A method for removing phosphorus from leachate wastewater from the hydrometallurgical industry
By combining Fenton reaction, wet catalytic oxidation and ozone catalytic oxidation, the problem of phosphorus removal from extraction wastewater in the hydrometallurgical industry was solved, achieving high-efficiency phosphorus removal, reducing production costs and improving wastewater quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGDONG BRUNP RECYCLING TECH CO LTD
- Filing Date
- 2023-09-22
- Publication Date
- 2026-07-10
AI Technical Summary
In the hydrometallurgical industry, phosphorus removal from extraction wastewater is difficult, resulting in significant losses of extractant, increased production costs, and impacts product quality and wastewater discharge.
The method employs a combination of Fenton reaction and wet catalytic oxidation with ozone catalytic oxidation. The solubility of the extractant is reduced by ultrasonic treatment, and hydroxyl radicals are generated using ferrous sulfate and hydrogen peroxide to oxidize the extractant. Subsequently, coagulants and flocculants are added for sedimentation, and finally, ozone catalyst is used to further oxidize and decompose the extractant to generate inorganic phosphorus precipitate.
It achieved a high phosphorus removal rate of over 97% in the extraction wastewater, reduced the loss of extractant, decreased production costs, and improved wastewater treatment efficiency.
Smart Images
Figure CN117545724B_ABST
Abstract
Description
Technical Field
[0001] This disclosure belongs to the field of wastewater treatment technology, specifically relating to a method for removing phosphorus from wastewater extracted from the hydrometallurgical industry. Background Technology
[0002] my country's new energy electric vehicle industry is developing rapidly, leading to a continuous increase in the demand for power batteries, which in turn generates a large number of waste batteries. These waste batteries contain a variety of rare and precious metals in high concentrations, making them highly valuable for recycling.
[0003] In the process of recycling valuable metals such as nickel, cobalt, and manganese from waste lithium-ion battery cathode materials, solvent extraction is commonly used to concentrate, purify, and remove impurities from the leachate. Solvent extraction involves mixing two immiscible or slightly soluble solvents (aqueous and organic phases) to transfer the solute from one solvent to the other (from the aqueous phase to the organic phase or vice versa). The organic phase consists of an extractant and a diluent, typically sulfonated kerosene. The most commonly used extractants are acidic phosphorus extractants, such as P204 (di(2-ethylhexyl) phosphate), often used for extracting aluminum or manganese; P507 (2-ethylhexylphosphonic acid mono-2-ethylhexyl ester), often used in the full extraction process of nickel, cobalt, and manganese; and C272 (di(2,4,4)trimethylpentylphosphonic acid), often used for selective extraction of cobalt or nickel-magnesium separation. Although the organic phase is composed of insoluble and non-degradable organic substances, in actual production, due to the large volume of solution processed and limited stirring and separation time, it is inevitable that organic phase will be entrained in the aqueous phase. This is especially true after saponification of the organic phase, which increases its hydrophilicity, leading to incomplete phase separation. The back-extraction liquor and raffinate carry away some organic matter, resulting in significant extractant loss and increased production costs. Furthermore, these oily substances can affect the quality of subsequent products and wastewater discharge, necessitating oil-water separation treatment. Summary of the Invention
[0004] This disclosure addresses the problem of phosphorus removal from extraction wastewater during the recycling process of retired lithium-ion batteries by proposing a method for removing phosphorus from extraction wastewater in the hydrometallurgical industry.
[0005] According to a first aspect of this disclosure, a method for removing phosphorus from extraction wastewater in the hydrometallurgical industry is proposed, comprising the following steps:
[0006] S1: Adjust the pH of the extraction wastewater to 3.5-4.5, add ferrous sulfate, and then perform ultrasonic treatment to obtain a suspension;
[0007] S2: Separate the solid and liquid phases of the suspension, take the liquid phase and stir it, add acid to adjust the pH to 3-3.5, add ferrous sulfate and hydrogen peroxide, introduce oxygen and pressurize, and heat to react.
[0008] S3: After adjusting the pH to 7.5-8 with alkali solution, add coagulant and flocculant in sequence, separate solid and liquid, adjust the pH to 6-7, carry out ozone oxidation, add aluminum sulfate after the reaction is complete, and detect the phosphorus content in the water after solid-liquid separation.
