Pozzolanic materials, methods of making and articles thereof

Abstract

The invention provides a method for preparing a pozzolanic material. The method comprises the following steps: collecting waste glass; crushing the waste glass into waste glass particles with a preset size; and grinding the waste glass particles to obtain fine ground glass micro powder with a preset particle size and preset particle size distribution, and taking the fine ground glass micro powder as the pozzolanic material. The invention also provides a pozzolanic material prepared by the method, and a product manufactured by utilizing the pozzolanic material.

Description

Technical Field

[0001] This invention relates to a volcanic ash material, its preparation method, and its products, particularly a volcanic ash material comprising activated waste glass, its preparation method, and its products. Background Technology

[0002] Modern construction primarily utilizes reinforced concrete, materials that are energy-intensive and generate significant carbon emissions. Concrete accounts for the largest share, with approximately four billion tons of cement produced globally annually. Producing one ton of cement clinker generates about 0.9 to 1.0 tons of carbon dioxide emissions. Therefore, to reduce carbon emissions and achieve the Net Zero target, it is necessary to consider reducing concrete usage or improving the amount of cement used in concrete formulations. However, effectively reducing cement usage while maintaining safety, workability, and durability remains a crucial challenge for the construction industry. Existing technologies have revealed the potential to use pozzolanic materials, fly ash, and other volcanic powders to replace a portion of the cement clinker, thereby reducing the amount of cement used in concrete.

[0003] Pozzolanic properties refer to the property of a material that, while not possessing hydraulic properties on its own, can generate hydraulic hydration products when mixed with lime and water at room temperature. Pozzolanic materials are mineral powder materials with pozzolanic properties, and can be divided into two categories: natural and artificially blended materials (see GB / T 2847-2022 for details). Fly ash is the powder collected from the flue gas of pulverized coal boilers in power plants, and possesses pozzolanic properties similar to those of pozzolanic materials (see GB / T 1596-2017 for details).

[0004] Because glass is non-biodegradable and cannot be decomposed through landfill or composting, and due to its non-flammable nature, recycling it is currently the best treatment method. Waste glass mainly comes from glass containers, flat glass, and TFT-LCD substrate glass. Furthermore, with the increasing demand for solar photovoltaic power, the amount of waste glass from solar photovoltaic panels will also increase accordingly in the future.

[0005] Currently, waste glass, after screening, crushing, and impurity removal, can be used as engineering aggregates, primarily in recycled products such as asphalt paving, brickwork, and cement products. However, these applications largely represent downgraded material recycling and fail to fully utilize the pozzolanic properties of waste glass's high amorphous silica content. Previous related technologies, such as patents CN103553491A and CN103172323A, only disclosed methods for applying waste glass to concrete preparation, but did not explore the issue of waste glass's reactivity. Furthermore, while patents TWI761284 and TWI796036 propose reacting glass powder with an alkali activator to form a novel inorganic cementitious material or inorganic solidified product without cement clinker, the use of alkali activators increases production costs, and its commercial application remains to be verified, resulting in low market acceptance.

[0006] Therefore, in order to solve the problems of insufficient activity of waste glass, low reuse rate and insufficient concrete performance when using waste glass as pozzolanic material in the existing technology, it is urgent to develop a method to improve the cementing activity of waste glass pozzolanic material, so as to improve its reuse rate and create high added value, which is an important goal of current technological development. Summary of the Invention

[0007] For the reasons mentioned above, the present invention provides a method for preparing volcanic ash materials from waste glass, and in particular a technique for activating and reprocessing waste glass into volcanic ash materials.

[0008] In one embodiment of the present invention, a method for preparing volcanic ash material includes the following steps: collecting waste glass; crushing the waste glass into waste glass particles of a predetermined size; and grinding the waste glass particles to obtain finely ground glass powder with a predetermined particle size and a predetermined particle size distribution, as volcanic ash material.

[0009] Preferably, the predetermined size of the waste glass particles may be less than about 10 mm.

[0010] Preferably, the predetermined particle size of the finely ground glass powder may be less than about 45 µm.

[0011] Preferably, the predetermined particle size distribution of the finely ground glass powder may be such that the sieve residue is less than about 5%.

[0012] Preferably, the finely ground glass powder is further treated with chemical additives.

[0013] Preferably, the chemical additives may include diethylene glycol, triethanolamine, triisopropanolamine, or any combination thereof.

[0014] Preferably, the finely ground glass powder can have a predetermined specific surface area, preferably about 2500 cm². 2 / g to approximately 8000 cm 2 / g.

