A method for rapid detoxification and resource utilization of secondary aluminum ash

Abstract

The invention discloses a method for rapid detoxification and resource utilization of secondary aluminum ash, comprising the following steps: S1, ball-milling the secondary aluminum ash and performing magnetic separation treatment to obtain iron-rich material and residual material, screening the residual material to obtain coarse secondary aluminum ash and fine secondary aluminum ash, mixing the fine secondary aluminum ash with water and stirring to obtain a mixed liquid material; S2, mixing the coarse secondary aluminum ash with sodium carbonate to form a ball milling system, heating and roasting the ball milling system, collecting the generated ammonia and combustible gas, then cooling and adding the mixed liquid material to the ball milling system, adding NaOH for ball milling and washing to obtain a water-washed liquid material; S3, recycling the collected ammonia and combustible gas; S4, performing filter pressing treatment on the water-washed liquid material to obtain wet ash and waste liquid, recycling the waste liquid, and drying the wet ash to prepare a high-aluminum material. The method of the invention fully utilizes the gas, liquid and solid components of the secondary aluminum ash treatment process in a step-by-step manner to achieve product clean value-added and zero waste discharge.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment, and particularly to a method for rapid detoxification and resource utilization of secondary aluminum ash. Background Art

[0002] Aluminum ash is the ash slag floating on the surface of the molten aluminum in the electrolytic aluminum or recycled aluminum process. The ash slag regularly removed during the melting and casting process is called primary aluminum ash. The mass fraction of metallic aluminum in primary aluminum ash is 70% - 80%. Due to the high content of metallic aluminum in primary aluminum ash, methods such as ash frying or pressing are usually used to recover the metallic aluminum therein. After the ash slag is cooled and finely ground and sieved to separate aluminum particles, the residue after the above treatment is called secondary aluminum ash. In addition, the dust collected by the dust removal device during the process of recovering metallic aluminum from primary aluminum ash, that is, dust removal ash, is also called secondary aluminum ash. According to the generation process, secondary aluminum ash can be divided into electrolytic aluminum ash and recycled aluminum ash. The former originates from the electrolytic aluminum process, and the latter comes from the recycled aluminum process.

[0003] The main phases in secondary aluminum ash include aluminum-containing compounds (such as Al2MgO4, Al2O3, AlN, etc.), metallic aluminum, other oxides (such as SiO2, Fe2O3, MgO, etc.), fluorides (such as NaF, Na3AlF6, CaF2, etc.), and chlorides (such as NaCl, KCl, etc.). These complex chemical components endow secondary aluminum ash with the dual characteristics of hazardous waste and valuable resources. Its pollution comes from AlN, fluorides, chlorides, and heavy metal cations, etc., while the valuable resource is mainly aluminum resources. Therefore, developing harmless treatment technologies for secondary aluminum ash, exploring economical and effective methods for utilizing and treating secondary aluminum ash, so as to realize the recycling of secondary aluminum ash resources, is the common goal of many researchers. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a method for rapid detoxification and resource utilization of secondary aluminum ash.

[0005] The technical solution of the present invention is: A method for rapid detoxification and resource utilization of secondary aluminum ash, comprising the following steps:

[0006] S1. Ball-mill the secondary aluminum ash and then perform magnetic separation treatment to obtain iron-rich material and remaining material. Subsequently, screen the remaining material to obtain coarse secondary aluminum ash and fine secondary aluminum ash, and then mix and stir the fine secondary aluminum ash with water to obtain a mixed liquid material;

[0007] S2. Mix the crude secondary aluminum ash with sodium carbonate to form a ball-milling system. The addition amount of sodium carbonate is 8-12 wt% of the mass of the crude secondary aluminum ash. Heat the ball-milling system to 500-600 °C and calcine for 10 min. During this period, control the ball-milling speed at 300-500 r / min, and collect the generated ammonia gas and combustible gas. Then cool down to 120-150 °C, add the mixed liquid material to the ball-milling system, and add NaOH for ball-milling and water washing to obtain a water-washed liquid material. The addition amount of NaOH is 1-3 wt% of the mass of the crude secondary aluminum ash.

