Preparation of color-changing heat-absorbing glass using iron-containing sludge of baotou steel

Abstract

The application provides a kind of glass that changes color and absorbs heat prepared by using iron-containing dust sludge of Baotou Steel, and the glass composition includes the following components by weight percentage: SiO2: 60-80%; iron-containing dust sludge: 10-20%; SnO2: 0.8-5%; Si: 0.1-5%; Na2CO3: 1-15%; CeCO3: 0.5-1%; H3BO3: 2-10%; NaCl: 1.5-5%; MgCO3: 2-6%; ZnO: 3-5%; LaCO3: 5-10%; AgNO3: 0.5-5%; KCl: 2.5-8%. The glass described in the application has an ultraviolet and infrared absorption rate of more than 90% before changing color, and a visible light transmittance of more than 70.0%.

Description

Technical Field

[0001] This invention belongs to the field of glass preparation technology, and in particular relates to the preparation of color-changing heat-absorbing glass using iron-containing dust and sludge from Baosteel. Background Technology

[0002] In terms of energy conservation and emission reduction, glass manufacturing is a high-energy-consuming, high-polluting, and high-carbon-emission process. According to the "Guidelines for Greenhouse Gas Emission Accounting Methods and Reporting of Chinese Flat Glass Manufacturers (Trial)" (hereinafter referred to as the "Accounting Guidelines") and other relevant documents, based on 5mm architectural glass, the total carbon dioxide emissions from the production of 35 million square meters of glass would be 454,735 tons, with approximately 13 kg of carbon dioxide produced per square meter of glass.

[0003] However, in terms of glass usage, while glass doors and windows ensure transparency, they also allow infrared radiation to pass through. This results in poor heat radiation blocking performance of glass doors and windows. Specifically, in summer, solar radiation enters the room through infrared rays, causing indoor temperatures to rise, while in winter, glass doors and windows become the main channels for heat loss. To maintain indoor temperatures, buildings need to use additional temperature control equipment such as air conditioning and heating, which undoubtedly increases energy consumption significantly and leads to secondary carbon emissions. Therefore, we must play a role in the energy conservation and emission reduction strategy of glass melting.

[0004] In the solar spectrum, approximately 7% of the energy is in the ultraviolet region, 46% is in the infrared region, and a significant 47% is in the visible light range. The intensity of visible light radiation varies with time of day and weather conditions. This necessitates that glass, while meeting its thermal insulation requirements, further control the amount of visible light transmitted, thus requiring color-changing thermal insulation materials.

[0005] Currently, there are two main types of color-changing thermal insulation materials. The first type is active color-changing materials, primarily electrochromic materials, which achieve color changing by requiring an external electrical input. However, this technology is expensive and requires additional electrical energy, making it uneconomical and environmentally friendly. Furthermore, current electrochromic products are limited by the area of ​​the glass, making it difficult to achieve uniform and rapid color changing on large glass surfaces. The second type is passive color-changing materials, primarily photochromic materials. These materials can meet the color-changing requirement without an external electrical input.

[0006] Photochromic materials are materials that intelligently change their color under visible or ultraviolet light. When photochromic materials are introduced into door and window components, under strong sunlight and excitation by ultraviolet and visible light, the material darkens in color, thereby reducing visible light transmittance and enhancing the thermal insulation performance of the doors and windows. Conversely, as the intensity of solar radiation decreases, the material lightens in color, increasing the visible light transmittance of the doors and windows, thus achieving a balance between visible light transmittance and thermal insulation performance.

[0007] Currently, the most widely used photochromic materials are organic photochromic materials, including spiropyran compounds, azobenzene compounds, benzoic acid anhydrides, and diarylethylene. These materials change color rapidly, but their stability under long-term ultraviolet irradiation is poor, and their synthesis methods are complex and expensive. Another problem with organic photochromic materials is the thermal fading effect. The thermal fading effect refers to the fading of the photochromic material when it is exposed to high ambient temperatures. In practical applications, when organic photochromic materials are combined with transparent heat-insulating materials, the transparent heat-insulating materials absorb infrared radiation and generate heat, which undoubtedly exacerbates the thermal fading effect of the photochromic material, leading to color change failure. Therefore, it is necessary to develop photochromic glass products with excellent photostability and excellent resistance to thermal fading.

