Powder alkali activator for inorganic polymeric material based on siliceous solid waste and method for preparing the same

Abstract

This invention relates to a powdered alkali activator for inorganic polymer materials based on siliceous solid waste and its preparation method. The technical solution involves: drying, crushing, and first grinding the siliceous solid waste to obtain pretreated siliceous solid waste powder; mixing the pretreated siliceous solid waste powder with a solid alkali at a mass ratio of 100:80-100 to obtain a mixture; thermally activating the mixture at 600-1000℃ for 0.5-2 hours, cooling, and then second grinding to obtain the powdered alkali activator for inorganic polymer materials based on siliceous solid waste. This invention features improved efficiency in the resource utilization of siliceous solid waste, significant reduction in cost and energy consumption, and a simple production process. The prepared powdered alkali activator for inorganic polymer materials based on siliceous solid waste is not only convenient to store and transport and safe to use, but also can replace water glass in the preparation of inorganic polymer materials with high compressive strength.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization and building material preparation technology. Specifically, it relates to a powdered alkali activator for inorganic polymer materials based on siliceous solid waste and its preparation method. Background Technology

[0002] Inorganic polymeric materials are non-metallic materials formed by the dissolution, recombination, and polymerization of active components from silicon-aluminum-rich raw materials under alkali activation, resulting in a three-dimensional network structure. They possess characteristics such as high early strength, strong corrosion resistance, and low energy consumption in preparation, and are considered a "green alternative" to traditional cement. Currently, the main alkali activator used in inorganic polymeric materials is water glass solution. Commercially available water glass requires high purity and low insoluble content, thus necessitating a strict production process. Currently, water glass production mainly employs two processes: dry and wet. The dry process typically involves melting high-purity quartz with Na₂CO₃ at approximately 1400℃ to obtain solid water glass with a modulus of 2.2–3.7, followed by dissolution and modulus adjustment to obtain the desired water glass solution. The wet process typically involves high-purity quartz sand with NaOH or KOH aqueous solution under high temperature and pressure, followed by filtration and concentration to obtain the water glass solution. These production processes not only rely on high-purity raw materials but also involve complex processes, leading to high costs and energy consumption, thus hindering the green development of inorganic polymeric materials.

[0003] Large quantities of siliceous solid waste, such as tailings slag, smelting slag, and stone waste, are generated. Traditional direct stockpiling methods not only consume land resources but also pose significant environmental risks. Siliceous solid waste is typically rich in SiO2, possessing the potential to be used as an auxiliary activator for inorganic polymer materials. Furthermore, inorganic polymer materials do not have high requirements for the purity and insoluble content of alkali activators. Therefore, fully activating the activity of siliceous solid waste and developing it into a powdered alkali activator for inorganic polymer materials has attracted the attention of those skilled in the art.

[0004] The patented technology, "Slag-Fly Ash Composite Solid Activator and Its Production Method" (CN102627426B), involves mixing NaOH, Na2CO3, low-modulus liquid water glass, and a modifier into a homogeneous solution, aging it in a vacuum for 24-48 hours, drying it at 140-170℃, and grinding it to obtain a solid activator. This activator is then combined with slag-fly ash to produce mineral admixtures or concrete. This technology uses a variety of purely chemical agents to prepare the solid activator, which not only fails to break away from the existing water glass production process but also adds aging and drying steps, resulting in a complex production process with high energy consumption and cost. It does not achieve efficient resource utilization of siliceous solid waste.

[0005] The patented technology, "An Alkali-Activated Cementitious Material and Its Preparation Method" (CN104446045A), involves mixing siliceous iron tailings powder, fly ash, and slag powder to form a composite powder. Liquid water glass is then added to the mixture after adjusting its modulus with NaOH, followed by curing to obtain the final product. While this technology achieves the resource utilization of siliceous iron tailings, its core technology utilizes liquid water glass. Due to its high viscosity and alkalinity, water glass is inconvenient to store and transport, posing safety hazards during on-site construction.

