Production process for blue glass
By employing a precise proportioning and phased control process for blue glass production, the problems of uneven coloring and insufficient mechanical properties in blue glass have been solved, resulting in improved optical purity and superior mechanical properties to meet the needs of high-end applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-04-14
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing blue glass production processes suffer from uneven coloring, insufficient mechanical properties, and poor optical performance, making it difficult to meet the needs of high-end applications.
Using precisely proportioned basic raw materials, colorants, and functional additives, combined with controlled steps such as staged mixing, melting in a reducing atmosphere, multi-stage clarification and homogenization, and float forming, including melting in an alumina furnace, stirring and clarification under a nitrogen-oxygen mixed protective atmosphere, four-stage annealing treatment, and chemical strengthening, we ensure the uniformity of composition and product consistency.
It achieves a synergistic improvement in high optical purity and excellent mechanical properties. The product has high UV cutoff capability, good thermal shock stability and high strength, meeting the needs of high-end applications.
Smart Images
Figure CN121850363A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of blue glass production technology, and more particularly to a production process for blue glass. Background Technology
[0002] Glass is an amorphous (non-crystalline) inorganic non-metallic material, typically made by rapidly cooling molten raw materials such as silica sand, soda ash (sodium carbonate), and limestone (calcium carbonate) at high temperatures. Due to the lack of long-range order in its atomic structure, glass is neither a typical solid nor a liquid, but rather a supercooled liquid. Ordinary glass is transparent, hard, and chemically stable, and is widely used in construction, furniture, optical instruments, and electronic equipment. Blue glass is made by adding specific metal oxides (such as cobalt oxide, copper oxide, or selenides) to a base glass formulation, resulting in shades ranging from light to dark blue. Blue glass is not only decorative but also functional: it effectively absorbs some ultraviolet light and the red wavelength of visible light, and is commonly used in filters, camera lenses, signal lights, artware, and building facades to create special visual effects or control light transmittance. Furthermore, in laboratory glassware and pharmaceutical packaging, blue glass can slow down the decomposition of photosensitive substances caused by light exposure, providing protection. Due to its unique color aesthetics and practical performance, blue glass occupies an important position in modern industrial and artistic design. Summary of the Invention
[0003] The purpose of this invention is to address the shortcomings of existing technologies by proposing a production process for blue glass.
[0004] To achieve the above objectives, the present invention adopts the following technical solution: A manufacturing process for blue glass, the process comprising the following steps: S1: Raw material pretreatment, the base glass raw material, colorant and functional additive are ground and dried separately, and then mixed in sequence; S2: The mixture is melted in a primary melting furnace under a reducing atmosphere, and a reducing agent is added; S3: Transfer the partially molten glass to the main furnace and stir and clarify it in a nitrogen-oxygen mixed protective gas environment; S4: Cool the clarified glass melt and continue stirring to homogenize it; S5: Formed by drawing in a tin bath using the float glass process; S6: Perform staged annealing treatment on the formed glass; S7: The annealed glass is cut and edged, followed by chemical strengthening and acid treatment.
[0005] Preferably, the weight percentage composition of the basic glass raw material is: SiO2: 57-63%, Al2O3: 8-10%, B2O3: 5-8%, CaO: 6.4-9%, MgO: 1.5-3.2%, Na2O: 10.4-12.3% and K2O: 2.5-3.2%.
[0006] Furthermore, the colorant has the following weight percentage composition: Co2O3: 0.002-0.005%, Er2O3: 0.28-1%, Nd2O3: 0.12-0.43%.
[0007] Furthermore, the functional additive has the following weight percentage composition: CeO2: 0.2-0.5%, Na2SO4: 0.4-0.65%, ZrO2: 1.1-2.3%, La2O3: 0.5-2.3%.
[0008] As a preferred embodiment of the present invention: in step S2, the melting hot spot temperature is 1500-1550℃, the excess air coefficient is 0.85-0.95, the melting time is 2-2.5 hours, the nitrogen flow rate is 25-45L / h, and the mixture is added in 3 batches with an interval of 20 minutes between each batch.
