Preparation method of high-activity micro-powder and high-activity micro-powder

Abstract

This disclosure relates to the field of inorganic non-metallic materials technology, and particularly to a method for preparing highly active micro-powder and the highly active micro-powder itself. The preparation method includes the following steps: Step 1, grinding high-silicon aluminum solid waste into fine powder; Step 2, adding waste acid to the fine powder and mixing to obtain a first mixture; Step 3, adding sodium sulfate to the first mixture, stirring evenly, and aging to obtain a second mixture; Step 4, adding limestone powder to the second mixture and mixing to obtain a third mixture; Step 5, subjecting the third mixture to heat treatment, cooling, crushing, and grinding sequentially to obtain the finished product. This method uses high-silicon aluminum industrial solid waste as the main raw material, combined with industrial by-products waste acid and sodium sulfate, to prepare highly active micro-powder through simple process steps. This achieves the resource utilization of industrial solid waste and industrial by-products, solving problems such as insufficient supply of highly active micro-powder in the Panxi region, environmental pollution from industrial solid waste stockpiling, and difficulties in disposing of industrial by-products.

Description

Technical Field

[0001] This disclosure relates to the field of inorganic non-metallic materials technology, and in particular to a method for preparing highly active micro powder and the highly active micro powder. Background Technology

[0002] With the rapid development of infrastructure construction in my country, the demand for high-activity micro powder in the building materials industry is increasing day by day. Among them, the Panxi region, as an important basic engineering construction area in my country, has an annual demand of more than 1.5 million tons of high-activity micro powder. It is mainly used in cement admixtures, commercial concrete admixtures, mortar modification, and building material reinforcement, etc. It is a key raw material for ensuring the quality of regional engineering construction and reducing the production cost of building materials.

[0003] However, there is a significant supply gap for high-activity micro-powders in the Panxi region. Currently, the widely used active micro-powders in the region are mainly low-activity products such as yellow phosphorus slag and secondary processed fly ash, with an activity level of only around 75. This cannot meet the quality requirements of high-end building materials and key projects for high-activity micro-powders. To fill this gap, the market mainly relies on imports of high-activity micro-powders such as 95-grade slag micro-powder and Grade 1 fly ash. This not only results in high transportation costs and high end-user prices but also makes the market susceptible to fluctuations in external supply, posing a threat to the stable development of the regional building materials industry.

[0004] Meanwhile, the Panxi region generates a large amount of high-silicon and alumina industrial solid waste. This waste, long stored in slag heaps, not only occupies significant land resources but also risks causing environmental problems such as dust, soil pollution, and water pollution, negatively impacting the regional ecological environment. Statistics show that the region generates over 1.5 million tons of coal gangue annually, with a stockpile exceeding 5 million tons. The total amount of low-quality fly ash, slag, and other solid waste exceeds 800,000 tons. This high-silicon and alumina industrial solid waste contains abundant SiO2 and Al2O3, possessing the potential to be converted into high-value building material raw materials. However, it has not yet been efficiently utilized and is mostly disposed of through stockpiling, resulting in a serious waste of resources.

[0005] In addition, industrial production in the Panxi region generates a large number of by-products, such as waste acid from the sulfuric acid process for titanium dioxide production and industrial sodium sulfate after vanadium extraction from vanadium slag. If these by-products are discharged directly, they will cause serious environmental pollution, and their treatment costs are high, which puts a great deal of environmental pressure on enterprises.

[0006] Therefore, developing a simple, low-cost method that enables the co-processing and resource utilization of industrial solid waste and industrial by-products to prepare highly active micro powders is a problem that needs to be considered by those skilled in the art. Summary of the Invention

[0007] To address the aforementioned technical problems, this disclosure provides a method for preparing highly active micro powder, comprising the following steps: Step 1: Grind the high-silicon aluminum solid waste into fine powder; Step 2: Add waste acid to the fine powder and mix to obtain the first mixture; Step 3: Add sodium sulfate to the first mixture, stir well, and then age to obtain the second mixture; Step 4: Add limestone powder to the second mixture and mix to obtain the third mixture; Step 5: The third mixture is subjected to heat treatment, cooling, crushing and grinding in sequence to obtain the finished product.

[0008] In some embodiments, the amounts of waste acid, sodium sulfate, and limestone powder added are 5-30%, 5-10%, and 5-20% of the mass of the fine powder, respectively.

