A method for resource utilization of aluminum ash slag

Abstract

This invention discloses a method for the resource utilization of aluminum ash slag. Through a clever design combining dry and wet methods and integrating the entire process for resource recovery, it achieves near-complete resource recovery of valuable elements in the aluminum ash slag. It eliminates the need for large stockpiles, saving land resources and preventing environmental pollution. This is a highly efficient aluminum ash slag treatment technology with a high recovery rate of aluminum sheets. The process is simple, energy-saving, and environmentally friendly, resulting in a high resource recovery rate. The obtained products are of high quality and strength, leading to excellent engineering and economic benefits.

Description

Technical Field

[0001] This invention relates to the resource utilization of aluminum ash slag, specifically to a method for the resource utilization of aluminum ash slag, belonging to the technical field of aluminum ash slag resource utilization. Background Technology

[0002] The aluminum industry is a typical high-energy-consuming and high-polluting industry, generating a large amount of solid waste, especially hazardous waste, during production and processing, which hinders the green development of the aluminum industry. Aluminum ash slag is a solid waste generated during primary aluminum smelting, aluminum alloy processing, and aluminum recycling. Aluminum ash slag contains a large amount of aluminum, alumina, and chloride salts, as well as small amounts of fluorides, silicon, and other heavy metals. Furthermore, due to differences in the origin of the original ore, the composition of aluminum ash slag obtained using the same smelting process varies considerably. In addition, during the high-temperature smelting process, liquid metallic aluminum reacts with nitrogen in the air to form aluminum nitride. Fine aluminum nitride is black. After cooling, the aluminum nitride (AlN) in the aluminum ash easily reacts with water in the air to produce ammonia. Therefore, aluminum ash slag has a foul odor, is a black powder, and contains many large particles of metallic aluminum flakes (granules) and salts, and may contain trace amounts of Al4C3 and Al2S3.

[0003] The fluorides, heavy metals, and other toxic substances contained in aluminum ash slag also pose significant environmental hazards. Improper disposal can lead to soil, groundwater, and air pollution. Fluoride pollution can affect plant photosynthesis and respiration, and damage human bones, teeth, and the central nervous system.

[0004] Currently, most aluminum ash slag treatment involves building stockpiles, which not only wastes land resources but also causes environmental pollution. Therefore, it is necessary to develop more efficient aluminum ash slag treatment technologies. Summary of the Invention

[0005] To address the problems of severe land resource waste and environmental pollution caused by unsatisfactory removal of fluorides and heavy metals in existing aluminum ash slag treatment technologies, this invention provides a method for the resource utilization of aluminum ash slag. This invention cleverly combines dry and wet methods with a comprehensive resource-based process design, achieving near-complete resource recovery of valuable elements in the aluminum ash slag. The process is simple, energy-efficient, environmentally friendly, and boasts a high resource recovery rate.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is specifically as follows:

[0007] A method for the resource utilization of aluminum ash slag, the method comprising the following steps:

[0008] 1) First, crush and grind the aluminum ash slag, and then screen it to obtain coarse aluminum ash slag and fine aluminum ash slag.

[0009] 2) Heat the coarse aluminum ash slag to melt it into a liquid. After removing the scum from the liquid, cool it to obtain aluminum ingots. Return the collected scum to the aluminum ash slag from step 1).

[0010] 3) Add fluorine-fixing agent and catalyst to fine aluminum ash slag and mix to obtain a mixture. Then, screen the mixture to obtain a coarse mixture and a fine mixture. The coarse mixture is mixed with the coarse aluminum ash slag in step 2), and the fine mixture is processed in the next step.

[0011] 4) After the fine mixture is mixed evenly, it is subjected to oxidation treatment, and then a sulfur fixation reaction is carried out. After the reaction is completed, the sulfur-fixed material is obtained.

[0012] 5) The sulfur-fixing material is mixed with flocculant and water and subjected to sedimentation treatment to obtain sediment residue and sedimentation liquid. The sediment residue is dried and used as a concrete raw material, while the sedimentation liquid is subjected to further treatment.

[0013] 6) Concentrate the sediment and adjust the pH of the concentrate to carry out the aluminum precipitation reaction. After precipitation, filter the solution and dry the filter residue to obtain aluminum hydroxide powder. Further concentrate the filtrate to obtain the refining agent raw material.

