Aluminum ash calcination denitrogenation whitening agent, preparation method and application thereof

Abstract

This invention discloses an aluminum ash calcination denitrification whitening agent, its preparation method, and its application. By weight, the whitening agent comprises: 80-94 parts of grinding coating agent, 45-72 parts of hydrotalcite, 42-50 parts of perlite powder, 100-128 parts of diatomaceous earth, 58-65 parts of combustion aid, 75-90 parts of dispersant, 100-120 parts of adsorption and penetrating agent, 15-172 parts of dendritic mesoporous silica hollow spheres, 30-40 parts of aluminum wire, 280-300 parts of alumina, and 18-26 parts of silicate. At room temperature, the adsorbent and penetrant are mixed and stirred with the treated aluminum ash, and a dispersant is added and the mixture is stirred further. A grinding coating agent, hydrotalcite, perlite powder, diatomaceous earth, combustion improver, dendritic mesoporous hollow silica spheres, alumina, and silicates are added and thoroughly mixed to obtain a final mixture. The mixture is then sprayed into a burner in powder form and reacted with air. After stirring and calcination, aluminum wire is added and stirred and calcined again, followed by stirring and cooling to room temperature. This invention achieves the removal of toxic components from aluminum ash and the improvement of the whiteness of the calcined product.

Description

Technical Field

[0001] This invention belongs to the field of aluminum ash treatment technology, specifically, it relates to an aluminum ash calcination denitrification and whitening agent, its preparation method and its application. Background Technology

[0002] Aluminum ash is a solid waste generated during the production of electrolytic aluminum, aluminum processing, and recycled aluminum. While possessing the characteristics of hazardous solid waste, it also possesses the characteristics of a valuable resource. Improper disposal not only harms the environment but also wastes precious secondary aluminum resources. The harmless treatment and high-value resource utilization of aluminum ash has become a major technological requirement for the sustainable development of the aluminum industry.

[0003] Primary aluminum ash is mainly aluminum slag produced during aluminum production. It is grayish-white and primarily consists of metallic aluminum and aluminum oxides. Secondary aluminum ash is the residue left after metallic aluminum extraction from primary aluminum ash or a product of aluminum refining. It is grayish-black in color and has a more complex composition, mainly containing small amounts of metallic aluminum, alumina, aluminum nitride, soluble salts, and some heavy metals. The chemical composition and whiteness of aluminum ash are crucial parameters, determining not only its application but also its commercial value. Due to the presence of ferric hydroxide, other oxides, or organic impurities and pollutants, secondary aluminum ash is a dark gray or black granular substance, currently limiting its application to low-value-added fields such as cement, chemical raw materials, soil conditioners, and roadbeds. Removing impurities and whitening secondary aluminum ash can significantly improve its utilization value and reduce the environmental damage caused by hazardous waste storage.

[0004] Currently, there are numerous reports on the harmless treatment and resource utilization methods for aluminum ash, especially secondary aluminum ash, mainly divided into pyrometallurgical and wet methods. However, research on aluminum ash whitening is scarce. Compared to wet methods, pyrometallurgical methods have advantages such as simpler processes, shorter procedures, and higher removal rates of toxic components. Although the pyrometallurgical technique of high-temperature calcination of aluminum ash to produce alumina has attracted attention and importance in the industry, the key challenge lies in the removal of complex salts such as chlorides and fluorides formed by Na, K, F, and Cl elements in the aluminum ash. This results in low whiteness after calcination, significantly impacting its application areas and the quality of commercial products. Therefore, adopting low-cost methods with simple process conditions to improve the calcination detoxification and whitening of aluminum ash is of significant practical importance. Summary of the Invention

[0005] To address the issues of low removal rate of calcined toxic components and low whiteness in aluminum ash, especially secondary aluminum ash, the purpose of this invention is to provide an aluminum ash calcination denitrification and whitening agent, its preparation method, and its application, so as to achieve efficient removal of toxic components in aluminum ash and improve the whiteness of calcination products, thereby maximizing the value of aluminum ash and reducing secondary pollution problems.

