Method for purifying acid-dissolved aluminum in aluminum sludge based on cationic resin

Abstract

The invention discloses a method for purifying acid-dissolved aluminum in aluminum sludge based on cationic resin, which comprises the following steps: standing sludge in a sedimentation tank until sludge and water are separated, and removing supernate to obtain concentrated sludge; adjusting the pH value of the concentrated sludge to be acidic, dissolving aluminum, standing, precipitating and separating the acid-dissolved sludge, and collecting acid leaching supernate; carrying out acid-alkali-acid alternate cleaning on ion exchange resin of the strong acid hydrogen cation exchange column until the ion exchange resin is neutral, filling the column, enabling the acid leaching supernatant to pass through the column, and carrying out ion exchange to complete the adsorption and collection of the dissolved aluminum; and eluting the cation exchange column with acid liquor to perform backwashing aluminum removal on the resin column to obtain a purified aluminum extracting solution, and synchronously realizing regeneration of the aluminum adsorption capacity of the resin. By regulating and controlling the pH value of the acidizing fluid, efficient dissolution and Al-NOM complexing breaking of aluminum in the sludge are achieved, strong acid hydrogen type cation exchange resin is introduced, separation of aluminum from organic matter and heavy metal ions is achieved, and systematic aluminum sludge treatment for purifying aluminum salt in the water supply sludge is achieved through resin regeneration and aluminum liquid collection.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge treatment and resource utilization, and specifically relates to a method for purifying aluminum by acid dissolution in aluminum sludge based on cationic resin. Background Art

[0002] The safe and stable supply of tap water is an important part of ensuring the basic conditions for urban life and production. Water plants often use coagulants in production to strengthen the separation of impurities in raw water. The added coagulants combine with various pollutants in the raw water to form floccules, which are then finally discharged and disposed of after forming aluminum sludge through precipitation. At present, there are three main methods for treating water purification sludge. The first is to discharge it directly into the nearby river, but the aluminum in the sludge water will pose an ecological threat to aquatic organisms, and will also promote the uplift of the riverbed, further affecting the navigation and flood control and drainage capacity of the river; the second is to discharge it into the urban municipal pipe network and transport it to the sewage treatment plant for unified treatment, but because there are still a lot of clay and other sediments in the water purification sludge, it will not only cause the blockage of the drainage pipes, but also increase the treatment load of the sewage treatment plant; the third is to dehydrate the sludge and dispose of it separately, such as soil improvement, use as building materials or water treatment adsorption materials. Overall, the potential environmental and ecological risks caused by the high content of aluminum in aluminum sludge seriously restrict the final disposal methods and channels of aluminum sludge.

[0003] The main components of aluminum sludge include water treatment coagulants, raw water impurities including turbidity particles and natural organic matter (NOM), and trace heavy metals from coagulants or natural water bodies. NOM mainly includes humic acid, fulvic acid (FA) and other humic substances. Aluminum salt coagulants are usually used in the water purification process of water plants. The aluminum content accounts for 29.7±13.3% of the dry weight of aluminum sludge. The aluminum concentration in the production sludge is as high as 250-400 mg / L. Therefore, the recovery of aluminum salts in sludge has multiple functions such as resource utilization, sludge harmlessness, and sludge reduction.

[0004] Based on the amphoteric characteristics of aluminum salts that are soluble in both acid and alkali, sulfuric acid and sodium hydroxide can be used to dissolve aluminum in sludge, which are the currently commonly used acidification and alkalization methods. Relatively speaking, the acidification method has a higher extraction efficiency for aluminum. Studies have found that when aluminum is extracted by acidification, fulvic acid (FA) and trace heavy metals are present in the dissolution solution. The dissolved aluminum and FA are usually stably present in the acidified dissolution solution in the form of Al-NOM complexes. Direct reuse in the water purification system will produce the risk of increased disinfection by-products. Therefore, it is necessary to separate the dissolved aluminum from organic matter and trace heavy metals, that is, to purify aluminum. The complex characteristics of aluminum and organic matter make the current conventional separation methods such as membrane separation, ozone oxidation technology, and XAD-8 macroporous resin adsorption unable to be applied to the complete separation of fulvic acid and aluminum, or the adsorption capacity is limited.