[0008] In summary, this invention presents a method for preparing color-changing heat-absorbing glass using iron-containing dust and sludge from Baosteel. Summary of the Invention

[0009] In view of this, the present invention aims to overcome the defects in the prior art and proposes a method for preparing color-changing heat-absorbing glass using iron-containing dust and sludge from Baogang Steel Plant.

[0010] To achieve the above objectives, the technical solution created by this invention is implemented as follows:

[0011] In a first aspect, the present invention provides a color-changing heat-absorbing glass prepared using iron-containing dust, wherein the glass comprises, by weight percentage, the following components:

[0012] SiO2: 60-80%; Iron-containing dust and sludge: 10-20%; SnO2: 0.8-5%; Si: 0.1-5%; Na2CO3: 1-15%; CeCO3: 0.5-1%; H3BO3: 2-10%; NaCl: 1.5-5%; MgCO3: 2-6%; ZnO: 3-5%; LaCO3: 5-10%; AgNO3: 0.5-5%; KCl: 2.5-8%.

[0013] Preferably, the iron-containing sludge used comprises, by weight percentage, the following components: TFe: 50.20%; FeO: 17.42%; SiO2: 3.86%; CaO: 10.10%; MgO: 2.09%; Al2O3: 1.46%; K2O: 0.915%; C: 5.91%; S: 0.233%; P: 0.24%.

[0014] Secondly, the present invention provides a method for preparing the above-mentioned color-changing heat-absorbing glass using iron-containing dust and sludge, comprising the following steps:

[0015] (1) First, add the iron-containing dust and mud into the crusher to disperse and refine the powder;

[0016] (2) Weigh AgNO3 and add it into the crusher to mix with iron-containing dust and mud. While mixing evenly, refine the powder and make it fully contacted.

[0017] (3) Mix the two powders obtained in steps (1) and (2), pour them into a mortar, weigh an equal amount of SnO2, grind them with a grinding pestle, disperse and mix them, and put them into a platinum crucible after mixing. This is called raw material one. Raw material one is placed in the same crucible for melting.

[0018] (4) Weigh the remaining components according to the proportion and mix them evenly; use a 50-mesh sieve to sieve, crush and mix the raw materials, and put them into a platinum crucible after mixing evenly. This is called raw material two.

[0019] (5) Place raw material one and raw material two into a high-temperature melting furnace at the same time and melt at 1300℃ for 1-3 hours. After melting, pour the solution of raw material one into raw material two, and then heat to 1450℃ to melt for 1.5-4 hours. Stir at a stirring rate of 10-60 r / min for 30-80 minutes to obtain a clear glass melt.

[0020] (6) Use a 10cm thick stainless steel plate as the base, place the stainless steel mold on the plate, pour in the glass solution, and wait for the liquid to cool and solidify.

[0021] (7) Place the formed glass into an annealing furnace at 400-600℃ for annealing time of 8-12 hours, and then cool it to room temperature with the furnace.

[0022] This invention employs a melting method involving two separate crucibles for melting, followed by mixing, resulting in glass that possesses both color-changing properties and high infrared and ultraviolet absorption, while maintaining high visible light transmittance. The time from color change to fading and back to normal is short, approximately one minute. Furthermore, the use of iron-containing dust from Baotou Steel as a raw material, whose composition perfectly matches the raw materials required for glass melting, reduces both costs and environmental pollution. This method has not been previously reported.

[0023] Compared with existing technologies, the present invention has the following advantages:

[0024] (1) Compared with the prior art, the advantage of this invention is that the use of iron-containing dust is a form of waste utilization, saving treatment costs and reducing environmental pollution. By using two raw materials to melt separately and then mix and melt together, the invention can achieve both color-changing and heat-absorbing functions. The composition of raw material one, silver nitrate and tin dioxide, has oxidizing properties and can oxidize the iron element in the iron-containing dust to ferric (Fe3+). After the two solutions are mixed, the carbon and sulfur in the iron-containing dust, as well as the silicon added in raw material two, can adjust the content of ferrous ions. Using the amount of carbon to adjust the content of ferrous ions makes it difficult to control the glass color, which can easily result in a brown color. Moreover, excessive carbon can also produce CO2 bubbles that cannot be discharged and remain in the glass. Therefore, this invention directly utilizes the carbon contained in the iron-containing dust, making it easy to control the generation of bubbles and the color of the glass during the melting process. By using separate melting and then mixing methods, the ratio of ferrous to ferric iron in the final solution can be made appropriate, resulting in high absorption of both infrared and ultraviolet light while maintaining high transmittance of visible light; the presence of silver and chloride ions in the solution makes the glass prone to discoloration and fading.

