Amber glass suitable for oxy-fuel combustion melting furnace and preparation method of amber glass

Abstract

The invention discloses amber glass suitable for an oxy-fuel combustion melting furnace and a preparation method of the amber glass, and belongs to the technical field of glass manufacturing. The glass is prepared from the following raw materials: SiO2, Al2O3, CaO, MgO, Na2O, K2O and a composite coloring agent. The composite coloring agent is composed of ferrosilicon alloy powder, coated carbon microspheres and zinc sulfide, a reduction micro-area can be constructed in molten glass, the total-oxygen strong oxidizing atmosphere is effectively resisted, and stable sulfur-carbon coloring is achieved. The preparation method comprises the steps of ingredient mixing, founding, clarifying and homogenizing, forming and annealing and the like, founding is carried out in an oxygen-fuel combustion melting furnace with an isolation protection layer, and the protection layer is a porous ceramic cover plate composite inert ceramic ball and can isolate the atmosphere and maintain the local reduction environment. According to the invention, the contradiction between an oxygen-fuel combustion technology and a sulfur-carbon coloring process is solved, and the production of amber glass with deep color, few bubbles and stable quality is realized.

Description

Technical Field

[0001] This invention belongs to the field of glass manufacturing technology, specifically, it relates to a method for preparing amber glass suitable for an oxygen-fired melting furnace. Background Technology

[0002] Sulfur-carbon coloring is a common amber-colored glass coloring technique. It involves adding reducing agents such as sulfur powder and carbon powder to the glass batch, forming sulfides (such as FeS and Na2S) and polysulfides (such as Na2S) during the melting process. x The pigments interact with iron ions in the glass, producing an amber color ranging from light yellow to dark brown. This coloring process needs to be carried out in a reducing or weakly oxidizing atmosphere.

[0003] However, with increasingly stringent environmental protection requirements, oxy-fuel combustion technology has been widely applied and promoted in glass melting furnaces. This technology, by using pure oxygen instead of air for combustion, significantly improves thermal efficiency and reduces emissions of harmful gases such as nitrogen oxides, becoming an important direction for the green transformation of the glass industry. However, because the furnace atmosphere of oxy-fuel combustion technology is a strongly oxidizing atmosphere, it conflicts with the reducing or weakly oxidizing environment required for sulfur-carbon coloring processes, posing a serious challenge to the production of high-quality amber glass.

[0004] In an oxy-fuel combustion environment, if traditional coloring systems such as iron oxide red, carbon powder, and sodium sulfate are used directly, the strong oxidizing atmosphere will cause a large amount of carbon powder, acting as a reducing agent, to be burned off before it can participate in the effective coloring reaction. The ferrous ions already generated are also easily re-oxidized to ferric ions, making it difficult for the coloring centers to form stably. Ultimately, the glass will have a pale color, failing to achieve the desired color depth. Simultaneously, the unconsumed residual carbon powder will undergo violent side reactions with sulfates during the clarification stage, producing large amounts of carbon dioxide, sulfur dioxide, and other gases, forming bubbles and ash bubbles that are difficult to remove. This severely affects the light transmittance and appearance quality of the glass, leading to a significant decrease in the finished product yield.

[0005] Currently, to address the aforementioned contradictions, many industry players are resorting to significantly increasing the amount of carbon powder and sulfur powder used to compensate for oxidation losses, or avoiding full oxy-fuel combustion technology and continuing to use traditional air-assisted combustion kilns. However, the former not only has low raw material utilization and high costs, but also easily exacerbates bubble defects and environmental pressures; the latter cannot leverage the energy-saving and environmental advantages of full oxy-fuel combustion, running counter to the industry's trend towards cleaner production.

[0006] Therefore, how to effectively and stably achieve sulfur-carbon coloring while fully leveraging the advantages of oxy-fuel combustion technology, and produce high-quality amber glass with deep color and few bubbles, has become a key technical challenge that urgently needs to be overcome in this field. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art and provide an amber glass suitable for oxy-fuel combustion furnace and its preparation method. Through the synergistic effect of a novel composite colorant and a novel furnace structure, this invention successfully constructs a stable reaction space suitable for sulfur and carbon coloring in an oxy-fuel combustion furnace, thereby efficiently and stably producing high-quality amber glass with deep color and few bubbles.