[0005] Since NOM is closely related to the production of disinfection by-products during the disinfection of tap water, excessive NOM content will limit the safety of the on-site use of aluminum recovery liquid in the water plant, resulting in the current use of aluminum salts recovered during aluminum sludge treatment being limited to sewage treatment plants. Defects such as poor economic efficiency of off-site reuse and mismatched treatment systems have, to a certain extent, limited the feasibility and enthusiasm of aluminum salt resource utilization in aluminum sludge.

[0006] Therefore, it is necessary to develop a method to separate aluminum from organic matter in the acidified solution, purify the dissolved aluminum and reuse it directly in situ as a coagulant in the tap water production process. Summary of the invention

[0007] In order to solve the problem of separation of dissolved aluminum and organic matter in the process of aluminum sludge treatment, the purpose of the present invention is to provide a method for purifying acid-dissolved aluminum in aluminum sludge based on cationic resin, and the efficient dissolution of aluminum in the sludge and the decomplexation of Al-NOM complex are achieved by adjusting the pH of the acidified solution, the reaction time and other conditions, the introduction of strong acid hydrogen type cationic exchange resin, based on the preferential adsorption of aluminum by the active groups on the resin, the separation of aluminum and organic matter and heavy metal ions coexisting in the acid leaching supernatant is achieved, the elution exchange column is used to achieve the regeneration of the resin and the collection of the purified aluminum solution, and the systematic aluminum sludge treatment for the purification of aluminum salts in water supply sludge is achieved, so as to provide technical support for the recovery of aluminum salts for in-situ reuse in the tap water generation process.

[0008] The present invention is achieved through the following technical solutions.

[0009] One aspect of the present invention provides a method for purifying aluminum in aluminum sludge by acid dissolution based on cationic resin, comprising:

[0010] The aluminum sludge in the sedimentation tank is left to stand until the mud and water are separated, and the supernatant is removed to obtain concentrated sludge;

[0011] The pH of the concentrated sludge obtained is adjusted to acidic, the acid-dissolved sludge is subjected to static sedimentation and separation, and the acid leaching supernatant is collected after static sedimentation;

[0012] The ion exchange resin of the strong acid hydrogen type cation exchange column is cleaned alternately by acid-base-acid, then rinsed to neutrality and filled into the column, and the acid leaching supernatant is passed through the column to perform ion exchange to complete the adsorption and collection of the dissolved aluminum;

[0013] After aluminum adsorption is saturated, the ion exchange column is eluted with an acid solution to backwash the resin column to remove aluminum, thereby obtaining a purified aluminum extract and simultaneously regenerating the aluminum adsorption capacity of the resin; the cationic resin is completely regenerated with an acid solution to remove heavy metal pollutants accumulated in the resin.

[0014] Preferably, concentrated sulfuric acid is used to adjust the pH of the concentrated sludge to 2.0 and stirred for 1 to 2 hours.

[0015] Preferably, the acid-dissolved sludge is subjected to static sedimentation separation for 2 to 3 hours.

[0016] Preferably, the ion exchange resin of the strong acid hydrogen type cation exchange column is cleaned by alternately cleaning the resin with a mass concentration of 1M sulfuric acid solution → deionized water, 1M sodium hydroxide solution → deionized water, and 1M sulfuric acid solution → deionized water, and then soaking in 1M H2SO4 solution for 24 to 48 hours.

[0017] Preferably, the cleaned hydrogen-type cation exchange resin is rinsed with deionized water until the pH value is 6-7 and then filled into the column.