[0014] Preferably, the method further includes:

[0015] 7) Collect and combine the waste gases generated in steps 3), 4), and 5) and wash them to obtain ammonia water. Recycle the evaporated water generated from the two concentration processes in step 6) back to step 5) for use.

[0016] Preferably, steps 3), 4), and 5) are all performed in an atmosphere protected by a protective gas. Preferably, the protective gas is one of nitrogen, helium, neon, and argon, with nitrogen being the most preferred.

[0017] Preferably, the aluminum ash is one or more of aluminum ash I, aluminum ash II, and aluminum ash III. More preferably, it is a mixed aluminum ash obtained by mixing aluminum ash I, aluminum ash II, and aluminum ash III in a mass ratio of 1-3:1-2:1.5-3, and more preferably, a mixed aluminum ash obtained by mixing in a ratio of 1.6-2:1.1-1.5:2-2.5. Wherein:

[0018] Aluminum ash slag I comprises: Al content 39%–42%, Ca content 2%–3.5%, Mg content 0%–1.2%, F content 1%–3%, Cl content 10%–12%, S content 0.5%–0.8%, and N content 1%–5%;

[0019] Aluminum ash slag II comprises: Al content 20%–32%, Ca content 2.5%–4.5%, Mg content 2.2%–4%, F content 1.5%–2%, Cl content 6%–9%, ​​S content 0.2%–0.5%, and N content 2%–4%;

[0020] Aluminum ash slag III comprises: Al content 40%–48%, Ca content 0%–1%, Mg content 1.8%–3.8%, F content 2%–3%, Cl content 1%–5%, S content 0.4%–0.5%, and N content 3%–4%.

[0021] Preferably, in step 1), the particle size of the coarse aluminum ash is 1.8–5 mm, more preferably 2–4 mm, for example, one of 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm, 3.8 mm, 4 mm, 4.2 mm, 4.5 mm, 4.8 mm, and 5 mm. The particle size of the fine aluminum ash is 0.5–1.9 mm, more preferably 1–1.7 mm, for example, one of 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, and 1.9 mm.

[0022] Preferably, in step 3), the particle size of the coarse mixture is 1.5–5 mm, more preferably 2–4.5 mm, for example, one of 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm, 3.8 mm, 4 mm, 4.2 mm, 4.5 mm, 4.8 mm, and 5 mm. The particle size of the fine mixture is 0.5–1.9 mm, more preferably 1–1.4 mm, for example, one of 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, and 1.9 mm.

[0023] Preferably, in step 3), the fluoride-fixing agent is calcium acetate and / or calcium magnesium acetate. Preferably, it is a mixture of calcium acetate and calcium magnesium acetate, with a mass ratio of 1:1.5-5, more preferably 1:2-3.

[0024] Preferably, in step 3), the catalyst is a mixture of polymethyl acrylate and calcium oxide. Preferably, the mass ratio of polymethyl acrylate to calcium oxide is 1:3.5-8, more preferably 1:4-5.5.

[0025] Preferably, the amount of the fluorine-fixing agent added is 2-8% of the mass of the fine alumina ash, preferably 3-5%, for example, one of 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, and 8%. The amount of the catalyst added is 3-10% of the mass of the fine alumina ash, preferably 4-8%, for example, one of 3%, 3.2%, 4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, and 10%.

[0026] Preferably, in step 4), the oxidation treatment involves introducing an oxidizing gas into the fine mixture to carry out an oxidation reaction. The oxidizing gas is oxygen or ozone.

[0027] Preferably, in step 4), the sulfur fixation reaction specifically involves introducing carbon dioxide into the oxidized fine mixture.

[0028] Preferably, the carbon dioxide injection rate is 10–30 m³ / h. 3 / h, preferably 15-25m 3 / h. The reaction time is 30-120 min, preferably 40-100 min.

[0029] Preferably, in step 5), the flocculant is nonionic polyacrylamide. The mixing mass ratio of the sulfur-fixing material, flocculant, and water is 50–58:5–9:40–50, preferably 52–56:6–8:42–48. The sedimentation time is 30–120 min, preferably 40–100 min.

