A method for treating anodizing wastewater of a nickel-tin-containing aluminum alloy photovoltaic profile

Abstract

The present application relates to a kind of nickel tin containing aluminum alloy photovoltaic section anodizing wastewater processing method, comprising S1 nickel tin containing anodizing wastewater is filtered by clay layer, and filtrate is collected;S2 the filtrate collected in S1, by γ-alumina layer is filtered, and filtrate is collected;S3 the filtrate collected in S2, with polyaluminium chloride is mixed, after reaction, mixed liquor is collected, and next step is carried out;S4 the mixed liquor collected in S3, with polyacrylamide is mixed, after reaction, filtration, and filtrate is collected;S5 the filtrate collected in S4, by anion exchange resin is adsorbed and reacted, and obtainable wastewater is discharged, and the anion exchange resin is the polymer of styrene and divinylbenzene and vinyl-N, N, N-trimethyl benzyl ammonium chloride.It is suitable for the sewage treatment after the anodization of aluminum profile, and the content of nickel, tin and aluminum in sewage can reach the requirement of table 2 of "Electroplating Pollutant Discharge Standard" GB21900-2008.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology for aluminum alloy photovoltaic profiles, and in particular to a method for treating anodizing wastewater from nickel-tin aluminum alloy photovoltaic profiles. Background Technology

[0002] Aluminum profiles used in the photovoltaic field are generally 6-series aluminum alloys, such as 6005, 6061, and 6063. These alloys themselves do not possess special corrosion resistance. Because the environments in which photovoltaic profiles are used place high demands on the surface of aluminum alloys, these 6-series alloys are often anodized to increase their corrosion resistance and extend their service life under certain extreme climates.

[0003] The core of aluminum profile anodizing is to pass electricity through the aluminum profile in a sulfuric acid bath, forming a dense anodic oxide film on the surface. Then, through coloring and sealing baths, the aluminum profile surface acquires a specific color and improved corrosion and weather resistance. Typically, the total nickel ion content in the coloring and sealing baths is 50 g / L, and the tin ion content is 40 g / L. When the mixed chemicals in the baths become ineffective due to repeated use, the bath solution is replaced, resulting in a significant amount of waste liquid.

[0004] Wastewater from aluminum profile anodizing requires centralized treatment, primarily to remove heavy metals. These heavy metals are among the most dangerous pollutants in wastewater frequently discharged into the environment, causing serious adverse effects on human life and the ecological environment. For example, nickel and tin can enter the human food chain through seepage into groundwater and absorption by plants, causing various health problems, including eczema and allergies, lung cancer and pulmonary fibrosis, chronic bronchitis and sinusitis, heart and liver dysfunction, skin irritation, and headaches. After treatment, the tin and nickel content in the wastewater should meet the "Electroplating Pollutant Discharge Standard" GB21900-2008. Other pollutants, such as total aluminum and phosphates, should also meet the national "Integrated Wastewater Discharge Standard" GB 8978-1996 before discharge.

[0005] Currently, the common method for treating anodizing wastewater involves acid-base neutralization, followed by the addition of PAC (polyaluminum chloride) and then PAM (polyacrylamide) for flocculation. However, this treatment method results in a pale blue-green wastewater, and testing reveals that nickel and tin levels have not been reduced to the maximum limits stipulated by national standards. The levels of other pollutants also do not fully meet the national emission standards. The standard emission limits for nickel and tin specified in Table 2 of the "Electroplating Pollutant Emission Standard" GB21900-2008 are ≤0.5 mg / L. Summary of the Invention

[0006] The purpose of this invention is to overcome the problem of substandard pollutants in existing anodizing wastewater treatment methods and to provide a method for treating anodizing wastewater from nickel-tin aluminum alloy photovoltaic profiles.

[0007] The specific plan is as follows:

[0008] A method for treating nickel-tin-containing anodizing wastewater includes the following steps:

[0009] S1 filters nickel-tin-containing anodizing wastewater through a clay layer and collects the filtrate;

[0010] S2 filters the filtrate collected in S1 through a γ-alumina layer and collects the filtrate.