[0006] The patented technology, "A Concrete Activator Based on Inorganic Solid Waste and Its Preparation Method" (CN120423813B), uses waste glass, tailings, and fly ash as high-silica solid waste base materials, combined with carbide slag, by-product Na2CO3, modified composite enzyme microcapsules, polyether polyol, surfactant, and organic acid. The concrete activator is prepared through pulping, hydrothermal reaction, and post-treatment. This technology introduces a variety of modifier auxiliary components, which not only makes the preparation process complex, but also makes the concrete activator a liquid slurry, which is inconvenient for transportation and on-site construction.

[0007] In summary, existing methods suffer from several drawbacks, including heavy reliance on traditional water glass production processes, low utilization of siliceous solid waste, high production costs and energy consumption, cumbersome process flow, difficulties in storage and transportation, and insufficient construction safety. Summary of the Invention

[0008] The present invention aims to overcome the defects of the prior art and provides a method for preparing a powdered alkaline activator for inorganic polymer materials based on siliceous solid waste that can improve the efficient resource utilization of siliceous solid waste, significantly reduce costs and energy consumption, and has a simple production process. The powdered alkaline activator for inorganic polymer materials based on siliceous solid waste prepared by this method is not only convenient to store and transport and safe to construct, but also can replace water glass in the preparation of inorganic polymer materials with high compressive strength.

[0009] To achieve the above objectives, the specific steps of the technical solution adopted by the present invention are as follows: Step 1: Dry, crush, and grind the siliceous solid waste to obtain pretreated siliceous solid waste powder.

[0010] Step 2: Mix the pretreated siliceous solid waste powder with solid alkali at a mass ratio of 100:80~100 to obtain a mixture.

[0011] Step 3: Activate the mixture at 600~1000℃ for 0.5~2h, cool, and grind a second time to obtain a powder alkali activator for inorganic polymer materials based on siliceous solid waste.

[0012] The siliceous solid waste is one of the following: tailings slag, smelting slag, stone waste, and glass waste; the siliceous solid waste contains: SiO2 content ≥ 55wt%, Al2O3 content ≤ 10wt%, and CaO content ≤ 12wt%.

[0013] The drying process refers to a moisture content of ≤8wt%.

[0014] The equipment used for the first grinding is either a ball mill or a vibratory mill.

[0015] The particle size of the pretreated siliceous solid waste powder is <200μm.

[0016] The solid base is NaOH or KOH.

[0017] The cooling method is natural cooling, and the cooling temperature is room temperature.

[0018] The second grinding process uses the same equipment as the first grinding process.

[0019] The particle size of the powder alkali activator for the inorganic polymer materials based on siliceous solid waste is <74μm.

[0020] By adopting the above technical solution, the present invention has the following advantages compared with the prior art: 1. This invention involves thermally activating siliceous solid waste by mixing it with a solid alkali such as NaOH or KOH. This process disrupts the stable quartz crystal structure within the siliceous solid waste, promoting the dissolution of active silicate substances. As the reaction proceeds, the quartz in the siliceous solid waste is completely transformed into low-polymerization Q... 2 The silicate structure has a high degree of solubility. This process transforms siliceous solid waste from a low-activity raw material into an effective silicon source that can directly participate in alkali-activated reactions, improving the efficient resource utilization of siliceous solid waste. It not only significantly reduces costs and energy consumption, but also simplifies the production process.

[0021] 2. This invention pretreats siliceous solid waste, then combines it with solid alkali and thermally activates it to directly obtain a powdered alkali activator for inorganic polymer materials based on siliceous solid waste (hereinafter referred to as "powdered alkali activator"). This integrates "silicon source supply" and "alkali activation function" into a single powder, not only avoiding the dependence on external solution-based silicon sources in traditional inorganic polymer material preparation processes, but also eliminating the reliance on high-purity raw materials and complex, stringent production processes of traditional water glass production. This provides a foundation for completely replacing water glass in the preparation of inorganic polymer materials. Therefore, the prepared powdered alkali activator is not only convenient to store and transport, and safe to use, but can also replace water glass in the preparation of inorganic polymer materials.