[0008] The objective of this invention can be achieved through the following technical solutions: An amber-colored glass suitable for use in an oxygen-fired melting furnace is made from the following raw materials by weight percentage: 70-76% SiO2, 0.5-3% Al2O3, 8-13% CaO, 1-4% MgO, 10-16% Na2O, 0-2% K2O, with the balance being a composite colorant.

[0009] Preferably, the mass percentage of CaO+MgO is 10-12% of the total.

[0010] Preferably, the mass percentage of Na2O+K2O is 10-14% of the total.

[0011] Preferably, the composite colorant is composed of ferrosilicon alloy powder (FeSi), coated carbon microspheres, and zinc sulfide (ZnS) in a mass ratio of (0.1-0.5):(0.1-0.3):(0.2-1.0).

[0012] Preferably, the silicon-iron alloy powder contains 15-30% Si by weight and has a particle size of 200-800 mesh.

[0013] Preferably, the coated carbon microspheres are prepared by the following steps: inorganic sol is coated onto the surface of ultrafine carbon powder by spray granulation, and the coating layer is densified by high-temperature heat treatment at 600-900°C in a protective atmosphere of nitrogen or argon to obtain coated carbon microspheres.

[0014] Preferably, the inorganic sol is two or more of silica sol, borate aqueous solution, and soluble metal salt solution.

[0015] Preferably, the particle size D50 of the coated carbon microspheres is 20-100 μm, the coating layer is SiO2 with a mass ratio of 10-40%, and the particle size of the ultrafine carbon powder is 1-10 μm.

[0016] The composite colorant of this invention is composed of ferrosilicon alloy powder, coated carbon microspheres and ZnS. The silicon on the surface of the ferrosilicon alloy powder will preferentially oxidize at high temperature to form a dense SiO2 protective film, which can delay the further oxidation of iron and silicon inside, and protect the iron to the deep layer of the glass melt before it reacts and is not oxidized in advance, thereby constructing a local and strong reduction micro-region inside the glass melt. The carbon microspheres in the composite colorant are obtained by microencapsulating ultrafine carbon powder with SiO2. The SiO2 coating layer acts as a protective layer during the batching stage and the initial melting stage to prevent carbon from being oxidized by the kiln atmosphere. When the temperature rises to the glass transition temperature, the carbon powder is released inside the glass melt, which greatly improves the carbon powder utilization rate and inhibits the generation of bubbles by reacting with sulfate. The zinc sulfide in the composite colorant has a much higher thermal stability than traditional sodium sulfate colorants. It can remain stable to very high temperatures under an oxidizing atmosphere and continuously and steadily releases sulfur during the glass melting process. 2- Ions provide a reliable and uniform supply of sulfur for the coloring reaction, avoiding the bubble problems caused by the violent volatilization or decomposition of sulfur.

[0017] This invention also provides a method for preparing amber glass suitable for use in an oxygen-fired furnace, comprising the following steps: S1. Weigh the raw materials and mix them thoroughly to obtain the batch material; S2. The batch material obtained in step S1 is put into an oxygen-fired melting furnace with an atmosphere isolation function for melting to obtain molten glass. S3. After clarifying and homogenizing the glass liquid obtained in step S2, it is transported to the forming equipment for forming and annealing treatment, and finally amber glass suitable for oxygen-fired melting furnace is obtained.

[0018] Preferably, the melting temperature is 1560-1620℃.

[0019] Preferably, the clarification temperature is 1500-1560℃; the homogenization temperature is 1420-1470℃.

[0020] Preferably, the interior of the oxygen-fired melting furnace with atmosphere isolation function consists of a melting zone, a furnace sill, and a clarification and homogenization zone from front to back. An oxygen-fired torch is installed at the top of the furnace, and an isolation and protective layer is installed above the glass liquid surface in the furnace cavity of the melting zone.

[0021] Preferably, the insulating protective layer is a porous ceramic cover plate with several small holes, each containing a hollow or solid inert ceramic ball.

[0022] Preferably, the inert ceramic sphere is made of alumina or zirconium corundum and has a diameter of 20mm-50mm.