[0030] Preferably, in step 6), the concentration factor of the sediment is 2 to 7 times, and more preferably 2.5 to 5 times.

[0031] Preferably, the pH of the concentrate is adjusted to 7-8.5, more preferably 7.5-8.2.

[0032] Preferably, the concentration factor of the filtrate is 2 to 6 times, and more preferably 3 to 5 times.

[0033] In existing technologies, the treatment of aluminum ash slag mostly involves open-air stockpiling or only targeted recovery of some resources (such as aluminum, iron, and silicon), resulting in unsatisfactory recovery effects and environmental pollution problems such as secondary residues and waste gas. This invention, through research, proposes a targeted treatment process that can achieve near-complete resource recovery of valuable elements in aluminum ash slag. Furthermore, this process is simple, energy-saving, environmentally friendly, and has a high resource recovery rate.

[0034] In this invention, most of the metallic aluminum in aluminum slag is recovered first through mechanical dry separation. This is mainly achieved by crushing the aluminum slag (e.g., crushing to a particle size of 5-10 mm) to initially refine the slag, followed by ball milling (e.g., ball milling to a particle size of 1-2 mm) for further refinement. These two refinements release as much metallic aluminum as possible from the inclusions in the aluminum slag. Coarse and fine particles are then separated by sieving. The coarse particles with a high aluminum content are smelted at high temperature, and the slag, which is converted from impurities, is removed before cooling and casting to obtain high-quality aluminum ingots. In other words, the mechanical and physical processes of crushing, ball milling, and sieving initially separate metallic aluminum from impurities (equivalent to stripping and enriching metallic aluminum from the slag phase). Then, the impurities included in the metallic aluminum are removed by smelting (the slag also contains aluminum, so it is mixed and recycled with other aluminum slag for the aforementioned treatment), ultimately yielding high-quality metallic aluminum ingots.

[0035] In this invention, the fine particulate material (i.e., fine aluminum ash slag) separated by mechanical dry method contains a large amount of impurities and aluminum, and some aluminum elements exist in the form of stable compounds. Specific fluorine-fixing agents and catalysts are added to the undersized fine particulate material to fix the fluorine in the fine particulate material and simultaneously promote the agglomeration of aluminum-containing powder. That is, under the combined action of the fluorine-fixing agent and catalyst, some of the aluminum-containing powder in the fine particulate material agglomerates into large particles, and these large particles have a high aluminum content. Therefore, high-frequency vibrating screening is continued, and the large particles formed by the agglomeration of aluminum-containing powder are returned for high-temperature smelting to further achieve the separation and recovery of metallic aluminum from impurities.

[0036] In this invention, the fluorine-fixing agent is calcium acetate and / or calcium magnesium acetate, preferably a mixture of calcium acetate and calcium magnesium acetate, with a mixing mass ratio of 1:1.5-5 (preferably 1:2-3). The catalyst is a mixture of polymethyl acrylate and calcium oxide, with a mixing mass ratio of 1:3.5-8 (preferably 1:4-5). During the reaction, the catalyst promotes the reaction and also promotes the solidification of the aluminum-containing powder. A mixing ratio of polymethyl acrylate and calcium oxide that is too high or too low will reduce the catalytic effect.

[0037] It should be noted that the undersize material collected by the high-frequency vibrating screen needs to be continuously stirred and reacted for a period of time to achieve deep fluorine fixation. Fine particulate materials have a higher fluorine content and generally require pretreatment, while the sulfur content is lower and can be treated later. Fluorine fixation involves combining fluoride ions with calcium ions to form calcium fluoride (which is then incorporated into the concrete raw materials).

[0038] In this invention, aluminum ash slag also contains a certain amount of sulfur. By introducing an oxidizing gas into the undersize material of a high-frequency vibrating screen and stirring, the sulfur is oxidized. Then, carbon dioxide is introduced and stirring is continued to achieve sulfur fixation. That is, by introducing carbon dioxide into the material, an acidic environment is created, and under the high-intensity oxidation of ozone, the sulfides in the material form calcium sulfate stabilizers in the acidic environment to achieve sulfur fixation.