[0009] In step S1, adjusting the pH of the extraction wastewater to 4 reduces the solubility of the extractant and facilitates subsequent adjustment of the Fenton influent pH to 3-3.5. In step S2, adding acid is to adjust the pH of the liquid phase to meet the pH requirements of the Fenton influent. In step S3, adding alkali to adjust the pH to 7.5-8 is to remove Fe. 3+ Fe 3+ It will react with inorganic phosphorus to produce a precipitate, further reducing the phosphorus content in the solution.
[0010] In some embodiments, in step S1, the solid-liquid ratio of the ferrous sulfate to the extraction wastewater is 0.001–0.01 g / mL. Adding ferrous sulfate can reduce the solubility of the extractant.
[0011] In some embodiments, in step S1, the ultrasonic treatment is performed at 30–40°C; and / or, the frequency of the ultrasonic treatment is 35–40 kHz; and / or, the duration of the ultrasonic treatment is 0.5–1 hour. Ultrasound has the effect of demulsifying and removing oil, and better results can be achieved within this parameter range.
[0012] In some embodiments, in step S2, the stirring speed is 100 to 300 rpm.
[0013] In some embodiments, in step S2, the molar ratio of ferrous sulfate to hydrogen peroxide is 1:(3-10).
[0014] In some embodiments, in step S2, the concentration of hydrogen peroxide is 27.5% to 35%; and / or, the mass ratio of hydrogen peroxide to COD of the extraction wastewater is (1 to 2): 1.
[0015] In some embodiments, in step S2, the oxygen is introduced and pressurized to a pressure of 0.2 to 0.5 MPa.
[0016] In some embodiments, step S2 involves a two-stage reaction; the first stage reaction occurs at 30–40°C for 2–3 hours; the second stage reaction occurs at 120–150°C for 1–2 hours. Under the conditions of the first stage reaction, most of the extractant (organophosphate ester) in the wastewater is oxidized to small molecules, and a small portion is directly oxidized to inorganic phosphorus. Under the conditions of the second stage reaction, the remaining extractant and small molecules continue to be oxidized to inorganic phosphorus.
[0017] In some embodiments, the first stage reaction is a Fenton oxidation reaction, and the second stage reaction is a wet catalytic oxidation reaction. In the Fenton oxidation reaction, ferrous sulfate reacts with hydrogen peroxide to generate hydroxyl radicals, which can oxidize the extractant into smaller molecules; in the wet catalytic oxidation reaction, the extractant can be decomposed into inorganic phosphorus by high temperature and high pressure.
[0018] In some embodiments, step S2 further includes a stirring step, wherein the stirring speeds for the first-stage reaction and the second-stage reaction are independently selected from 400 to 600 rpm.
[0019] In some embodiments, in step S3, the cooling refers to the temperature of the reaction solution dropping to 20-25°C.
[0020] In some embodiments, in step S3, the reaction solution is stirred after cooling, and the stirring speed is 100-300 rpm.
[0021] In some embodiments, in step S3, the coagulant is polyaluminum chloride (PAC); the polyaluminum chloride is added to achieve a concentration of 200–300 ppm. Polyaluminum chloride is used to precipitate inorganic phosphorus.
[0022] In some embodiments, the basicity of the polyaluminum chloride is 60% to 80%. This polyaluminum chloride exhibits good flocculation and sedimentation effects.
[0023] In some embodiments, in step S3, the flocculant is polyacrylamide (PAM); and / or, the molecular weight of the polyacrylamide is approximately 1200W; and / or, the amount of polyacrylamide added is 3-5 ppm. Using this amount of flocculant can save costs and facilitate subsequent flocculation, sedimentation, and filtration.
[0024] In some embodiments, in step S3, the ozone oxidation uses activated carbon loaded with metal oxides as a catalyst. The activated carbon adsorbs the extractant onto its surface, and the metal oxides loaded on the activated carbon act as a catalyst, causing the extractant to be decomposed by ozone oxidation.