[0011] S3: The filtrate collected in S2 is mixed with polyaluminum chloride, and the mixture is collected after the reaction for the next step.

[0012] S4. The mixture collected in S3 is mixed with polyacrylamide, reacted, filtered, and the filtrate is collected.

[0013] S5 involves passing the filtrate collected in S4 through an anion exchange resin for adsorption to obtain dischargeable wastewater. The anion exchange resin is a polymer of styrene, divinylbenzene, and vinyl-N,N,N-trimethylphenylamine chloride.

[0014] Furthermore, the nickel-tin-containing anodizing wastewater mentioned in S1 originates from the wastewater generated during the anodizing, coloring, and sealing processes of aluminum profiles. After acid-base neutralization, the pH value is 6.5-7.5.

[0015] Furthermore, the nickel content in the nickel-tin-containing anodizing wastewater is 1-50 mg / L, preferably 1-10 mg / L; the tin content is 1-50 mg / L, preferably 1-10 mg / L.

[0016] Furthermore, in S1, the aluminum content in the nickel-tin-containing anodizing wastewater is 1-50 mg / L, preferably 1-10 mg / L; the phosphate content is 0.1-20 mg / L; the total phosphorus content is 0.1-20 mg / L; the total nitrogen content is 1-100 mg / L; the suspended solids content is 1-100 mg / L; and the chemical oxygen demand is 90-200 mg / L.

[0017] Furthermore, the clay mentioned in S1 is 100-500 mesh clay produced by Lingshou County Huizi Mineral Products Co., Ltd., preferably 300 mesh;

[0018] Preferably, the amount of clay layer used is 1-3 kg / ton of wastewater, more preferably 2 kg / ton of wastewater.

[0019] Furthermore, the preparation method of γ-alumina described in S2 is as follows: urea, aluminum nitrate and water are mixed and reacted in a high-pressure reactor at 180-220℃ for 1-3 hours. After cooling to room temperature, a white precipitate is obtained by centrifugation. The precipitate is washed with distilled water and dried to obtain a white powder. The white powder is then placed in a furnace at 900-1000℃ and calcined for 3-5 hours.

[0020] Preferably, the amount of γ-alumina used is 1-3 kg / ton of wastewater, more preferably 2 kg / ton of wastewater.

[0021] Furthermore, the dosage of polyaluminum chloride in S3 is 0.2-1.0 kg / ton of wastewater, preferably 0.5-0.6 kg / ton of wastewater; the treatment time is 15-30 h.

[0022] Furthermore, the amount of polyacrylamide used in S4 is 0.03-0.1 kg / ton of wastewater, preferably 0.05-0.06 kg / ton of wastewater; the treatment time is 15-30 h.

[0023] Furthermore, the anion exchange resin described in S5 is soaked in saturated brine before use, followed by alkali soaking and acid soaking, and finally rinsed until neutral before use.

[0024] Preferably, the flow rate of wastewater in the anion exchange resin is (2-5)*10. -2 m / s.

[0025] Furthermore, in S5, the content of nickel in the dischargeable wastewater is less than or equal to 0.1 mg / L, the content of tin is less than or equal to 0.1 mg / L, the content of aluminum is less than or equal to 0.5 mg / L; the content of phosphate is less than or equal to 0.5 mg / L, the content of total phosphorus is less than or equal to 1.0 mg / L, the content of total nitrogen is less than or equal to 10 mg / L, the content of suspended solids is less than or equal to 10 mg / L, and the chemical oxygen demand is less than or equal to 10 mg / L.

[0026] Beneficial effects: The method for treating anodizing wastewater from aluminum alloy photovoltaic profiles containing nickel and tin provided by this invention is applicable to wastewater treatment after anodizing of aluminum profiles, including wastewater generated from processes such as anodizing, coloring, and sealing. The wastewater has a high content of nickel and tin, and also contains a certain amount of aluminum. Traditional PAC+PAM treatment methods are difficult to make the nickel, tin, and aluminum content in the wastewater meet the requirements of Table 2 of the "Electroplating Pollutant Discharge Standard" GB21900-2008.