[0006] To achieve the above objectives, the present invention provides an aluminum ash calcination denitrification and whitening agent, which, by weight, comprises 80-94 parts of a grinding coating agent, 45-72 parts of hydrotalcite, 42-50 parts of perlite powder, 100-128 parts of diatomaceous earth, 58-65 parts of a combustion aid, 75-90 parts of a dispersant, 100-120 parts of an adsorption and penetrating agent, 15-172 parts of dendritic mesoporous silica hollow spheres, 30-40 parts of aluminum wire, 280-300 parts of alumina, and 18-26 parts of silicate; the dispersant, by mass percentage, comprises: 10%-36% of a hydrophobic component, 40%-54% of a carboxymethyl sulfone derivative, and 10%-50% of a hydrophilic surfactant.

[0007] Furthermore, the grinding coating agent includes one or two of white corundum micro powder and zirconium dioxide; the hydrotalcite includes one or more of magnesium aluminum hydrotalcite, calcium aluminum hydrotalcite, zinc aluminum hydrotalcite, and magnesium aluminum zinc hydrotalcite.

[0008] Furthermore, the adsorbent is nano-magnesium hydroxide; the silicate includes one or more of sodium silicate, potassium silicate, calcium hydrogen silicate, calcium silicate, and potassium aluminum silicate.

[0009] Furthermore, the combustion aid includes at least two of potassium nitrate, calcium hypochlorite, sodium hypochlorite, potassium hypochlorite, and ammonium hypochlorite.

[0010] Furthermore, the hydrophobic component includes one or more of silicone oil, chlorinated paraffin, stearic acid, hardened oil, palm wax, castor oil, octadecylsilane, and hexadecyltrimethoxysilane; the carboxymethyl sulfone derivative includes one or more of hexadecyl carboxymethyl sulfone, tetradecyl carboxymethyl sulfone, dodecyl carboxymethyl sulfone, and butyl carboxymethyl sulfone; and the hydrophilic surfactant includes one or more of lauryl alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether condensate, sodium dodecyl sulfate, sodium dodecyl sulfonate, and sodium dodecylbenzene sulfonate.

[0011] Furthermore, the aluminum wire has a diameter of 0.1 mm to 1.0 mm and a length of ≤15 mm; the alumina contains ≥98.5% Al2O3.

[0012] A method for preparing an aluminum ash calcination denitrification and brightening agent includes:

[0013] (1) Preparation of dispersant: The hydrophilic surfactant and carboxymethyl sulfone derivative are mixed and stirred evenly according to the mass percentage, and the temperature is raised to 40-60°C. Then, the hydrophobic component is added dropwise. After the addition is completed, the temperature is kept constant and stirring is continued for 30-60 minutes to obtain whitening component A as a dispersant.

[0014] (2) The grinding coating agent, hydrotalcite, perlite powder, diatomaceous earth, combustion aid, dendritic mesoporous silica hollow spheres, alumina and silicate are stirred and mixed according to the weight parts to obtain whitening agent component B;

[0015] (3) Set aside whitening agent component A and whitening agent component B separately for later use.

[0016] An application of a calcined aluminum ash denitrification and whitening agent is disclosed, which utilizes the aforementioned calcined aluminum ash denitrification and whitening agent to achieve calcination denitrification and whitening of aluminum ash. Specifically, the following steps are included:

[0017] S1 crushes, grinds, and sieves the aluminum ash to obtain the processed aluminum ash.

[0018] S2 At room temperature, the adsorbent and penetrant are mixed with the aluminum ash treated in step S1 and stirred for 30 minutes. Then, the whitening agent component A is added according to the weight parts and the mixture is stirred for another 30 minutes.

[0019] S3. Add the whitening agent component B to step S2 according to the stated weight parts, and stir thoroughly to obtain a mixture;

[0020] S4 then injects the mixture into the burner in powder form at a certain speed to mix and react with air. After stirring and calcining for 45 to 60 minutes, aluminum wire is added and stirred and calcined for another 60 to 90 minutes. Finally, the mixture is stirred and cooled to room temperature.

[0021] The principles of this invention include:

[0022] (1) Nano magnesium hydroxide has high adsorption capacity and is preferentially added to aluminum ash. It can quickly adsorb and penetrate into the aluminum ash particles. The dispersant further enhances the hydrophobicity of the aluminum ash particle surface, thereby reducing the agglomeration of aluminum ash particles during calcination, which helps the aluminum ash to be fully calcined and the carbon inside the particles to fully contact with oxygen.