[0015] Preferably, the waste glass can come from glass containers, flat glass, solar photovoltaic panel glass, TFT-LCD liquid crystal substrate glass, or any combination thereof.

[0016] Preferably, the method further includes screening the waste glass according to its type and / or color before the crushing step and / or grinding step.

[0017] In another embodiment of the present invention, a pozzolanic material prepared by the method described above is provided. Preferably, the pozzolanic material further includes fly ash, calcined clay, or a combination thereof.

[0018] In another embodiment of the invention, an article is provided comprising a body having a predetermined shape, and a volcanic ash material prepared as described above.

[0019] Preferably, the predetermined shape of the article may include a circle, square, cone, arch, sphere, column, or any shape designed as required.

[0020] Preferably, the product can be a building, decoration, container, or mold, etc.

[0021] Preferably, the product may also include cement.

[0022] Preferably, the product may also include concrete or cement mortar. Attached Figure Description

[0023] Figure 1 This is a flowchart of a method for preparing volcanic ash materials according to an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of a volcanic ash article according to an embodiment of the present invention.

[0025] Figure 3 The results of an activity test of finely ground glass powder applied to ordinary silicate cement concrete according to an embodiment of the present invention are shown.

[0026] Symbol Explanation

[0027] S11-S14: Steps

[0028] 2: Volcanic ash products

[0029] 21: Ontology

[0030] 22: Finely ground glass powder Detailed Implementation

[0031] To achieve the above objectives, the present invention adopts the following technical solution: waste glass is crushed, ground and activated, thereby turning the waste glass into a highly active pozzolanic material, thereby increasing its addition ratio in cement concrete and improving the fresh mixing performance and hardening performance of concrete.

[0032] definition

[0033] The term "cement" used in this article refers to a building material, specifically hydraulic cement, which is made by grinding clinker with calcium silicate as its main component. When cement is mixed with water, a hydration reaction occurs, producing calcium silicate hydrate (CSH) and calcium hydroxide (Ca(OH)2).

[0034] The term "hydration reaction" used in this article refers to the chemical reaction between components such as tricalcium silicate (C3S) and dicalcium silicate (C2S) in cement and water after mixing, producing hydration products such as calcium silicate hydrate (CSH) and calcium hydroxide (Ca(OH)2). Calcium silicate hydrate (CSH) gradually forms and creates a robust structure, giving concrete excellent mechanical properties and durability.

[0035] The term "pozzolanic reaction" used in this article refers to a chemical reaction occurring in cement-based materials, involving the reaction between pozzolanic materials (such as fly ash, calcined clay, or the finely ground glass powder described in this article) and calcium hydroxide (Ca(OH)2) generated during cement hydration. Specifically, amorphous silica (SiO2) in pozzolanic materials reacts with Ca(OH)2 in the presence of water to generate additional calcium silicate hydrate (CSH), which can fill the microchannels of cement paste, refine the pores, improve water tightness, thereby increasing the compressive strength, density, and durability of concrete, cement mortar, or cement products, and improving their later-stage strength.

[0036] The term "grinding and grading system" used in this article refers to the process of feeding raw materials (such as waste glass particles) into a grinding mill for grinding. This grinding mill can be a ball mill, vertical roller mill, ring roller mill, or Raymond mill, etc. The process can involve continuous feeding and discharging, or a single batch of raw material can be fed in for grinding. After grinding, the material enters a micronizer for particle size control. Finer particles are output as the final product, while coarser particles are returned to the grinding mill for further grinding until the desired particle size is achieved.

[0037] The term "waste glass particles" as used in this article refers to waste glass that has been crushed by the present invention but has not been ground by a grinding and grading system (hereinafter referred to as "physical activation") or treated with chemical additives (hereinafter referred to as "chemical activation"), and has a predetermined size.

[0038] The term "finely ground glass powder" as used in this article refers to waste glass powder material with a predetermined particle size and predetermined particle size distribution, prepared by further processing the aforementioned waste glass particles through the physical activation and / or chemical activation steps of this invention.

[0039] The term "activity index" used in this article refers to the ability of finely ground glass micropowder, when used as a pozzolanic material, to undergo a secondary reaction with calcium hydroxide (Ca(OH)2) produced after cement hydration. The activity index is an indicator for evaluating the activity of pozzolanic materials. It represents the ratio of the compressive strength of a mixture of pozzolanic material and cement mortar (test group) to that of pure cement mortar (control group) at a certain mixing ratio (usually 20% by weight of the pozzolanic material replacing cement). The higher the value, the greater the contribution of the pozzolanic material to improving the compressive strength of the mixture. This test method follows the relevant provisions of 10896, "Method for sampling and testing of fly ash or natural pozzolanic mineral admixtures for use as a mineral admixture in Portland-cement concrete."