[0022] 3. The powdered alkali activator prepared in this invention, upon contact with siliceous alumina raw materials and water, can rapidly release silicate components such as Na2SiO3 and K2SiO3 formed from NaOH and KOH in the siliceous solid waste and solid alkali, increasing the pH of the system and promoting the breakage of Si–O–Si / Al in the siliceous alumina raw materials used to prepare inorganic polymer materials. This allows the siliceous alumina components in the raw materials to dissolve in the form of monomers or oligomers. Simultaneously, the active silicon component of the prepared powdered alkali activator can supplement the reactive silicon source of the system. This dual effect is beneficial for promoting the formation of inorganic polymer materials with a continuous and dense three-dimensional network structure. According to the national standard GB / T17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)," the inorganic polymer materials prepared using the powdered alkali activator based on siliceous solid waste prepared in this invention were tested, and their compressive strength was 35.21~72.86 MPa.

[0023] Therefore, this invention has the advantages of improving the efficient resource utilization of siliceous solid waste, significantly reducing costs and energy consumption, and having a simple production process. The prepared inorganic polymer material powder alkali activator based on siliceous solid waste is not only convenient to store and transport and safe to construct, but can also replace water glass to prepare inorganic polymer materials with high compressive strength. Attached Figure Description

[0024] Figure 1 The XRD pattern of a powder alkali activator for inorganic polymer materials based on siliceous solid waste prepared according to the present invention; Figure 2 for Figure 1 The image shown is an appearance diagram of an inorganic polymer material prepared using a powdered alkaline activator based on siliceous solid waste. Figure 3 for Figure 1 The image shown is a SEM image of an inorganic polymer material prepared using a powdered alkali activator based on siliceous solid waste. Detailed Implementation

[0025] The present invention will be further described below with reference to specific embodiments, but this is not intended to limit the scope of protection thereof: An inorganic polymer material powder alkali activator based on siliceous solid waste and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: Dry, crush, and grind the siliceous solid waste to obtain pretreated siliceous solid waste powder.

[0026] Step 2: Mix the pretreated siliceous solid waste powder with solid alkali at a mass ratio of 100:80~100 to obtain a mixture.

[0027] Step 3: Activate the mixture at 600~1000℃ for 0.5~2h, cool, and grind a second time to obtain a powder alkali activator for inorganic polymer materials based on siliceous solid waste.

[0028] The siliceous solid waste is one of the following: tailings slag, smelting slag, stone waste, and glass waste; the siliceous solid waste contains: SiO2 content ≥ 55wt%, Al2O3 content ≤ 10wt%, and CaO content ≤ 12wt%.

[0029] The equipment used for the first grinding is either a ball mill or a vibratory mill.

[0030] The solid base is NaOH or KOH.

[0031] In this specific implementation: The drying process refers to a moisture content of ≤8wt%.

[0032] The particle size of the pretreated siliceous solid waste powder is <200μm.

[0033] The cooling method is natural cooling, and the cooling temperature is room temperature.

[0034] The second grinding process uses the same equipment as the first grinding process.

[0035] The particle size of the powder alkali activator for the inorganic polymer materials based on siliceous solid waste is <74μm.

[0036] The details will not be repeated in the examples.

[0037] Example 1 An inorganic polymer material powder alkali activator based on siliceous solid waste and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: Dry, crush, and grind the siliceous solid waste to obtain pretreated siliceous solid waste powder.

[0038] Step 2: Mix the pretreated siliceous solid waste powder with solid alkali at a mass ratio of 100:80 to obtain a mixture.

[0039] Step 3: The mixture is thermally activated at 600°C for 2 hours, cooled, and then milled a second time to obtain a powder alkali activator for inorganic polymer materials based on siliceous solid waste.

[0040] The siliceous solid waste is glass waste; the siliceous solid waste contains: SiO2 content of 73.22 wt%, Al2O3 content of 1.43 wt%, and CaO content of 11.50 wt%.

[0041] The equipment used for the first grinding was a ball mill.

[0042] The solid base is KOH.

