically relates to a carbonized glass formula and a preparation method thereof. Background Art

[0003] Energy conservation and carbon reduction are current and future trends. Due to its high energy consumption and carbon emissions, the glass industry is listed as one of my country's key carbon emission sectors. In glass production, one of the main sources of CO2 emissions is the decomposition of raw materials containing carbonates, such as limestone, dolomite, and soda ash, at high temperatures.

[0004] Raw materials that can release gas during the heating process include carbonates (such as Na2CO3, CaCO3, MgCO3, BaCO3, etc.), water, nitrates, borax, boric acid, and aluminum hydroxide. The production of 1000kg of soda-lime glass requires approximately 1200kg of raw materials. Of the 200kg mass difference, approximately 150kg is caused by the production of CO2 by carbonates in the raw materials during the high-temperature decarbonization process, and the rest is caused by water discharged during the melting of the batch, the decomposition of clarifiers, and volatiles. The production of CO2 is directly related to the decomposition of various carbonates. CO2 mainly comes from the thermal decomposition of various carbonates, decomposition products when forming silicates, the decomposition of double salts, and the decomposition reaction of low-melting eutectic mixtures.

[0005] Traditional glassmaking batches are fed into the furnace in powder form. Excessive fines in the powder can harm the working environment and human health, corrode structural equipment, clog the lattice, and reduce the life of the furnace. Dispersion of the powder can also alter the original proportions of the components. For example, the volatility of powdered alkali metals and boron during melting is much greater than that of granular forms, which can affect product quality, including glass homogeneity. Powdered glass batches also have a porosity of 40% to 50%, resulting in low thermal conductivity, long melting times, and wasted energy.

[0006] In recent years, countries around the world, including my country, have been researching the use of granulated materials instead of powdered batch materials for melting. Existing technology uses batch granulators to compress powdered materials into briquettes or pellets for glass melting, improving raw material utilization and saving energy. The project's completion will be of great significance to my country's low-carbon economy. Effective measures, including raw material substitution, the use of reactive raw materials, and increased use of cullet, will be implemented to control CO2 emissions at the source. With the goal of decarbonizing glass batches, research into decarbonizing glass batch process technologies will be conducted, overcoming key technical challenges in raw material substitution and granulation, improving batch melting efficiency, reducing energy consumption, and minimizing carbon emissions. Summary of the Invention

[0007] The purpose of this application is to overcome the defects of the prior art and provide a decarbonized glass formula and a preparation method thereof, which can reduce CO2 emissions during the glass production process and produce a glass with few bubbles and good homogeneity.

[0008] The purpose of this application can be achieved through the following technical solutions:

[0009] The first aspect of the present application provides a decarbonized glass formula, which includes the following components, by mass percentage: 53-60% quartz sand, 12-18% wollastonite, 5-12% albite, 0.5-2% spodumene, and 15-20% NaOH.

[0010] The introduction of active raw materials in this application can accelerate the formation of silicates and accelerate the clarification and homogenization of glass, while also lowering the melting temperature and reducing the amount of carbonate used. From the silicate reaction process of the batch material, it can be seen that CaO eventually reacts with SiO2 to form CaSiO3. Therefore, wollastonite (CaSiO3) can be used as a glass raw material. Its theoretical composition is 48.3% CaO and 51.7% SiO2. It only needs to be melted, and no large amount of high-temperature gas is generated. It can replace CaCO3 by introducing CaO, reducing the use of carbonates, and can also reduce heat consumption and lower the melting temperature of the glass liquid, thereby achieving the effect of CO2 emission reduction. Sodium feldspar (chemical composition: Na(AlSi3O8)) and spodumene (chemical composition: LiAl(Si2O6)) containing R2O are used to replace part of the Na2O and Al2O3 in the glass components. Lithium oxide and sodium oxide are both network-external oxides. When the O / Si ratio is small, Li2O mainly plays a role in breaking the network and has a very good fluxing effect, which can reduce the melting temperature and melt viscosity and promote the clarification and homogenization of the glass liquid.

