Aluminum ash recovery process

Abstract

The invention discloses an aluminum ash recovery process, and belongs to the technical field of aluminum ash treatment. The aluminum ash recovery process comprises the following process steps: mixing and stirring aluminum ash and an extracting agent A in a first reactor to react for a first reaction time, filtering to obtain a first filtrate, introducing the first filtrate into a second reactor, adding an extracting agent and a regenerant B, and stirring to react for a second reaction time to obtain a second filtrate; a regenerated extracting agent A and a metal aluminum element recovery product are formed and filtered, a second filtrate flows back into the first reactor to continue to participate in the reaction, and filter residues contain the metal aluminum element recovery product; the second filtrate contains a regenerated extractant A; the extracting agent A is concentrated hydrochloric acid with the concentration of 36-38%; and the extractant regenerant B is sodium hydroxide.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, in particular to an aluminum ash recovery process. Background Art

[0002] With the rapid development of global industry, aluminum, as the second largest metal after iron, is widely used in aerospace, construction, automobile and other industries. China's aluminum production occupies an important position in the world. In 2020, the world's aluminum production capacity was 65.27 million tons, and China's aluminum production reached 37.08 million tons, accounting for more than half of the world's total production. However, with the increase in aluminum production, the problem of handling aluminum ash, the waste generated during the smelting process, has become increasingly serious.

[0003] Aluminum ash is a by-product of the high-temperature process of aluminum smelting, mainly composed of elemental aluminum, alumina and other impurities. According to statistics, each ton of aluminum products will produce about 110 kilograms of aluminum ash. In 2020, the aluminum ash production of the entire industry in my country reached 3.94 million tons, of which the slag production rates of primary production, aluminum processing, aluminum casting processing and recycled production were 2%, 4%, 5% and 8% respectively, and the corresponding slag production was 750,000 tons, 1.83 million tons, 400,000 tons and 960,000 tons respectively. These aluminum ashes not only contain a large amount of reusable aluminum elements, but also if not handled properly, will cause serious pollution to the environment, such as damage to the atmosphere, water quality and soil. Therefore, how to effectively treat aluminum ash and realize its resource utilization has become an urgent problem to be solved.

[0004] Therefore, the applicant has designed an aluminum ash recovery process to recycle the aluminum ash, and the content of each component of the recovered aluminum hydroxide can meet the requirements of the national standard GB / T 4294-2010. Summary of the invention

[0005] The purpose of the present invention is to provide an aluminum ash recovery process to solve the technical problems mentioned in the above background technology.

[0006] The technical solution for achieving the purpose of the present invention is: An aluminum ash recovery process comprises the following process steps: mixing aluminum ash and an extractant A in a first reactor and stirring the mixture for a first reaction time, filtering and taking a first filtrate, passing the first filtrate into a second reactor, adding an extractant and a regenerating agent B and stirring the mixture for a second reaction time to form a regenerated extractant A and a metal aluminum element recovery product, filtering, and reflowing the second filtrate into the first reactor to continue the reaction, wherein the filter residue contains the metal aluminum element recovery product; and the second filtrate contains the regenerated extractant A.

[0007] Furthermore, the extractant A is concentrated hydrochloric acid with a concentration of 36-38%.

[0008] Furthermore, the extractant regeneration agent B is sodium hydroxide.

[0009] Furthermore, the aluminum ash is the aluminum ash generated at the bottom of a furnace when an aluminum ingot is melted in a melting furnace during the aluminum casting process.

[0010] Furthermore, the mass ratio of the aluminum ash, the extractant A, and the extractant B is 100:204~205:1.84~1.94.

[0011] Furthermore, the first reaction time is 2.8-3.2 hours; the second reaction time is 50-70 minutes.

[0012] Furthermore, the aluminum ash is aluminum ash generated during the reaction of adding a slag remover into aluminum liquid formed by melting an aluminum ingot during the aluminum casting process.

[0013] Furthermore, the mass ratio of the aluminum ash, the extractant A, and the extractant B is 100:357~358:3.21~3.54.

[0014] Furthermore, the first reaction time is 4.3-4.7 h; the second reaction time is 50-70 min.

[0015] Furthermore, the metallic aluminum element recovery product includes aluminum hydroxide.