[0008] S3. Absorb the collected ammonia gas through an ammonia absorption system and prepare a 20 wt% ammonia water product. Collect the collected combustible gas through a gas collection system and use it as secondary fuel.

[0009] S4. Filter-press the water-washed liquid material obtained in S2 to obtain wet ash with a water content of 10-15 wt% and waste liquid. Purify and evaporate and crystallize the waste liquid to obtain a salt-containing product and water. Dry the wet ash to prepare a high-aluminum material.

[0010] Further, the mass ratio of the fine secondary aluminum ash to water is 1:2-5.

[0011] Note: The hydrolysis of aluminum nitride in secondary aluminum ash requires an alkaline solution catalytic condition. The introduction of sodium carbonate can improve the purity of the product obtained after ball-milling and water washing of secondary aluminum ash, and the obtained product has a single phase, which is especially suitable for the recovery and treatment of aluminum ash with a low aluminum element content. At the same time, using a sodium carbonate solution to hydrolyze aluminum nitride in aluminum ash can also realize the recycling of the sodium carbonate solution.

[0012] Based on the alkali leaching process of the present invention, a pretreatment method of introducing sodium carbonate and ball-milling with crude secondary aluminum ash at 120-150 °C is adopted. Compared with the traditional method, the calcination time is short, the required energy consumption is less, and the Al recovery rate is high.

[0013] Further, the method of adding the mixed liquid material to the ball-milling system is as follows:

[0014] Divide the mixed liquid material into n portions of mixed liquid material aliquots. Among them, a single portion of the mixed liquid material aliquot needs to satisfy that after being added to the ball-milling system, the temperature of the ball-milling system can be reduced to 80-90 °C within 90 s.

[0015] When the temperature of the ball-milling system reaches 120-150 °C, add a single portion of the mixed liquid material aliquot to make the temperature of the ball-milling system drop to 80-90 °C, and then let the temperature of the ball-milling system return to 120-150 °C. Repeat this operation until the addition of the mixed liquid material is completed.

[0016] Description: By adopting the method of adding the mixed liquid material multiple times, on the one hand, the temperature of the ball milling system is controlled by using the mixed liquid material, so that a temperature difference contact occurs when the two systems are mixed, to improve the effect of ball milling and water washing. On the other hand, the water content of the ball milling system can be controlled, thereby improving the ball milling treatment effect and further increasing the recovery rate of Al.

[0017] Furthermore, the NaOH is added into the ball milling system together with the first single portion of the mixed material liquid.

[0018] Description: By adding the full amount of NaOH, the initial mixed system of the ball milling system and the mixed material liquid will be at a high NaOH concentration content. And subsequent continuous addition of the mixed material liquid will cause the alkali liquid concentration in the whole mixed system to decrease in a reverse direction. However, adopting the full amount addition method will make the overall operation more convenient, simplify the operation steps and be easier to operate.

[0019] Furthermore, the NaOH is divided into n portions, and each portion of NaOH is added into the ball milling system together with each single portion of the mixed material liquid.

[0020] Description: By adding the NaOH in portions, the initial mixed system of the ball milling system and the mixed material liquid will be at a relatively low NaOH concentration content. But subsequent continuous addition of the mixed material liquid and NaOH will make the alkali liquid concentration in the whole mixed system relatively stable, which can make the treatment effect of ball milling and water washing more stable. However, compared with the full amount addition, the NaOH also needs to be added in portions, and the operation steps are relatively complex. Therefore, it can be selected correspondingly according to the actual use requirements.

[0021] Furthermore, 2 - 5% of calcium oxide by mass is doped in the sodium carbonate.

[0022] Description: It is found through experiments that doping a certain amount of calcium oxide in the sodium carbonate can significantly affect the leaching performance of secondary aluminum ash. By introducing calcium oxide, the temperature and alkali amount required by the process system can be reduced, thereby increasing the recovery rate of Al.