[0025] In some embodiments, the metal oxide is at least one of titanium dioxide, copper oxide, or manganese dioxide. The ozone catalyst enriches the extractant on its surface, and ozone more readily generates hydroxyl radicals on the surface of the catalyst metal oxide, thereby improving ozone oxidation efficiency.
[0026] In some embodiments, in step S3, the ozone oxidation is carried out in an ozone catalytic oxidation reactor; the catalyst filling amount is 50% to 60% of the height of the ozone catalytic oxidation reactor. When ozone is introduced, the solution volume in the reactor will expand, requiring a safety margin of 40% to 50% for expansion.
[0027] In some embodiments, the ozone oxidation time in step S3 is 10–30 minutes. After the ozone oxidation process, most of the remaining extractant has been oxidized and decomposed.
[0028] In some embodiments, in step S3, the amount of aluminum sulfate added is 50–200 ppm. Aluminum sulfate itself is acidic, and since the wastewater has a neutral pH, it will continuously hydrolyze, producing polynuclear carboxyl complexes that react with orthophosphates in the water to form phosphate precipitates, thus achieving phosphorus removal.
[0029] In some embodiments, after the ozone oxidation reaction is completed in step S3, the exhaust gas enters the ozone decomposition device.
[0030] The principle of the removal method described in the first aspect of this disclosure is as follows: The Fenton reaction partially oxidizes the extractant (organophosphate ester) into inorganic phosphorus and small molecules. A wet catalytic oxidation reaction further oxidizes the extractant and small molecules into inorganic phosphorus. Subsequently, polyaluminum chloride is added to remove the oxidized inorganic phosphorus. The coagulant (e.g., PAC) and flocculant (e.g., PAM) are added sequentially to facilitate filtration. The remaining extractant in the solution is adsorbed by an ozone catalyst, and an oxidation reaction occurs on the catalyst surface with ozone, decomposing the extractant into inorganic phosphorus. Finally, aluminum sulfate is added to precipitate the inorganic phosphorus, achieving the phosphorus removal effect.
[0031] According to a second aspect of this disclosure, a method for lithium battery recycling is proposed, comprising the steps of a method for removing phosphorus from extraction wastewater in a hydrometallurgical industry as described in the first aspect of this disclosure. This lithium battery recycling method, incorporating the method described in the first aspect of this disclosure, effectively removes organophosphorus compounds from the extraction wastewater, making the lithium battery recycling method more environmentally friendly.
[0032] According to one embodiment of this disclosure, at least the following beneficial effects are achieved:
[0033] (1) This disclosure first reduces the hydrophilicity of the extractant by adding ferrous sulfate, thus solidifying some of the oil. Then, it uses ultrasound to convert the dispersed oil and emulsified oil (W / O) / (O / W) in the extraction wastewater into suspended oil for removal. Finally, it uses wet catalytic oxidation to oxidize and remove the extractant. Adding oxygen during the wet catalytic oxidation process increases the pressure and, to some extent, inhibits the decomposition of hydrogen peroxide, increasing the reaction rate. Furthermore, the orthophosphate formed by the decomposition of the extractant reacts with Fe in the solution. 3+ It directly generates precipitate, reducing the need for subsequent phosphorus removal agents.
[0034] (2) The process disclosed herein uses a catalyst containing activated carbon for ozone catalytic oxidation at the downstream end to deeply remove undecomposed extractant. Using the method disclosed herein, the phosphorus removal rate can reach over 97%. Attached Figure Description
[0035] The present disclosure will be further described below with reference to the accompanying drawings and embodiments, wherein:
[0036] Figure 1 This is a flowchart of a method for removing phosphorus from wastewater extracted from the hydrometallurgical industry, as described in Embodiment 1 of this disclosure. Detailed Implementation
[0037] The following will clearly and completely describe the concept and technical effects of this disclosure in conjunction with the embodiments, so as to fully understand the purpose, features and effects of this disclosure. In the embodiments / comparative examples, the wastewater is extraction wastewater from the ternary battery recycling industry; PAM is 1200 nonionic polyacrylamide; PAC and PAM are analytical grade reagents; and the activated carbon support catalyst is RHCY03.