[0009] In some embodiments, the aging time in step 3 is 5 to 10 hours.

[0010] In some embodiments, the heat treatment temperature in step 5 is 500~1200℃.

[0011] In some embodiments, in step 2, the concentration of the waste acid is 15-25%.

[0012] In some embodiments, the waste acid and sodium sulfate are derived from industrial byproducts.

[0013] In some embodiments, in step 4, the particle size distribution of the limestone powder is ≤200 mesh.

[0014] In some embodiments, in step 1, the high-silicon aluminum solid waste includes at least one of coal gangue, fly ash, slag, and mineral processing tailings.

[0015] The disclosed embodiments also provide a highly active micro powder, which is prepared using the above-described preparation method.

[0016] In some embodiments, the specific surface area of ​​the highly active micro powder is greater than 400 m². 2 / kg.

[0017] By adopting the above technical solution, this disclosure has at least the following beneficial effects: This invention discloses a method for preparing highly active micro powder, using high-silicon aluminum industrial solid waste as the main raw material, combined with industrial by-product waste acid and sodium sulfate, to prepare highly active micro powder through simple process steps. This method realizes the resource utilization of industrial solid waste and industrial by-products, solves the problems of insufficient supply of highly active micro powder in the Panxi region, environmental pollution from industrial solid waste stockpiling, and difficulties in the disposal of industrial by-products, while reducing the production cost of highly active micro powder and enhancing the market competitiveness of the product. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of a method for preparing highly active micro powder according to an embodiment of the present disclosure. Detailed Implementation

[0020] The embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of this disclosure by way of example, but should not be used to limit the scope of this disclosure. This disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0021] These embodiments are provided to make the disclosure thorough and complete, and to fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0022] It should be noted that, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationship, are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] Furthermore, the terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Terms such as "including" or "contains" mean that the element preceding the word encompasses the element listed after the word, and do not exclude the possibility of encompassing other elements as well.

[0024] It should also be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure depending on the specific circumstances. When a particular device is described as being located between a first device and a second device, an intermediary device may or may not be present between the particular device and the first or second device.

[0025] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0026] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0027] As mentioned in the background section, the Panxi region generates a large amount of high-silicon, alumina industrial solid waste. This waste, long stored in slag heaps, not only occupies significant land resources but also poses environmental problems such as dust, soil pollution, and water pollution, negatively impacting the regional ecological environment. This high-silicon, alumina industrial solid waste contains abundant SiO2 and Al2O3, possessing the potential to be converted into high-value building material raw materials. However, it has not yet been efficiently utilized and is mostly disposed of through stockpiling, resulting in a serious waste of resources. Furthermore, industrial production in the Panxi region also generates a large number of byproducts, such as waste acid from the sulfuric acid process for titanium dioxide production and industrial sodium sulfate from vanadium slag sodium extraction. Direct discharge of these byproducts would cause serious environmental pollution, and their treatment costs are high, placing significant environmental pressure on enterprises. Therefore, developing a simple, low-cost method that enables the co-processing and utilization of industrial solid waste and byproducts to prepare highly active micro-powders is a problem that those skilled in the art need to consider. Based on the above, this disclosure provides a method for preparing highly active micro powder and the highly active micro powder itself. The preparation method uses high-silicon aluminum industrial solid waste as the main raw material, combined with industrial by-product waste acid and sodium sulfate, and prepares highly active micro powder through simple process steps. This realizes the resource utilization of industrial solid waste and industrial by-products, solves the problems of insufficient supply of highly active micro powder in the Panxi region, environmental pollution from industrial solid waste stockpiling, and difficulties in the disposal of industrial by-products, and at the same time reduces the production cost of highly active micro powder and enhances the market competitiveness of the product.

[0028] This disclosure provides a method for preparing highly active micro powder in some embodiments, such as... Figure 1 As shown, the process includes the following steps: Step 1, grinding high-silicon aluminum solid waste into fine powder; Step 2, adding waste acid to the fine powder and mixing to obtain a first mixture; Step 3, adding sodium sulfate to the first mixture, stirring evenly, and aging to obtain a second mixture; Step 4, adding limestone powder to the second mixture and mixing to obtain a third mixture; Step 5, subjecting the third mixture to heat treatment, cooling, crushing, and grinding in sequence to obtain the finished product.