[0023] Further, the remaining material is divided into coarse secondary aluminum ash and fine secondary aluminum ash through a vibrating screen. The particle size of the coarse secondary aluminum ash is ≥0.3 mm, and the particle size of the fine secondary aluminum ash is <0.3 mm.

[0024] Description: By dividing the secondary aluminum ash into coarse and fine secondary aluminum ash according to the above particle size, the requirements of the process of the present invention for coarse and fine secondary aluminum ash can be well met, so that when used in combination with the process of ball milling and water washing, it has a better resource treatment effect for aluminum ash.

[0025] Furthermore, the purification and evaporation crystallization treatment method in S4 is: filtering the waste liquid using liquid filter paper and then introducing it into an MVR evaporator for evaporation to obtain a salt-containing product and water.

[0026] Note: Through the above treatment, the waste liquid in the secondary aluminum ash treatment process can be fully utilized to achieve clean product value-added and zero waste discharge, thereby achieving the advantages of no secondary pollution, safety, reliability, and green environmental protection of the method of the present invention.

[0027] Furthermore, the high-aluminum material is processed to obtain a refractory material, and the processing method is: kaolin with an Al content of 20-30% and a high-aluminum material are mixed in a mass ratio of 4:6 and pressed into a billet, and then fired in a tunnel kiln at 1550-1560°C for 24-32 hours to obtain a refractory material.

[0028] Description: The high-aluminum material obtained after treatment has high alumina content and low impurity content, meeting the use requirements of high-grade bauxite. It can be used as an intermediate product for the preparation of refractory materials, water purifiers, steelmaking refining agents, metallurgical-grade alumina, etc., realizing the full quantitative resource utilization of aluminum ash.

[0029] The beneficial effects of the present invention are:

[0030] (1) The present invention adds a regulator and a catalyst to carry out a hydrolysis and leaching reaction under ball milling and water washing, and achieves catalytic enhanced decomposition of active components such as aluminum nitride and rapid leaching of soluble salts (Na, K, Cl, F, etc.) by precisely controlling process conditions such as reaction temperature and reaction time, thereby achieving the purpose of efficient separation of active components and soluble salt components.

[0031] (2) The high-aluminum material prepared by the present invention has a leaching toxicity content lower than the limit value in the "Hazardous Waste Identification Standard - Leaching Toxicity Identification" (GB5085.3-2007), and an alumina content of >70%. It can be used as a substitute product for high-quality bauxite to prepare refractory materials, calcium aluminate for water treatment agents, steelmaking refining agents, metallurgical-grade alumina and other products, thereby realizing the value-added utilization of aluminum ash.

[0032] (3) The process of the present invention is simple, safe and reliable, without secondary pollution, and fully utilizes the gas, liquid and solid components of the secondary aluminum ash treatment process in a cascade manner to achieve clean product value-added and zero waste emissions. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with specific implementation methods to better reflect the advantages of the present invention.

[0034] Embodiment 1: A method for rapid detoxification and resource utilization of secondary aluminum ash, comprising the following steps:

[0035] S1. After ball-milling secondary aluminum ash, perform magnetic separation to obtain iron-rich material and remaining material. Subsequently, screen the remaining material to obtain coarse secondary aluminum ash and fine secondary aluminum ash, and then mix and stir the fine secondary aluminum ash with water to obtain a mixed liquid material; wherein, the mass ratio of the fine secondary aluminum ash to water is 1:4;

[0036] S2. Mix the coarse secondary aluminum ash with sodium carbonate to form a ball-milling system. The addition amount of sodium carbonate is 9 wt% of the mass of the coarse secondary aluminum ash, and heat the ball-milling system to 560 °C and calcine for 10 min. During this period, control the ball-milling speed at 420 r / min, and collect the generated ammonia gas and combustible gas; then cool down to 135 °C, add the mixed liquid material to the ball-milling system, and add NaOH for ball-milling and water washing. After ball-milling and water washing for 120 min, obtain a water-washed liquid material. The addition amount of NaOH is 2.5 wt% of the mass of the coarse secondary aluminum ash;