[0025] (2) The 10cm×5cm×0.5cm glass produced by this invention, when measured with a transmittance tester, showed that before discoloration, the ultraviolet and infrared absorption rates reached over 90%, and the visible light transmittance reached over 70.0%; after discoloration, the ultraviolet and infrared absorption rates reached over 98.0%, and the visible light transmittance reached over 25.5%. Upon exposure to sunlight (or ultraviolet radiation), the glass immediately deepens in color, exhibiting even better infrared blocking, absorbing almost all ultraviolet and infrared rays. When the light source is removed, the glass fades and returns to its original color very quickly, in about one minute. Detailed Implementation

[0026] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0027] The invention will be described in detail below with reference to specific embodiments.

[0028] A color-changing heat-absorbing glass prepared using iron-containing dust and sludge, wherein the glass comprises, by weight percentage, the following components: SiO2: 60-80%; iron-containing dust and sludge: 10-20%; SnO2: 0.8-5%; Si: 0.1-5%; Na2CO3: 1-15%; CeCO3: 0.5-1%; H3BO3: 2-10%; NaCl: 1.5-5%; MgCO3: 2-6%; ZnO: 3-5%; LaCO3: 5-10%; AgNO3: 0.5-5%; KCl: 2.5-8%.

[0029] The iron-containing dust and sludge used were produced by Tianjin Baogang Rare Earth Research Institute Co., Ltd., and all chemical reagents used were of analytical grade.

[0030] Example

[0031] Table 1. Component ratios for Examples 1-4

[0032]

[0033]

[0034] The preparation process of the color-changing heat-absorbing glass in Examples 1-4 is as follows:

[0035] (1) Weigh the iron-containing dust and add it into the crusher for further processing.

[0036] (2) Accurately weigh AgNO3 and add it into the crusher to mix with iron-containing dust and sludge for 30 minutes.

[0037] (3) Pour the powder from the crusher into a mortar, weigh SnO2, grind it with a grinding pestle, stir it with a mortar and pestle, and put it into a platinum crucible after mixing. The preparation of raw material one is complete.

[0038] (4) Weigh the remaining components accurately according to the calculated weight and mix them evenly. Use a 50-mesh sieve to sieve the raw materials, crush and mix them. After mixing evenly, put them into a platinum crucible. Raw material two is now ready.

[0039] (5) Place the two platinum crucibles containing raw material one and raw material two into a high-temperature melting furnace at the same time and melt at 1300℃ for 2 hours. After melting, pour the solution in the platinum crucible containing raw material one into the platinum crucible containing raw material two, and then heat it to 1450℃ for 2 hours. At the same time, start stirring at a stirring rate of 40r / min for 50 minutes.

[0040] (6) Place a 10cm thick stainless steel plate on a flat surface, and select a 10cm×5cm×0.5cm stainless steel mold to place on the plate. Pour the molten glass solution into the mold and wait for the liquid to cool for 2.5 minutes.

[0041] (7) Place the formed glass into an annealing furnace at 500°C for 9 hours and cool it to room temperature with the furnace.

[0042] (8) Use a transmittance tester to test the data, irradiate the glass with an ultraviolet lamp, use a stopwatch to time the time, and observe the fading time of the glass.

[0043] Table 2 Test data for Examples 1-4

[0044]

[0045] As shown in the table above, the photochromic heat-insulating glass prepared by this invention has an absorption rate of over 90% for both infrared and ultraviolet rays and a visible light transmittance of over 70% before color change. It effectively blocks the transmission of light energy into the room, thus effectively controlling the indoor temperature, while maintaining high visible light transmittance without reducing indoor visibility. When the light intensity increases, the glass automatically darkens, improving the blocking effect. The blocking rate for both infrared and ultraviolet rays is over 98%. However, the darkening affects the transmittance of visible light. When the light intensity decreases, the glass quickly changes from its dark state back to its original color, demonstrating a very fast automatic color-changing response.