[0039] In this invention, the material after the sulfur fixation reaction is mixed with a flocculant (e.g., nonionic polyacrylamide) and water in a certain ratio (e.g., the ratio of sulfur fixation material, flocculant, and water is 50%-58%: 5%-9%: 40%-45%). This mixture coagulates the microparticles generated after the sulfur fixation reaction and the microparticles generated in the aforementioned steps, promoting the settling of the coagulated material and the clarification of the liquid. After introducing carbon dioxide and adding water, an acidic environment is created, which dissolves most of the aluminum-containing substances. The aluminum-free materials form precipitates under the action of the flocculant, making them easier to remove.

[0040] In this invention, the material after sulfur fixation and sedimentation is filtered to obtain filter residue (the filter residue has a complex composition, containing carbonates and a small amount of sulfates; the fixed fluorine also enters the filter residue, which can be used as a concrete raw material to produce low-strength concrete, realizing the resource utilization of the filter residue) and filtrate. The filter residue is dried to obtain concrete raw material. The filtrate is concentrated to obtain a concentrated salt solution and a portion of distilled water, which can be recycled. The concentrated salt solution is crystallized while the pH is adjusted, which further dissolves metallic impurities other than aluminum in the concentrated salt solution and precipitates aluminum hydroxide, improving the purity of aluminum hydroxide. After crystallization and precipitation, a second filtration is performed to obtain wet aluminum hydroxide powder and a second filtrate. The wet aluminum hydroxide powder is dried to obtain aluminum hydroxide powder. Simultaneously, the second filtrate is further evaporated and concentrated to finally obtain a refining agent raw material. The refining agent raw material is a powdered or granular flux composed of various inorganic salts (i.e., the filtrate is concentrated to obtain various inorganic salts). Its purpose is to remove hydrogen and floating oxide inclusions from the molten aluminum during aluminum refining.

[0041] In this invention, ammonia gas is generated during processes such as fluorine fixation and sulfur fixation sedimentation. Therefore, a protective gas (such as nitrogen) is introduced during these processes to create a protective atmosphere, while the generated ammonia gas is carried out and sent to a specialized scrubbing device for scrubbing, absorption, and separation to obtain ammonia water, thereby achieving the resource recovery of harmful waste gas. Furthermore, the protective gas after ammonia removal can be recycled.

[0042] In this invention, the aluminum ash slag is a mixed aluminum ash slag composed of various aluminum ash slags with significantly different components. In existing primary aluminum production processes, due to different ore sources, the final aluminum ash slag has significantly different component contents. Some aluminum ash slags have high chlorine content (e.g., ore from coastal factories or mining areas), while others have high calcium or magnesium content. Due to the varying recoverable element content in the aluminum ash slag, targeted considerations are necessary for its full resource recovery. Therefore, a single processing method cannot be used to handle aluminum ash slags with different component contents. Establishing a dedicated resource recovery production line for each type of aluminum ash slag would involve excessive investment costs and difficulties in achieving full resource recovery, lacking economic efficiency and failing to meet the needs of economically minded enterprises. This invention utilizes a mixture of three special components of aluminum ash slag and has developed a comprehensive resource recovery process for this mixed aluminum ash slag. On one hand, it achieves the goal of recycling multiple types of aluminum ash slag using the same resource recovery process; on the other hand, the different components of the aluminum ash slag complement each other, promoting and improving the quality of resource-recovered products at each stage, thus achieving truly efficient comprehensive resource recovery of aluminum ash slag. All aluminum ash slag is resource-recovered: aluminum flakes are recycled; ammonia water is sold as a product; high-alumina materials are sold to alumina manufacturers, floor tile factories, or water purification agent factories; high-salt water is used as a raw material for refining agents, also for product sales; and concrete is used as a raw material in concrete preparation.

[0043] Compared with the prior art, the present invention has the following beneficial technical effects:

[0044] 1. The aluminum ash slag resource utilization process of the present invention does not require the establishment of a large stockpile, saving land resources and avoiding environmental pollution. It is a more efficient aluminum ash slag treatment technology, realizing the efficient and maximum resource utilization of existing aluminum ash slag, which is cleaner and has a high recycling rate.