[0018] Preferably, the acid leaching supernatant passes through the column in a bottom-in-top-out continuous flow manner with a flow rate of 0.12 to 0.15 BV / min.

[0019] Preferably, after aluminum adsorption is saturated, the ion exchange column is cleaned with deionized water, and after being emptied, the resin column is backwashed with 1.1M sulfuric acid backwash solution at a flow rate of 0.02 to 0.03 BV / min to remove aluminum.

[0020] Preferably, the cationic resin is completely cleaned with 1.8 M sulfuric acid solution at 80-90° C. and stirred for 1-2 hours to elute the heavy metal pollutants accumulated in the resin.

[0021] The present invention adopts the above technical solution, which has the following beneficial effects:

[0022] 1. The present invention can achieve efficient dissolution of Al in sludge and decomplexation of Al-NOM by adjusting the pH of the sludge after centrifugation with concentrated sulfuric acid. The appropriate pH can dissolve the aluminum produced by the flocculant polyaluminium chloride in the sludge without destroying the aluminum component in the original water sludge; the sedimentation performance and dehydration performance of the sludge after acid dissolution are increased, which is beneficial to energy conservation and emission reduction.

[0023] 2. The present invention utilizes a strong acid hydrogen type cation exchange column to perform acid-base-acid alternating cleaning on the ion exchange resin, then rinses it to neutrality and fills the column to separate the acidified liquid aluminum and organic matter. The maximum exchange capacity of the resin is achieved by acid-base-acid alternating cleaning; the sludge acid extract passes through the hydrogen type cation exchange column to achieve a local pH reduction, the complex structure of aluminum and organic matter is destroyed, the aluminum ions are retained by the ion exchange column, and the organic matter flows out of the exchange column, thereby achieving effective separation of aluminum and organic matter.

[0024] 3. Use elution exchange columns to achieve resin regeneration and aluminum liquid collection, and realize systematic aluminum sludge treatment for purification of aluminum salts in water sludge.

[0025] 4. Compared with the direct use of sludge acidified liquid, the present application realizes the method for purifying aluminum in the acidified liquid by using a strong hydrogen type cation exchange resin. The operation steps are simple, the dissolution and leaching efficiency of aluminum is high, the resin regeneration is good, and the complexation problem between aluminum and organic matter in the sludge acid solution is solved, so that the aluminum in the leached liquid is easy to purify in the water supply treatment. In addition, since the present method uses sludge acid leaching liquid to purify aluminum, the sedimentation performance and dehydration performance of the sludge are greatly improved after sulfuric acid treatment, which is convenient for the subsequent treatment of the sludge, thereby achieving the effect of energy saving and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute an improper limitation of the present invention. In the drawings:

[0027] Figure 1 The present invention is a flow chart of the method for purifying aluminum in aluminum sludge;

[0028] Figure 2 A diagram showing the construction of a cation exchange resin column in a specific embodiment of the present invention;

[0029] Figure 3 Graph showing the adsorption capacity of the resin for Al and the elution efficiency in specific embodiment 6 of the present invention;

[0030] Figure 4 This is a comparison chart of the flocculation effect of Al recovery by the present invention and commercial flocculant (PAC). DETAILED DESCRIPTION

[0031] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The exemplary embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0032] like Figure 1 As shown, the embodiment of the present invention provides a method for purifying aluminum by acid dissolution in aluminum sludge based on cationic resin, comprising the following steps:

[0033] S1: Take a mud sample from a horizontal flow sedimentation tank as a typical aluminum sludge, let it stand for 24 hours until the mud and water are separated, and remove the supernatant to obtain a thick, wall-hanging concentrated sludge.

[0034] S2: The concentrated sludge in the thick wall-hanging state obtained in step 1 is adjusted to pH = 2.0 with concentrated sulfuric acid, and stirred for 1 to 2 hours to dissolve the aluminum in the sludge. The acid-dissolved sludge is allowed to stand for 2 to 3 hours to separate the mud and water, and then the acid leaching supernatant is collected.