[0016] By adopting the above technical solution, the present invention has the following beneficial effects: In the present invention, aluminum ash is first treated by an extractant A to filter and extract the aluminum element therein. Next, the aluminum-containing filtrate reacts with an extractant regeneration agent B, and the aluminum element therein is converted into aluminum hydroxide precipitation, and the extractant A is regenerated. The aluminum hydroxide solid is recovered by solid-liquid separation, and the extractant A is returned to the first reaction step for recycling. This process not only realizes the effective separation of the aluminum element, but also can regenerate the extractant A. This recycling method significantly reduces the raw material cost and ensures that the aluminum element in the aluminum ash is efficiently recovered. At the same time, the aluminum hydroxide solid finally obtained fully meets the requirements of the GB / T 4294-2010 standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the content of the present invention more clearly understood, the following is a detailed description of the present invention according to the specific embodiments and the accompanying drawings. Figure 1 It is a process flow chart of the aluminum ash recovery process of the present invention. DETAILED DESCRIPTION

[0018] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0019] The following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0021] The raw materials of the embodiments and comparative examples are as follows: aluminum ash I and aluminum ash II are respectively collected from the aluminum ash produced at the bottom of the melting furnace when the aluminum ingots are melted in the aluminum casting production process of a certain automobile parts company in Nanjing, and the aluminum ash produced in the reaction process of adding a slag remover to the aluminum liquid formed by the melting of the aluminum ingots. The aluminum content of aluminum ash I is about 26.97%, and the aluminum content of aluminum ash II is 43.38%; concentrated hydrochloric acid is analytically pure and was purchased from Yangzhou Hubao Chemical Reagent Co., Ltd.; sodium hydroxide is analytically pure and was purchased from Shanghai Chemical Reagent Co., Ltd. Example 1

[0022] See Figure 1 The aluminum ash I of this embodiment is aluminum ash generated at the bottom of a melting furnace when aluminum ingots are melted in a process of producing aluminum castings by a certain automobile parts company in Nanjing.

[0023] An aluminum ash recovery process comprises the following process steps: 100 parts by mass of aluminum ash and 204 parts by mass of concentrated hydrochloric acid as an extractant A are mixed and stirred in a first reactor for reaction for 2.8 hours, a first filtrate is taken after filtration, the first filtrate is passed into a second reactor, 1.84 parts by mass of an extractant regeneration agent B is added and stirred for reaction for 50 minutes, and then filtered, the second filtrate is refluxed into the first reactor to continue to participate in the reaction, the filter residue contains aluminum hydroxide as a recovered product of the metal aluminum element; the second filtrate contains the regenerated extractant A, and the recovery rate of the metal aluminum element is 87.4%. Example 2

[0024] The aluminum ash I of this embodiment is aluminum ash generated at the bottom of a melting furnace when aluminum ingots are melted during the process of producing aluminum castings by a certain automobile parts company in Nanjing.

[0025] An aluminum ash recovery process comprises the following process steps: 100 parts by mass of aluminum ash and 204.5 parts by mass of concentrated hydrochloric acid as an extractant A are mixed and stirred in a first reactor for reaction for 3 hours, a first filtrate is taken after filtration, the first filtrate is passed into a second reactor, 1.89 parts by mass of an extractant regeneration agent B is added and stirred for reaction for 60 minutes, and then filtered, the second filtrate is refluxed into the first reactor to continue to participate in the reaction, the filter residue contains aluminum hydroxide as a recovered product of the metal aluminum element; the second filtrate contains the regenerated extractant A, and the recovery rate of the metal aluminum element is 87.5%. Example 3

[0026] See Figure 1 The aluminum ash I of this embodiment is aluminum ash generated at the bottom of a melting furnace when aluminum ingots are melted in a process of producing aluminum castings by a certain automobile parts company in Nanjing.

[0027] An aluminum ash recovery process comprises the following process steps: 100 parts by mass of aluminum ash and 205 parts by mass of concentrated hydrochloric acid as an extractant A are mixed and stirred in a first reactor for reaction for 3.2 hours, a first filtrate is taken after filtration, the first filtrate is passed into a second reactor, 1.94 parts by mass of an extractant regeneration agent B is added and stirred for reaction for 70 minutes, and then filtered, the second filtrate is refluxed into the first reactor to continue to participate in the reaction, the filter residue contains aluminum hydroxide as a recovered product of the metal aluminum element; the second filtrate contains the regenerated extractant A, and the recovery rate of the metal aluminum element is 87.5%. Example 4

[0028] The aluminum ash II of this embodiment is aluminum ash generated by a reaction process in which a slag remover is added to aluminum liquid formed by melting aluminum ingots during the process of producing aluminum castings by a certain automobile parts company in Nanjing.

[0029] An aluminum ash recovery process comprises the following process steps: 100 parts by mass of aluminum ash and 357 parts by mass of concentrated hydrochloric acid as an extractant A are mixed and stirred in a first reactor for reaction for 4.3 hours, a first filtrate is taken after filtration, the first filtrate is passed into a second reactor, 3.21 parts by mass of an extractant regeneration agent B are added and stirred for reaction for 50 minutes, and then filtered, the second filtrate is refluxed into the first reactor to continue to participate in the reaction, the filter residue contains aluminum hydroxide as a recovered product of the metal aluminum element; the second filtrate contains the regenerated extractant A, and the recovery rate of the metal aluminum element is 78.0%. Example 5

[0030] The aluminum ash II of this embodiment is aluminum ash generated by a reaction process in which a slag remover is added to aluminum liquid formed by melting aluminum ingots during the process of producing aluminum castings by a certain automobile parts company in Nanjing.

