A method for removing fluorine and COD from the sulfurized liquid of copper smelting process wastewater

Abstract

The present application belongs to the technical field of wastewater treatment, and specifically discloses a method for removing fluorine and COD from copper smelting process wastewater after sulfuration, which comprises the following steps: first, calculating the amount of potassium permanganate required for the reaction of fluorine and sodium silicate in the copper smelting process wastewater after sulfuration; then, adding the potassium permanganate into the copper smelting process wastewater after sulfuration for heating and stirring to obtain a mixed solution; then, adding a coagulant into the mixed solution for mixing and stirring to obtain a flocculation solution; finally, filtering the flocculation solution to obtain a precipitate containing nickel and a purified solution. The introduction of potassium permanganate promotes the transformation of sodium silicofluoride, and the fluorine-containing compounds are removed from the system in the form of precipitation. The newly generated sodium permanganate can effectively degrade the COD in the wastewater, improve the fluorine removal efficiency and depth, and also help to degrade the COD to a certain extent, thereby reducing the wastewater treatment cost.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater, applicable to the treatment of wastewater from non-ferrous metal metallurgy. Background Technology

[0002] The main source of fluoride-containing wastewater is the flue gas purification process. During the washing of smelting flue gas in this process, water glass is typically used to transfer fluoride from the gas phase to the liquid phase, resulting in wastewater with a high fluoride content (1000-6000 mg / L). The wastewater is generally pretreated using a sulfidation method, where sodium hydrosulfide solution is added to remove most heavy metal pollutants. However, fluoride compounds and fluoride ions cannot be completely removed at this stage, so lime slurry solution is added for neutralization. Because sodium fluorosilicate reacts with alkali, the fluoride fixed in the water glass redissolves into the wastewater. Finally, a precipitation method is used to precipitate fluoride ions and calcium ions to form calcium fluoride precipitate, removing most of the fluoride.

[0003] While the above-mentioned process can remove most of the fluoride from the wastewater, it prolongs the fluoride removal process, generates a large amount of fluoride-containing waste residue, and increases the difficulty of subsequent waste residue treatment. Furthermore, the existing process does not treat the COD in the wastewater, requiring separate treatment of COD, which increases the cost of wastewater treatment. Therefore, we need to propose a method to remove fluoride and COD from the sulfidation liquid of copper smelting wastewater to solve the above-mentioned problems. This method can significantly reduce the addition of calcium ions, improve the efficiency and depth of fluoride removal, and also help degrade COD, thereby reducing the cost of wastewater treatment. Summary of the Invention

[0004] The purpose of this invention is to provide a method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater. This method can significantly reduce the addition of calcium ions, improve the efficiency and depth of fluoride removal, and also help degrade COD, thereby reducing wastewater treatment costs and solving the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater includes the following steps:

[0007] S1. Calculate the amount of potassium permanganate required to react with sodium fluorosilicate based on the total sodium fluorosilicate content in the sulfidation liquid of copper smelting process wastewater.

[0008] S2. Add potassium permanganate to the sulfidation liquid of copper smelting process wastewater, heat and stir, and after thorough mixing and uniform reaction, obtain a mixed liquid.

[0009] S3. Add the coagulant aid to the mixture and mix thoroughly. After stirring evenly, let it stand for 10-30 minutes to obtain the flocculent liquid.

[0010] S4. Filter the flocculant to obtain a nickel-containing precipitate and a purified liquid.

[0011] Preferably, in step S1, the amount of potassium permanganate is calculated as follows:

[0012] A1. Determine the molar mass of sodium fluorosilicate (M_Na2SiF6);

[0013] A2. Calculate the amount of sodium fluorosilicate (n_Na2SiF6) by dividing the total content of sodium fluorosilicate by the molar mass, with the total content expressed in grams.

[0014] A3. Determine the molar ratio of potassium permanganate to sodium fluorosilicate based on the chemical reaction equation (a);

[0015] A4. Calculate the amount of potassium permanganate required (n_KMnO4): n_KMnO4=a*n_Na2SiF6;

[0016] A5. Determine the molar mass of potassium permanganate (M_KMnO4);

[0017] A6. Calculate the required mass of potassium permanganate (m_KMnO4): m_KMnO4=n_KMnO4*M_KMnO4.

[0018] Preferably, in step S2, the molar ratio of the amount of potassium permanganate added to the sodium fluorosilicate content in the sulfidation liquid of copper smelting process wastewater is 1.5-5:1.

[0019] Preferably, the reaction conditions for adding potassium permanganate to the sulfidated copper smelting wastewater are: a reaction temperature of 70-100℃ and a reaction time of 3-12h.

[0020] Preferably, when the potassium permanganate reacts with the sulfided liquid of copper smelting process wastewater, the potassium permanganate reacts with the organic matter in the wastewater, oxidizing the organic matter into carbon dioxide and water.