[0035] S3: Use a strong acid hydrogen type cation exchange resin with a diameter of D = 1.0 cm and a height of H = 10 cm, see Figure 2As shown, Amberlite 732 strong acid hydrogen type cation exchange resin is washed with pure water until it is colorless: the resin is soaked and washed with 3BV of 1M H2SO4, and then rinsed with deionized water; then soaked and washed with 3BV of 1MNaOH, and then rinsed with deionized water; finally, the resin is soaked and washed with 3BV of 1M H2SO4, and then rinsed with deionized water to ensure that the resin is completely converted into hydrogen type resin, and then soaked in 1M H2SO4 solution for 24 to 48 hours for storage.

[0036] Take 5g of the washed hydrogen-type resin and rinse it with deionized water until the pH is 6-7 and fill the column. The acid leaching supernatant is passed through the cationic resin column in the form of bottom-in and top-out continuous flow for ion exchange to achieve the separation of aluminum from the coexisting organic matter and heavy metals in the acid leaching supernatant. During the exchange process, the peristaltic pump flow rate is controlled to 0.12-0.15BV / min.

[0037] For the coexisting metal ions in the acid leaching supernatant, since aluminum ions have a higher binding energy with the active sulfonic acid groups on the cation exchange resin, Al is at the highest level of resin adsorption capacity in the coexistence system, so the resin exchange can be used to separate the recovered aluminum from trace heavy metals, fundamentally solving the problem of heavy metal enrichment in the aluminum reuse process. And after passing through the cation exchange resin, the concentration of organic matter and other metal ions in the eluent meets the requirements of water treatment agents for water supply plants.

[0038] S4: After the exchange is completed, the cation exchange column is cleaned with 3BV of deionized water, and after being emptied, the resin column is backwashed with 6.5BV of 1.1MH2SO4 backwash solution at a flow rate of 0.02-0.03BV / min to obtain a purified aluminum extract and achieve regeneration of the resin aluminum adsorption capacity.

[0039] Specifically, after the acid leaching solution passes through the resin column, aluminum and organic matter can be effectively separated. The organic matter passes through the resin column, and aluminum is retained on the resin. A purified aluminum extract can be obtained by reverse elution with sulfuric acid.

[0040] Strong hydrogen type cationic resin is completely regenerated. The resin structure is relatively stable and can be used multiple times. When the resin adsorption performance decreases, it can be regenerated by sulfuric acid to restore the adsorption of Al and elute the heavy metal pollutants accumulated in the resin.

[0041] The present invention is further described in detail below through different embodiments.

[0042] Example 1

[0043] S1: Take a mud sample from a horizontal flow sedimentation tank as a typical aluminum sludge, let it stand for 24 hours until the mud and water are separated, and remove the upper layer of clear water to obtain concentrated sludge in a wall-hanging state.

[0044] S2: The concentrated sludge obtained in step S1 was adjusted to pH = 2 with concentrated sulfuric acid, stirred for 2 hours to dissolve Al in the sludge, and allowed to stand for 2 hours after acid dissolution, and the acid leaching supernatant was collected, and the aluminum ion concentration was 150 mg / L, COM Mn It is 90mg / L.

[0045] S3: Take 5g of the washed resin and rinse it with deionized water until the pH is 6.5, then fill the column, and let the acid-leached supernatant pass through the resin column from bottom to top. The flow rate during the exchange process is controlled at 0.12 BV / min.

[0046] S4: After the exchange is completed, the exchange column is cleaned with 3BV of deionized water. After emptying, the resin column is eluted from top to bottom with 6.5BV of 1.1M H2SO4 eluent at a flow rate of 0.02BV / min to obtain a purified aluminum extract.

[0047] Example 2

[0048] S1: Take a mud sample from the horizontal flow sedimentation tank as a typical aluminum sludge, let it stand for 24 hours until the mud and water are separated, and remove the upper layer of clear water to obtain concentrated sludge in a wall-hanging state.