[0027] The method provided by this invention, based on the traditional PAC+PAM treatment method, uses clay to significantly reduce the chemical oxygen demand of wastewater, and combines γ-alumina and anion exchange resin to make the content of nickel, tin and aluminum in wastewater meet the requirements of Table 2 of the "Electroplating Pollutant Discharge Standard" GB21900-2008, while the total nitrogen and total phosphorus content meet the discharge requirements. Attached Figure Description

[0028] To more clearly illustrate the technical solution of the present invention, the accompanying drawings will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0029] Figure 1 This is a schematic diagram of the process flow provided in one embodiment 1 of the present invention. Detailed Implementation

[0030] Preferred embodiments of the present invention will now be described in more detail. While preferred embodiments of the present invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products. In the following embodiments, unless otherwise specified, "%" refers to weight percentage.

[0031] The wastewater used in this embodiment is anodizing wastewater from nickel-tin aluminum alloy photovoltaic profiles, which has been neutralized by acid and alkali. It originates from the aluminum profile anodizing process, where the aluminum profiles are electrolyzed in a sulfuric acid bath to form a dense anodic oxide film on their surface. This is followed by coloring and sealing treatments. The wastewater generated during these processes is collected and neutralized to pH 7 before being used as nickel-tin anodizing wastewater. Its main indicators are shown in Table 1. It should be noted that the method provided by this invention is not limited to anodizing wastewater from aluminum alloy photovoltaic profiles; it is also applicable to anodizing wastewater with similar composition.

[0032] Table 1. Composition of Nickel-Tin Containing Anodizing Wastewater (mg / L)

[0033] Element concentration nickel 3.20 tin 2.90 aluminum 6.50 phosphate 1.20 Total phosphorus 2.80 Total nitrogen 27 ammonia nitrogen 19 suspended matter 59 Fluorides 12 Chemical oxygen demand (CODcr) 98

[0034] Example 1

[0035] Process flow as follows Figure 1 As shown, 20 tons of wastewater are first passed through two parallel filter tanks containing 20 kg of clay. The clay is reused daily after being washed with clean water. The clay originates from Lingshou County Huizi Mineral Products Co., Ltd., and has a particle size of 300 mesh.

[0036] After the wastewater is filtered using clay as the filter material, the collected filtrate is sent to two parallel filter tanks containing 20 kg of γ-alumina in each tank. The γ-alumina can be reused daily by washing with clean water after use. This γ-alumina has a high specific surface area, exhibiting a nano-adsorption effect. The synthesis method of γ-alumina is as follows: 18 parts by weight of high-purity aluminum nitrate are dissolved in 100 parts by weight of distilled water to obtain an aluminum nitrate solution; 6 parts by weight of urea are dissolved in 25 parts by weight of distilled water, and then the prepared aluminum nitrate solution is added. The mixture is placed in a high-pressure reactor and reacted at 200°C for 2 hours. After cooling to room temperature, centrifugation yields a white precipitate, which is washed with distilled water and dried at 70°C for 1 hour to obtain a white powder. The white powder is then placed in a furnace at 950°C and kept warm for 4 hours to obtain the final product.

[0037] After being treated by γ-alumina adsorption filtration, the wastewater is fed into wastewater tank 1. Wastewater tank 1 is pre-filled with 1 ton of clean water and 10 kg of polyaluminum chloride (PAC). After it is completely dissolved, the wastewater treated by γ-alumina adsorption is pumped into wastewater tank 1. After being treated by PAC for 24 hours, it is then sent to wastewater tank 2.

[0038] Wastewater tank 2 is pre-filled with 1 ton of clean water. 1 kg of polyacrylamide (PAM) is added and completely dissolved before the wastewater is pumped into wastewater tank 2. To enhance the reaction effect, aeration is added to the bottom of wastewater tank 2. After reacting for 24 hours, the mixture is allowed to stand. Then, the generated sludge is discharged from the filter press for further treatment, and the resulting filtrate is sent to wastewater tank 3.