[0045] 2. This invention employs a dry-wet separation extraction method for aluminum flakes. First, a dry method is used to extract most of the aluminum from the aluminum ash, achieving early and efficient recovery. Subsequently, a wet method is used for further aluminum extraction, resulting in a high aluminum flake recovery rate (up to approximately 95%). This invention also utilizes a wet mechanical-chemical process for fluoride fixation and ammonia removal, which is highly efficient, environmentally friendly, provides complete treatment, and has low operating costs.

[0046] 3. The invention features an ingenious process that is energy-saving and environmentally friendly, with a high resource recovery rate. The resulting products are of high quality (high grade, good chemical composition) and high strength. The process also achieves ultra-low emissions, resulting in excellent engineering and economic benefits. Attached Figure Description

[0047] Figure 1 This is a process flow diagram of the aluminum ash slag resource utilization method of the present invention.

[0048] Figure 2 This is a complete process flow diagram of the aluminum ash slag resource utilization method of the present invention. Detailed Implementation

[0049] To further illustrate the specific solutions of the present invention in detail, the technical solutions claimed by the present invention will be described below in conjunction with the accompanying drawings and embodiments. The following embodiments are merely preferred embodiments of the present invention and should not be considered as limitations on the scope of protection claimed by the present invention.

[0050] Example 1

[0051] A method for the resource utilization of aluminum ash slag, the method comprising the following steps:

[0052] 1) First, crush and grind the aluminum ash slag, and then screen it to obtain coarse aluminum ash slag and fine aluminum ash slag;

[0053] 2) Heat the coarse aluminum ash slag to melt it into a liquid. After removing the scum from the liquid, cool it to obtain aluminum ingots. Return the collected scum to the aluminum ash slag from step 1).

[0054] 3) Add fluorine-fixing agent and catalyst to fine aluminum ash slag and mix to obtain a mixture. Then, screen the mixture to obtain a coarse mixture and a fine mixture. Mix the coarse mixture with the coarse aluminum ash slag in step 2), and the fine mixture is processed in the next step.

[0055] 4) After the fine mixture is mixed evenly, it is subjected to oxidation treatment, and then a sulfur fixation reaction is carried out. After the reaction is completed, the sulfur-fixed material is obtained.

[0056] 5) Mix the sulfur-fixing material with flocculant and water and allow it to settle to obtain sediment and sediment liquid; dry the sediment and use it as a concrete raw material, and process the sediment liquid for the next step.

[0057] 6) Concentrate the sediment and adjust the pH of the concentrate to carry out the aluminum precipitation reaction. After precipitation, filter the solution and dry the filter residue to obtain aluminum hydroxide powder. Further concentrate the filtrate to obtain the refining agent raw material.

[0058] Example 2

[0059] Repeat Example 1, except that the method further includes:

[0060] 7) Collect and combine the waste gases generated in steps 3), 4), and 5) and wash them to obtain ammonia water; recycle the evaporated water generated in the two concentration processes in step 6) to use in step 5).

[0061] Example 3

[0062] Example 2 was repeated, except that steps 3), 4), and 5) were all performed under a nitrogen atmosphere.

[0063] The aluminum ash slag is a mixed aluminum ash slag composed of aluminum ash slag I, aluminum ash slag II, and aluminum ash slag III mixed in a mass ratio of 1.8:1.3:2.4; wherein:

[0064] The chemical composition of aluminum slag I is as follows: Al content 39%–42%, Si content 2%–5%, Fe content 1%–2%, Ca content 2%–3.5%, Mg content 0%–1.2%, F content 1%–3%, Na content 2%–7%, Cl content 10%–12%, S content 0.5%–0.8%, K content 0.2%–0.4%, and N content 1%–5%.

[0065] The chemical composition of aluminum ash slag II is as follows: Al content 20%–32%, Si content 1%–4%, Fe content 1%–1.5%, Ca content 2.5%–4.5%, Mg content 2.2%–4%, F content 1.5%–2%, Na content 3%–5%, Cl content 6%–9%, ​​S content 0.2%–0.5%, K content 0.3%–0.45%, and N content 2%–4%.

[0066] The chemical composition of aluminum ash slag III is as follows: Al content 40%–48%, Si content 3%–4%, Fe content 0.5%–1.8%, Ca content 0%–1%, Mg content 1.8%–3.8%, F content 2%–3%, Na content 4%–6%, Cl content 1%–5%, S content 0.4%–0.5%, K content 0.1%–0.2%, and N content 3%–4%.