[0037] S3. Absorb the collected ammonia gas through an ammonia absorption system and prepare a 20 wt% ammonia water product, and collect the collected combustible gas through a gas collection system for use as secondary fuel;

[0038] S4. Perform pressure filtration on the water-washed liquid material obtained in S2 to obtain wet ash with a water content of 12 wt% and waste liquid. Subject the waste liquid to purification and evaporation crystallization treatment to obtain a salt-containing product and water. Specifically, the method of the purification and evaporation crystallization treatment in S4 is: filter the waste liquid using a liquid filter paper and then introduce it into an MVR evaporator for evaporation at 70 °C to obtain a salt-containing product and water; dry the wet ash at 80 °C to prepare a high-aluminum material; at the same time, the high-aluminum material can be processed to obtain refractory materials. The processing method is: mix kaolin with an Al content of 25% and the high-aluminum material in a mass ratio of 4:6, press them into a blank, and then fire them in a tunnel kiln at 1555 °C for 28 h to obtain refractory materials. The obtained high-aluminum material is not limited to being used for preparing refractory materials, and can also be used for the production and preparation of products such as water purification agents, steelmaking refining agents, and metallurgical-grade alumina;

[0039] It can be understood that the water content of the wet ash depends on the influence of the pressure filtration equipment and the required water content of the wet ash, and its water content range is not limited, and can be selected correspondingly according to the actual production situation.

[0040] It should be noted that the remaining material is screened into coarse secondary aluminum ash and fine secondary aluminum ash through a vibrating screen. The particle size of the coarse secondary aluminum ash is ≥0.3 mm, and the particle size of the fine secondary aluminum ash is <0.3 mm;

[0041] It should be noted that the ammonia absorption system and gas collection system used in this embodiment are both existing technologies and are not specifically limited herein.

[0042] Example 2: The difference between this example and Example 1 is that the mass ratio of the fine secondary aluminum ash to water is 1:2.

[0043] Example 3: The difference between this example and Example 1 is that the mass ratio of the fine secondary aluminum ash to water is 1:5.

[0044] Example 4: The difference between this example and Example 1 is that the ball milling system is heated to 500 °C, the ball milling speed is controlled at 300 r / min and calcined for 10 min, and then cooled to 120 °C.

[0045] Example 5: The difference between this example and Example 1 is that the ball milling system is heated to 600 °C, the ball milling speed is controlled at 500 r / min and calcined for 10 min, and then cooled to 150 °C.

[0046] Example 6: The difference between this example and Example 1 is that the addition amount of sodium carbonate is 8 wt% of the mass of the coarse secondary aluminum ash; the addition amount of NaOH is 1 wt% of the mass of the coarse secondary aluminum ash.

[0047] Example 7: The difference between this example and Example 1 is that the addition amount of sodium carbonate is 12 wt% of the mass of the coarse secondary aluminum ash; the addition amount of NaOH is 3 wt% of the mass of the coarse secondary aluminum ash.

[0048] Example 8: The difference between this example and Example 1 is that the method of adding the mixed liquid material to the ball milling system is as follows:

[0049] The mixed liquid material is divided into n portions of mixed liquid sub-portions on average. Among them, a single portion of the mixed liquid sub-portion needs to meet the requirement that the temperature of the ball milling system can be reduced to 85 °C within 90 s after being added to the ball milling system. Taking this example as an example, n is 4, and when a single portion of the mixed liquid sub-portion is 15 °C and 500 mL, it can meet the cooling requirement of the corresponding amount of the ball milling system;

[0050] When the temperature of the ball milling system reaches 135 °C, add a single portion of the mixed liquid sub-portion to make the temperature of the ball milling system drop to 85 °C, and then let the temperature of the ball milling system return to 135 °C. Repeat this operation until the addition of the mixed liquid material is completed.

[0051] At the same time, the NaOH is added to the ball milling system together with the first single portion of the mixed liquid sub-portion.