[0038] Example 1
[0039] A method for removing organophosphorus compounds from wastewater extracted in the hydrometallurgical industry, such as Figure 1 As shown, the specific steps include the following:
[0040] (1) Take 1.5L of sodium saponification wastewater (oil content is 39mg / L, COD is 18000mg / L, P is 417mg / L) into a beaker, adjust the pH to 4, add 15g of ferrous sulfate, put the beaker into an ultrasonic cleaner, set the temperature to 40℃, and the reaction time to 1h to demulsify and remove oil.
[0041] (2) Remove the beaker, remove the solidified floating oil and sediment on the water surface, place the beaker on a magnetic stirrer, add the stirring rod, adjust the speed to 200 rpm, and stir continuously while checking the COD value. At the same time, add sulfuric acid dropwise to the saponified water after oil removal, and use a pH meter to monitor and control the pH value of the solution in real time while stirring continuously until the pH of the solution is adjusted to 3. Then add 45g of ferrous sulfate heptahydrate.
[0042] (3) Pour the stirred solution into a high-pressure reactor, add 54 mL of 30% hydrogen peroxide (the molar ratio of FeSO4·7H2O to H2O2 is 1:3.26, and the mass ratio of H2O2 to COD is about 1:1), close the high-pressure reactor, and introduce oxygen into it to make the pressure reach 0.4 MPa. Set the temperature of the first stage reaction (Fenton oxidation reaction) to 30℃, the rotation speed to 600 rpm, and the reaction time to 2 h. Set the temperature of the second stage reaction (wet catalytic oxidation) to 140℃, the rotation speed to 600 rpm, and the reaction time to 2 h.
[0043] (4) Pour the solution from (3) into a beaker and let it stand until the temperature drops to room temperature. Place the beaker on a magnetic stirrer, add the stirring rod, adjust the speed to 200 rpm, and stir continuously. At the same time, add sodium hydroxide to the solution and use a pH meter to monitor and control the pH value of the solution in real time, adjusting the pH to 8. Then add 0.45 g of PAC to the beaker, followed by 4.5 mL of 1200 W molecular weight PAM solution (mass concentration 1‰). Finally, filter the solution.
[0044] (5) Pour the filtrate into a beaker, place the beaker on a magnetic stirrer, add the stirring rod, adjust the speed to 200 rpm, and stir continuously. Add sulfuric acid dropwise to the filtrate, and use a pH meter to monitor and control the pH value of the solution in real time while stirring continuously until the pH value of the solution is maintained in the range of 6-7. Then add it to the ozone catalytic oxidation reactor, which is filled with activated carbon carrier catalyst to a height of 50% of the reactor height. The ozone generation rate of the air source ozone generator is 10 g / h, and the ozone flow rate in the reactor is controlled at 30 L / h. After reacting for 0.5 h, filter the solution, add 0.2 g of aluminum sulfate, stir for 10 min, and filter again. The phosphorus content of the effluent is 6.98 mg / L. The waste gas generated during the ozone catalytic oxidation process is treated in an ozone cracking device.
[0045] Example 2
[0046] A method for removing organophosphorus compounds from extraction wastewater in the hydrometallurgical industry includes the following specific steps:
[0047] (1) Take 1.5L of the lithium extraction residue (oil content 33.5mg / L, COD 800mg / L, P 36mg / L) into a beaker, adjust the pH to 4, add 1.5g of ferrous sulfate, put the beaker into an ultrasonic cleaner, set the temperature to 40℃, and the reaction time to 1h to demulsify and remove oil.
[0048] (2) Remove the beaker, remove the floating oil and sediment from the water surface, place the beaker on a magnetic stirrer, add the stirring rod, adjust the speed to 200 rpm, and stir continuously while checking the COD value. At the same time, add sulfuric acid dropwise to the raffinate after oil removal, and use a pH meter to monitor and control the pH value of the solution in real time while stirring continuously until the pH of the solution is adjusted to 3. Then add 2.25 g of ferrous sulfate heptahydrate.
