Process method for preparing sodium aluminate from waste residues in short kiln

Abstract

The invention discloses a process method for preparing sodium aluminate from waste residues in a short kiln, which comprises the following process steps: S1, carrying out desalting pretreatment on the waste residues, and after roasting, reserving samples of the waste residues to be treated; s2, roasting the roasted waste residue and an additive in a short kiln, dissolving out, and carrying out solid-liquid separation to obtain a dissolved solution; and S3, carrying out sodium aluminate dissolution rate detection on the dissolution liquid. The invention relates to the technical field of waste residue resource utilization, the aluminum ash slag is used as a main raw material for desalting, mixing, roasting to prepare sodium aluminate and dissolving out to obtain a sodium aluminate solution, the sodium aluminate can be prepared from the aluminum ash slag in a short kiln in the process, and compared with a traditional method for preparing a high-aluminum material from the aluminum ash slag and a traditional method for preparing the sodium aluminate from the aluminum ash slag in a long kiln, the method has the advantages that the cost is low; the product added value is higher, the process flow is short, and the energy consumption is low.

Description

Technical Field

[0001] This invention relates to the field of waste residue resource utilization technology, specifically a process for preparing sodium aluminate from waste residue using a short kiln. Background Technology

[0002] Currently, China generates over 5 million tons of aluminum ash slag annually, with a low recovery rate. Current disposal methods fall into two main categories: pyrometallurgical and hydrometallurgical processes. Pyrometallurgical sintering is used to produce high-alumina materials, while hydrometallurgical treatment is used to produce water purification agents. A series of documents issued by my country, including the "Solid Waste Pollution Prevention and Control Law of the People's Republic of China," the "13th Five-Year Plan for Ecological and Environmental Protection," the "National Hazardous Waste List," and the "Environmental Protection Tax Law of the People's Republic of China," have clearly stipulated that aluminum ash slag requires key monitoring and emission control limits. This signifies that my country has fully entered the stage of harmless and resource-based treatment of aluminum ash slag. However, long kiln sintering is energy-intensive and requires a large land area. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a process for preparing sodium aluminate using a short kiln from waste residue, which solves the problems of high energy consumption and large footprint associated with long kiln sintering in existing technologies.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a process for preparing sodium aluminate from waste slag using a short kiln, comprising the following process steps: S1. The waste residue is pretreated by desalination, and samples of the waste residue are retained after roasting for further processing; S2. The calcined waste residue and additives are dissolved after short kiln calcination, and the dissolved liquid is obtained by solid-liquid separation; S3. The sodium aluminate dissolution rate of the dissolved solution is tested.

[0005] Preferably, the waste residue in S1 is aluminum ash residue from the recycled aluminum industry.

[0006] Preferably, the calcination temperature in S2 is 850-1100℃, and the calcination time is 1 hour.

[0007] Preferably, the mass ratio of the additive to the desalinated aluminum ash is (3-8):10.

[0008] Preferably, the additive is sodium carbonate and sodium chloride. Beneficial effects

[0009] This invention provides a process for preparing sodium aluminate from aluminum ash slag using a short kiln. It offers the following advantages: This invention uses aluminum ash slag as the main raw material for desalination, mixing, roasting to prepare sodium aluminate, and leaching to obtain a sodium aluminate solution. This process can prepare sodium aluminate from aluminum ash slag using a short kiln, which, compared to the traditional method of preparing high-alumina materials from aluminum ash slag using a long kiln, results in higher product added value, a shorter process flow, and lower energy consumption. Attached Figure Description

[0010] Figure 1 For the phase analysis of sodium aluminate and leaching residue under different firing conditions of the present invention, the conditions were: aluminum ash / sodium carbonate mass ratio: 10:8, 5% sodium chloride, 900℃, 1h; Figure 2 For the phase analysis of sodium aluminate and leaching residue under different firing conditions of the present invention, the conditions were: aluminum ash / sodium carbonate mass ratio: 10:8, 1100℃, 1h, sodium aluminate leaching rate: 2597.88 ppm; Figure 3 For the phase analysis of sodium aluminate and leaching residue under different firing conditions of the present invention, the conditions were: aluminum ash / sodium carbonate mass ratio: 10:8, 10% sodium chloride, 900℃, 1h; Figure 4 For the phase analysis of sodium aluminate and leaching residue under different firing conditions of the present invention, the conditions were: aluminum ash / sodium carbonate mass ratio: 10:8, 20% sodium chloride, 900℃, 1h; Figure 5 For the phase analysis of sodium aluminate and leaching residue under different firing conditions of the present invention, the conditions were: aluminum ash / sodium carbonate mass ratio: 10:8, 1000℃, 1h, sodium aluminate leaching rate: 1710.94ppm; Figure 6 The first case of phase analysis of the residue after dissolution of sodium aluminate prepared by different processes of the present invention; Figure 7 The second scenario is the phase analysis of the residue after dissolution of sodium aluminate prepared by different processes according to the present invention. Figure 8 The third scenario is the phase analysis of the residue after dissolution of sodium aluminate prepared by different processes according to the present invention. Figure 9 The fourth scenario is the phase analysis of the residue after dissolution of sodium aluminate prepared by different processes according to the present invention. Figure 10 The fifth scenario is the phase analysis of the residue after dissolution of sodium aluminate prepared by different processes according to the present invention. Detailed Implementation