[0009] As a further aspect of the present invention: in step S3, the main furnace temperature is maintained at 1575-1585℃, the stirring speed is 10r / min, the stirring direction is opposite to the glass melt flow direction, and a nitrogen-oxygen mixed protective gas is introduced from bottom to top, the bubbling frequency is 0.6Hz, the bubble diameter is 3-5mm, and the clarification time is 10-15 hours.
[0010] As a further embodiment of the present invention: in step S4, the glass melt is cooled to 1350-1425°C at a rate of 80-100°C / h, the stirring speed is initially 30 rpm, and then gradually reduced to 10 rpm, and stirring is continued for 5-8 hours, while the melting furnace is kept at 65-75% of its full load.
[0011] Based on the aforementioned scheme: In step S6, the upper limit of the annealing temperature is 580℃. After holding at this temperature for 60 minutes, the temperature is reduced in four stages: the first stage is 580-420℃ at a cooling rate of 3.5℃ / min; the second stage is 420-300℃ at a cooling rate of 2.0℃ / min; the third stage is 300-150℃ at a cooling rate of 1.2℃ / min; and the fourth stage is 150℃ for natural cooling to room temperature. The annealing furnace atmosphere is dry air with a dew point <-40℃.
[0012] Based on the aforementioned scheme: In step S7, chemical strengthening is achieved by immersing a molten salt mixture of potassium nitrate and sodium nitrate in a 50%:50% mass ratio at 410-430℃ for 3 hours.
[0013] Based on the aforementioned scheme: in step S7, the surface compressive stress is ≥750MPa and the stress layer depth is 80-95μm; the acid treatment uses a mixed solution containing 4% hydrofluoric acid, 3% nitric acid and 1% phosphoric acid, and is soaked at room temperature for 3-4 minutes.
[0014] The beneficial effects of this invention are as follows: A production process for blue glass achieves a synergistic improvement in high optical purity and excellent mechanical properties through precise proportioning of basic raw materials, colorants, and functional additives, combined with controlled steps such as staged mixing, reducing atmosphere melting, multi-stage clarification and homogenization, and float glass forming. Strict control over raw material purity, particle size, feeding sequence, and thermal regime ensures component uniformity and product consistency.
[0015] A production process for blue glass involves using an alumina furnace, carbon powder reducing agent, and a nitrogen-oxygen mixed protective atmosphere during the melting and refining stages to promote Fe production within the temperature range of 1500–1585°C. 2+ It forms and enhances the homogenization of molten glass. Bubbling and reverse stirring strengthen convection, effectively remove bubbles and impurities, improve light transmittance and structural density, provide high-quality molten glass for subsequent forming, and reduce the defect rate.
[0016] A production process for blue glass employs a four-stage temperature control curve for annealing combined with low dew point dry air to effectively release internal stress; chemical strengthening and acid treatment further enhance surface compressive stress (≥750 MPa) and hardness (650–750 kgf / mm²). 2 The final product features high UV cutoff (<380 nm), good thermal shock resistance (200–250℃), and high strength (800–1000 MPa in three-point bending), meeting the needs of high-end applications.
[0017] A production process for blue glass employs a staged mixing strategy. First, basic glass raw materials are mixed, and then Co2O3 and other colorants and functional additives are added sequentially. The mixing time of high-value components is extended to effectively avoid component segregation. The particle size of the raw materials is controlled according to category and dried at 120°C, which improves the mixing uniformity and melting reaction efficiency, laying the foundation for subsequent stable coloring and performance consistency. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of a production process for blue glass proposed in this invention. Detailed Implementation
[0019] The technical solution of this patent will be further described in detail below with reference to specific embodiments.
[0020] The embodiments of this patent are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this patent, and should not be construed as limiting this patent.