[0067] In step 1), the particle size of coarse aluminum ash is 2-5 mm; the particle size of fine aluminum ash is 1-1.6 mm.

[0068] In step 3), the coarse mixture has a particle size of 1.6–5 mm; the fine mixture has a particle size of 1–1.5 mm. The fluorine-fixing agent is calcium acetate; the catalyst is a mixture of polymethyl acrylate and calcium oxide, with a mass ratio of polymethyl acrylate to calcium oxide of 1:4.5; the amount of fluorine-fixing agent added is 4% of the mass of the fine alumina ash; the amount of catalyst added is 7.5% of the mass of the fine alumina ash.

[0069] In step 4), the oxidation treatment involves introducing ozone into the fine mixture to carry out an oxidation reaction; in step 4), the amount of carbon dioxide introduced is 20m³. 3 / h; reaction time is 80min.

[0070] In step 5), the flocculant is nonionic polyacrylamide; the mixing mass ratio of sulfur-fixing material, flocculant, and water is 52:7:45; and the sedimentation time is 70 min.

[0071] In step 6), the concentration factor of the sediment is 5 times; the pH of the concentrate is adjusted to 7-8.5; and the concentration factor of the filtrate is 4 times.

[0072] Example 4

[0073] Repeat Example 3, except that in step 3), the fluorinating agent is calcium magnesium acetate.

[0074] Example 5

[0075] Repeat Example 3, except that in step 3), the fluoride-fixing agent is a mixture of calcium acetate and calcium magnesium acetate, with a mass ratio of 1:1.

[0076] Example 6

[0077] Repeat Example 3, except that in step 3), the fluoride-fixing agent is a mixture of calcium acetate and calcium magnesium acetate, with a mass ratio of 1:1.5.

[0078] Example 7

[0079] Repeat Example 3, except that in step 3), the fluoride-fixing agent is a mixture of calcium acetate and calcium magnesium acetate, with a mass ratio of 1:2.

[0080] Example 8

[0081] Repeat Example 3, except that in step 3), the fluoride-fixing agent is a mixture of calcium acetate and calcium magnesium acetate, with a mass ratio of 1:2.5.

[0082] Example 9

[0083] Repeat Example 3, except that in step 3), the fluoride-fixing agent is a mixture of calcium acetate and calcium magnesium acetate, with a mass ratio of 1:3.

[0084] Example 10

[0085] Repeat Example 3, except that in step 3), the fluoride-fixing agent is a mixture of calcium acetate and calcium magnesium acetate, with a mass ratio of 1:3.5.

[0086] Example 11

[0087] Repeat Example 3, except that in step 3), the fluoride-fixing agent is a mixture of calcium acetate and calcium magnesium acetate, with a mass ratio of 1:4.5.

[0088] Example 12

[0089] Repeat Example 3, except that in step 3), the fluoride-fixing agent is a mixture of calcium acetate and calcium magnesium acetate, with a mass ratio of 1:5.5.

[0090] Example 13

[0091] Repeat Example 8, except that in step 3), the mass ratio of polymethyl acrylate to calcium oxide is 1:3.5.

[0092] Example 14

[0093] Repeat Example 8, except that in step 3), the mass ratio of polymethyl acrylate to calcium oxide is 1:4.

[0094] Example 15

[0095] Repeat Example 8, except that in step 3), the mass ratio of polymethyl acrylate to calcium oxide is 1:5.

[0096] Example 16

[0097] Example 8 was repeated, except that the mixing mass ratio of the first type of aluminum ash, the second type of aluminum ash, and the third type of aluminum ash was 1.6:1.1:2.5.

[0098] Example 17

[0099] Example 8 was repeated, except that the mixing mass ratio of the first type of aluminum ash, the second type of aluminum ash, and the third type of aluminum ash was 2:1.5:2.

[0100] Example 18

[0101] Example 8 is repeated, except that the aluminum ash slag is only the first type of aluminum ash slag.

[0102] Example 19

[0103] Example 8 is repeated, except that the aluminum ash is only the second type of aluminum ash.