[0049] S2: The concentrated sludge obtained in step S1 was adjusted to pH = 2 with concentrated sulfuric acid, stirred for 1.5 hours to dissolve Al in the sludge, and then allowed to stand for 3 hours to collect the acid leaching supernatant. The aluminum ion concentration was 121 mg / L, COM Mn It is 60mg / L.

[0050] S3: Take 5g of the washed resin and rinse it with deionized water until the pH is 6 and fill the column; the acid leaching supernatant in step S2 passes through the resin column from bottom to top. The flow rate during the exchange process is controlled at 0.13BV / min.

[0051] S4: After the exchange is completed, the exchange column is cleaned with 3BV of deionized water. After emptying, the resin column is eluted from top to bottom with 6.5BV of 1.1M H2SO4 eluent at a flow rate of 0.03BV / min to obtain a purified aluminum extract.

[0052] Example 3

[0053] S1: Take a mud sample from a horizontal flow sedimentation tank as a typical aluminum sludge, let it stand for 24 hours until the mud and water are separated, and remove the upper layer of clear water to obtain concentrated sludge in a wall-hanging state.

[0054] S2: The concentrated sludge obtained in step S1 was adjusted to pH = 2 with concentrated sulfuric acid, stirred for 1 hour to dissolve Al in the sludge, and then allowed to stand for 2.5 hours to collect the acid leaching supernatant. The aluminum ion concentration was 425 mg / L, COM Mn It is 120mg / L.

[0055] S3: Take 5g of the washed resin and rinse it with deionized water until the pH is 7 and fill the column; the acid leaching supernatant in step S2 passes from bottom to top. During the exchange process, the peristaltic pump flow rate is controlled at 0.14BV / min.

[0056] S4: After the exchange is completed, the exchange column is cleaned with 3BV of deionized water. After emptying, the resin column is eluted from top to bottom with 6.5BV of 1.1M H2SO4 eluent at a flow rate of 0.02BV / min to obtain a purified aluminum extract.

[0057] Example 4

[0058] S1: Take the mud sample from the horizontal flow sedimentation tank as a typical aluminum sludge, let it stand for 24 hours until the mud and water are separated, and remove the upper layer of clear water to obtain concentrated sludge in a wall-hanging state.

[0059] S2: The concentrated sludge obtained in step S1 was adjusted to pH = 2 with concentrated sulfuric acid, stirred for 1.5 hours to dissolve Al in the sludge, and then allowed to stand for 2 hours to collect the acid leaching supernatant. The aluminum ion concentration was 314 mg / L, COM Mn It is 105mg / L.

[0060] S3: Take 5g of the washed resin and rinse it with deionized water until the pH is 6 and fill the column; the acid leaching supernatant in step S2 passes through the resin column from bottom to top. The flow rate during the exchange process is controlled at 0.14BV / min.

[0061] S4: After the exchange is completed, the exchange column is cleaned with 3BV of deionized water. After emptying, the resin column is eluted from top to bottom with 6.5BV of 1.1M H2SO4 eluent at a flow rate of 0.03BV / min to obtain a purified aluminum extract.

[0062] Example 5

[0063] S1: Take a mud sample from the horizontal flow sedimentation tank as a typical aluminum sludge, let it stand for 24 hours until the mud and water are separated, and remove the upper layer of clear water to obtain concentrated sludge in a wall-hanging state.

[0064] S2: The concentrated sludge obtained in step S1 was adjusted to pH = 2 with concentrated sulfuric acid, stirred for 1 hour to dissolve Al in the sludge, and then left to stand for 1 hour to collect the acid leaching supernatant. The aluminum ion concentration was 413 mg / L, COM Mn It is 110mg / L.

[0065] S3: Take 5g of the washed resin and rinse it with deionized water until the pH is 7 and fill the column; the acid leaching supernatant in step S2 passes through the resin column from bottom to top. The flow rate during the exchange process is controlled at 0.15BV / min.