[0052] Example 9: The difference between this example and Example 8 is that when the temperature of the ball milling system reaches 135 °C, add a single portion of the mixed liquid sub-portion to make the temperature of the ball milling system drop to 80 °C, and then let the temperature of the ball milling system return to 135 °C.

[0053] Example 10: The difference between this example and Example 8 is that when the temperature of the ball milling system reaches 135°C, a single portion of the mixed material liquid is added once to reduce the temperature of the ball milling system to 90°C, and then the temperature of the ball milling system is reheated to 135°C.

[0054] Example 11: The difference between this example and Example 8 is that the NaOH is divided into n equal portions, where n is 4, and each portion of NaOH is added to the ball milling system together with each single portion of the mixed material liquid.

[0055] Example 12: The difference between this example and Example 8 is that 4% by mass of calcium oxide is doped in the sodium carbonate.

[0056] Example 13: The difference between this example and Example 12 is that 2% by mass of calcium oxide is doped in the sodium carbonate.

[0057] Example 14: The difference between this example and Example 12 is that 5% by mass of calcium oxide is doped in the sodium carbonate.

[0058] Example 15: The difference between this example and Example 1 is that the high-aluminum material can be processed to obtain refractory materials. The processing method is as follows: Kaolin with 20% Al content and the high-aluminum material are mixed and pressed into a blank in a mass ratio of 4:6, and then fired at 1550°C in a tunnel kiln for 24 hours to obtain refractory materials.

[0059] Example 16: The difference between this example and Example 1 is that the high-aluminum material can be processed to obtain refractory materials. The processing method is as follows: Kaolin with 30% Al content and the high-aluminum material are mixed and pressed into a blank in a mass ratio of 4:6, and then fired at 1560°C in a tunnel kiln for 32 hours to obtain refractory materials.

[0060] Experimental Example 1: Based on the "Identification Standard for Hazardous Wastes - Identification of Leaching Toxicity" (GB5085.3 - 2007), the leaching toxicity content of the high-aluminum materials prepared by the methods of Examples 1 - 14 of the present invention was detected, and their leaching toxicity contents were all lower than the limits in the "Identification Standard for Hazardous Wastes - Identification of Leaching Toxicity" (GB5085.3 - 2007), meeting the requirements.

[0061] Experimental Example 2: Experiment on the recovery effect of aluminum resources in secondary aluminum ash

[0062] Experimental reagents: 20% hexamethylenetetramine solution, 0.02 mol / L EDTA solution, 1% NaOH solution, methyl orange indicator, 0.1% 1-(2-pyridylazo)-2-naphthol, 0.01 mol / L copper standard solution, HCl-HNO mixed acid;

[0063] Among them, the copper standard solution is prepared by weighing 2.5 g of CuSO4·5H2O, adding 3 drops of 1:1 H2SO4 into a 1000 mL large beaker, dissolving with distilled water and diluting to 1 L;

[0064] The HCl-HNO mixed acid is prepared by mixing 400 mL of HCl and 100 mL of HNO3 in 500 mL of water.

[0065] Experimental method: Based on the EDTA method, first add the prepared high-aluminum materials (with the same mass) of each example into an excessive amount of EDTA solution (not necessarily quantitative), then adjust the pH to 3.5, and methyl orange indicator can be used for indication. Boil for 3 min to completely complex Al 3+ with EDTA;

[0066] Meanwhile, other interfering ions will also react with EDTA. Adjust the pH to 5.5 with hexamethylenetetramine and use 1-(2-pyridylazo)-2-naphthol for indication. Remove the excessive EDTA with the copper standard solution while it is hot. At this time, add an appropriate amount of NH4F. Utilize the property that F - forms a more stable complex with Al 3+ to displace an equal amount of EDTA complexed with Al 3+ . After heating and boiling, titrate with the copper standard solution to the end point. The reactions are as follows:

[0067] AlY - +6F - =AlF6 3- +Y 4-

[0068] Y 4- +Cu 2+ =CuY 2-

[0069] Calculate the aluminum content in the high-aluminum materials from this.