[0021] Example 1: A production process for blue glass, such as Figure 1 As shown, its raw materials consist of three parts: basic glass raw materials, colorants, and functional additives. The weight parts of the basic glass raw materials are: SiO2: 57-63%, Al2O3: 8-10%, B2O3: 5-8%, CaO: 6.4-9%, MgO: 1.5-3.2%, Na2O: 10.4-12.3%, and K2O: 2.5-3.2%. The weight parts of the colorants are: Co2O3: 0.002-0.005%, Er2O3: 0.28-1%, and Nd2O3: 0.12-0.43%. The weight parts of the functional additives are: CeO2: 0.2-0.5%, Na2SO4: 0.4-0.65%, ZrO2: 1.1-2.3%, and La2O3: 0.5-2.3%.
[0022] In basic glass raw materials, Al2O3 can improve the weather resistance and hardness of glass; B2O3 can be used at lower contents to reduce boron volatilization, lower costs, while improving thermal stability and network compactness, reducing the coefficient of thermal expansion while maintaining stability; CaO can reduce low-temperature viscosity, improve forming performance, and prevent crystallization; MgO can optimize melting rate and chemical stability; Na2O can promote melting and ion exchange, which helps balance fluxing performance; K2O can reduce high-temperature viscosity and improve gloss. Co2O3 has the advantages of stable coloring, being unaffected by atmosphere, and exhibiting a pure blue color; Er2O can work synergistically with Co2O3 to fine-tune the blue hue, enhance visible light transmittance, and improve infrared cutoff performance; Nd2O3 can improve strength and colorfastness. CeO2 alone improves clarification and UV resistance; Na2SO4 assists in clarification and improves uniformity; ZrO2 can enhance surface hardness and scratch resistance without affecting melting; La2O3 can reduce high-temperature viscosity and increase Young's modulus. The production process includes the following steps: S1: Raw material pretreatment: Grind the raw materials according to their categories, preferably using a ball mill. The purity of all raw materials must be ≥99.5%. The particle size of the base glass raw material is 80-90 mesh, and the particle size of the colorant and functional additives is controlled at 250-350 mesh. The raw materials are then dried, preferably at 120°C for 3.5 hours. Next, the base glass raw material is first added to a mixer and mixed for five minutes, then Co2O3 is added and mixed again for five minutes. Finally, Er2O3 and Nd2O are added. 、 Mix CeO2, Na2SO4, ZrO2 and La2O3 for 15 minutes to extend the mixing time of expensive colorants and functional additives and improve the mixing effect; S2: Melting in a reducing atmosphere; the mixed material is fed into a primary melting furnace made of alumina material and melted under a reducing atmosphere; carbon powder is added as a reducing agent during the melting process to promote Fe... 2+ The preferred melting point temperature is controlled at 1500-1550℃, the excess air coefficient is 0.85-0.95, the melting time is 2-2.5 hours, and nitrogen is introduced as a protective gas with a flow rate of 25-45 L / h. The feeding method is to add the material in batches to balance the heat load of the melting furnace, preferably in 3 batches with an interval of 20 minutes between each batch. S3: Transfer the partially molten glass to the main furnace, then raise the furnace temperature and maintain it between 1575-1585℃. Introduce a nitrogen-oxygen protective gas mixture while simultaneously starting the stirrer to clarify the glass for 10-15 hours. During stirring, use a bubbling device to introduce the nitrogen-oxygen protective gas mixture from bottom to top to increase convection in the glass melt, promoting homogenization and reduction reactions, and further improving Fe content. 