[0011] Compared with the process of preparing glass using traditional raw materials, this application reduces CO2 emissions. In the traditional soda-lime-silica glass batch, the CO2 release process is that the batch begins to release CO2 at around 600°C. It is the result of the reaction between the previously generated double salt CaNa2(CO3)2 and SiO2: CaNa2(CO3)2+2SiO2→Na2SiO3+CaSiO3+2CO2↑;

[0012] At 720-900℃, sodium carbonate and silicon dioxide react: Na2CO3+SiO2→Na2SiO3+CO2↑;

[0013] At 740-800℃, CaNa2(CO3)2 and Na2CO3 low-temperature eutectic forms and melts, and begins to react with SiO2: CaNa2(CO3)2+Na2CO3+3SiO2→2Na2SiO3+CaSiO3+3CO2↑;

[0014] At 912℃ and 960℃, CaCO3 and CaNa2(CO3)2 decompose successively:

[0015] At 1010℃, CaO and SiO2 react: CaO+SiO2→CaSiO3;

[0016] In the above process, the complete decomposition of 1 ton of calcium carbonate produces 0.440 tons of CO2, while 1 ton of sodium carbonate produces 0.415 tons of CO2. Therefore, the CO2 emission factor of the raw materials can be determined based on the content of sodium oxide, calcium oxide, etc. in the glass. Furthermore, researching low-gassing rate glass formulations will also become a key task in CO2 emission reduction.

[0017] The second aspect of the present application provides a method for preparing decarbonized glass, which is as follows:

[0018] The reduced carbon glass formula is subjected to an extrusion granulation process. The extrusion granulation technology specifically includes: adding 2-5% water and 5-10% silica sol binder to ensure the moisture content and good adhesive effect of the batch material, and then feeding it into an extrusion molding machine after sufficient mixing. The pressure of the extrusion molding machine is controlled at 50-150 MPa, and spherical or flaky granules with a diameter of 5-15 mm are extruded. The granulated batch material granules are preheated to 500°C and then put into a kiln for melting to obtain the reduced carbon glass.

[0019] The third aspect of the present application provides a method for preparing decarbonized glass, which is as follows:

[0020] The reduced carbon glass formula described in the first aspect of the present application is subjected to an extrusion granulation process, the granulated batch granules are preheated to 500° C., and then put into a kiln for melting to obtain the reduced carbon glass.

[0021] In some embodiments of the present application, the extrusion granulation technology specifically includes: adding 2-5% water and 5-10% silica sol binder to ensure the moisture of the batch and good adhesive effect, and then feeding it into an extrusion molding machine after sufficient mixing to extrude into spherical or flaky granules with a diameter of 5-15 mm.

[0022] In some embodiments of the present application, the pressure of the extrusion molding machine is controlled to be 50-150 MPa.

[0023] In the preparation method of the decarbonized glass described in the second aspect or the third aspect of the present application, the melting procedure includes: first raising the temperature to 1000-1200°C for 1-2 hours; raising the temperature from 1000-1200°C to 1500-1600°C for 2-3 hours, and keeping warm for 2-3 hours; then casting and molding by the iron plate casting method, and then undergoing annealing, cutting and polishing steps; preferably, the melting procedure includes: first raising the temperature to 1100°C for 1.5 hours; raising the temperature from 1100°C to 1540°C for 2.5 hours, and keeping warm for 2 hours; then casting and molding by the iron plate casting method, and then undergoing annealing, cutting and polishing steps.

[0024] Beneficial effects of this application:

[0025] The present application can effectively reduce CO2 emissions during the glass production process and produce glass with fewer bubbles and good homogeneity;

[0026] The preparation method of the present application can improve the utilization rate of granulated batch materials, shorten the melting time, lower the melting temperature, improve the glass melting quality, reduce unit energy consumption, and reduce carbon emissions. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0028] The silica sol binder used in the following examples and comparative examples was purchased from Shandong Better New Materials Co., Ltd., with the product model being N3020.

[0029] Glass substrate bubble test: Take the same field of view of the glass substrate and observe it under a magnifying glass, read the number of bubbles, and then calculate the number of bubbles per unit area.

[0030] Glass substrate homogeneity test: Fluorescence testing is performed at different locations within a certain area within the central portion of the glass cross-section. The glass composition at each location is measured. Finally, the composition difference (ΔSiO2, i.e., the difference between the maximum and minimum SiO2 values) is calculated by subtracting the minimum SiO2 value (mass %) from the maximum SiO2 value (mass %) to characterize the homogeneity of the components.