[0011] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0012] Example:

[0013] Raw materials: aluminum ash, sodium carbonate, sodium chloride Experimental plan: The tested aluminum ash slag was passed through an 80-mesh sieve, and the undersize portion was collected. The 80-mesh slag underwent desalination pretreatment (only the undersize portion was selected; the oversize portion was discarded. The purpose of sieving is that the aluminum ash slag varies in composition, type, and particle size, typically containing some metallic aluminum lumps, which are detrimental to the preparation of sodium aluminate. Sieving removes large particles, and the smaller particles also react more uniformly with sodium carbonate). Treatment conditions: 900℃, sintering for 4 hours. After sintering, the aluminum ash slag was mixed with sodium carbonate to investigate the effects of the aluminum ash slag / sodium carbonate mass ratio, sintering temperature, and sintering time on the subsequent sodium aluminate dissolution rate.

[0014] Chemical composition (mass percentage) of aluminum ash slag under different desalination conditions

[0015]

[0016] (1) (2) Experimental results: Appropriately increasing the proportion of sodium carbonate increases the dissolution rate of sodium aluminate. (1)(3) / (7)(8) Experimental results: Increasing the sintering temperature and extending the sintering time are not conducive to improving the sodium aluminate dissolution rate. (4)(5) / (8)(9) Experimental results: The optimal ratio of aluminum ash slag to sodium carbonate is 10:8. (10) Experimental results: Under the conditions of aluminum ash slag and sodium carbonate mass ratio of 10:8, 10% NaCl, 900℃, and 1h sintering, the sodium aluminate dissolution rate was 5277.38%.

[0017] XRF analysis (900℃) of sodium aluminate composition prepared by different types of aluminum ash slag and different calcination times

[0018] Phase analysis of sodium aluminate and leaching residue under different firing conditions refer to Figures 1-5 Different processes were used to prepare sodium aluminate. The phase compositions were similar, but the diffraction peak intensities differed. The phases with relatively better crystallinity showed higher diffraction peak intensities. Main components: sodium aluminate, magnesium oxide.

[0019] A comparative experiment was conducted under the following five conditions: Aluminum ash / sodium carbonate mass ratio: 10:8, 5% sodium chloride, 900℃, 1h Aluminum ash / sodium carbonate mass ratio: 10:8, 1100℃, 1h, sodium aluminate leaching rate: 2597.88 ppm Aluminum ash / sodium carbonate mass ratio: 10:8, 10% sodium chloride, 900℃, 1h Aluminum ash / sodium carbonate mass ratio: 10:8, 20% sodium chloride, 900℃, 1h Aluminum ash / sodium carbonate mass ratio: 10:8, 1000℃, 1h, sodium aluminate leaching rate: 1710.94ppm refer to Figures 6-10 Phase analysis of the residues after dissolution of sodium aluminate prepared by different processes showed that the phase compositions were similar. Compared with the undissolved residue, the diffraction peaks of the undissolved residue were wavy and the diffraction peak intensities decreased, indicating a significant amorphous phase in the residue. The main diffraction peak substance was magnesium oxide.

[0020] in conclusion: Figure 3 and Figure 9 Sintering without adding sodium chloride and appropriately increasing the sintering temperature can improve the sodium aluminate dissolution rate to a certain extent. Figure 1 , Figure 5 and Figure 7 Adding sodium chloride during sintering lowers the sintering temperature and reduces the sintering time, thereby increasing the sodium aluminate dissolution rate.

[0021] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for preparing sodium aluminate from waste residue using a short kiln, characterized in that, The process includes the following steps: S1. The waste residue is pretreated by desalination, and samples of the waste residue are retained after roasting for further processing; S2. The calcined waste residue and additives are dissolved after short kiln calcination, and the dissolved liquid is obtained by solid-liquid separation; S3. The sodium aluminate dissolution rate of the dissolved solution is tested.

2. The process for preparing sodium aluminate from waste residue using a short kiln according to claim 1, characterized in that, The waste residue in S1 is aluminum ash residue from the recycled aluminum industry.

3. The process for preparing sodium aluminate from waste residue using a short kiln according to claim 2, characterized in that, The roasting temperature in S2 is 850-1100℃, and the roasting time is 1 hour.

4. The process for preparing sodium aluminate from waste residue using a short kiln according to claim 3, characterized in that, The mass ratio of the additive to the desalinated aluminum ash is (3-8):

10.

5. The process for preparing sodium aluminate from waste residue using a short kiln according to claim 4, characterized in that, The additives are sodium carbonate and sodium chloride.

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