[0049] (3) Pour the stirred solution into a high-pressure reactor, add 4.8 mL of 30% hydrogen peroxide (the molar ratio of FeSO4·7H2O to H2O2 is 1:5.81, and the mass ratio of H2O2 to COD is about 1.5:1), close the high-pressure reactor, and introduce oxygen into it to make the pressure reach 0.2 MPa. Set the temperature of the first stage reaction to 30℃, the rotation speed to 600 rpm, and the reaction time to 2 h. Set the temperature of the second stage reaction to 130℃, the rotation speed to 600 rpm, and the reaction time to 2 h.
[0050] (4) Pour the solution from (3) into a beaker and let it stand until the temperature drops to room temperature. Place the beaker on a magnetic stirrer, add the stirring rod, adjust the speed to 200 rpm, and stir continuously. At the same time, add sodium hydroxide to the solution and use a pH meter to monitor and control the pH value of the solution in real time, adjusting the pH to 8. Then add 0.45g of PAC to the beaker, followed by 4.5mL of 1200W molecular weight PAM solution (mass concentration 1‰). Finally, filter the solution.
[0051] (5) Pour the filtrate into a beaker, place the beaker on a magnetic stirrer, add the stirring rod, adjust the speed to 200 rpm, and stir continuously. Add sulfuric acid dropwise to the filtrate, and use a pH meter to monitor and control the pH value of the solution in real time while stirring continuously until the pH value of the solution is maintained in the range of 6-7. Then add it to the ozone catalytic oxidation reactor. The reactor is filled with activated carbon carrier catalyst, and the filling height is 50% of the reactor height. The ozone generation rate of the air source ozone generator is 10 g / h, and the ozone flow rate in the reactor is controlled at 30 L / h. After reacting for 0.5 h, filter the solution. Add 0.1 g of aluminum sulfate, stir for 10 min, and then filter. The phosphorus content of the effluent is 0.82 mg / L. The waste gas generated in the ozone catalytic oxidation process enters the ozone cracking device for treatment.
[0052] Example 3
[0053] A method for removing organophosphorus compounds from extraction wastewater in a hydrometallurgical industry includes the following specific steps:
[0054] (1) Take 1.5L of the raffinate after nickel and cobalt extraction (oil content is 47mg / L, COD is 1900mg / L, P is 82mg / L) into a beaker, adjust the pH to 4, add 3g of ferrous sulfate, put the beaker into an ultrasonic cleaner, set the temperature to 40℃, and the reaction time to 1h to demulsify and remove oil.
[0055] (2) Remove the beaker, remove the floating oil and sediment from the water surface, place the beaker on a magnetic stirrer, add the stirring rod, adjust the speed to 200 rpm, and stir continuously while checking the COD value. At the same time, add sulfuric acid dropwise to the raffinate after oil removal, and use a pH meter to monitor and control the pH value of the solution in real time while stirring continuously until the pH of the solution is adjusted to 3. Then add 5.25 g of ferrous sulfate heptahydrate.
[0056] (3) Pour the stirred solution into a high-pressure reactor, add 7.6 mL of 30% hydrogen peroxide (the molar ratio of FeSO4·7H2O to H2O2 is 1:3.94, and the mass ratio of H2O2 to COD is about 1:1), close the high-pressure reactor, and introduce oxygen into it to make the pressure reach 0.2 MPa. Set the temperature of the first stage reaction to 30℃, the rotation speed to 600 rpm, and the reaction time to 2 h. Set the temperature of the second stage reaction to 120℃, the rotation speed to 600 rpm, and the reaction time to 2 h.
[0057] (4) Pour the solution from (3) into a beaker and let it stand until the temperature drops to room temperature. Place the beaker on a magnetic stirrer, add the stirring rod, adjust the speed to 200 rpm, and stir continuously. At the same time, add sodium hydroxide to the solution and use a pH meter to monitor and control the pH value of the solution in real time, adjusting the pH to 7.5. Then add 0.45g of PAC to the beaker, followed by 4.5mL of 1200W molecular weight PAM solution (mass concentration 1‰). Finally, filter the solution.