[0029] The process principle is as follows: High-silicon aluminum industrial solid waste includes one of the following: coal gangue, low-quality fly ash, slag, and mineral processing tailings. Its main chemical components are SiO2 content of 30-70%, Al2O3 content of 10-30%, and also contain small amounts of impurities such as calcium feldspar (CaAl2Si2O8), potassium-sodium feldspar (KAlSi3O8, NaAlSi3O8).

[0030] After high-silicon aluminum industrial solid waste is ground into fine powder, the SiO2 and Al2O3 inside mainly exist in the form of inert crystals with a very low activity index, making it unsuitable for direct application in the building materials field. This invention achieves the transformation of inert components into active components by adding waste acid and sodium sulfate, combined with aging and heat treatment processes.

[0031] 1. Acid leaching reaction stage (steps 2-3): After adding waste acid to high-silicon aluminum solid waste fine powder, the H2SO4 in the waste acid reacts with Al2O3, calcium feldspar, potassium sodium feldspar, etc. in the solid waste, releasing Al³⁺. + Ca² + K + Na + Plasma simultaneously disrupts the crystal structure of solid waste, converting inert SiO2 into active SiO2. Upon addition of sodium sulfate (Na2SO4), the Na2SO4 dissolves and ionizes to release Na+. + and SO4² - SO4² - With Ca² in solution + Al³ + This combination produces sulfates such as calcium sulfate (CaSO4) and aluminum sulfate (Al2(SO4)3), as shown in the following chemical reaction formula: (1) Reaction of Al2O3 with sulfuric acid: Al2O3 + 3H2SO4 = Al2(SO4)3 + 3H2O; This reaction is one of the core reactions in the acid leaching stage. Al2O3 in high-silicon aluminum solid waste undergoes a metathesis reaction with H2SO4 in waste acid to generate water-soluble aluminum sulfate, realizing the transformation of Al2O3 from inert to active, laying the foundation for the formation of subsequent active components. This reaction is consistent with the core reaction of the sulfuric acid method for extracting alumina from coal gangue, and can effectively realize the dissolution and activation of aluminum elements^{(3)}.

[0032] (2) Reaction of anorthite with sulfuric acid: CaAl2Si2O8 + 4H2SO4 = CaSO4 + Al2(SO4)3 + 2SiO2 + 4H2O; As one of the main impurities in high-silica aluminum solid waste, calcium feldspar reacts with sulfuric acid to produce calcium sulfate, aluminum sulfate and active SiO2. This not only removes some impurities but also increases the content of active components in the system. At the same time, SiO2 is precipitated in an active form, which enhances the activity of subsequent reactions.

[0033] (3) Reaction of potassium feldspar with sulfuric acid: 2KAlSi3O8 + 4H2SO4 = K2SO4 + Al2(SO4)3 + 6SiO2 + 4H2O; (4) Reaction of albite with sulfuric acid: 2NaAlSi3O8 + 4H2SO4 = Na2SO4 + Al2(SO4)3 + 6SiO2 + 4H2O; Potassium feldspar and sodium feldspar undergo similar reactions with sulfuric acid to produce corresponding sulfates and active SiO2, further releasing the active components in the solid waste. At the same time, the generated CaSO4, K2SO4, and Na2SO4 can act as reaction aids (electrocalcite series activators) to promote the subsequent hydration reaction.

[0034] 2. Aging Stage (Step 3): After thorough stirring, the purpose of aging is to ensure the acid leaching reaction proceeds fully, allowing the inert components in the solid waste to be fully converted into active components. Simultaneously, it ensures the generated sulfates are evenly dispersed in the system, preventing uneven product activity due to incomplete localized reactions. During aging, the double salt gradually dissolves, and Al³⁺… + Ca² + SO4² - The plasma diffuses further, preparing for subsequent reactions with limestone powder and heat treatment.

[0035] 3. Mixing and Heat Treatment Reaction Stage (Steps 4-5): After adding limestone powder, the CaCO3 in the limestone powder reacts with the remaining H2SO4 in the system to adjust the pH of the system. Simultaneously, during heat treatment, CaCO3 decomposes to generate free calcium oxide (CaO), and the added sodium sulfate (Na2SO4) reacts with a small amount of active silica (SiO2) to form active components such as sodium silicate (Na2SiO3), which can be used as an early strength activator. The specific chemical reaction formula is as follows: (1) Reaction of limestone powder with residual sulfuric acid: CaCO3 + H2SO4 = CaSO4 + CO2↑ + H2O; This reaction can consume the remaining waste acid in the system, preventing excessive acid from corroding subsequent heat treatment equipment, and at the same time generate calcium sulfate, further increasing the content of active ingredients in the product.