[0023] (2) Although the aluminum oxide, magnesium oxide, and calcium oxide in aluminum ash, especially secondary aluminum ash, are white, they may form black or dark-colored compounds when they react with other substances (such as iron hydroxide). Grinding coatings have high hardness and grinding ability, and can destroy or coat the colored substances adhering to the surface of aluminum oxide during stirring and calcination.

[0024] (3) Hydrotalcite has a layered structure, perlite powder has the characteristics of high-temperature expansion and high adsorption, diatomaceous earth has a special porous structure with a large specific surface area and porosity, and dendritic mesoporous hollow silica spheres not only have a three-dimensional dendritic skeleton and a large central radial emission mesoporous structure, but also have a varied pore surface structure, a larger specific surface area and a higher loading capacity. All of these can remove the colored substances (Fe) in aluminum ash. 3+ Fe 2+It can be displaced or adsorbed into the structure without showing color;

[0025] (4) Compared with oxygen in the air, the combustion aid has been fully mixed with aluminum ash before the high-temperature reaction. Under high temperature, the combustion aid gradually decomposes to produce oxygen and chloride, which are in more complete contact with aluminum ash and the calcination reaction is more complete. The chloride produced further decomposes to produce Cl2 and HCl, which can transform colored metal oxides into low-melting-point, highly volatile chlorides, thus achieving the removal of impurities and whitening of aluminum ash. The calcium salts remaining in the system can fix the soluble fluorine in aluminum ash, thus achieving the detoxification of aluminum ash by calcination.

[0026] (5) The added alumina can further reduce the content of carbon and coloring metal oxides. The carboxymethyl sulfone derivative in the dispersant can be transformed into ketones under the high temperature catalysis of metal oxides. The addition of aluminum wire achieves the balanced regulation of weak oxidation-weak reduction atmosphere, converts cuprous oxide into divalent copper or copper element, and reduces reddish-brown trivalent iron into divalent iron compound, further improving the gray whiteness of aluminum.

[0027] (6) In addition, spinel is the result of the oxidation of magnesium, an alloying element in aluminum scrap, during the melting process. The formation of spinel gives aluminum ash its black color. Acidic perlite powder and silicates can reduce the effect of spinel in aluminum ash on whiteness.

[0028] The beneficial effects of this invention include:

[0029] 1. The aluminum ash calcination denitrification and whitening agent prepared by this invention and its calcination denitrification and whitening process detoxify and whiten aluminum ash, greatly expanding the scope of its resource utilization, alleviating environmental pollution problems, and having important guiding significance for the research on the large-scale comprehensive utilization of aluminum ash.

[0030] 2. This calcination denitrification and whitening process improves the whiteness of aluminum ash while converting the toxic aluminum nitride into aluminum oxide, and at the same time reduces the fluorine content in the aluminum ash.

[0031] 3. This calcination denitrification and whitening process does not require an additional heat source. The heat released by the combustion of aluminum ash can also be carried by the blower into the material dryer to dry the material, which has great economic value.

[0032] 4. The aluminum gray produced by this invention has a whiteness of ≥86%, which meets the application requirements of most fields. Detailed Implementation

[0033] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the following technical solutions.

[0034] Example 1

[0035] This embodiment provides a process for achieving denitrification and whitening of aluminum ash through calcination, including the following steps:

[0036] S1. Crush, grind, and sieve the aluminum ash to obtain the treated aluminum ash;

[0037] S2. Mix 240g lauryl alcohol polyoxyethylene ether and 400g butyl carboxymethyl sulfone evenly, heat to 40℃, then add 360g silicone oil dropwise. After the addition is complete, keep the temperature constant and continue stirring for 40min to obtain dispersant F1.

[0038] S3. At room temperature, mix 120g of nano magnesium hydroxide with 30kg of treated aluminum ash from step S1 and stir for 30min. Then add 75g of dispersant F1 and continue mixing for 30min.