[0040] The term "screen residue" used in this article refers to the ratio of finely ground glass powder that does not pass through and remains on the screen after the aforementioned finely ground glass powder is sieved through a screen with a predetermined aperture, to all finely ground glass powder before sieving.

[0041] The term "about" used herein is used to modify a term or value so that it is not an absolute value, but cannot be found in the prior art. In some embodiments, "about" encompasses values ​​within 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% (inclusive) or any intermediate range (e.g., ±2% to 6%) of the measured value. This includes at least the degree of expected experimental, technical, and instrumental errors in the method, analysis, or measurement.

[0042] Example

[0043] See Figure 1This is a flowchart of a method for preparing volcanic ash material according to an embodiment of the present invention. The preparation method includes step S11: collecting waste glass; step S12: crushing the waste glass into waste glass particles of a predetermined size, preferably less than about 10 mm, more preferably less than about 8 mm, and even more preferably less than about 5 mm; step S13: grinding (physical activation) the waste glass particles using a grinding and grading system to obtain finely ground glass powder with a predetermined particle size and predetermined particle size distribution; the predetermined particle size must be less than about 75 µm, preferably less than about 45 µm, more preferably less than about 35 µm, and even more preferably less than about 25 µm; the predetermined particle size distribution preferably has a sieve residue of less than about 5%, more preferably less than about 3%, and even more preferably less than about 1%, as a volcanic ash material; (if necessary) step S14: further chemically activating the finely ground glass powder using chemical additives.

[0044] In one embodiment, before the crushing and / or grinding steps, the waste glass is further screened according to its type and / or color, for example, into colorless transparent glass and colored glass. The screening method may include, but is not limited to, magnetic separation, air separation, or sieving.

[0045] In one embodiment, the chemical activation method uses one or any combination of chemical additives such as diethylene glycol, triethanolamine, and triisopropanolamine as surface modifiers to improve the charge dispersion on the surface of waste glass particles, thereby enhancing the hydration reaction of pozzolanic materials. The addition ratio can be adjusted as needed (e.g., 0.035% of the weight of finely ground glass powder).

[0046] In one embodiment, the finely ground glass powder prepared by the method of the present invention has a predetermined specific surface area, preferably about 2500 cm². 2 / g to approximately 8000 cm 2 / g, more preferably about 3000 cm 2 / g to approximately 6000 cm 2 / g.

[0047] In one embodiment, the selected waste glass can come from various types of glass, such as glass containers, flat glass, solar photovoltaic panel glass, and glass electronic screens. Based on its main components, it can be classified as soda-lime glass, borosilicate glass, or quartz glass; based on its type, it can be ordinary glass or tempered glass.

[0048] In one embodiment, by Figure 1 The volcanic ash materials prepared by this method may include not only finely ground glass powder, but also common fly ash, calcined clay, etc.

[0049] See Figure 2This is a schematic diagram of a volcanic ash product according to an embodiment of the present invention. As shown, the volcanic ash product 2 includes a body 21 and finely ground glass powder 22 of the present invention. The body 21 can be designed into any shape according to the needs of the user or builder, such as a two-dimensional or three-dimensional circular, square, conical, arched, spherical, columnar, or irregular shape. In one embodiment, the volcanic ash product 2 may also include a binding material such as cement. In one embodiment, the volcanic ash product 2 may also be concrete or cement mortar. The volcanic ash product 2 can be, for example, a building, decoration, container, or mold.

[0050] Example

[0051] Materials and Methods

[0052] Waste glass sources may include container glass, flat glass, solar photovoltaic panels, and / or TFT-LCD liquid crystal substrate glass. Container glass and flat glass may come from waste glass generated by glass recycling and processing facilities, while solar photovoltaic panel glass may come from waste solar photovoltaic panel processing facilities, or from waste electronic components, scraps, and defective products generated during the solar photovoltaic panel manufacturing process; TFT-LCD liquid crystal substrate glass comes from waste glass substrates used in the TFT-LCD manufacturing process.