2 ⁺ ratio; the preferred stirring speed is 10 r / min, the stirring direction is opposite to the glass melt flow direction, the bubbling frequency is 0.6 Hz, and the bubble diameter is 3-5 mm; S4: Homogenization and stirring. Cool the clarified glass melt to 1350-1425℃ at a rate of 80-100℃ / h, and then continue stirring for 5-8 hours to ensure homogenization of the glass melt. The stirring speed is initially 30 rpm, and then gradually reduced to 10 rpm, maintaining the furnace at 65-75% of full load. S5: Float forming; The homogenized molten glass is introduced into a tin bath and drawn into shape at 1110-1140℃ with a drawing speed of 0.8m / min and a glass width of 4m. A molten glass protective gas with a formula ratio of 92%N2+8%H2 is used to prevent oxidation of the molten glass. S6: Annealing: The formed glass is placed in an annealing furnace. The upper limit of the annealing temperature is 580℃. It is held at this temperature for 60 minutes and then slowly cooled down. The first stage is from 580 to 420℃, with a cooling rate of 3.5℃ / min; The second stage is from 420 to 300℃, with a cooling rate of 2.0℃ / min; The third stage is from 300 to 150℃, with a cooling rate of 1.2℃ / min; The fourth stage involves natural cooling from 150 degrees Celsius to room temperature. The annealing furnace atmosphere is dry air with a dew point of <-40℃. Using a smoother annealing cooling curve can reduce stress, while stricter dew point control can effectively prevent surface defects. S7: Post-processing and strengthening. First, the annealed glass is cut, and then the edges are ground. After the edge grinding is completed, chemical strengthening is carried out by molten salt mixed with potassium nitrate and sodium nitrate in a mass ratio of 50%:50% and soaking at a temperature of 410-430℃ for 3 hours. The preferred surface compressive stress is ≥750MPa and the stress layer depth is 80-95μm. The glass is then subjected to acid treatment, which consists of 4% hydrofluoric acid, 3% nitric acid, and 1% phosphoric acid. The acid treatment soaking time is 3–4 minutes, and the solution temperature is maintained at room temperature. The acid treatment is used to remove surface impurities and microcracks, and to enhance the surface hardness and smoothness of the glass.
[0023] A production process for blue glass, incorporating colorants Co2O3, Er2O3, Nd2O3 and functional additives CeO2, Na2SO4, ZrO2, and La2O3, not only enhances the purity and stability of the blue color but also improves the glass's weather resistance and UV resistance. Strict raw material pretreatment is required, with all raw materials demanding a purity of ≥99.5%. Particle size is controlled separately for each type using a ball mill. After drying, a staged mixing method ensures uniform dispersion of the components, avoiding segregation and laying a solid foundation for subsequent processes. The production process involves multiple stages, including melting in a reducing atmosphere, clarification and homogenization, float forming, and annealing. The melting stage takes place in an alumina furnace, with the hot spot temperature controlled at 1500-1550℃, and nitrogen protective gas is introduced. This, combined with batch feeding and the use of carbon powder reducing agent, promotes the Fe... 2 The glass melt is formed to optimize the coloring effect; during the clarification stage, the temperature is raised to 1575-1585℃, a nitrogen-oxygen mixture is introduced, and the stirrer and bubbling device are started to enhance the convection of the glass melt and remove bubbles; during the forming stage, the float glass process is adopted, the drawing temperature is 1110-1140℃, and the tin bath protective gas is 92%N2+8%H2 to ensure smooth forming; the annealing process is designed with a four-stage cooling curve, and the dew point of the annealing furnace atmosphere is <-40℃, which effectively reduces internal stress. These steps, through precise temperature, time, and atmosphere control, improve product homogeneity and yield. Simultaneously, by synergistically coloring the product with Co2O3 as the primary colorant and Er2O3 and Nd2O3, the final product exhibits a high-purity, uniform blue color with a UV cutoff edge below 380nm, effectively blocking most UVA and UVB rays. It also boasts a surface compressive stress ≥750MPa, a stress layer depth of 80-95μm, a three-point bending strength of 800-1000MPa, and a Vickers hardness of 650-750kgf / mm². 2The coefficient of thermal expansion is 70-80×10⁻⁶. -7 / K; elastic modulus 75-80GPa; can withstand sudden temperature changes of 200-250℃. It possesses excellent optical and mechanical properties, and optimizes the balance between production efficiency and product quality, ensuring high product quality stability. It has high technical feasibility and market application potential.