[0058] (5) Pour the filtrate into a beaker, place the beaker on a magnetic stirrer, add the stirring rod, adjust the speed to 200 rpm, and stir continuously. Add sulfuric acid dropwise to the filtrate, and use a pH meter to monitor and control the pH value of the solution in real time while stirring continuously until the pH value of the solution is maintained in the range of 6-7. Then add it to the ozone catalytic oxidation reactor, which is filled with activated carbon carrier catalyst to a height of 50% of the reactor height. The ozone generation rate of the air source ozone generator is 10 g / h, and the ozone flow rate in the reactor is controlled at 30 L / h. After reacting for 0.5 h, filter the solution, add 0.2 g of aluminum sulfate, stir for 10 min, and then filter. The phosphorus content of the effluent is 1.79 mg / L. The waste gas generated during the ozone catalytic oxidation process is treated in an ozone cracking device.
[0059] Comparative Example 1
[0060] Take 1.5 L of the pre-lithiation extract (oil content 34 mg / L, COD 1100 mg / L, P 39 mg / L) in a beaker. Remove the oil directly using ultrasound without adding ferrous sulfate, then remove the floating oil and sediment from the water surface and measure the COD value. Pour the solution into a high-pressure reactor. Set up only one reaction stage in the reactor, adding 4.6 g of ferrous sulfate heptahydrate and 5.5 mL of 30% hydrogen peroxide (FeSO4·7H2O to H2O2 molar ratio 1:3.26, H2O2 to COD mass ratio approximately 1.11:1). Introduce oxygen to reach a pressure of 0.4 MPa. Set the reaction temperature to 30℃, the rotation speed to 600 rpm, and the reaction time to 2 h. Add sodium hydroxide to the effluent, and use a pH meter to monitor and control the pH value of the solution in real time, adjusting it to 7.5. Add 0.45g of PAC to the beaker, followed by 4.5mL of 1200W molecular weight PAM solution (1‰ mass concentration). Filter the solution, and the oil content of the filtrate is measured to be 29.50mg / L. Add this solution to the silica-alumina based packing ozone catalytic reactor for reaction, controlling the ozone flow rate at 30L / h for 0.5h. After filtration, add 0.1g of aluminum sulfate to the filtrate, stir for 10min, and then filter again. The pH of the filtrate is 22.12mg / L. The silica-alumina based packing is a conventional ozone catalyst for wastewater end-of-pipe treatment, mainly composed of alumina, silica, and magnesium chromium zirconium oxide. The type used is RHCY02, and it is filled to 50% of the height of the ozone catalytic oxidation reactor.
[0061] Test case
[0062] The phosphorus content of the solutions in each treatment stage of Examples 1, 2, 3 and Comparative Example 1 was detected, and the results are shown in Table 1.
[0063] Table 1. Data on phosphorus removal status
[0064]
[0065]
[0066] The total removal rate % is calculated as follows: (phosphorus content in raw solution - phosphorus content in effluent after ozone catalytic oxidation) / phosphorus content in raw solution * 100%.
[0067] The ultrasonic degreasing effect with the addition of ferrous sulfate was most significant at higher phosphorus (P) concentrations (Example 1), and the removal effects in other examples were also superior to those in the comparative example. For example, in Example 2, the P removal rate with ultrasonic degreasing using ferrous sulfate was (36.46-30.24) / 36.46≈17.06%, while in Comparative Example 1, without the addition of ferrous sulfate, the P removal rate with direct ultrasonic degreasing was (39.34-36.88) / 39.34≈6.25%. In Example 2, the two-stage reaction process in the reactor resulted in a P removal rate of (30.24-9.07) / 30.24≈70%, while Comparative Example 1 did not undergo a two-stage reaction and did not involve catalytic oxidation of organophosphorus oxides. The process of converting phosphorus into inorganic phosphorus achieved a removal rate of only (39.34-29.50) / 39.34≈20.01%. In Example 2, the ozone catalytic oxidation (activated carbon supported catalyst) and the addition of aluminum sulfate for phosphorus removal achieved a removal rate of (9.07-0.82) / 9.07≈90.96%, while in Comparative Example 1, the ozone catalytic oxidation with a silicon-aluminum based filler catalyst and the addition of aluminum sulfate for phosphorus removal achieved a removal rate of (29.50-22.12) / 29.50≈25.02%. The overall removal rate of organic phosphorus in Example 2, using the entire process, reached 97.76%, significantly higher than the 43.77% removal rate of Comparative Example 1.