[0039] S4. Add 86g zirconium dioxide, 54g aluminum magnesium hydrotalcite, 20g zinc aluminum hydrotalcite, 42g perlite powder, 106g diatomaceous earth, 30g potassium nitrate, 28g sodium hypochlorite, 100g dendritic mesoporous silica hollow spheres, 280g alumina, and 20g calcium silicate to step S3, stir and mix thoroughly. Then, spray the mixture into the burner in powder form at a certain speed to mix and react with air. After stirring and calcining for 45 minutes, add 33g aluminum wire (0.1mm, 10mm) and stir and calcin for another 90 minutes. Then, stir and cool to room temperature. The reaction temperature throughout the process is in the range of 850-1100℃.

[0040] Example 2

[0041] This embodiment provides a process for achieving denitrification and whitening of aluminum ash through calcination, including the following steps:

[0042] S1. Crush, grind, and sieve the aluminum ash to obtain the treated aluminum ash;

[0043] S2. Mix 240g of nonylphenol polyoxyethylene ether condensate, 260g of sodium dodecyl sulfate, and 400g of hexadecyl carboxymethyl sulfone until homogeneous, heat to 45°C, and then add 100g of hexadecyltrimethoxysilane dropwise. After the addition is complete, continue stirring at a constant temperature for 30 minutes to obtain dispersant F2.

[0044] S3. At room temperature, mix 100g of nano magnesium hydroxide with 30kg of aluminum ash treated in step S1 and stir for 30min. Then add 90g of dispersant F2 and continue to mix and stir for 30min.

[0045] S4. Add 80g of white corundum micro powder, 60g of magnesium aluminum zinc hydrotalcite, 46g of perlite powder, 128g of diatomaceous earth, 40g of calcium hypochlorite, 25g of ammonium hypochlorite, 125g of dendritic mesoporous silica hollow spheres, 300g of alumina, and 20g of sodium silicate to step S3, stir and mix thoroughly. Then, spray the mixture into the burner in powder form at a certain speed to mix and react with air. After stirring and calcining for 52 minutes, continue to add aluminum wire (0.2mm, 10mm) and stir and calcinate for 80 minutes. Then, stir and cool to room temperature. The reaction temperature throughout the process is in the range of 920~1080℃.

[0046] Example 3

[0047] This embodiment provides a process for achieving denitrification and whitening of aluminum ash through calcination, including the following steps:

[0048] S1. Crush, grind, and sieve the aluminum ash to obtain the treated aluminum ash;

[0049] S2. Mix 280g sodium dodecylbenzenesulfonate, 200g tetradecyl carboxymethyl sulfone, and 340g dodecyl carboxymethyl sulfone evenly, heat to 60℃, and then add 100g chlorinated paraffin and 80g stearic acid dropwise. After the addition is complete, continue to stir at a constant temperature for 60min to obtain dispersant F3.

[0050] S3. At room temperature, mix 112g of nano magnesium hydroxide with 30kg of aluminum ash treated in step S1 and stir for 30min. Then add 82g of dispersant F3 and continue to mix and stir for 30min.

[0051] S4. Add 94g zirconium dioxide, 45g calcium aluminum hydrotalcite, 50g perlite powder, 128g diatomaceous earth, 40g potassium nitrate, 25g sodium hypochlorite, 74g dendritic mesoporous silica hollow spheres, 294g alumina, 10g calcium hydrogen silicate, and 16g calcium silicate to step S3, stir and mix thoroughly. Then, spray the mixture into the burner in powder form at a certain speed to mix and react with air. After stirring and calcining for 60 minutes, continue to add aluminum wire (0.5mm, 6mm) and stir and calcinate for another 60 minutes. Then, stir and cool to room temperature. The reaction temperature throughout the process is in the range of 870~1120℃.

[0052] Example 4

[0053] This embodiment provides a process for achieving denitrification and whitening of aluminum ash through calcination, including the following steps:

[0054] S1. Crush, grind, and sieve the aluminum ash to obtain the treated aluminum ash;

[0055] S2. Mix 365g sodium dodecyl sulfonate and 450g tetradecyl carboxymethyl sulfone evenly, heat to 50℃, then add 185g octadecylsilane dropwise. After the addition is complete, keep the temperature constant and continue stirring for 60min to obtain dispersant F4.

[0056] S3. At room temperature, mix 120g of nano magnesium hydroxide with 30kg of aluminum ash treated in step S1 and stir for 30min. Then add 86g of dispersant F4 and continue mixing for 30min.