[0104] Example 20

[0105] Example 8 is repeated, except that the aluminum ash slag is only the third type of aluminum ash slag.

[0106] Example 21

[0107] Example 8 is repeated, except that the aluminum ash slag is only the first type of aluminum ash slag and the second type of aluminum ash slag.

[0108] Example 22

[0109] Example 8 is repeated, except that the aluminum ash slag is only the first type of aluminum ash slag and the third type of aluminum ash slag.

[0110] Example 23

[0111] Example 8 is repeated, except that the aluminum ash slag is only the second type of aluminum ash slag and the third type of aluminum ash slag.

[0112] Comparative Example 1

[0113] Repeat Example 8, except that a solid fluoride agent is not used in step 3).

[0114] Comparative Example 2

[0115] Repeat Example 8, except that no catalyst is used in step 3), and the fluorinating agent is only calcium acetate.

[0116] Comparative Example 3

[0117] Repeat Example 8, except that no catalyst is used in step 3), and the fluorinating agent is only calcium magnesium acetate.

[0118] Comparative Example 4

[0119] Repeat Example 8, except that no catalyst is used in step 3).

[0120] Comparison table of main process parameters and effects:

[0121]

[0122]

Claims

1. A method for resource utilization of aluminum dross, characterized in that: The method comprises the following steps: 1) first crushing and grinding the aluminum ash residue, and then screening to obtain coarse aluminum ash residue and fine aluminum ash residue; 2) heating and melting the coarse aluminum ash residue into a molten liquid, removing the dross from the molten liquid, and then cooling to obtain aluminum ingots; the collected dross is returned to the aluminum ash residue of step 1); 3) adding a fluorine-fixing agent and a catalyst to the fine aluminum ash residue to obtain a mixture, and screening the mixture to obtain coarse mixture and fine mixture; the coarse mixture is mixed with the coarse aluminum ash residue for step 2), and the fine mixture is subjected to the next step; the fluorine-fixing agent is calcium acetate and / or calcium magnesium acetate; the catalyst is a mixture of poly(methyl acrylate) and calcium oxide; 4) mixing the fine mixture uniformly, then performing an oxidation treatment, and then performing a sulfur-fixing reaction to obtain a sulfur-fixed material; 5) mixing the sulfur-fixed material with a flocculating agent and water to perform a sedimentation treatment to obtain sedimentation residue and sedimentation liquid; the sedimentation residue is dried to be used as a concrete raw material, and the sedimentation liquid is subjected to the next step; 6) concentrating the sedimentation liquid, adjusting the pH of the concentrated liquid to perform an aluminum precipitation reaction, filtering after the precipitation is completed, drying the filter residue to obtain aluminum hydroxide powder, and further concentrating the filtrate to obtain a refining agent raw material.

2. The method of claim 1, wherein: The method further comprises: 7) collecting and combining the waste gas generated in steps 3), 4), and 5) to perform leaching to obtain ammonia water; and recycling the evaporation water generated in the two concentration treatments in step 6) to step 5).

3. The method according to claim 1 or 2, characterized in that: Steps 3), 4), and 5) are performed in an atmosphere protected by a protective gas.

4. The method of claim 3, wherein: The protective gas is one of nitrogen, helium, neon, and argon.

5. The method of claim 4, wherein: The protective gas is nitrogen.

6. The method of any one of claims 1-2, 4-5, wherein: The aluminum ash residue is one or more of aluminum ash residue I, aluminum ash residue II, and aluminum ash residue III; wherein: The aluminum ash residue I comprises: Al content of 39% to 42%, Ca content of 2% to 3.5%, Mg content of 0% to 1.2%, F content of 1% to 3%, Cl content of 10% to 12%, S content of 0.5% to 0.8%, and N content of 1% to 5%; The aluminum ash residue II comprises: Al content of 20% to 32%, Ca content of 2.5% to 4.5%, Mg content of 2.2% to 4%, F content of 1.5% to 2%, Cl content of 6% to 9%, S content of 0.2% to 0.5%, and N content of 2% to 4%; The aluminum ash residue III comprises: Al content of 40% to 48%, Ca content of 0% to 1%, Mg content of 1.8% to 3.8%, F content of 2% to 3%, Cl content of 1% to 5%, S content of 0.4% to 0.5%, and N content of 3% to 4%.