[0021] Preferably, in step S3, the coagulant is set as polyacrylamide with a molecular weight of 8 million to 18 million.

[0022] Preferably, the mixture is subjected to flocculation reaction after the addition of a coagulant aid. The amount of coagulant aid added is 1-5 mL / (L·sulfurized liquid), the mass fraction of the coagulant aid is 0.1%-0.5%, and the flocculation reaction conditions are: reaction time of 1-5 min and reaction temperature of 20-25℃.

[0023] Preferably, when adding the coagulant, the coagulant is added to the mixture by pumping, and then the mixture is rapidly stirred at a stirring rate of 400-800 r / min using a stirring device to evenly disperse the coagulant in the liquid. After stirring for 1-5 minutes, the stirring speed is reduced to 200-300 r / min, and the mixture is slowly stirred for 1-5 minutes. After stirring, the mixture is allowed to stand for 10-30 minutes to allow the flocs sufficient time to settle to the bottom of the container.

[0024] Preferably, in step S4, the precipitate needs to undergo nickel recovery, and the specific operation is as follows:

[0025] B1. The nickel-containing precipitate is mixed with hydrochloric acid or nitric acid solution to dissolve the nickel and obtain a leachate; this usually needs to be carried out under heating and stirring conditions to improve leaching efficiency.

[0026] B2. Filter the leachate through a filtration device to obtain insoluble residue and clear liquid;

[0027] B3. Precipitate nickel in the clear liquid using sodium hydroxide or potassium hydroxide to obtain the precipitated nickel compound.

[0028] B4. Calcining the precipitated nickel compound at high temperature converts it into nickel oxide or metallic nickel.

[0029] Preferably, the purified liquid needs to undergo further purification treatment, and the specific purification steps are as follows:

[0030] C1. Use activated carbon filtration equipment to filter the solution and remove organic matter, heavy metal ions or pigments to obtain the filtrate.

[0031] C2. Use a reverse osmosis device to perform reverse osmosis on the filtrate to remove dissolved solids and obtain reverse osmosis solution;

[0032] C3. Sterilize the reverse osmosis solution using an ultraviolet disinfection device to obtain the treated solution;

[0033] C4. If the treated liquid meets the emission standards, it is returned to the process for recycling; if the treated liquid does not meet the emission standards, it is returned to C1.

[0034] The method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater proposed in this invention has the following advantages compared with the prior art:

[0035] 1. This invention first calculates the amount of potassium permanganate required for the reaction of sodium fluorosilicate in the sulfidation liquid of copper smelting process wastewater. Then, potassium permanganate is added to the sulfidation liquid of copper smelting process wastewater and heated and stirred to obtain a mixed liquid. A coagulant aid is then added to the mixed liquid and stirred to obtain a flocculent liquid. Finally, the flocculent liquid is filtered to obtain a nickel-containing precipitate and a purified liquid. The introduction of potassium permanganate promotes the transformation of sodium fluorosilicate, allowing fluoride-containing compounds to leave the system in the form of precipitate. The newly generated sodium permanganate can effectively degrade COD in wastewater, improving the efficiency and depth of defluorination while also helping to degrade COD and reducing wastewater treatment costs.

[0036] 2. This invention can reduce calcium ion deposition and scaling in the defluorination process. Moreover, the operation method of this invention is simple, the process is simple and reliable, and it is easy to industrialize, thus having significant economic and social benefits. Attached Figure Description

[0037] Figure 1 This is a flowchart of the present invention;

[0038] Figure 2 This is a flowchart illustrating the process of nickel recovery from the precipitate of this invention.

[0039] Figure 3 This is a flowchart illustrating the purification process of the purified liquid according to the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] This invention provides, for example Figure 1-3 The method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater, as shown, includes the following steps:

[0043] S1. Calculate the amount of potassium permanganate required to react with sodium fluorosilicate based on the total sodium fluorosilicate content in the sulfidation liquid of copper smelting process wastewater.

[0044] The calculation method for the amount of potassium permanganate used is as follows:

[0045] A1. Determine the molar mass of sodium fluorosilicate (M_Na2SiF6);

[0046] A2. Calculate the amount of sodium fluorosilicate (n_Na2SiF6) by dividing the total content of sodium fluorosilicate by the molar mass, with the total content expressed in grams.

[0047] A3. Determine the molar ratio of potassium permanganate to sodium fluorosilicate based on the chemical reaction equation (a);

[0048] A4. Calculate the amount of potassium permanganate required (n_KMnO4): n_KMnO4=a*n_Na2SiF6;

[0049] A5. Determine the molar mass of potassium permanganate (M_KMnO4);

[0050] A6. Calculate the required mass of potassium permanganate (m_KMnO4): m_KMnO4=n_KMnO4*M_KMnO4.