[0039] In wastewater tank 3, two sets of anion exchange resin devices are installed in parallel. The resin used in the anion exchange resin devices is AMBERLITE IRA-400 anion exchange resin, which contains a polymer of styrene, divinylbenzene, and vinyl-N,N,N-trimethylphenylamine chloride. It is a strongly basic type I anion exchange resin. Before use, the resin is first soaked in saturated brine, with the amount being approximately twice the volume of the resin to be treated, for 18-20 hours. Then, the brine is drained, and the resin is rinsed with clean water until the effluent is no longer yellow. Next, a 2wt%-4wt% NaOH aqueous solution is used, with the same amount as above, and the resin is soaked in it for 2-4 hours (or rinsed at a low flow rate). After draining the alkali solution, the resin is rinsed until the effluent is nearly neutral. Finally, a 5wt% HCl solution is used, with the same amount as above, and the resin is soaked for 4-8 hours. After draining the acid solution, the resin is rinsed with clean water until it is neutral and ready for use. After one month of use, the resin in the above-mentioned anion exchange resin device needs to be eluted with an 8wt% sodium chloride solution before it can be used again.

[0040] In wastewater tank 3, two parallel resin filtration devices treat the wastewater through resin adsorption. The total flow rate of the two resin filtration devices is 4 * 10⁻⁶. -2 The flow rate is m / s, and after resin adsorption, the wastewater can meet the discharge standards. The main indicators are shown in Table 2.

[0041] Table 2. Test results (mg / L) after wastewater treatment.

[0042] Element Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 nickel 0.1 0.1 0.1 0.1 2.5 0.5 0.2 tin 0.1 0.1 0.1 0.1 2.2 0.6 0.2 aluminum 0.5 0.4 0.5 0.5 5.9 2.9 1.5 phosphate 0.4 0.5 0.4 0.4 1 0.8 0.5 Total phosphorus 0.6 0.5 0.5 0.6 1.5 1.1 0.8 Total nitrogen 10 9 7 3 20 15 18 ammonia nitrogen 8 8 8 2 18 16 13 suspended matter 6 5 6 4 55 26 38 Fluorides 5 5 4 5 11 11 8 Chemical oxygen demand (CODcr) 10 10 4 8 90 76 50

[0043] Example 2

[0044] First, 20 tons of wastewater are passed through two parallel filter tanks containing 20 kg of clay. The clay is washed daily with clean water and can be reused. The clay, sourced from Lingshou County Huizi Mineral Products Co., Ltd., has a particle size of 200 mesh.

[0045] After the wastewater is filtered using clay as the filter media, the collected filtrate is sent to two parallel filter tanks containing 25 kg of γ-alumina in each tank. The γ-alumina can be reused daily by rinsing with clean water after use. This γ-alumina has a high specific surface area, exhibiting a nano-adsorption effect. The synthesis method of γ-alumina is the same as in Example 1.

[0046] After being treated by γ-alumina adsorption filtration, the wastewater is fed into wastewater tank 1. Wastewater tank 1 is pre-filled with 1 ton of clean water and 12 kg of polyaluminum chloride (PAC). After it is completely dissolved, the wastewater treated by γ-alumina adsorption is pumped into wastewater tank 1. After being treated by PAC for 24 hours, it is then sent to wastewater tank 2.

[0047] Wastewater tank 2 is pre-filled with 1 ton of clean water. 1.5 kg of polyacrylamide (PAM) is added and completely dissolved before the wastewater is pumped into wastewater tank 2. To enhance the reaction effect, aeration is added to the bottom of wastewater tank 2. After reacting for 24 hours, the mixture is allowed to stand. The resulting sludge is then discharged through a filter press for further treatment, and the filtrate is sent to wastewater tank 3.

[0048] In wastewater tank 3, two sets of anion exchange resin devices are installed in parallel. The resin used in the anion exchange resin devices is AMBERLITE IRA-400 anion exchange resin, which contains a polymer of styrene, divinylbenzene, and vinyl-N,N,N-trimethylphenylamine chloride, and is a strongly basic type I anion exchange resin. The treatment method for this resin before use is the same as in Example 1.

[0049] In wastewater tank 3, two parallel resin filtration devices treat the wastewater through resin adsorption. The total flow rate of the two resin filtration devices is 5*10. -2The flow rate is m / s, and after resin adsorption, the wastewater can meet the discharge standards. The main indicators are shown in Table 2.