[0046] Table 3. Component ratios of Comparative Examples 1-3

[0047] Comparative Example 1 Comparative Example 2 Comparative Example 3 <![CDATA[SiO2]]> 71 65 62 Iron-containing dust and mud 12 14.5 <![CDATA[Sn02]]> 1.5 2 1.3 Si 0.5 0.3 0.2 <![CDATA[Na2CO3]]> 5 2 1.5 <![CDATA[CeCO3]]> 0.6 1 0.5 <![CDATA[H3BO3]]> 3 2.5 2 NaCl 2 1.6 1.7 <![CDATA[MgCO3]]> 2.5 2 3 ZnO 3.2 3.6 4 <![CDATA[LaCO3]]> 6 5 5.3 <![CDATA[AgNO3]]> 2 0.5 1 KCl 2.7 2.5 3

[0048] In Comparative Example 1, no iron-containing dust or sludge was added, and the remaining steps were the same as in Example 1.

[0049] Comparative Example 2 uses a method of blending all raw materials together, and single-crucible melting is carried out. The remaining steps are the same as in Example 2.

[0050] The annealing temperature of Comparative Example 3 was 450°C, and the remaining steps were the same as those of Example 3.

[0051] Comparative Example 4 replaced the iron-containing dust with ferrous oxide, and the remaining steps were the same as in Example 4. The specific composition is shown in the table below:

[0052] Table 4 shows the component ratios for Comparative Example 4.

[0053] <![CDATA[SiO2]]> FeO <![CDATA[Sn02]]> Si <![CDATA[Na2CO3]]> <![CDATA[CeCO3]]> <![CDATA[H3BO3]]> NaCl <![CDATA[MgCO3]]> ZnO <![CDATA[LaCO3]]> <![CDATA[AgNO3]]> KCl 68 11.6 0.8 0.1 1.1 0.7 2.1 1.5 2.6 3.4 5 0.6 2.5

[0054] Comparative Example 5 replaced the iron-containing dust with ferric oxide, and the remaining steps were the same as in Example 4. The specific composition is shown in the table below:

[0055] Table 5 shows the component ratios for Comparative Example 5.

[0056] <![CDATA[SiO2]]> <![CDATA[Fe2O3]]> <![CDATA[Sn02]]> Si <![CDATA[Na2CO3]]> <![CDATA[CeCO3]]> <![CDATA[H3BO3]]> NaCl <![CDATA[MgCO3]]> ZnO <![CDATA[LaCO3]]> <![CDATA[AgNO3]]> KCl 68 11.6 0.8 0.1 1.1 0.7 2.1 1.5 2.6 3.4 5 0.6 2.5

[0057] Data was tested using a transmittance meter, and the glass was irradiated with ultraviolet light and timed with a stopwatch to observe the fading time of the glass.

[0058] Table 6 Test data for comparative examples 1-5

[0059]