[0036] (2) Decomposition reaction of limestone powder: CaCO3 CaO + CO2↑ The CaCO3 in limestone powder undergoes a decomposition reaction to generate free calcium oxide (CaO) and carbon dioxide. Free calcium oxide is a key component for enhancing the activity of micro powder, and it can react with a variety of active substances to enhance the strength and activity of the product.

[0037] (3) Reaction of active SiO2 with sodium sulfate: SiO2 + Na2SO4 Na2SiO3+ SO3↑ ; The heat treatment process is a key step in enhancing the product's activity, generating various active components such as free calcium oxide, calcium sulfate, sodium aluminate, sodium silicate, active SiO2, and active Al2O3. Among these, sodium aluminate and sodium silicate significantly improve the hydration activity of the micronized powder, calcium sulfate enhances the reactivity of the micronized powder with cement and gypsum, and free calcium oxide promotes the formation of ettringite, ensuring the formation of the product's strength in the subsequent stages.

[0038] 4. Cooling and Grinding Stage (Step 5): After cooling, the heat-treated product becomes hard and needs to be crushed and ground. Crushing and grinding can further increase the specific surface area of ​​the product, fully exposing the active ingredients, which facilitates rapid reaction with cement, gypsum, etc., in subsequent applications in the building materials field to form a strong matrix.

[0039] Compared with existing technologies, this disclosure proposes a method for preparing highly active micro powder. Using high-silicon aluminum industrial solid waste as the main raw material, combined with industrial by-product waste acid and sodium sulfate, highly active micro powder is prepared through simple process steps. This realizes the resource utilization of industrial solid waste and industrial by-products, solves the problems of insufficient supply of highly active micro powder in the Panxi region, environmental pollution from industrial solid waste stockpiling, and difficulties in the disposal of industrial by-products. At the same time, it reduces the production cost of highly active micro powder and enhances the market competitiveness of the product.

[0040] In the above method, the amounts of waste acid, sodium sulfate, and limestone powder added are 5-30%, 5-10%, and 5-20% of the mass of the fine powder, respectively. Controlling the amount added ensures both the effect of improving product activity and avoids excessive addition that would reduce the content of active SiO2 and active Al2O3, thus affecting product performance.

[0041] In the above method, in step 3, the aging time is 5-10 hours. Aging for 5-10 hours after thorough stirring is intended to allow the acid leaching reaction to proceed fully, ensuring that the inert components in the solid waste are fully converted into active components. Simultaneously, it allows the generated sulfate to be evenly dispersed in the system, preventing uneven product activity due to incomplete local reactions.

[0042] In the above method, the heat treatment temperature in step 5 is 500~1200℃. If the heat treatment temperature is below 500℃, CaCO3 decomposes insufficiently, the content of free calcium oxide is insufficient, the amount of active ingredients generated is low, and the product activity is low; if the temperature is above 1200℃, the generated active SiO2 and active Al2O3 will undergo a crystallization reaction and transform into inert crystals, resulting in a decrease in product activity, while also increasing energy consumption and production costs.

[0043] In the above method, in step 2, the concentration of the waste acid is 15-25%. The concentration of the waste acid is controlled at 15%. ~ A concentration of 25% ensures sufficient reaction with high-silicon-alumina solid waste to release active SiO2 and active Al2O3, while avoiding problems such as excessively high concentration leading to overly vigorous reaction and severe equipment corrosion, or insufficient concentration leading to inadequate reaction and insufficient product activity.

[0044] In the above method, the waste acid and sodium sulfate are derived from industrial byproducts, thus achieving waste utilization.

[0045] In the above method, in step 4, the limestone powder has a particle size distribution of ≤200 mesh. Limestone powder with a particle size ≤200 mesh has small particles and a large specific surface area, allowing it to fully contact the mixture of "high-silicon aluminum industrial solid waste fine powder + waste acid + industrial sodium sulfate" from the previous step. This ensures a rapid and uniform reaction between the limestone powder and the acidic components in the mixture, effectively regulating the pH of the system and avoiding problems such as insufficient local reaction and uneven pH regulation caused by excessively large particles.