[0050] Example 3

[0051] First, 20 tons of wastewater are passed through two parallel filter tanks containing 30 kg of clay each. The clay is washed daily with clean water and can be reused. The clay comes from Lingshou County Huizi Mineral Products Co., Ltd., and has a particle size of 300 mesh.

[0052] After the wastewater is filtered using clay as the filter media, the collected filtrate is sent to two parallel filter tanks containing 25 kg of γ-alumina in each tank. The γ-alumina can be reused daily by rinsing with clean water after use. This γ-alumina has a high specific surface area, exhibiting a nano-adsorption effect. The synthesis method of γ-alumina is the same as in Example 1.

[0053] After being treated by γ-alumina adsorption filtration, the wastewater is fed into wastewater tank 1. Wastewater tank 1 is pre-filled with 1 ton of clean water and 12 kg of polyaluminum chloride (PAC). After it is completely dissolved, the wastewater treated by γ-alumina adsorption is pumped into wastewater tank 1. After being treated by PAC for 24 hours, it is then sent to wastewater tank 2.

[0054] Wastewater tank 2 was initially filled with 5 tons of clean water. 1.5 kg of polyacrylamide (PAM) was added and completely dissolved before the wastewater was pumped into wastewater tank 2. To enhance the reaction effect, aeration was added to the bottom of wastewater tank 2. After reacting for 24 hours, the mixture was allowed to stand. The resulting sludge was then discharged through a filter press for further treatment, and the filtrate was sent to wastewater tank 3.

[0055] In wastewater tank 3, two sets of anion exchange resin devices are installed in parallel. The resin used in the anion exchange resin devices is AMBERLITE IRA-400 anion exchange resin, which contains a polymer of styrene, divinylbenzene, and vinyl-N,N,N-trimethylphenylamine chloride, and is a strongly basic type I anion exchange resin. The treatment method for this resin before use is the same as in Example 1.

[0056] In wastewater tank 3, two parallel resin filtration devices treat the wastewater through resin adsorption. The total flow rate of the two resin filtration devices is 3 * 10⁻⁶. -2 The flow rate is m / s, and after resin adsorption, the wastewater can meet the discharge standards. The main indicators are shown in Table 2.

[0057] Example 4

[0058] First, 20 tons of wastewater are passed through two parallel filter tanks containing 20 kg of clay. The clay is washed daily with clean water and can be reused. The clay, sourced from Lingshou County Huizi Mineral Products Co., Ltd., has a particle size of 200 mesh.

[0059] After the wastewater is filtered using clay as the filter media, the collected filtrate is sent to two parallel filter tanks containing 30 kg of γ-alumina in each tank. The γ-alumina can be reused daily by rinsing with clean water after use. This γ-alumina has a high specific surface area, exhibiting a nano-adsorption effect. The synthesis method of γ-alumina is the same as in Example 1.

[0060] After being treated by γ-alumina adsorption filtration, the wastewater is fed into wastewater tank 1. Wastewater tank 1 is pre-filled with 1 ton of clean water and 15 kg of polyaluminum chloride (PAC). After it is completely dissolved, the wastewater treated by γ-alumina adsorption is pumped into wastewater tank 1. After being treated by PAC for 24 hours, it is then sent to wastewater tank 2.

[0061] Wastewater tank 2 is pre-filled with 1 ton of clean water. 2 kg of polyacrylamide (PAM) is added and completely dissolved before the wastewater is pumped into wastewater tank 2. To enhance the reaction effect, aeration is added to the bottom of wastewater tank 2. After reacting for 24 hours, the mixture is allowed to stand. The resulting sludge is then discharged through a filter press for further treatment, and the filtrate is sent to wastewater tank 3.

[0062] In wastewater tank 3, two sets of anion exchange resin devices are installed in parallel. The resin used in the anion exchange resin devices is AMBERLITE IRA-400 anion exchange resin, which contains a polymer of styrene, divinylbenzene, and vinyl-N,N,N-trimethylphenylamine chloride, and is a strongly basic type I anion exchange resin. The treatment method for this resin before use is the same as in Example 1.