[0060] The data above shows that before the glass changed color, Example 1 and Comparative Example 1 had a 74.6% difference in ultraviolet absorption rate, a 74.2% difference in infrared absorption rate, and a 21.6% difference in visible light transmittance; after the color change, the difference was 79.7% in ultraviolet absorption rate, 79.6% in infrared absorption rate, and -17.7% in visible light transmittance. The fading time of the glass in Comparative Example 1 was also extended by 32.8 seconds. Because Comparative Example 1 did not add iron-containing dust, there were no iron ions in the glass that strongly absorb infrared and ultraviolet light, resulting in poor glass performance. Comparing Example 2 and Comparative Example 2, before the glass changed color, the difference in ultraviolet absorption rate was 34.4%, the difference in infrared absorption rate was 36.9%, and the difference in visible light transmittance was 16.8%; after the color change, the difference was 36.8% in ultraviolet absorption rate, 37.6% in infrared absorption rate, and -16.3% in visible light transmittance. The fading time of the glass in Comparative Example 2 was also extended by 31 seconds. This is because Comparative Example 2 used a blending method, which prevented the oxidant from fully contacting the iron-containing dust, thus failing to generate enough iron ions and reducing the infrared and ultraviolet absorption rates of the glass. Compared with Comparative Example 3, before the glass changed color, the difference in ultraviolet absorption rate was 15.7%, the difference in infrared absorption rate was 13.5%, and the difference in visible light transmittance was 8.4%; after the glass changed color, the difference in ultraviolet absorption rate was 18.1%, the difference in infrared absorption rate was 15.6%, and the difference in visible light transmittance was 5.2%. The fading time of the glass in Comparative Example 3 also increased by 14.9 seconds. The annealing temperature of Comparative Example 3 was lower than that of Example 3, resulting in internal stress in the glass and reducing its various properties. Compared with Comparative Example 4, before the glass changed color, the difference in ultraviolet absorptivity was 11.7%, the difference in infrared absorptivity was 9.5%, and the difference in visible light transmittance was 8.6%; after the glass changed color, the difference in ultraviolet absorptivity was 15.8%, the difference in infrared absorptivity was 12.9%, and the difference in visible light transmittance was 0.5%. The fading time of the glass in Comparative Example 4 was also extended by 9.6 seconds. Compared with Comparative Example 5, before the glass changed color, the difference in ultraviolet absorptivity was 10.5%, the difference in infrared absorptivity was 9.7%, and the difference in visible light transmittance was 9.1%; after the glass changed color, the difference in ultraviolet absorptivity was 13.2%, the difference in infrared absorptivity was 12.3%, and the difference in visible light transmittance was 0.1%. The fading time of the glass in Comparative Example 5 was also extended by 10.8 seconds. Comparative Examples 4-5 show that replacing iron-containing dust with single ferrous and ferric iron reduces the iron content in the glass, thus decreasing the glass's absorption rate of infrared and ultraviolet light.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing color-changing heat-absorbing glass using iron-containing dust and sludge from steel-clad steel plants, characterized in that, The glass comprises, by weight percentage, the following components: SiO2: 60-80%; Iron-containing dust and sludge: 10-20%; SnO2: 0.8-5%; Si: 0.1-5%; Na2CO3: 1-15%; CeCO3: 0.5-1%; H3BO3: 2-10%; NaCl: 1.5-5%; MgCO3: 2-6%; ZnO: 3-5%; LaCO3: 5-10%; AgNO3: 0.5-5%; KCl: 2.5-8%; the sum of the weight percentages of all components is 100%. The iron-containing sludge used comprises the following components by weight percentage: TFe: 50.20%; FeO: 17.42%; SiO2: 3.86%; CaO: 10.10%; MgO: 2.09%; Al2O3: 1.46%; K2O: 0.915%; C: 5.91%; S: 0.233%. P：0.24%； The glass preparation method includes the following steps: (1) First, add the iron-containing dust and sludge into the crusher to disperse and refine the powder; (2) Weigh AgNO3 and add it into the crusher to mix with iron-containing dust and mud. While mixing evenly, refine the powder to ensure full contact. (3) Mix the two powders obtained in steps (1) and (2), pour them into a mortar, weigh SnO2, grind them with a grinding pestle, disperse and mix them, and put them into a platinum crucible after mixing. This is called raw material one. (4) Weigh the remaining components according to the proportion and mix them evenly; use a 50-mesh sieve to sieve, crush and mix the raw materials, and put them into a platinum crucible after mixing evenly. This is called raw material two. (5) Place the two platinum crucibles containing raw material one and raw material two into a high-temperature melting furnace at the same time, and melt at 1300℃ for 1-3 hours. After melting, pour the molten liquid in the platinum crucible containing raw material one into the platinum crucible containing raw material two, and then heat it to 1450℃ for 1.5-4 hours, and stir it at a stirring rate of 10-60 r / min for 30-80 minutes to obtain a clear glass melt. (6) Use a 10cm thick stainless steel plate as the base, place the stainless steel mold on the steel plate, pour in the molten glass, and wait for the liquid to cool and solidify. (7) Place the formed glass into an annealing furnace at 400-600℃ for annealing time of 8-12 hours, and then cool it to room temperature with the furnace.

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