[0043] The inorganic polymer material based on siliceous solid waste prepared in this embodiment was mixed with powdered alkali activator, metakaolin, and water at a mass ratio of 100:140:145. The mixture was stirred for 1.5 minutes at 2000 rpm and poured into molds. It was then cured for 7 days according to the national standard GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)". The compressive strength of the obtained inorganic polymer material was tested to be 35.21 MPa.

[0044] The metakaolin clay has a SiO2 content of 59.80 wt% and an Al2O3 content of 35.72 wt%.

[0045] Example 2 An inorganic polymer material powder alkali activator based on siliceous solid waste and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: Dry, crush, and grind the siliceous solid waste to obtain pretreated siliceous solid waste powder.

[0046] Step 2: Mix the pretreated siliceous solid waste powder with solid alkali at a mass ratio of 100:85 to obtain a mixture.

[0047] Step 3: The mixture is thermally activated at 700°C for 1.75 hours, cooled, and then milled a second time to obtain a powder alkali activator for inorganic polymer materials based on siliceous solid waste.

[0048] The siliceous solid waste is stone waste; the siliceous solid waste contains: SiO2 content of 70.44wt%, Al2O3 content of 9.96wt%, and CaO content of 1.67wt%.

[0049] The equipment used for the first grinding was a vibratory mill.

[0050] The solid alkali is NaOH.

[0051] The inorganic polymer material based on siliceous solid waste prepared in this embodiment was mixed with powdered alkali activator, fly ash, and water at a mass ratio of 100:120:120. The mixture was stirred for 1.5 minutes at 2000 rpm and poured into molds. It was then cured for 14 days according to the national standard GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)". The compressive strength of the obtained inorganic polymer material was tested to be 54.39 MPa.

[0052] The fly ash has a SiO2 content of 49.40 wt% and an Al2O3 content of 22.50 wt%.

[0053] Example 3 An inorganic polymer material powder alkali activator based on siliceous solid waste and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: Dry, crush, and grind the siliceous solid waste to obtain pretreated siliceous solid waste powder.

[0054] Step 2: Mix the pretreated siliceous solid waste powder with solid alkali at a mass ratio of 100:100 to obtain a mixture.

[0055] Step 3: Activate the mixture at 800°C for 1.5 hours, cool it, and grind it a second time to obtain a powder alkali activator for inorganic polymer materials based on siliceous solid waste.

[0056] The siliceous solid waste is smelting slag; the siliceous solid waste contains: SiO2 content of 55.98wt%, Al2O3 content of 6.27wt%, and CaO content of 3.77wt%.

[0057] The equipment used for the first grinding was a ball mill.

[0058] The solid alkali is NaOH.

[0059] The inorganic polymer material based on siliceous solid waste prepared in this embodiment was mixed with powdered alkali activator, fly ash, and water at a mass ratio of 100:140:120. The mixture was stirred for 1.5 minutes at 2000 rpm and poured into molds. It was then cured for 28 days according to the national standard GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)". The compressive strength of the obtained inorganic polymer material was tested to be 66.27 MPa.

[0060] The metakaolin clay has a SiO2 content of 57.50 wt% and an Al2O3 content of 29.11 wt%.

[0061] Example 4 An inorganic polymer material powder alkali activator based on siliceous solid waste and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: Dry, crush, and grind the siliceous solid waste to obtain pretreated siliceous solid waste powder.

[0062] Step 2: Mix the pretreated siliceous solid waste powder with solid alkali at a mass ratio of 100:90 to obtain a mixture.

[0063] Step 3: Activate the mixture at 900°C for 1 hour, cool it, and grind it a second time to obtain a powder alkali activator for inorganic polymer materials based on siliceous solid waste.

[0064] The siliceous solid waste is tailings slag; the siliceous solid waste contains: SiO2 content of 66.63wt%, Al2O3 content of 2.54wt%, and CaO content of 6.26wt%.

[0065] The equipment used for the first grinding was a ball mill.

[0066] The solid alkali is NaOH.

[0067] The inorganic polymer material based on siliceous solid waste prepared in this embodiment was mixed with powdered alkali activator, metakaolin, and water at a mass ratio of 100:160:170. The mixture was stirred for 1.5 minutes at 2000 rpm and poured into molds. It was then cured for 7 days according to the national standard GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)". The compressive strength of the obtained inorganic polymer material was tested to be 51.20 MPa.