[0046] In the above method, in step 1, the high-silicon aluminum solid waste includes at least one of the following: coal gangue, fly ash, slag, and mineral processing tailings. Coal gangue, fly ash, and slag are all industrial solid wastes produced in large quantities in the Panxi region. Selecting these raw materials can not only realize the resource utilization of solid waste, but also reduce the transportation cost of raw materials and meet the needs of regional industrial development.

[0047] On the other hand, this disclosure also provides a highly active micro powder, which is prepared using the above-described preparation method.

[0048] In some embodiments, the specific surface area of ​​the highly active micro powder is greater than 400 m². 2 / kg.

[0049] The technical solution of the present invention will be further described below through specific embodiments.

[0050] Example 1: 1. Raw material ratio (based on the mass of high-silicon aluminum industrial solid waste fine powder) High-silicon aluminum industrial solid waste: coal gangue (SiO2 content 45%, Al2O3 content 18%, and also contains a small amount of impurities such as calcium feldspar and potassium sodium feldspar); Waste acid: Waste acid from the sulfuric acid process of titanium dioxide production, concentration 15%, added at 5% of the mass of fine powder; Sodium sulfate: Industrial sodium sulfate, a byproduct of vanadium extraction from vanadium slag sodium leaching, is added at 5% of the mass of the fine powder. Limestone powder: particle size distribution ≤200 mesh, added at 5% of the mass of fine powder.

[0051] 2. Process Steps Step 1: Put the coal gangue into the grinding equipment and grind it into fine powder of 200 mesh or higher; Step 2: Take 100 kg of the above fine powder, add 5 kg of 15% sulfuric acid waste acid from the titanium dioxide process, stir evenly to obtain the first mixture; Step 3: Add 5 kg of industrial sodium sulfate to the first mixture above, stir evenly, and then place it in an aging device to age for 5 hours to obtain the second mixture; Step 4: Add 5 kg of limestone powder with a particle size ≤ 200 mesh to the second mixture above and stir evenly to obtain the third mixture; Step 5: Put the above third mixture into a heat treatment device and heat treat it at 500°C. After the heat treatment is completed, put the product into a cooling device to cool it to room temperature, and then put it into a crushing and grinding device to obtain the finished product.

[0052] 3. Product performance testing The test results are as follows: specific surface area: 403 m² / kg, activity index: 91%, main chemical components: free calcium oxide (1.5%), calcium sulfate (9.2%), aluminum sulfate (5.8%), sodium aluminate (4.2%), sodium silicate (4.5%), active SiO2 (29.3%), active Al2O3 (14.8%). The content of each active component is reasonable and can react with cement, gypsum, etc. to form an ettringite-based strength matrix.

[0053] Example 2: 1. Raw material ratio (based on the mass of high-silicon aluminum industrial solid waste fine powder) High-silicon aluminum industrial solid waste: coal gangue (SiO2 content 55%, Al2O3 content 22%, and also contains a small amount of impurities such as calcium feldspar and potassium sodium feldspar); Waste acid: Waste acid from the sulfuric acid process of titanium dioxide production, concentration 20%, added at 25% of the mass of fine powder; Sodium sulfate: Industrial sodium sulfate, a byproduct of vanadium extraction from vanadium slag sodium leaching, is added at 8% of the mass of the fine powder. Limestone powder: particle size distribution ≤200 mesh, added at 15% of the mass of fine powder.

[0054] 2. Process Steps Step 1: Put the coal gangue into the grinding equipment and grind it into fine powder of 200 mesh or higher; Step 2: Take 100 kg of the above fine powder, add 25 kg of 20% sulfuric acid waste acid from the titanium dioxide process, stir evenly to obtain the first mixture; Step 3: Add 8 kg of industrial sodium sulfate to the first mixture above, stir evenly, and then place it in an aging device to age for 7 hours to obtain the second mixture; Step 4: Add 15 kg of limestone powder with a particle size ≤ 200 mesh to the second mixture above and stir evenly to obtain the third mixture; Step 5: Put the above third mixture into a heat treatment device and heat treat it at 1000°C. After the heat treatment is completed, put the product into a cooling device to cool it to room temperature, and then put it into a crushing and grinding device to obtain the finished product.

[0055] 3. Product performance testing The test results are as follows: specific surface area: 401 m² / kg, activity index: 96%, main chemical components: free calcium oxide (2.8%), calcium sulfate (13.5%), aluminum sulfate (8.6%), sodium aluminate (6.3%), sodium silicate (6.8%), active SiO2 (33.7%), active Al2O3 (18.5%). The content of each active component is reasonable and can react with cement, gypsum, etc. to form an ettringite-based strength matrix.