[0070] Analysis method: Accurately weigh 0.10 g of the sample (accurate to 0.0002 g) into a small beaker, add 5 mL of the HCl-HNO3 mixed acid and 5 mL of water, and carefully heat and dissolve on an electric hot plate. After taking it off and cooling, slowly transfer it into a 100 mL volumetric flask, add water to the mark, and shake well.

[0071] Pipette 25.00 mL of the test solution into a 250 mL conical flask, add 20 mL of water and 15.00 mL of 0.02 mol / L EDTA. Using methyl orange as the indicator, slowly add 1% NaOH solution dropwise until the solution turns orange. Heat and boil for 2 - 3 min, remove from the heat, immediately add 10 mL of hexamethylenetetramine solution and 4 - 6 drops of 1-(2-pyridylazo)-2-naphthol. While the solution is still hot, add CuSO4 standard solution dropwise until the solution turns purple-red. Then add 1 g of NH4F, continue to heat and boil for 2 min, add an additional 6 drops of 1-(2-pyridylazo)-2-naphthol, and titrate with 0.01 mol / L copper standard solution until the solution changes from green to purple, which is the end point. Record the volume V of the consumed CuSO4 standard solution, and calculate the aluminum content in the sample:

[0072] ;

[0073] The results are shown in Table 1 below:

[0074] Table 1 Statistical table of aluminum content in high-aluminum materials in each example

[0075] ;

[0076] It can be seen from the results in Table 1 above that when using the method of the present invention to treat secondary aluminum ash, the aluminum content of the prepared high-aluminum materials is all > 96%. At the same time, there are some differences in the high-aluminum materials prepared under different process conditions. Based on the data comparison in Table 1 above, the following analysis is made:

[0077] 1) Influence of the proportion of different coarse and fine secondary aluminum ashes on the product

[0078] By comparing Example 2, Example 3 with Example 1, it can be seen that using different proportions of coarse and fine secondary aluminum ashes has a certain influence on the aluminum content of the prepared product. On the basis of Example 1, reducing or increasing the proportion of coarse and fine secondary aluminum ashes will cause a certain degree of decrease in the aluminum content of the prepared product. Therefore, the product prepared in Example 1 is relatively the best.

[0079] At the same time, in order to further explore the effect of coarse and fine secondary aluminum ashes, a control was set. Based on the method of Example 1, the remaining materials were not screened, the remaining materials were used as coarse secondary aluminum ash, water was used as the mixed liquid material, and the other processes remained unchanged. The results are shown in Table 2 below:

[0080] Table 2 Statistical table of aluminum content in high-aluminum materials in the control

[0081] ;

[0082] As can be seen from the results of Table 2 above, the treatment of secondary aluminum ash using the method of the present invention is significantly better than the control. By adopting the treatment methods of coarse and fine secondary aluminum ash, under the same parameter conditions, the aluminum content of the prepared high-aluminum material is increased from 96.27% to 97.81%.

[0083] 2) Effects of different ball milling speeds and roasting temperatures on the product

[0084] By comparing Example 4, Example 5 with Example 1, it can be seen that using different ball milling speeds and cooling gradients has a certain impact on the prepared product. On the basis of Example 1, reducing the ball milling speed and roasting temperature results in a certain degree of decrease in the aluminum content of the prepared product, while increasing the ball milling speed and roasting temperature leads to a certain degree of increase in the aluminum content of the prepared product but not significantly. Therefore, considering from the economic perspective and other aspects, the product prepared in Example 1 is relatively better.

[0085] 3) Effects of different sodium carbonate and NaOH addition amounts on the product

[0086] By comparing Example 6, Example 7 with Example 1, it can be seen that using different sodium carbonate and NaOH addition amounts has a certain impact on the prepared product. On the basis of Example 1, reducing the addition amounts of sodium carbonate and NaOH results in a certain degree of decrease in the aluminum content of the prepared product. On the basis of Example 1, increasing the addition amounts of sodium carbonate and NaOH leads to a certain increase in the aluminum content of the prepared product but not significantly. Therefore, considering from the economic and other aspects, Example 1 uses less raw materials and has similar effects, so the product prepared in Example 1 is relatively better.