[0063] In wastewater tank 3, two parallel resin filtration devices treat the wastewater through resin adsorption. The total flow rate of the two resin filtration devices is 2*10. -2 The flow rate is m / s, and after resin adsorption, the wastewater can meet the discharge standards. The main indicators are shown in Table 2.

[0064] Comparative Example 1

[0065] The nickel-tin anodizing wastewater, after being neutralized by acid and alkali, is treated using the traditional method, namely PAC+PAM. Specifically, 20 tons of wastewater are first fed into wastewater tank 1. Wastewater tank 1 is pre-filled with 1 ton of clean water, and 10 kg of polyaluminum chloride (PAC) is added. After it is completely dissolved, the wastewater is pumped into wastewater tank 1. After being treated by PAC for a period of time, it is then sent to wastewater tank 2.

[0066] Wastewater tank 2 was initially filled with 1 ton of clean water. 1 kg of polyacrylamide (PAM) was added and completely dissolved before the wastewater was pumped into wastewater tank 2. To enhance the reaction effect, aeration was added to the bottom of wastewater tank 2. After the reaction was complete, the mixture was allowed to stand. Then, the generated sludge was discharged from the system for further treatment through a filter press. The test results of the obtained filtrate are shown in Table 2.

[0067] Comparative Example 2

[0068] The nickel-tin anodizing wastewater, after being neutralized by acid and alkali, was treated using a clay + PAC + PAM scheme. Specifically, 20 tons of wastewater were first passed through two parallel filter tanks containing 20 kg of clay each. The clay was reused daily after being washed with clean water. The clay, sourced from Lingshou County Huizi Mineral Products Co., Ltd., had a particle size of 300 mesh.

[0069] After the wastewater is filtered through clay as the filter material, the filtrate is collected and sent to wastewater tank 1. Wastewater tank 1 is pre-filled with 1 ton of clean water and 10 kg of polyaluminum chloride (PAC). After it is completely dissolved, the wastewater that has been treated by clay adsorption is pumped into wastewater tank 1. After being treated by PAC for a period of time, it is then sent to wastewater tank 2.

[0070] Wastewater tank 2 was initially filled with 1 ton of clean water. 1 kg of polyacrylamide (PAM) was added and completely dissolved before the wastewater was pumped into wastewater tank 2. To enhance the reaction effect, aeration was added to the bottom of wastewater tank 2. After the reaction was complete, the mixture was allowed to stand. Then, the generated sludge was discharged from the system for further treatment through a filter press. The test results of the obtained filtrate are shown in Table 2.

[0071] Comparative Example 3

[0072] The nickel-tin anodizing wastewater, after acid-base neutralization, was treated using a clay + γ-alumina + PAC + PAM process. Specifically, 20 tons of wastewater were first passed through two parallel filter tanks containing 20 kg of clay each. The clay was reused daily after being washed with clean water. The clay, sourced from Lingshou County Huizi Mineral Products Co., Ltd., had a particle size of 300 mesh.

[0073] After the wastewater is filtered using clay as the filter material, the collected filtrate is fed into two parallel filter tanks containing 20 kg of γ-alumina in each tank. The γ-alumina can be reused daily by rinsing with clean water after use. This γ-alumina has a high specific surface area, exhibiting a nano-adsorption effect. The synthesis method of γ-alumina is the same as in Example 1.

[0074] After being treated by γ-alumina adsorption, the wastewater is fed into wastewater tank 1. Wastewater tank 1 is pre-filled with 1 ton of clean water and 10 kg of polyaluminum chloride (PAC). After it is completely dissolved, the wastewater treated by γ-alumina adsorption is pumped into wastewater tank 1. After being treated by PAC for a period of time, it is then sent to wastewater tank 2.

[0075] Wastewater tank 2 was initially filled with 1 ton of clean water. 1 kg of polyacrylamide (PAM) was added and completely dissolved before the wastewater was pumped into wastewater tank 2. To enhance the reaction effect, aeration was added to the bottom of wastewater tank 2. After the reaction was complete, the mixture was allowed to stand. Then, the generated sludge was discharged from the system for further treatment through a filter press. The test results of the obtained filtrate are shown in Table 2.