[0057] S4. Add 52g of white corundum micro powder, 42g of zirconium dioxide, 74g of zinc aluminum hydrotalcite, 42g of perlite powder, 100g of diatomaceous earth, 20g of potassium nitrate, 20g of calcium hypochlorite, 20g of sodium hypochlorite, 68g of dendritic mesoporous silica hollow spheres, 300g of alumina, and 18g of sodium silicate to step S3, and stir thoroughly to mix evenly. Then, spray the mixture into the burner in powder form at a certain speed to mix and react with air. After stirring and calcining for 45 minutes, add 38g of aluminum wire (0.2mm, 15mm) and stir and calcinate for another 68 minutes. Then, stir and cool to room temperature. The reaction temperature throughout the process is in the range of 860~1050℃.

[0058] Example 5

[0059] This embodiment provides an application of an aluminum ash calcination denitrification and whitening agent: using the heat released by the combustion of aluminum ash calcination denitrification and whitening agent in Example 4 to dry the material (washed sand).

[0060] Before drying, the water-washed sand had a moisture content of 6.24%. In Example 4, the combustion chamber temperature of the aluminum ash calcination denitrification and whitening process was in the range of 860-1050℃. The heat was directed to the material dryer through a blower. After drying for 30 minutes, the moisture content of the water-washed sand decreased to 1.82%, and after drying for 60 minutes, the moisture content of the water-washed sand decreased to 0.95%. Throughout the drying process, the temperature at the tail end of the material dryer was in the range of 76-89℃.

[0061] Comparative Example 1

[0062] This comparative example does not include the whitening agent of this invention, and comprises:

[0063] S1. Crush, grind, and sieve the aluminum ash to obtain the treated aluminum ash;

[0064] S2. The treated aluminum ash is sprayed into the burner in powder form at a certain speed and mixed with air to react. After stirring and calcining for 135 minutes, it is stirred and cooled to room temperature. The reaction temperature throughout the process is in the range of 840 to 1100℃.

[0065] Comparative Example 2

[0066] This comparative example adds the whitening agent all at once, including:

[0067] S1. Crush, grind, and sieve the aluminum ash to obtain the treated aluminum ash;

[0068] S2. Thoroughly mix 120g of nano magnesium hydroxide, 75g of dispersant F1, 86g of zirconium dioxide, 54g of aluminum magnesium hydrotalcite, 20g of zinc aluminum hydrotalcite, 42g of perlite powder, 106g of diatomaceous earth, 30g of potassium nitrate, 28g of sodium hypochlorite, 100g of dendritic mesoporous silica hollow spheres, 280g of alumina, 20g of calcium silicate, and 33g of aluminum wire (0.1mm, 10mm) with 30kg of treated aluminum ash from step S1. Then, spray the mixture into a burner in powder form at a certain speed to mix and react with air. After stirring and calcining for 135 minutes, cool to room temperature. The reaction temperature throughout the process is within the range of 840~1026℃.

[0069] Comparative Example 3

[0070] This comparative example did not contain any dispersant or adsorbent / penetrating agent, and included:

[0071] S1. Crush, grind, and sieve the aluminum ash to obtain the treated aluminum ash;

[0072] S2. Thoroughly mix 86g zirconium dioxide, 54g aluminum-magnesium hydrotalcite, 20g zinc-aluminum hydrotalcite, 42g perlite powder, 106g diatomaceous earth, 30g potassium nitrate, 28g sodium hypochlorite, 100g dendritic mesoporous silica hollow spheres, 280g alumina, 20g calcium silicate, and 30kg of treated aluminum ash from step S1. Then, spray the mixture into a burner in powder form at a certain speed to mix and react with air. After stirring and calcining for 45 minutes, add 33g aluminum wire (0.1mm, 10mm) and stir and calcin for another 90 minutes. Then, stir and cool to room temperature. The reaction temperature throughout the process is within the range of 865~1140℃.

[0073] Comparative Example 4

[0074] This comparative example did not include alumina or aluminum wire, and included:

[0075] S1. Crush, grind, and sieve the aluminum ash to obtain the treated aluminum ash;

[0076] S2. Mix 240g lauryl alcohol polyoxyethylene ether and 400g butyl carboxymethyl sulfone evenly, heat to 40℃, then add 360g silicone oil dropwise. After the addition is complete, keep the temperature constant and continue stirring for 40min to obtain dispersant F1.