[0031] An aluminum ash recovery process comprises the following process steps: 100 parts by mass of aluminum ash and 357.5 parts by mass of concentrated hydrochloric acid as an extractant A are mixed and stirred in a first reactor for reaction for 4.5 hours, a first filtrate is taken after filtration, the first filtrate is passed into a second reactor, 3.37 parts by mass of an extractant regeneration agent B are added and stirred for reaction for 60 minutes, and then filtered, the second filtrate is refluxed into the first reactor to continue to participate in the reaction, the filter residue contains aluminum hydroxide as a recovered product of the metal aluminum element; the second filtrate contains the regenerated extractant A, and the recovery rate of the metal aluminum element is 78.3%. Example 6

[0032] The aluminum ash II of this embodiment is aluminum ash generated by a reaction process in which a slag remover is added to aluminum liquid formed by melting aluminum ingots during the process of producing aluminum castings by a certain automobile parts company in Nanjing.

[0033] An aluminum ash recovery process comprises the following process steps: 100 parts by mass of aluminum ash and 358 parts by mass of concentrated hydrochloric acid as an extractant A are mixed and stirred in a first reactor for reaction for 4.7 hours, a first filtrate is taken after filtration, the first filtrate is passed into a second reactor, 3.54 parts by mass of an extractant regeneration agent B are added and stirred for reaction for 70 minutes, and then filtered, the second filtrate is refluxed into the first reactor to continue to participate in the reaction, the filter residue contains aluminum hydroxide as a recovered product of the metal aluminum element; the second filtrate contains the regenerated extractant A, and the recovery rate of the metal aluminum element is 78.2%. Effect example

[0034] The recovery rate of metallic aluminum in aluminum ash is calculated according to the following formula:

[0035] Wherein, is the recovery rate of metallic aluminum; c is the analytical concentration of Al in the first filtrate (mol / L); V is the volume of the first filtrate (L); 26.98 is the relative atomic mass of aluminum; m is the mass of aluminum ash (g); and w% is the mass fraction of aluminum in aluminum ash.

[0036] The content of each element in the filter residue prepared in the embodiment at 110° C. was analyzed according to GB / T 4294-2010. The following Table 1 shows the analysis results, wherein ND means not detected.

[0037]

[0038] The minimum content of aluminum hydroxide recovered from Table 1 is 99.41%, and the maximum contents of impurities SiO2, Fe2O3, and Na2O are 0.0198%, 0.006%, and 0.0353%, respectively, which are lower than the requirements of GB / T 4294-2010 that SiO2 should not exceed 0.02%, Fe2O3 should not exceed 0.02%, and Na2O should not exceed 0.04%. Other impurity ions (Cd+ Hg+ Pb+ Cr6+ + As) content is 0.00115%, which is far below the standard limit of 0.01%.

[0039] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An aluminum ash recovery process, characterized in that: The method comprises the following process steps: mixing aluminum ash and extractant A in a first reactor and stirring the mixture for a first reaction time, filtering and taking a first filtrate, passing the first filtrate into a second reactor, adding an extractant and regenerating agent B and stirring the mixture for a second reaction time to form a regenerated extractant A and a metal aluminum element recovery product, filtering, and reflowing the second filtrate into the first reactor to continue to react, wherein the filter residue contains the metal aluminum element recovery product; and the second filtrate contains the regenerated extractant A.

2. The aluminum ash recovery process according to claim 1, characterized in that: The extractant A is concentrated hydrochloric acid with a concentration of 36-38%.

3. The aluminum ash recovery process according to claim 2, characterized in that: The extractant regeneration agent B is sodium hydroxide.

4. The aluminum ash recovery process according to claim 3, characterized in that: The aluminum ash is the aluminum ash generated at the bottom of a furnace when an aluminum ingot is melted in a melting furnace during the aluminum casting process.

5. The aluminum ash recovery process according to claim 4, characterized in that: The mass ratio of the aluminum ash, the extractant A, and the extractant B is 100:204-205:1.84-1.

94.

6. The aluminum ash recovery process according to claim 4, characterized in that: The first reaction time is 2.8-3.2 hours; the second reaction time is 50-70 minutes.

7. The aluminum ash recovery process according to claim 3, characterized in that: The aluminum ash is the aluminum ash generated in the process of adding a slag remover to the aluminum liquid formed by melting the aluminum ingot during the aluminum casting process.

8. The aluminum ash recovery process according to claim 7, characterized in that: The mass ratio of the aluminum ash, the extractant A, and the extractant B is 100:357-358:3.21-3.

54.

9. The aluminum ash recovery process according to claim 7, characterized in that: The first reaction time is 4.3-4.7 hours; the second reaction time is 50-70 minutes.

10. The aluminum ash recovery process according to any one of claims 1 to 9, characterized in that: The metallic aluminum element recovery product includes aluminum hydroxide.

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