[0076] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0077] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0078] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for treating nickel-tin containing anodizing wastewater, characterized by: It comprises the following steps: S1: filtering the nickel-tin-containing anodizing wastewater through a clay layer to collect the filtrate; the nickel-tin-containing anodizing wastewater contains 1-50 mg / L of nickel, 1-50 mg / L of tin, and 1-50 mg / L of aluminum; the clay layer is used in an amount of 1-3 kg per ton of wastewater; S2: filtering the filtrate collected in S1 through a gamma-alumina layer to collect the filtrate; the gamma-alumina is used in an amount of 1-3 kg per ton of wastewater; the gamma-alumina is prepared by mixing urea, aluminum nitrate, and water, and then reacting at 180-220 ℃ in a high-pressure reactor for 1-3 hours, cooling to room temperature, centrifuging to obtain white precipitate, washing with distilled water, drying to obtain white powder, and then calcining the white powder in a furnace at 900-1000 ℃ for 3-5 hours; S3: mixing the filtrate collected in S2 with polyaluminum chloride, and collecting the mixed solution after reaction for the next step; S4: mixing the mixed solution collected in S3 with polyacrylamide, filtering after reaction, and collecting the filtrate; S5 carries out adsorption reaction on the filtrate collected in S4 by anion exchange resin to obtain dischargeable wastewater, the anion exchange resin is a polymer of styrene and divinylbenzene and vinyl-N,N,N-trimethylbenzylammonium chloride; the flow rate of the wastewater in the anion exchange resin is (2-5) x 10 -2 m / s; The dischargeable wastewater contains not more than 0.1 mg / L of nickel, not more than 0.1 mg / L of tin, and not more than 0.5 mg / L of aluminum; The phosphate content is not more than 0.5 mg / L, the total phosphorus content is not more than 1.0 mg / L, the total nitrogen content is not more than 10 mg / L, the suspended solids content is not more than 10 mg / L, and the chemical oxygen demand is not more than 10 mg / L.

2. The method for treating nickel-tin-containing anodizing wastewater according to claim 1, characterized by: The nickel-tin-containing anodizing wastewater in S1 is derived from the sewage generated in the processes of anodizing, coloring, and sealing of aluminum profiles, and has a pH of 6.5-7.5 after acid-base neutralization.

3. The method for treating nickel-tin containing anodizing wastewater according to claim 2, characterized by: The nickel-tin-containing anodizing wastewater in S1 contains 1-10 mg / L of nickel and 1-10 mg / L of tin.

4. The method for treating nickel-tin-containing anodizing wastewater according to claim 3, characterized by: The nickel-tin-containing anodizing wastewater in S1 contains 1-10 mg / L of aluminum, 0.1-20 mg / L of phosphate, 0.1-20 mg / L of total phosphorus, 1-100 mg / L of total nitrogen, 1-100 mg / L of suspended solids, and 90-200 mg / L of chemical oxygen demand.

5. The method for treating nickel-tin containing anodizing wastewater according to any one of claims 1 to 4, characterized in that: The clay in S1 is 100-500 mesh clay.

6. The method for treating nickel-tin containing anodizing wastewater according to claim 5, characterized by: The clay in S1 is 300 mesh clay.

7. The method for treating nickel-tin containing anodizing wastewater according to claim 5, characterized by: The clay layer is used in an amount of 2 kg per ton of wastewater.

8. The method for treating nickel-tin containing anodizing wastewater according to any one of claims 1 to 4, characterized in that: The gamma-alumina in S2 is used in an amount of 2 kg per ton of wastewater.

9. The method for treating nickel-tin containing anodizing wastewater according to claim 8, characterized by: The polyaluminum chloride in S3 is used in an amount of 0.2-1.0 kg per ton of wastewater, and the treatment time is 15-30 h.

10. The method for treating nickel-tin containing anodizing wastewater according to claim 9, characterized in that: The polyacrylamide in S4 is used in an amount of 0.03-0.1 kg per ton of wastewater, and the treatment time is 15-30 h.

11. The method for treating nickel-tin containing anodizing wastewater according to claim 10, characterized in that: The anion exchange resin in S5 is soaked in saturated saline water before use, and then soaked in alkali and acid, and finally rinsed to neutral.

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