[0077] S3. At room temperature, mix 120g of nano magnesium hydroxide with 30kg of treated aluminum ash from step S1 and stir for 30min. Then add 75g of dispersant F1 and continue mixing for 30min.

[0078] S4. Add 86g zirconium dioxide, 54g aluminum magnesium hydrotalcite, 20g zinc aluminum hydrotalcite, 42g perlite powder, 106g diatomaceous earth, 30g potassium nitrate, 28g sodium hypochlorite, 100g dendritic mesoporous silica hollow spheres, and 20g calcium silicate to step S3, stir and mix thoroughly. Then, spray the mixture into the burner in powder form at a certain speed to mix and react with air. After stirring and calcining for 135 minutes, stir and cool to room temperature. The reaction temperature throughout the process is in the range of 905~1060℃.

[0079] Examples and comparative studies on the denitrification and whitening effect of calcined aluminum ash:

[0080] The aluminum ash used in this experiment was obtained from a non-ferrous metal recycling company in Yunnan Province. After calcination, the aluminum ash in the examples and comparative examples was ground, and the whiteness was tested using a WSB-2 whiteness meter. The test results are expressed as R457 blue light whiteness. The total aluminum nitride was determined using the Kjeldahl distillation method (“Determination of Aluminum Nitride in Aluminum Ash by Kjeldahl Method”, Cong Linlin et al., Chemical Analysis and Metrology, 2020, Vol. z1). The main components and phases of the calcined products were analyzed using XRF, XRD, and ICP-MS in combination.

[0081] The test results are shown in Table 1.

[0082] Table 1 Technical Specifications of Aluminum Ash After Calcination, Denitrification, and Whitening

[0083] Whiteness % <![CDATA[Al2O3 content / %]]> Al content % AlN content % F content % Cl content % <![CDATA[Specific surface area m 2 / g]]> Untreated aluminum ash 40.8 30.92 17.78 8.58 2.54 4.53 — Example 1 87.4 88.64 0 0.12 0.02 0.27 22.79 Example 2 86.4 87.96 0 0.11 0.01 0.18 21.46 Example 3 86.2 88.50 0 0.14 0.02 0.23 22.08 Example 4 87.0 87.88 0 0.16 0.03 0.25 21.92 Comparative Example 1 72.3 77.50 0 0.35 0.06 0.19 18.41 Comparative Example 2 81.7 86.62 0 0.17 0.02 0.29 20.95 Comparative Example 3 81.0 86.93 0 0.18 0.02 0.28 19.72 Comparative Example 4 79.3 82.19 0 0.16 0.02 0.29 20.03

[0084] As can be seen from the data in Table 1, the aluminum ash calcination denitrification and whitening agent prepared by the present invention and its calcination denitrification and whitening process in Examples 1-4 can efficiently remove toxic components from aluminum ash, especially secondary aluminum ash, and significantly improve the whiteness of aluminum ash, especially secondary aluminum ash calcination products, thus meeting the application requirements of alumina in most fields.

[0085] Table 1 further shows that after the calcination denitrification and whitening process, the whiteness of Examples 1-4 reached over 86%, the Al2O3 content reached over 87%, the AlN removal rate reached over 98%, the soluble fluorine content removal rate reached over 98.8%, and the chlorine content decreased to below 0.27%. Compared with Example 1, Comparative Example 1, without the addition of calcination denitrification whitening agent, had a whiteness of only 72.3%, an Al2O3 content of 77.50%, and a lower chlorine content than Example 1, possibly because the whitening agent in Example 1 introduced chloride ions. Compared with Example 1, Comparative Example 2, in which the whitening agent was added all at once, saw a decrease in whiteness of about 5% and a decrease in specific surface area of ​​8%, indicating that the calcination denitrification and whitening process has a significant impact on the yield, whiteness, and fineness of the calcined product. Compared with Example 1, Comparative Example 3, without the addition of dispersant and adsorbent / permeable agent, saw a decrease in specific surface area of ​​13.5%, the most affected, possibly because the addition of dispersant and adsorbent / permeable agent reduced the agglomeration of materials during calcination. Compared with Example 1, Comparative Example 4 did not include alumina and aluminum wire, resulting in a decrease in whiteness of approximately 8% and a decrease in Al2O3 content of 6.45%. The decrease in Al2O3 content should be attributed more to the influence of alumina and aluminum wire in the whitening agent, while the decrease in whiteness should be attributed to the reducing effect of aluminum wire on the entire system.