[0066] S4: After the exchange is completed, the exchange column is cleaned with 3BV of deionized water. After emptying, the resin column is eluted from top to bottom with 6.5BV of 1.1M H2SO4 eluent at a flow rate of 0.02BV / min to obtain a purified aluminum extract.

[0067] The specific liquid sample conditions and aluminum purification and recovery effects in the above 5 embodiments are shown in Table 1.

[0068] Table 1 Different concentrations of Al and COD Mn Purification and recovery effects after strong acid cation exchange resin

[0069]

[0070] According to Examples 1-5, the effects of strong acid hydrogen type cation exchange resin on the concentration of each aluminum ion and COD Mn The influent has a good treatment effect, and its aluminum ion adsorption efficiency exceeds 97.8%, COD Mn The interception rate is less than 3.64%, and it has a wide spectrum of adaptability to the high adsorption rate of aluminum ions and the high pass rate of organic matter. The aluminum recovery efficiency in the embodiment is high. After passing through the resin column, the removal efficiency of the total organic matter in the de-elution liquid reaches 99.98%, indicating that aluminum and organic matter are separated after the acid leaching liquid passes through the resin column.

[0071] Example 6

[0072] Compared with Examples 1-5, the difference is that in Example 6, the resin column undergoes multiple cycles of "supernatant liquid passing through the column - resin column regeneration", and the resin column is completely regenerated after the cycle. Mn Keep it at the same concentration.

[0073] S1: Take a mud sample from a horizontal flow sedimentation tank as a typical aluminum sludge, let it stand for 24 hours until the mud and water are separated, and remove the upper layer of clear water to obtain concentrated sludge in a wall-hanging state.

[0074] S2: The concentrated sludge obtained in step S1 was adjusted to pH = 2 with concentrated sulfuric acid, stirred for 2 hours to dissolve Al in the sludge, and the acid leaching supernatant was collected after standing for 2 hours. The aluminum ion concentration was 580 mg / L, COM Mn It is 136mg / L.

[0075] S3: Take 5g of the washed resin and rinse it with deionized water until the pH is 6 and fill the column; take the acid leaching supernatant in step S2 and pass it through the resin column from bottom to top. The flow rate during the exchange process is controlled at 0.13BV / min.

[0076] S4: After the exchange is completed, the exchange column is cleaned with 3BV of deionized water, and after being emptied, the resin column is eluted with 6.5BV of 1.1M H2SO4 eluent at a flow rate of 0.02BV / min to obtain a purified aluminum extract.

[0077] S5: The acid leaching supernatant obtained in step S2 is passed through the regenerated resin column from bottom to top at a flow rate of 0.13 BV / min. After the exchange is completed, the resin is regenerated in step S4; after 5 cycles of "supernatant column-resin regeneration", the resin is completely regenerated with 6.5 BV 1.1M sulfuric acid at 80°C for 1 hour. The structural stability of the resin is examined, and the completely regenerated resin is subjected to steps S3-S4 to test the change in the resin's adsorption efficiency for aluminum.

[0078] The exchange capacity and elution efficiency of the strong acid hydrogen type cationic resin for aluminum obtained in Example 6 are as follows: Figure 3 As shown in the figure, after 5 cycles of testing, the adsorption capacity of the resin for Al is greater than 24 mg / g, and the aluminum recovery efficiency is relatively high. Using the resin column after elution and exchange with 1.1M sulfuric acid, the elution of aluminum can reach more than 98.3%, and the aluminum recovery efficiency reaches 97.8%. After thorough regeneration, the resin column still maintains a high retention rate and recovery efficiency for aluminum in the acid leaching solution, indicating that the hydrogen-type cationic resin has good stability in the process of recovering aluminum.