[0051] S2. Add potassium permanganate to the sulfidation liquid of copper smelting process wastewater, heat and stir, and after thorough mixing and uniform reaction, obtain a mixed liquid.

[0052] The molar ratio of potassium permanganate added to sodium fluorosilicate in the sulfidated liquid of copper smelting process wastewater is 1.5-5:1. The reaction conditions for adding potassium permanganate to the sulfidated liquid of copper smelting process wastewater are: reaction temperature of 70-100℃ and reaction time of 3-12h.

[0053] When potassium permanganate reacts with the sulfidation liquid of copper smelting process wastewater, the potassium permanganate reacts with the organic matter in the wastewater, oxidizing the organic matter into carbon dioxide and water, thereby reducing the content of organic pollutants in the wastewater and achieving COD degradation.

[0054] S3. Add the coagulant aid to the mixture and mix thoroughly. After stirring evenly, let it stand for 10-30 minutes to obtain the flocculent liquid.

[0055] The coagulant is set as polyacrylamide with a molecular weight of 8 million to 18 million;

[0056] The mixture is subjected to flocculation reaction after the addition of a coagulant aid. The amount of coagulant aid added is 1-5 mL / (L·sulfurized liquid), and the mass fraction of the coagulant aid is 0.1%-0.5%. The flocculation reaction conditions are: reaction time of 1-5 min and reaction temperature of 20-25℃.

[0057] When adding the coagulant, the coagulant is pumped into the mixture, and then the mixture is rapidly stirred at a stirring rate of 400-800 r / min using a stirring device to ensure that the coagulant is evenly dispersed in the liquid. After stirring for 1-5 minutes, the stirring speed is reduced to 200-300 r / min, and the mixture is slowly stirred for 1-5 minutes. After stirring, the mixture is allowed to stand for 10-30 minutes to allow sufficient time for the flocs to settle to the bottom of the container.

[0058] S4. Filter the flocculant to obtain a nickel-containing precipitate and a purified liquid.

[0059] The precipitate needs to be subjected to nickel recovery, and the specific operation is as follows:

[0060] B1. The nickel-containing precipitate is mixed with hydrochloric acid or nitric acid solution to dissolve the nickel and obtain a leachate; this usually needs to be carried out under heating and stirring conditions to improve leaching efficiency.

[0061] B2. Filter the leachate through a filtration device to obtain insoluble residue and clear liquid;

[0062] B3. Precipitate nickel in the clear liquid using sodium hydroxide or potassium hydroxide to obtain the precipitated nickel compound.

[0063] B4. Calcining the precipitated nickel compound at high temperature converts it into nickel oxide or metallic nickel.

[0064] The purified liquid needs to undergo further purification treatment. The specific purification steps are as follows:

[0065] C1. Use activated carbon filtration equipment to filter the solution and remove organic matter, heavy metal ions or pigments to obtain the filtrate.

[0066] C2. Use a reverse osmosis device to perform reverse osmosis on the filtrate to remove dissolved solids and obtain reverse osmosis solution;

[0067] C3. Sterilize the reverse osmosis solution using an ultraviolet disinfection device to obtain the treated solution;

[0068] C4. If the treated liquid meets the emission standards, it is returned to the process for recycling; if the treated liquid does not meet the emission standards, it is returned to C1.

[0069] Example 2

[0070] According to the method provided in Example 1, the fluoride and COD recovery operation was carried out for the first time on the sulfidation liquid of copper smelting process wastewater to confirm the recovery status of fluoride and COD. The specific operation steps are as follows:

[0071] 1. The fluoride (F) content and COD value in the sulfidation liquid of copper smelting process wastewater were tested, and the values ​​are shown in the table below:

[0072] Element types F (mg / L) COD (mg / L) content 1200 1126

[0073] 2. Calculate the amount of potassium permanganate needed, as follows:

[0074] 21. The molar ratio of potassium permanganate added to sodium fluorosilicate content in the sulfidation solution of copper smelting wastewater is 1.5:1. Knowing the proportion of the molar mass of F in sodium fluorosilicate to the total molar mass of sodium fluorosilicate, the molar mass of sodium fluorosilicate (M_Na2SiF6) is 188.07 g / mol. Details are as follows:

[0075] M(Na2SiF6)=2*M(Na)+M(Si)+6*M(F)

[0076] = 2 * 22.99 + 28.09 + 6 * 19.00

[0077] = 45.98 + 28.09 + 114.00

[0078] =188.07 g / mol

[0079] Since the chemical formula of sodium fluorosilicate is Na₂SiF₆, we can see that each molecule contains 6 F atoms. Therefore, the total molar mass ratio of F in sodium fluorosilicate is:

[0080] Ratio = 6 * M(F) / M_Na2SiF6

[0081] =6 * 19.00 / 188.07

[0082] =114.00 / 188.07

[0083] = 0.606 (approximately equal to)