[0023] The oxy-fuel combustion furnace of this invention contains an insulating protective layer. Its function is as follows: during oxy-fuel combustion, the high-temperature flame generates heat to the protective layer through convection and radiation, ensuring uniform and efficient heating of the molten glass below and guaranteeing the thermal efficiency of oxy-fuel combustion. Simultaneously, this protective layer isolates the molten glass below from direct contact between reactive gases such as O2 and CH4 in the upper combustion atmosphere of the furnace cavity, preventing the colorant from being oxidized and creating a relatively stable physicochemical environment for the reaction of the composite colorant system.

[0024] The beneficial effects of this invention are: Advantage 1: The composite colorant of this invention is a novel colorant system of FeSi, coated carbon and ZnS, which can build an efficient and stable coloring reaction field inside the glass melt, and obtain amber glass with deep color, pure tone and uniform and stable color. Advantage 2: This invention utilizes an oxygen-filled melting furnace with an isolation layer to create a stable physicochemical environment outside the molten glass, which greatly improves the stability of glass coloring. At the same time, it avoids the violent reaction of sulfur and carbon that would generate a large number of bubbles, thus greatly improving production stability and unifying the environmental protection process and coloring process that were traditionally incompatible. Attached Figure Description

[0025] The invention will now be further described with reference to the accompanying drawings.

[0026] Figure 1 This is a schematic diagram of an oxygen-fired furnace with atmosphere isolation function used in an embodiment of the present invention. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] The schematic diagram of the all-oxygen combustion furnace with atmosphere isolation function used in the following embodiments of the present invention is shown below. Figure 1As shown. Specifically, it includes: the furnace body 1 is constructed of high-grade refractory material and AZS electrofused bricks; the all-oxygen combustion lance 2 is installed on the top of the furnace arch to ensure a flat flame and uniform heating; the insulating protective layer 3 is a porous ceramic cover plate with several small holes containing hollow inert ceramic spheres. The ceramic spheres are made of high-purity sintered alumina and have a diameter of 50mm. The insulating protective layer 3 is located in the furnace cavity space of the melting zone 4, above the glass melt surface, covering more than 90% of the glass melt surface area, and can move with the glass melt. The glass melt floats slightly due to convection and surface fluctuations caused by feeding, achieving dynamic sealing; the melting zone 4 is located at the front end, below the isolation protective layer, and the batch material enters this area through the feeding port 7 for melting; the kiln sill 5 is located between the melting zone 4 and the clarification and homogenization zone 6, used to change the direction or speed of the liquid flow, promoting homogenization and impurity retention; the clarification and homogenization zone 6 is located below the isolation protective layer 3, forming a relatively independent protective space for further homogenization, clarification and cooling of the glass melt; the feeding port 7 and the flue gas outlet 8 are located at the end of the kiln.

[0029] A method for preparing amber glass suitable for use in an oxygen-fired furnace includes the following steps: S1. Weigh the raw materials according to the raw material ratio in Table 1 and mix them thoroughly to obtain the batch material; S2. The batch material obtained in step S1 is put into an oxygen-fired melting furnace with an atmosphere isolation function and melted at 1600°C to obtain molten glass. S3. After clarifying the glass melt obtained in step S2 at 1530°C and homogenizing it at 1450°C, the glass melt is transported to the forming equipment for forming and annealing treatment, and finally amber glass suitable for all-oxygen combustion furnace is obtained, namely Examples 1-6. The raw materials include a composite colorant, which consists of ferrosilicon alloy powder, coated carbon microspheres, and zinc sulfide; wherein, the ferrosilicon alloy powder contains 30% Si by weight and has a particle size of 800 mesh; the coated carbon microspheres are prepared by the following steps: silica sol and borate aqueous solution are coated onto the surface of ultrafine carbon powder by spray granulation, and the coating layer is densified by high-temperature heat treatment at 600°C in a protective atmosphere of nitrogen or argon to obtain coated carbon microspheres; the particle size D50 of the coated carbon microspheres is 50 μm, the coating layer is SiO2, the coating layer mass ratio is 40%, and the core carbon powder particle size is 10 μm.

[0030] Table 1 The comparative examples were prepared by weighing the raw materials according to the proportions in Table 2 and mixing them thoroughly to obtain the batch; however, the amber-colored glass prepared using a traditional kiln was also prepared as in Comparative Examples 1 and 2.