[0024] The above description represents a preferred embodiment of the present invention. The scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, combined with existing technology or common knowledge, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A manufacturing process for blue glass, the process comprising the following steps: S1: Raw material pretreatment, the base glass raw material, colorant and functional additive are ground and dried separately, and then mixed in sequence; S2: The mixture is melted in a primary melting furnace under a reducing atmosphere, and a reducing agent is added; S3: Transfer the partially molten glass to the main furnace and stir and clarify it in a nitrogen-oxygen mixed protective gas environment; S4: Cool the clarified glass melt and continue stirring to homogenize it; S5: Formed by drawing in a tin bath using the float glass process; S6: Perform staged annealing treatment on the formed glass; S7: The annealed glass is cut and edged, followed by chemical strengthening and acid treatment.
2. The production process for blue glass according to claim 1, characterized in that, The weight percentage composition of the basic glass raw materials is as follows: SiO2: 57-63%, Al2O3: 8-10%, B2O3: 5-8%, CaO: 6.4-9%, MgO: 1.5-3.2%, Na2O: 10.4-12.3%, and K2O: 2.5-3.2%.
3. The production process for blue glass according to claim 1, characterized in that, The colorant has the following weight percentage composition: Co2O3: 0.002-0.005%, Er2O3: 0.28-1%, Nd2O3: 0.12-0.43%.
4. The production process for blue glass according to claim 2, characterized in that, The functional additives have the following weight percentage composition: CeO2: 0.2-0.5%, Na2SO4: 0.4-0.65%, ZrO2: 1.1-2.3%, La2O3: 0.5-2.3%.
5. The production process for blue glass according to claim 1, characterized in that, In step S2, the melting hot spot temperature is 1500-1550℃, the excess air coefficient is 0.85-0.95, the melting time is 2-2.5 hours, the nitrogen flow rate is 25-45L / h, and the mixture is added in 3 batches with an interval of 20 minutes between each batch.
6. A production process for blue glass according to claim 5, characterized in that, In step S3, the main furnace temperature is maintained at 1575-1585℃, the stirring speed is 10r / min, the stirring direction is opposite to the glass melt flow direction, and a nitrogen-oxygen mixed protective gas is introduced from bottom to top. The bubbling frequency is 0.6Hz, the bubble diameter is 3-5mm, and the clarification time is 10-15 hours.
7. A production process for blue glass according to claim 5, characterized in that, In step S4, the glass melt is cooled to 1350-1425℃ at a rate of 80-100℃ / h, the stirring speed is initially 30 rpm, and then gradually reduced to 10 rpm, and stirring is continued for 5-8 hours, while the melting furnace is kept at 65-75% of full load.
8. The production process for blue glass according to claim 1, characterized in that, In step S6, the upper limit of the annealing temperature is 580℃. After holding at this temperature for 60 minutes, the temperature is reduced in four stages: the first stage is 580-420℃ at a cooling rate of 3.5℃ / min; the second stage is 420-300℃ at a cooling rate of 2.0℃ / min; the third stage is 300-150℃ at a cooling rate of 1.2℃ / min; and the fourth stage is 150℃ for natural cooling to room temperature. The annealing furnace atmosphere is dry air with a dew point <-40℃.
9. A production process for blue glass according to claim 8, characterized in that, In step S7, chemical strengthening is achieved by immersing a molten salt mixture of potassium nitrate and sodium nitrate in a 50%:50% mass ratio at 410-430°C for 3 hours.
10. A production process for blue glass according to claim 9, characterized in that, In step S7, the surface compressive stress is ≥750MPa and the stress layer depth is 80-95μm; the acid treatment uses a mixed solution containing 4% hydrofluoric acid, 3% nitric acid and 1% phosphoric acid, and is soaked at room temperature for 3-4 minutes.