[0079] Comparison of the flocculation effect of the aluminum recovery in the present invention and the commercial flocculant PAC ( Figure 4 ), the optimal coagulant dosage is selected with NTU around 1.00 as the control standard. The actual investigation of this test shows that the optimal dosage of PAC is about 12 mg / L, and the aluminum dosage is about 1.91 mg / L. At this dosage, the effluent NTU is controlled at 0.90, TOC is about 2.10 mg / L, and pH is 7.65; compared with the coagulation results of aluminum recovery under this aluminum dosage, the effluent NTU is about 1.05, TOC is about 2.37 mg / L, and pH is about 7.20. It can be considered that under the optimal working conditions, the coagulation efficiency of aluminum leachate is close to that of PAC. From the perspective of TOC, it meets the safety requirements, and the aluminum leachate is feasible for reuse as a coagulant.

[0080] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A method for purifying aluminum by acid dissolution in aluminum sludge based on cationic resin, characterized in that: include: The sludge in the sedimentation tank is left to stand until the mud and water are separated, and the supernatant is removed to obtain concentrated sludge; The pH of the concentrated sludge obtained is adjusted to acidic to dissolve aluminum, the sludge after acid dissolution is statically precipitated and separated, and the acid leaching supernatant is collected after static precipitation; The ion exchange resin of the strong acid hydrogen type cation exchange column is cleaned alternately by acid-base-acid, then rinsed to neutrality and filled into the column, and the acid leaching supernatant is passed through the column to perform ion exchange to complete the adsorption and collection of the dissolved aluminum; After the aluminum adsorption is saturated, the cation exchange column is eluted with an acid solution to backwash the resin column to remove the aluminum, thereby obtaining a purified aluminum extract and simultaneously achieving the regeneration of the aluminum adsorption capacity of the resin.

2. The method for purifying aluminum by acid dissolution in aluminum sludge based on cationic resin according to claim 1, characterized in that: Use concentrated sulfuric acid to adjust the concentrated sludge pH to 2.0 and stir for 1 to 2 hours.

3. The method for purifying aluminum by acid dissolution in aluminum sludge based on cationic resin according to claim 1, characterized in that: The acid-dissolved sludge is allowed to settle and separate for 2 to 3 hours.

4. The method for purifying aluminum by acid dissolution in aluminum sludge based on cationic resin according to claim 1, characterized in that: To clean the ion exchange resin of the strong acid hydrogen type cation exchange column, use 1M sulfuric acid solution → deionized water, 1M sodium hydroxide solution → deionized water, 1M sulfuric acid solution → deionized water to clean the resin alternately, and then soak in 1MH2SO4 solution for 24 to 48 hours.

5. The method for purifying aluminum by acid dissolution in aluminum sludge based on cationic resin according to claim 1, characterized in that: The cleaned hydrogen-type cation exchange resin is rinsed with deionized water until the pH is 6-7 and then filled into the column.

6. The method for purifying aluminum by acid dissolution in aluminum sludge based on cationic resin according to claim 1, characterized in that: The acid leaching supernatant passes through the column in a bottom-in-top-out continuous flow manner with a flow rate of 0.12-0.15 BV / min.

7. The method for purifying aluminum by acid dissolution in aluminum sludge based on cationic resin according to claim 1, characterized in that: After aluminum adsorption is saturated, the ion exchange column is cleaned with deionized water, and after being emptied, the resin column is backwashed with 1.1M sulfuric acid backwash solution at a flow rate of 0.02-0.03BV / min to remove aluminum.

8. The method for purifying aluminum by acid dissolution in aluminum sludge based on cationic resin according to claim 1, characterized in that: The cationic resin is completely cleaned by using a 1.8 M sulfuric acid solution at 80 to 90° C. with stirring for 1 to 2 hours, and the heavy metal pollutants accumulated in the resin are eluted.

9. A method for purifying aluminum by acid dissolution in aluminum sludge based on cationic resin as described in any one of claims 1 to 8, and its application in water purification in a waterworks.

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