[0053] The collected waste glass is processed through sorting and / or color screening, crushing, and other methods to obtain high-purity waste glass particles. Subsequently, the waste glass particles are physically activated into fine glass powder through a grinding and grading system, and chemical activation methods are used as needed to increase the specific surface area (fineness) of the waste glass particles, thereby forming a highly active pozzolanic material.

[0054] Waste glass abrasiveness test

[0055] Waste glass of the same source and quality was uniformly crushed to less than 5 mm using a crusher. The waste glass particles were then fed into a ball mill for grinding. Different grinding times (20 minutes, 40 minutes, 60 minutes, and 80 minutes) were set, and the amount of finely ground glass powder that did not pass through a 45 µm sieve (hereinafter referred to as "45 µm sieve residue") was measured. The smaller the value, the more uniform the particle size distribution of the finely ground glass powder. The desired value was a 45 µm sieve residue of less than approximately 5% (see Example A for details). The results of different grinding times on the 45 µm sieve residue are shown in Table 1.

[0056] Table 1

[0057] Since glass has a Mohs hardness of 6, which is only slightly lower than quartz (hardness 7) and higher than limestone (hardness 3), waste glass is a relatively difficult material to grind. The results of the waste glass grindability test in Table 1 show that a physical activation method is needed to improve the grinding fineness and particle size distribution of the waste glass particles, thereby obtaining the desired finely ground glass powder.

[0058] Finely ground glass powder applied to the activity index of cement

[0059] Example A

[0060] Table 2 shows the results of the activity index test on the 45 µm sieve residue of finely ground glass powder from the same source and of the same quality, according to the 10896 test method (as a pozzolanic material replacing 20% ​​of the cement weight), at different grinding times. The results indicate that the activity index increases as the 45 µm sieve residue decreases. When grinding for 60 minutes, the 45 µm sieve residue of the finely ground glass powder is the desired 5.1%, at which point the 28-day activity index reaches approximately 85% of the control group, demonstrating good pozzolanic reaction, as shown in test group C. If the grinding time is extended to 80 minutes, the 45 µm sieve residue of the finely ground glass powder is only 2.8%, exhibiting the best activity index, as shown in test group D. Therefore, after physical activation of waste glass, the particle size distribution of the finely ground glass powder is a key factor affecting the activity index. Considering that the activity index of the test group has reached more than 85% of the control group, the desired value is that the 45 µm sieve residue of the finely ground glass powder should be less than approximately 5%.

[0061] Table 2

[0062] Example B

[0063] Table 3 shows the activity index test results of finely ground glass powder from the same source, of the same quality, and ground for the same time, under different chemical activation methods according to the 10896 test method. The results indicate that the use of different types of chemical additives affects the activity index and 45 µm sieve residue of the finely ground glass powder. Among them, experimental groups E to G (using chemical additive combinations whose main components are (a) diethylene glycol, (b) triethanolamine, and (c) triisopropanolamine, respectively) effectively improved the grinding efficiency of waste glass (i.e., reduced 45 µm sieve residue) and further increased the activity index of the finely ground glass powder as a pozzolanic material. In contrast, control groups H and I (using chemical additive combinations whose main components are (d) isopropanol:ethylene glycol = 1:1 and (e) sodium acrylate:sodium sulfate:sodium silicate = 17:2:1, respectively) had a smaller impact on the grinding efficiency of waste glass, resulting in the activity indices of experimental groups H and I being similar to or even lower than those of experimental group D without added chemical additives. The results show that appropriate selection of chemical additives (such as combinations (a), (b), and (c)) can effectively improve the grinding efficiency of waste glass and enhance its activity index as a pozzolanic material.

[0064] Table 3

[0065] Example C

[0066] Table 4 shows the test results of finely ground glass powders of the same mass, grinding time, and chemical activation method, produced from different types of waste glass, according to test method 10896, and their activity index. The finely ground glass powders produced from the four waste glass sources all had a 45 µm sieve residue of less than 5%, and their specific surface area ranged from 3300 to 5790 cm². 2 / g, with an activity index (28 days) of 95-105%, indicating that after physical and chemical activation treatments of the present invention, finely ground glass powder of different types of waste glass can be used as highly reactive pozzolanic material and can be effectively applied to cement products or cement concrete.

[0067] Table 4

[0068] The activity index of finely ground glass powder applied to concrete

[0069] In this experiment, solar photovoltaic panel glass was ground and graded using physical and chemical activation methods to produce finely ground glass powder with a sieve residue (45 µm) of less than 5%, replacing 15% of the cement weight. Compared to container glass and flat glass, because solar photovoltaic panel glass is a type of tempered glass, the finely ground glass powder produced using solar photovoltaic panel glass has a wider particle size distribution and a slightly lower specific surface area under the same physical and chemical activation methods, but its 45 µm sieve residue can still be controlled within 5%.