Claims
1. A method for removing phosphorus from extraction wastewater in the hydrometallurgical industry, characterized in that, Includes the following steps: S1: Adjust the pH of the extraction wastewater to 3.5-4.5, add ferrous sulfate, and then perform ultrasonic treatment to obtain a suspension; S2: Separate the solid and liquid phases of the suspension, take the liquid phase and stir it, add acid to adjust the pH to 3-3.5, add ferrous sulfate and hydrogen peroxide, introduce oxygen and pressurize, and heat to react. S3: After adjusting the pH to 7.5-8 with alkali solution, add coagulant and flocculant in sequence, separate solid and liquid, adjust the pH to 6-7, carry out ozone oxidation, add aluminum sulfate after the reaction is complete, and detect the phosphorus content in the water after solid-liquid separation.
2. The method for removing phosphorus from wastewater extracted from hydrometallurgical industries according to claim 1, characterized in that, In step S1, the solid-liquid ratio of the ferrous sulfate to the extraction wastewater is 0.001 to 0.01 g / mL.
3. The method for removing phosphorus from wastewater extracted from hydrometallurgical industries according to claim 1, characterized in that, In step S1, the ultrasonic treatment is performed at 30–40°C; the frequency of the ultrasonic treatment is 35–40 kHz; and the duration of the ultrasonic treatment is 0.5–1 h.
4. The method for removing phosphorus from wastewater extracted from hydrometallurgical industries according to claim 1, characterized in that, In step S2, the molar ratio of ferrous sulfate to hydrogen peroxide is 1:(3-10).
5. The method for removing phosphorus from wastewater extracted from hydrometallurgical industries according to claim 1 or 4, characterized in that, In step S2, the concentration of hydrogen peroxide is 27.5% to 35%; and / or, the mass ratio of hydrogen peroxide to COD of the extraction wastewater is (1 to 2):
1.
6. The method for removing phosphorus from wastewater extracted from hydrometallurgical industries according to claim 1, characterized in that, In step S2, the oxygen is introduced and pressurized to a pressure of 0.2 to 0.5 MPa.
7. The method for removing phosphorus from wastewater extracted from hydrometallurgical industries according to claim 1, characterized in that, In step S2, the heating reaction is a two-stage reaction; wherein, the temperature of the first stage reaction is 30-40℃ and the reaction time is 2-3h; the temperature of the second stage reaction is 120-150℃ and the reaction time is 1-2h.
8. The method for removing phosphorus from wastewater extracted from hydrometallurgical industries according to claim 1, characterized in that, In step S3, the coagulant is polyaluminum chloride; the polyaluminum chloride is added so that the concentration of the polyaluminum chloride is 200-300 ppm.
9. The method for removing phosphorus from wastewater extracted in the hydrometallurgical industry according to claim 8, characterized in that, The basicity of the polyaluminum chloride is 60% to 80%.
10. The method for removing phosphorus from wastewater extracted from hydrometallurgical industries according to claim 1, characterized in that, In step S3, the flocculant is polyacrylamide; and / or, the molecular weight of the polyacrylamide is approximately 1200W; and / or, the amount of polyacrylamide added is 3-5 ppm.
11. The method for removing phosphorus from wastewater extracted from hydrometallurgical industries according to claim 1, characterized in that, In step S3, the ozone oxidation uses activated carbon loaded with metal oxides as a catalyst.
12. The method for removing phosphorus from wastewater extracted from hydrometallurgical industries according to claim 11, characterized in that, The metal oxide is at least one of titanium dioxide, copper oxide, or manganese dioxide.
13. The method for removing phosphorus from wastewater extracted from hydrometallurgical industries according to claim 1, characterized in that, In step S3, the ozone oxidation time is 10 to 30 minutes.
14. The method for removing phosphorus from wastewater extracted from hydrometallurgical industries according to claim 1, characterized in that, In step S3, the amount of aluminum sulfate added is 50 to 200 ppm.
15. A method for recycling lithium batteries, comprising the steps of the method for removing phosphorus from wastewater in the hydrometallurgical industry as described in any one of claims 1-14.