[0031] Table 2 The performance of the examples and comparative examples was measured, and the results are shown in Table 3. Table 3 As can be seen from the performance test results in Table 3, the embodiments of the present invention clearly show that the glass color is amber and the color is uniform. The visible light transmittance (380-780nm) of the glass is ≤35%, the color uniformity and stability are greatly improved, the bubbles >2mm disappear, and the number of bubbles 1-2mm is reduced to less than 2. In contrast, the comparative example uses a traditional kiln, and the glass obtained is yellowish-green, which is lighter in color. The visible light transmittance (380-780nm) of the glass is >45%, and the number of bubbles is more.

[0032] Therefore, the composite colorant system and the all-oxygen combustion furnace structure with atmosphere isolation function provided by the present invention can effectively solve the contradiction between the strong oxidizing atmosphere of all-oxygen combustion and the traditional sulfur-carbon coloring reduction requirements. It successfully produces high-quality amber glass with deep color, low light transmittance and few bubble defects under all-oxygen combustion conditions. Its comprehensive performance is significantly better than that of products prepared by traditional methods and equipment, and it has important application value in the field of glass manufacturing technology.

[0033] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions 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 one or more embodiments or examples.

[0034] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. An amber-colored glass suitable for use in an oxygen-fired melting furnace, characterized in that, It is made from the following raw materials in the following mass percentages: 70-76% SiO2, 0.5-3% Al2O3, 8-13% CaO, 1-4% MgO, 10-16% Na2O, 0-2% K2O, with the balance being a composite colorant; wherein the mass percentage of CaO+MgO accounts for 10-12% of the total; and the mass percentage of Na2O+K2O accounts for 10-14% of the total.

2. The amber glass suitable for use in an oxy-fuel combustion furnace according to claim 1, characterized in that, The composite colorant is composed of ferrosilicon alloy powder, coated carbon microspheres, and zinc sulfide in a mass ratio of (0.1-0.5):(0.1-0.3):(0.2-1.0).

3. The amber glass suitable for use in an oxy-fuel combustion furnace according to claim 2, characterized in that, The silicon-iron alloy powder contains 15-30% Si by weight and has a particle size of 200-800 mesh.

4. The amber glass suitable for use in an oxy-fuel combustion furnace according to claim 2, characterized in that, The coated carbon microspheres are prepared by the following steps: inorganic sol is coated onto the surface of ultrafine carbon powder by spray granulation, and the coating layer is densified by high-temperature heat treatment at 600-900℃ in a protective atmosphere of nitrogen or argon to obtain coated carbon microspheres.

5. The amber glass suitable for use in an oxy-fuel combustion furnace according to claim 2, characterized in that, The coated carbon microspheres have a particle size D50 of 20-100 μm, the coating layer is SiO2 with a mass ratio of 10-40%, and the ultrafine carbon powder has a particle size of 1-10 μm.

6. A method for preparing amber glass suitable for an oxy-fuel combustion furnace, used to prepare the amber glass suitable for an oxy-fuel combustion furnace as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Weigh the raw materials and mix them thoroughly to obtain the batch material; S2. The batch material obtained in step S1 is put into an oxygen-fired melting furnace with an atmosphere isolation function for melting to obtain molten glass. S3. After clarifying and homogenizing the glass liquid obtained in step S2, it is transported to the forming equipment for forming and annealing treatment, and finally amber glass suitable for oxygen-fired melting furnace is obtained.

7. The method for preparing amber glass suitable for an oxy-fuel combustion furnace according to claim 6, characterized in that, The melting temperature is 1560-1620℃.

8. The method for preparing amber glass suitable for an oxy-fuel combustion furnace according to claim 6, characterized in that, The clarification temperature is 1500-1560℃; the homogenization temperature is 1420-1470℃.

9. The method for preparing amber glass suitable for an oxy-fuel combustion furnace according to claim 6, characterized in that, The interior of the oxygen-fired melting furnace with atmosphere isolation function consists of a melting zone, a furnace sill, and a clarification and homogenization zone, from front to back. An oxygen-fired lance is installed at the top of the furnace, and an isolation and protective layer is installed above the glass liquid surface in the furnace cavity of the melting zone.

10. The method for preparing amber glass suitable for an oxy-fuel combustion furnace according to claim 9, characterized in that, The insulating protective layer is a porous ceramic cover plate with several small holes, each containing a hollow or solid inert ceramic ball.

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