[0068] The metakaolin clay has a SiO2 content of 53.50 wt% and an Al2O3 content of 41.73 wt%.

[0069] Example 5 An inorganic polymer material powder alkali activator based on siliceous solid waste and its preparation method. The steps of the preparation method described in this embodiment are as follows: Step 1: Dry, crush, and grind the siliceous solid waste to obtain pretreated siliceous solid waste powder.

[0070] Step 2: Mix the pretreated siliceous solid waste powder with solid alkali at a mass ratio of 100:95 to obtain a mixture.

[0071] Step 3: Activate the mixture at 1000℃ for 0.5h, cool it, and grind it a second time to obtain a powder alkali activator for inorganic polymer materials based on siliceous solid waste.

[0072] The siliceous solid waste is glass waste; the siliceous solid waste contains: SiO2 content of 79.12wt%, Al2O3 content of 1.21wt%, and CaO content of 10.05wt%.

[0073] The equipment used for the first grinding was a vibratory mill.

[0074] The solid base is KOH.

[0075] The inorganic polymer material based on siliceous solid waste prepared in this embodiment was mixed with powdered alkali activator, slag, and water at a mass ratio of 100:110:105. The mixture was stirred for 1.5 minutes at 2000 rpm and then poured into a mold. It was cured for 28 days according to the national standard GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)". The compressive strength of the obtained inorganic polymer material was tested to be 72.86 MPa.

[0076] The metakaolin clay has a SiO2 content of 31.44 wt% and an Al2O3 content of 16.05 wt%.

[0077] This specific implementation method has the following advantages compared with the prior art: 1. This specific implementation method involves thermally activating siliceous solid waste by mixing it with a solid alkali such as NaOH or KOH. This process disrupts the stable quartz crystal structure within the siliceous solid waste, promoting the dissolution of active silicate substances. As the reaction proceeds, the quartz in the siliceous solid waste is completely transformed into low-polymerization Q... 2 The silicate structure has a high degree of solubility. This process transforms siliceous solid waste from a low-activity raw material into an effective silicon source that can directly participate in alkali-activated reactions, improving the efficient resource utilization of siliceous solid waste. It not only significantly reduces costs and energy consumption, but also simplifies the production process.

[0078] 2. This specific embodiment pre-treats siliceous solid waste, then combines it with solid alkali and thermally activates it to directly obtain a powdered alkali activator for inorganic polymer materials based on siliceous solid waste. This integrates "silicon source supply" and "alkali activation function" into a single powder, not only avoiding the dependence on external solution-based silicon sources in traditional inorganic polymer material preparation processes, but also eliminating the reliance on high-purity raw materials and complex, stringent production processes of traditional water glass production. This provides a foundation for completely replacing water glass in the preparation of inorganic polymer materials. The prepared powdered alkali activator for inorganic polymer materials based on siliceous solid waste is shown in the attached figure: Figure 1 The XRD pattern of the powdered alkali activator for inorganic polymer materials based on siliceous solid waste prepared in Example 4; from Figure 1 It can be seen that the main phase of the powdered alkali activator prepared in Example 4 is sodium silicate, which can replace water glass in the preparation of inorganic polymer materials. It is not only convenient to store and transport, but also safe to use during construction.