[0087] Experimental Example 3: Influence of the optimization of the mixed liquid material addition method on the aluminum resource recovery effect in secondary aluminum ash

[0088] Regarding the aluminum content results of the high-aluminum materials prepared under different processes, they were measured according to the above experimental method, and the results are shown in Table 3 below:

[0089] Table 3 Statistical table of the aluminum content of the high-aluminum materials in each example

[0090] ;

[0091] As can be seen from the results in Table 3 above, after using the method of adding in portions and doping calcium oxide, the aluminum content of the prepared high-aluminum material has increased to a certain extent. After optimizing the method of adding the mixed liquid material to the ball-milling system, the aluminum content of the prepared high-aluminum material is > 98%. After doping calcium oxide, the aluminum content of the prepared high-aluminum material is further increased, and the aluminum content is > 99%. At the same time, there are some differences in the high-aluminum materials prepared under different process conditions. Based on the data comparison in Table 3 above, the following analysis is made:

[0092] 1) Influence of different adding methods of mixed liquid materials on the product

[0093] By comparing Example 8 with Example 1, it can be seen that using different adding methods of mixed liquid materials has a certain influence on the aluminum content of the prepared product. Among them, the product prepared in Example 8 is relatively the best.

[0094] At the same time, by comparing Example 9, Example 10 with Example 8, it can be seen that when treating with different temperature differences, on the basis of Example 1, reducing or increasing the stage temperature difference results in a certain degree of reduction in the aluminum content of the prepared product. Therefore, the product prepared in Example 8 is relatively the best.

[0095] Furthermore, in order to verify the advantages of the adding method, a control is set up now. The control is based on Example 8. In a pressurized environment, a mixed liquid of the same temperature is added to the system, and the time interval between each addition is 90 s, and the other parameters remain unchanged. The results are shown in Table 4:

[0096] Table 4 Statistical table of aluminum content of high-aluminum material in the control

[0097] ;

[0098] As can be seen from the results in Table 4 above, using the adding method of the present invention to treat secondary aluminum ash is significantly better than the control. By adopting the treatment method of mixing with temperature difference, under the same parameter conditions, the aluminum content of the prepared high-aluminum material is increased from 98.07% to 98.75%.

[0099] 2) Influence of different adding methods of NaOH on the product

[0100] It can be seen from the comparison between Example 11 and Example 8 that the use of different NaOH addition methods has a certain impact on the prepared products. When adding NaOH in portions, compared with adding all of the NaOH at once, the aluminum content of the prepared products decreases to a certain extent, but the difference is not very obvious. It can be seen that adding all of the NaOH at once will make the initial concentration of NaOH in the mixed system of the ball-milling system and the mixture liquid separation high, while continuously adding the mixture liquid separation later will cause the concentration of the alkali solution in the whole mixed system to decrease. Adding NaOH in portions will make the initial concentration of NaOH in the mixed system of the ball-milling system and the mixture liquid separation relatively low, but continuously adding the mixture liquid separation and NaOH later will make the concentration of the alkali solution in the whole mixed system relatively stable, which can make the treatment effect of ball-milling and water-washing more stable. However, compared with adding all of it at once, NaOH also needs to be added in portions, and the operation steps are relatively complex. Therefore, a choice can be made between the two addition methods according to actual production requirements.

[0101] 3) Influence of different amounts of sodium carbonate doped with calcium oxide on the product

[0102] It can be seen from the comparison between Example 12 and Example 8 that using different sodium carbonates doped with calcium oxide has a certain impact on the prepared products. By introducing calcium oxide, the temperature and alkali amount required for the process system can be reduced, thereby improving the treatment effect at the current temperature and alkali amount. Therefore, the product prepared in Example 12 is relatively better.

[0103] At the same time, it can be seen from the comparison between Example 13, Example 14 and Example 12 that when using different amounts of sodium carbonate doped with calcium oxide for treatment, on the basis of Example 12, reducing or increasing the amount of doped calcium oxide will cause the aluminum content of the prepared products to decrease to a certain extent. Therefore, the product prepared in Example 12 is relatively the best.