7. The method of claim 6, wherein: The aluminum ash residue is a mixed aluminum ash residue obtained by mixing aluminum ash residue I, aluminum ash residue II, and aluminum ash residue III in a mass ratio of 1-3:1-2:1.5-3.

8. The method of claim 7, wherein: The aluminum ash residue is a mixed aluminum ash residue obtained by mixing aluminum ash residue I, aluminum ash residue II, and aluminum ash residue III in a mass ratio of 1.6 to 2:1.1 to 1.5:2 to 2.

5.

9. The method of any one of claims 1-2, 4-5, 7-8, wherein: In step 1), the particle size of the coarse aluminum ash residue is 1.8 to 5 mm; the particle size of the fine aluminum ash residue is 0.5 to 1.9 mm; and / or In step 3), the particle size of the coarse mixture is 1.5-5 mm; and the particle size of the fine mixture is 0.5-1.9 mm.

10. The method of claim 9, wherein: In step 1), the particle size of the coarse aluminum ash is 2-4 mm; the particle size of the fine aluminum ash is 1-1.7 mm; and / or In step 3), the particle size of the coarse mixture is 2-4.5 mm; and the particle size of the fine mixture is 1-1.4 mm.

11. The method of any one of claims 1-2, 4-5, 7-8, 10, wherein: In step 3), the fluorine-fixing agent is a mixture of calcium acetate and calcium magnesium acetate, and the mixing mass ratio of the two is 1:1.5-5; and / or In step 3), the mixing mass ratio of the poly-methyl-acrylate and the calcium oxide in the catalyst is 1:3.5-8.

12. The method of claim 11, wherein: The mixing mass ratio of the calcium acetate and the calcium magnesium acetate is 1:2-3; and the mixing mass ratio of the poly-methyl-acrylate and the calcium oxide is 1:4-5.

13. The method of claim 11, wherein: The adding amount of the fluorine-fixing agent is 2-8% of the mass of the fine aluminum ash; and the adding amount of the catalyst is 3-10% of the mass of the fine aluminum ash.

14. The method of claim 13, wherein: The adding amount of the fluorine-fixing agent is 3-5% of the mass of the fine aluminum ash; and the adding amount of the catalyst is 4-8% of the mass of the fine aluminum ash.

15. The method of any one of claims 1-2, 4-5, 7-8, 10, 12-14, wherein: In step 4), the oxidation treatment is an oxidation reaction by introducing an oxidizing gas into the fine mixture; and the oxidizing gas is oxygen or ozone.

16. The method of any one of claims 1-2, 4-5, 7-8, 10, 12-14, wherein: In step 4), the sulfur-fixing reaction is specifically introducing carbon dioxide into the fine mixture after the oxidation.

17. The method of claim 16, wherein: The amount of carbon dioxide introduced is 10 to 30 m 3 / h; the reaction time is 30 to 120 min.

18. The method of claim 17, wherein: The amount of carbon dioxide introduced is 15-25 m 3 / h; the reaction time is 40-100 min.

19. The method of any one of claims 1-2, 4-5, 7-8, 10, 12-14, 17-18, wherein: In step 5), the flocculating agent is non-ionic polyacrylamide; the mixing mass ratio of the sulfur-fixing material, the flocculating agent and water is 50-58:5-9:40-50; and the settling treatment time is 30-120 min.

20. The method of claim 19, wherein: The mixing mass ratio of the sulfur-fixing material, the flocculating agent and water is 52-56:6-8:42-48; and the settling treatment time is 40-100 min.

21. The method of any one of claims 1-2, 4-5, 7-8, 10, 12-14, 17-18, 20, wherein: In step 6), the concentration multiple of the settling liquid is 2-7 times; and / or The adjusting of the pH of the concentrated liquid is specifically adjusting the pH of the concentrated liquid to 7-8.5; and / or The concentration multiple of the filtrate is 2-6 times.

22. The method of claim 21, wherein: The concentration multiple of the settling liquid is 2.5-5 times; the adjusting of the pH of the concentrated liquid is specifically adjusting the pH of the concentrated liquid to 7.5-8.2; and the concentration multiple of the filtrate is 3-5 times.

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