[0079] 3. The alkali activator powder for inorganic polymer materials based on siliceous solid waste prepared in this specific embodiment, upon contact with siliceous aluminate raw materials and water, can rapidly release silicate components such as Na2SiO3 and K2SiO3 formed from NaOH and KOH in the siliceous solid waste and solid alkali, increasing the pH of the system and promoting the breakage of Si–O–Si / Al in the siliceous aluminate raw materials used to prepare inorganic polymer materials. This allows the siliceous aluminate components in the raw materials to dissolve in the form of monomers or oligomers. Simultaneously, the active silicon component of the alkali activator powder for inorganic polymer materials based on siliceous solid waste can supplement the reactive silicon source of the system. This dual effect is beneficial for promoting the formation of inorganic polymer materials with a continuous and dense three-dimensional network structure. The prepared alkali activator powder for inorganic polymer materials based on siliceous solid waste is shown in the attached figure. Figure 2 , 3 As shown: Figure 2 for Figure 1 The image shown is an appearance diagram of an inorganic polymer material prepared using a powdered alkaline activator based on siliceous solid waste. Figure 3 for Figure 1 The image shown is a SEM image of an inorganic polymer material prepared using a powdered alkali activator based on siliceous solid waste; from... Figure 2 It can be seen that the inorganic polymer material prepared using the powdered alkali activator based on the siliceous solid waste obtained in Example 4 has a complete appearance, a smooth surface, and no cracking, chipping, or powdering is observed. Figure 3 It can be seen that the inorganic polymer material prepared by the powder alkali activator based on the siliceous solid waste obtained in Example 4 did not show obvious large pores and through cracks, and had good structural density and high compressive strength.

[0080] The inorganic polymer material prepared using the powdered alkali activator based on siliceous solid waste obtained in this specific embodiment was tested: the compressive strength was 35.21~72.86 MPa. The testing standard for this specific embodiment is based on the national standard GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)".

[0081] Therefore, this specific embodiment has the characteristics of improving the efficient resource utilization of siliceous solid waste, significantly reducing costs and energy consumption, and having a simple production process. The prepared inorganic polymer material powder alkali activator based on siliceous solid waste is not only convenient to store and transport and safe to construct, but can also replace water glass to prepare inorganic polymer materials with high compressive strength.

Claims

1. A method for preparing a powdered alkali activator for inorganic polymer materials based on siliceous solid waste, characterized in that... The specific steps of the preparation method are as follows: Step 1: Dry, crush, and grind the siliceous solid waste to obtain pretreated siliceous solid waste powder; Step 2: Mix the pretreated siliceous solid waste powder with solid alkali at a mass ratio of 100:80~100 to obtain a mixture; Step 3: Activate the mixture at 600~1000℃ for 0.5~2h, cool, and grind a second time to obtain a powder alkali activator for inorganic polymer materials based on siliceous solid waste.

2. The method for preparing the powdered alkali activator for inorganic polymer materials based on siliceous solid waste according to claim 1, characterized in that, The siliceous solid waste is one of the following: tailings slag, smelting slag, stone waste, and glass waste; the siliceous solid waste contains: SiO2 content ≥ 55wt%, Al2O3 content ≤ 10wt%, and CaO content ≤ 12wt%.

3. The method for preparing the powdered alkali activator for inorganic polymer materials based on siliceous solid waste according to claim 1, characterized in that, The drying process refers to a moisture content of ≤8wt%.

4. The method for preparing the powdered alkali activator for inorganic polymer materials based on siliceous solid waste according to claim 1, characterized in that, The equipment used for the first grinding is either a ball mill or a vibratory mill.

5. The method for preparing the powdered alkali activator for inorganic polymer materials based on siliceous solid waste according to claim 1, characterized in that, The particle size of the pretreated siliceous solid waste powder is <200μm.

6. The method for preparing the powdered alkali activator for inorganic polymer materials based on siliceous solid waste according to claim 1, characterized in that, The solid base is NaOH or KOH.

7. The method for preparing the powdered alkali activator for inorganic polymer materials based on siliceous solid waste according to claim 1, characterized in that, The cooling method is natural cooling, and the cooling temperature is room temperature.

8. The method for preparing the powdered alkali activator for inorganic polymer materials based on siliceous solid waste according to claim 1, characterized in that, The second grinding process uses the same equipment as the first grinding process.

9. The method for preparing the powdered alkali activator for inorganic polymer materials based on siliceous solid waste according to claim 1, characterized in that, The particle size of the powder alkali activator for the inorganic polymer materials based on siliceous solid waste is <74μm.

10. A powdered alkaline activator for inorganic polymer materials based on siliceous solid waste, characterized in that, The alkali activator for inorganic polymer materials based on siliceous solid waste is prepared by the method described in any one of claims 1 to 9.

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