[0031] Example 1

[0032] A carbonized glass batch material (1000 g) comprises 56.80% by mass of quartz sand, 15.70% by mass of wollastonite, 8.10% by mass of albite, 1.40% by mass of spodumene, and 18.00% by mass of NaOH. The glass is prepared according to these components, and 2% by mass of water and 6% by mass of a silica sol binder are added. After thorough mixing, the mixture is fed into an extruder. The pressure of the extruder is controlled at 70 MPa, and spherical granules with a diameter of 8 mm are formed by extrusion. The granulated batch material is preheated to 500° C. using flue gas, and then placed in a kiln for melting. The temperature is first raised to 1100° C. for 1.5 hours, then raised from 1100° C. to 1540° C. for 2.5 hours, and then kept warm for 2 hours. The mixture is then cast by an iron plate casting method, and then annealed, cut, and polished to obtain a glass substrate.

[0033] Example 2-3

[0034] Except for adjusting the raw material ratio as shown in Table 1, the rest is the same as Example 1.

[0035] Comparative Examples 1-4

[0036] Except for adjusting the raw material ratio as shown in Table 1, the rest is the same as Example 1.

[0037] Table 1 Percentage of glass raw materials in various embodiments and comparative examples

[0038] Comparative Example 5

[0039] A conventional glass batch material (1000 g) includes 63.83% by mass of SiO2, 1.71% by mass of Al2O3, 21.84% by mass of Na2CO3, 12.20% by mass of CaCO3, and 0.42% by mass of Li2CO3. The glass is prepared according to these components and melted according to the following melting process: heating the glass from room temperature to 1100°C for 2 hours; heating the glass from 1100°C to 1550°C for 2.5 hours, and maintaining the temperature for 2 hours. The glass is then cast using an iron plate casting method, and then subjected to annealing, cutting, and polishing steps to obtain a glass substrate.

[0040] The test results of the above embodiments and comparative examples are shown in Table 2. The CO2 emission in the glass raw materials refers to the theoretical amount of CO2 in the carbonate calculated by combining the mass difference between the batch before melting and the glass after melting.

[0041] Table 2 Test results of various embodiments and comparative examples

[0042] As can be seen from the above table, the weight percentages of the various raw materials for the glass substrates of Examples 1-3 of the present application are controlled within the range of the present application, the CO2 emissions during the preparation of the glass substrates are all 0, and the prepared glass substrates have few bubbles and good homogeneity; whereas the weight percentages of the various raw materials for the glass substrates of Comparative Examples 1-4 are not controlled within the range of the present application, resulting in the inability to prepare stable and qualified glass substrates, and the prepared glass substrates have many bubbles and poor homogeneity.

[0043] Example 1 and Comparative Example 5 utilize the same oxide formulation and similar melting process, differing in that Example 1 utilizes active raw materials, granulates the batch, and utilizes kiln flue gas for preheating. This demonstrates that the method proposed in this application can effectively reduce CO₂ emissions, avoid the "dust-raising" effect of traditional batches, improve the melting efficiency of granulated batches, shorten melting time, lower melting temperature, improve glass melting quality, reduce specific energy consumption, and reduce carbon emissions, resulting in highly homogeneous glass.

[0044] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0045] The above content is merely an example and explanation of the present application. Technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present application.

Claims

1. A decarbonized glass, characterized in that, Its formula, by mass percentage, includes the following components: 53 - 60% quartz sand, 12 - 18% wollastonite, 5 - 12% albite, 0.5 - 2% spodumene, and 15 - 20% NaOH.

2. The preparation method of the decarbonized glass according to claim 1, characterized in that, Specifically as follows: The formulation of the decarbonized glass is processed by the extrusion granulation process. The granulated mixture after granulation and forming is preheated to 500 °C and then put into a kiln for melting to obtain the decarbonized glass.

3. The preparation method of the decarbonized glass according to claim 2, wherein, The extrusion granulation process specifically includes: adding 2 - 5% water and 5 - 10% silica sol binder, fully mixing and then feeding into an extrusion molding machine to extrude spherical or flaky granules with a diameter of 5 - 15 mm.

4. The method for preparing decarbonized glass according to claim 3, wherein Control the pressure of the extrusion molding machine at 50 - 150 MPa.

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