[0070] The results of strength tests on ordinary silicate cement concrete using finely ground glass powder of the same mass, grinding time, and chemical activation method are as follows: Figure 3 The test results show that concrete produced using finely ground glass micropowder as a pozzolanic material achieves an activity index of approximately 94% of the control group (concrete using pure cement mortar) after 28 days. This indicates that the finely ground glass micropowder treated with the physical and chemical activation methods of this invention possesses strength in concrete approaching that of traditional cement and can partially replace cement. It is a low-carbon, highly reactive pozzolanic material that can be effectively applied to cement products or cement concrete.

[0071] in conclusion

[0072] Observations of the finely ground glass powder produced using waste glass in this invention show that, with appropriate physical and / or chemical activation treatment, the activity index of waste glass can be effectively improved. When applied to cement and concrete, compared to traditional cement, the activity index can reach approximately 85% or more in 7 days and approximately 95% or more in 28 days. Therefore, the particle size and particle size distribution of the finely ground glass powder are among the main factors affecting the activity index.

[0073] Based on the experimental results of the above-described examples of the present invention, at least the following advantages can be demonstrated:

[0074] I. This invention can effectively solve the problem of insufficient bonding activity of waste glass as a volcanic ash material, which leads to insufficient concrete performance.

[0075] Second, this invention utilizes activated finely ground glass powder as a pozzolanic material, which can not only improve the recycling rate of waste glass, but also replace part of the cement by adding the finely ground glass powder to concrete, thereby reducing the amount of cement added.

[0076] Third, the finely ground glass powder of the present invention is waste glass with a predetermined particle size and predetermined particle size distribution, which can undergo a good pozzolanic reaction with cement clinker, effectively improving the workability of concrete and thus creating high added value.

[0077] Many features and advantages of the present invention are apparent from the description; therefore, the appended claims are intended to cover all features and advantages falling within the true spirit and scope of the invention. Furthermore, since various modifications and variations will readily conceive of those skilled in the art, the invention is not limited to the specific processes, constructions, and operations shown and described, and all suitable modifications and equivalents fall within the scope of the invention.

[0078] Furthermore, those skilled in the art will understand that the inventive concept can be readily used as the basis for other methods, structures, and systems that achieve the various objectives of the present invention. Therefore, the appended claims should not be considered as limited by the description herein.

Claims

1. A method for preparing volcanic ash materials, comprising: Collect waste glass; The waste glass is crushed into waste glass particles of a predetermined size; and The waste glass particles are ground to obtain finely ground glass powder with a predetermined particle size and particle size distribution, which can be used as pozzolanic material.

2. The method of claim 1, wherein the predetermined size of the waste glass particles is less than about 10 mm.

3. The method of claim 1, wherein the predetermined particle size of the finely ground glass powder is less than about 45 µm.

4. The method of claim 1, wherein the predetermined particle size distribution of the finely ground glass powder is such that the sieve residue is less than about 5%.

5. The method of claim 1, wherein the finely ground glass powder is further treated with chemical additives.

6. The method of claim 5, wherein the chemical auxiliaries comprise diethylene glycol, triethanolamine, triisopropanolamine, or any combination thereof.

7. The method of claim 1, wherein the finely ground glass powder has a predetermined specific surface area.

8. The method of claim 7, wherein the predetermined specific surface area is about 2500 cm². 2 / g to approximately 8000 cm 2 / g.

9. The method of claim 1, wherein the waste glass is derived from glass containers, flat glass, solar photovoltaic panel glass, TFT-LCD liquid crystal substrate glass, or any combination thereof.

10. The method of claim 1, further comprising screening according to the type and / or color of the waste glass before the crushing step and / or the grinding step.

11. A volcanic ash material prepared by the method according to any one of claims 1 to 10.

12. The pozzolanic material of claim 11, further comprising fly ash, calcined clay, or a combination thereof.

13. An article comprising a body having a predetermined shape; and the volcanic ash material according to any one of claims 11 to 12.

14. The article of claim 13, wherein the predetermined shape comprises a circle, a square, a cone, an arch, a sphere, a column, or any shape designed as required.

15. The article of claim 13, comprising a building, decoration, container or mold.

16. The article of claim 13, further comprising cement.

17. The article of claim 13, further comprising concrete or cement mortar.

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