[0056] Example 3: 1. Raw material ratio (based on the mass of high-silicon aluminum industrial solid waste fine powder) High-silicon aluminum industrial solid waste: coal gangue (SiO2 content 65%, Al2O3 content 28%, and also contains a small amount of impurities such as calcium feldspar and potassium sodium feldspar); Waste acid: Waste acid from the sulfuric acid process of titanium dioxide production, concentration 25%, added at 30% of the mass of fine powder; Sodium sulfate: Industrial sodium sulfate, a byproduct of vanadium extraction from vanadium slag sodium leaching, is added at 10% of the mass of the fine powder. Limestone powder: particle size distribution ≤200 mesh, added at 20% of the mass of fine powder.

[0057] 2. Process Steps Step 1: Put the coal gangue into the grinding equipment and grind it into fine powder of 200 mesh or higher; Step 2: Take 100 kg of the above fine powder, add 30 kg of 20% sulfuric acid waste acid from the titanium dioxide process, stir evenly to obtain the first mixture; Step 3: Add 10 kg of industrial sodium sulfate to the first mixture above, stir evenly, and then place it in an aging device to age for 7 hours to obtain the second mixture; Step 4: Add 20 kg of limestone powder with a particle size ≤ 200 mesh to the second mixture above and stir evenly to obtain the third mixture; Step 5: Put the above third mixture into a heat treatment device and heat treat it at 1200℃. After the heat treatment is completed, put the product into a cooling device to cool it to room temperature, and then put it into a crushing and grinding device to obtain the finished product.

[0058] 3. Product performance testing The test results are as follows: specific surface area: 402 m² / kg, activity index: 97%, main chemical components: free calcium oxide (3.5%), calcium sulfate (15.2%), aluminum sulfate (10.7%), sodium aluminate (7.4%), sodium silicate (8.3%), active SiO2 (38.2%), active Al2O3 (20.5%). The content of each active component is reasonable and can react with cement, gypsum, etc. to form an ettringite-based strength matrix.

[0059] The active micro powders in all three embodiments have a specific surface area of ​​400 m² / kg and an activity index of over 90%. They can be directly applied to the building materials field, reacting with cement, gypsum, etc. to form an ettringite-based high-strength matrix with high strength. They can effectively replace purchased high-activity slag micro powders and reduce the production cost of building materials.

[0060] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0061] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner.

Claims

1. A method for preparing a highly active micro powder, characterized in that, Includes the following steps: Step 1: Grind the high-silicon aluminum solid waste into fine powder; Step 2: Add waste acid to the fine powder and mix to obtain the first mixture; Step 3: Add sodium sulfate to the first mixture, stir until homogeneous, and then age to obtain the second mixture; Step 4: Add limestone powder to the second mixture and mix to obtain the third mixture; Step 5: The third mixture is subjected to heat treatment, cooling, crushing and grinding in sequence to obtain the finished product.

2. The method for preparing highly active micro powder according to claim 1, characterized in that, The amounts of waste acid, sodium sulfate, and limestone powder added are 5-30%, 5-10%, and 5-20% of the mass of the fine powder, respectively.

3. The method for preparing highly active micro powder according to claim 2, characterized in that, In step 3, the aging time is 5 to 10 hours.

4. The method for preparing highly active micro powder according to claim 3, characterized in that, In step 5, the temperature of the heat treatment is 500~1200℃.

5. The method for preparing highly active micro powder according to claim 1, characterized in that, In step 2, the concentration of the waste acid is 15-25%.

6. The method for preparing highly active micro powder according to claim 1, characterized in that, The waste acid and the sodium sulfate are derived from industrial byproducts.

7. The method for preparing highly active micro powder according to claim 1, characterized in that, In step 4, the limestone powder has a particle size distribution of ≤200 mesh.

8. The method for preparing highly active micro powder according to claim 1, characterized in that, In step 1, the high-silicon aluminum solid waste includes at least one of coal gangue, fly ash, slag, and mineral processing tailings.

9. A highly active micro powder, characterized in that, include: It is prepared using the preparation method described in any one of claims 1-8.

10. The highly active micro powder according to claim 9, characterized in that, The specific surface area of ​​the highly active micro powder is greater than 400 m². 2 / kg.

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