Claims

1. The application of a calcined aluminum ash denitrification and whitening agent, characterized in that: The aforementioned aluminum ash calcination denitrification and whitening agent is used to achieve aluminum ash calcination denitrification and whitening. The aluminum ash calcination denitrification and whitening agent comprises, by weight: 80-94 parts grinding coating agent, 45-72 parts hydrotalcite, 42-50 parts perlite powder, 100-128 parts diatomaceous earth, 58-65 parts combustion aid, 75-90 parts dispersant, 100-120 parts adsorption and penetrating agent, 15-172 parts dendritic mesoporous silica hollow spheres, 30-40 parts aluminum wire, 280-300 parts alumina, and 18-26 parts silicate; the dispersant comprises, by mass percentage: 10%-36% hydrophobic component, 40%-54% carboxymethyl sulfone derivative, and 10%-50% hydrophilic surfactant. The preparation method of the aluminum ash calcination denitrification and whitening agent includes: (1) Preparation of dispersant: The hydrophilic surfactant and carboxymethyl sulfone derivative are mixed and stirred evenly according to the mass percentage, and the temperature is raised to 40~60℃. Then the hydrophobic component is added dropwise. After the addition is completed, the temperature is kept constant and stirring is continued for 30min~60min to obtain whitening agent component A as dispersant; (2) The grinding coating agent, hydrotalcite, perlite powder, diatomaceous earth, combustion aid, dendritic mesoporous silica hollow spheres, alumina and silicate are mixed according to the weight parts to obtain whitening agent component B; (3) Set aside whitening agent component A and whitening agent component B separately for later use; The application includes the following steps: S1 involves crushing, grinding, and sieving the aluminum ash to obtain the processed aluminum ash. S2 At room temperature, the adsorbent and penetrant are mixed and stirred with the aluminum ash treated in step S1 for 30 minutes. Then, the whitening agent component A is added according to the weight parts and the mixture is stirred and stirred for another 30 minutes. S3 Add the whitening agent component B to step S2 according to the stated weight parts, and stir thoroughly to obtain a mixture; S4 The mixture is then injected into the burner in powder form at a certain speed to mix and react with air. After stirring and calcining for 45 to 60 minutes, aluminum wire is added and stirred and calcined for another 60 to 90 minutes. Finally, the mixture is stirred and cooled to room temperature.

2. The application according to claim 1, characterized in that: The grinding coating agent includes one or two of white fused alumina micro powder and zirconium dioxide; The hydrotalcite mentioned includes one or more of magnesium aluminum hydrotalcite, calcium aluminum hydrotalcite, zinc aluminum hydrotalcite, and magnesium aluminum zinc hydrotalcite.

3. The application according to claim 1, characterized in that: The adsorbent and penetrant is nano-magnesium hydroxide; The silicates mentioned include one or more of sodium silicate, potassium silicate, calcium hydrogen silicate, calcium silicate, and potassium aluminum silicate.

4. The application according to claim 1, characterized in that: The combustion aid includes at least two of potassium nitrate, calcium hypochlorite, sodium hypochlorite, potassium hypochlorite, and ammonium hypochlorite.

5. The application according to claim 1, characterized in that: The hydrophobic component includes one or more of silicone oil, chlorinated paraffin, stearic acid, hardened oil, palm wax, castor oil, octadecylsilane, and hexadecyltrimethoxysilane; the carboxymethyl sulfone derivative includes one or more of hexadecyl carboxymethyl sulfone, tetradecyl carboxymethyl sulfone, dodecyl carboxymethyl sulfone, and butyl carboxymethyl sulfone; the hydrophilic surfactant includes one or more of lauryl alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether condensate, sodium dodecyl sulfate, sodium dodecyl sulfonate, and sodium dodecylbenzene sulfonate.

6. The application according to any one of claims 1-5, characterized in that: The aluminum wire has a diameter of 0.1mm to 1.0mm and a length of ≤15mm; The alumina contains ≥98.5% Al2O3.