Claims

1. A method for rapid detoxification and resource utilization of secondary aluminum ash, characterized in that, It includes the following steps: S1. After ball-milling secondary aluminum ash, perform magnetic separation to obtain iron-rich material and residue. Subsequently, screen the residue to obtain coarse secondary aluminum ash and fine secondary aluminum ash. Then, mix the fine secondary aluminum ash with water and stir to obtain a mixed liquid material. The mass ratio of the fine secondary aluminum ash to water is 1:2 - 5. The particle size of the coarse secondary aluminum ash is ≥0.3 mm, and the particle size of the fine secondary aluminum ash is <0.3 mm; S2. Mix the coarse secondary aluminum ash with sodium carbonate to form a ball-milling system. The addition amount of sodium carbonate is 8 - 12 wt% of the mass of the coarse secondary aluminum ash; and heat this ball-milling system to 500 - 600 °C and calcine for 10 min. During this period, control the ball-milling speed at 300 - 500 r / min. Then, cool it down to 120 - 150 °C, add the mixed liquid material to the ball-milling system, and add NaOH for ball-milling and water-washing to obtain a water-washed liquid material. The addition amount of NaOH is 1 - 3 wt% of the mass of the coarse secondary aluminum ash. Collect the generated ammonia gas and combustible gas; The method of adding the mixed liquid material to the ball-milling system is: Divide the mixed liquid material into n portions of mixed liquid material aliquots. Among them, a single portion of the mixed liquid material aliquot should meet the requirement that after being added to the ball-milling system, the temperature of the ball-milling system can be reduced to 80 - 90 °C within 90 s; When the temperature of the ball-milling system reaches 120 - 150 °C, add one portion of the mixed liquid material aliquot to make the temperature of the ball-milling system drop to 80 - 90 °C. Then, let the temperature of the ball-milling system return to 120 - 150 °C. Repeat this operation until the addition of the mixed liquid material is completed; S3. Absorb the collected ammonia gas through an ammonia absorption system and prepare it into a 20 wt% ammonia water product. Collect the collected combustible gas through a gas collection system and use it as secondary fuel; S4. Perform pressure filtration on the water-washed liquid material obtained in S2 to obtain wet ash with a water content of 10 - 15 wt% and waste liquid. Subject the waste liquid to purification and evaporation crystallization treatment to obtain a salt-containing product and water; dry the wet ash to prepare a high-aluminum material.

2. The method for rapid detoxification and resource utilization of secondary aluminum ash according to claim 1, characterized in that, The NaOH is added to the ball-milling system together with the first portion of the mixed liquid material aliquot.

3. A method for rapid detoxification and resource utilization of secondary aluminum ash according to claim 1, characterized in that, Divide the NaOH into n portions, and each portion of NaOH is added to the ball-milling system together with each portion of the mixed liquid material aliquot.

4. A method for rapid detoxification and resource utilization of secondary aluminum ash according to claim 1, characterized in that, 2 - 5% of calcium oxide by mass is doped in the sodium carbonate.

5. A method for rapid detoxification and resource utilization of secondary aluminum ash according to claim 1, characterized in that, The residue is separated into coarse secondary aluminum ash and fine secondary aluminum ash by a vibrating screen.

6. The method for rapid detoxification and resource utilization of secondary aluminum ash according to claim 1, characterized in that, The method of the purification and evaporation crystallization treatment in S4 is: Filter the waste liquid with a liquid filter paper and then introduce it into an MVR evaporator for evaporation to obtain a salt-containing product and water.

7. A method for rapid detoxification and resource utilization of secondary aluminum ash according to claim 1, characterized in that, Process the high-aluminum material to obtain a refractory material. The processing method is: Mix kaolin with an Al content of 20 - 30% and the high-aluminum material in a mass ratio of 4:6 and press them into a blank. Then, fire them in a tunnel kiln at 1550 - 1560 °C for 24 - 32 h to obtain a refractory material.