[0084] 22. Calculate the total content of sodium fluorosilicate:

[0085] m_Na2SiF6 = F content / F ratio

[0086] =1200mg / L / 0.606

[0087] ≈1980.49mg / L

[0088] 23. Calculate the amount of potassium permanganate (n_KMnO4) required for the reaction:

[0089] n_KMnO4=a*n_Na2SiF6

[0090] =1.5*(m_Na2SiF6 / M_Na2SiF6)

[0091] =1.5*(1980.49mg / L / 188.07g / mol)

[0092] ≈1.5*(1.98049g / L / 188.07g / mol)

[0093] ≈1.5*0.01053mol / L

[0094] ≈0.015795mol / L

[0095] 24. Calculate the required mass of potassium permanganate (m_KMnO4):

[0096] m_KMnO4=n_KMnO4*M_KMnO4

[0097] = 0.015795 mol / L * 158.04 g / mol

[0098] ≈2.513g / L;

[0099] 3. Potassium permanganate was added to the sulfidation solution of copper smelting process wastewater at a ratio of 2.513 g / L. The mixture was heated and stirred until fully mixed and homogeneous to obtain a mixed solution. The reaction temperature was 70℃ and the reaction time was 12 h. The fluorine (F) content and COD value in the reaction solution were measured, and the values ​​are shown in the table below:

[0100] Element types F (mg / L) COD (mg / L) content 1161.6 200

[0101] This table shows that the COD value decreases significantly after the reaction with potassium permanganate. The lower the COD value, the more it helps in degradation and reduces wastewater treatment costs.

[0102] 4. Add the coagulant aid to the mixture and stir thoroughly. After stirring evenly, let it stand for 10-30 minutes to obtain the flocculent liquid. The reaction time is 5 minutes and the reaction temperature is 20℃. Filter the flocculent liquid to obtain a nickel-containing precipitate and a purified liquid. Detect the fluorine (F) content and COD value in the purified liquid. The values ​​are shown in the table below:

[0103] Element types F (mg / L) COD (mg / L) content 38.33 168

[0104] The data in the table shows that the fluorine recovery rate is 96.7%, which is greater than 90%, and can effectively improve the recovery of hydrogen.

[0105] Example 3

[0106] According to the method provided in Example 1, a second actual operation was performed on the sulfidation liquid of copper smelting process wastewater to recover fluorine and COD, and the recovery status of fluorine and COD was confirmed. The specific operation steps are as follows:

[0107] 1. The fluoride (F) content and COD value in the sulfidation liquid of copper smelting process wastewater were tested, and the values ​​are shown in the table below:

[0108] Element types F (mg / L) COD (mg / L) content 1569 1236

[0109] 2. Calculate the amount of potassium permanganate needed, as follows:

[0110] The molar ratio of potassium permanganate added to sodium fluorosilicate in the sulfidation solution of copper smelting wastewater is 3:1. Knowing the proportion of the molar mass of phosphorus (F) in sodium fluorosilicate to the total molar mass of sodium fluorosilicate, the molar mass of sodium fluorosilicate (M_Na2SiF6) is 188.07 g / mol. Since the chemical formula of sodium fluorosilicate is Na2SiF6, the total molar mass ratio of F in sodium fluorosilicate is:

[0111] Ratio = 6 * M(F) / M_Na2SiF6

[0112] =6 * 19.00 / 188.07

[0113] =114.00 / 188.07

[0114] = 0.606 (approximately equal to)

[0115] Calculate the total content of sodium fluorosilicate:

[0116] m_Na2SiF6 = F content / F ratio

[0117] =1569mg / L / 0.606

[0118] ≈2591.43mg / L

[0119] Calculate the amount of potassium permanganate (n_KMnO4) required for the reaction:

[0120] n_KMnO4=a*n_Na2SiF6

[0121] =3*(m_Na2SiF6 / M_Na2SiF6)

[0122] =3*(2591.43mg / L / 188.07g / mol)

[0123] ≈3*(2.59143g / L / 188.07g / mol)

[0124] ≈3*0.01377mol / L

[0125] ≈0.04131mol / L

[0126] Calculate the required mass of potassium permanganate (m_KMnO4):

[0127] m_KMnO4=n_KMnO4*M_KMnO4

[0128] = 0.04131 mol / L * 158.04 g / mol

[0129] ≈6.527g / L;

[0130] 3. Potassium permanganate was added to the sulfidation solution of copper smelting process wastewater at a ratio of 6.527 g / L. The mixture was heated and stirred until fully mixed and homogeneous to obtain a mixed solution. The reaction temperature was 80℃ and the reaction time was 6 h. The fluorine (F) content and COD value in the reaction solution were measured, and the values ​​are shown in the table below:

[0131] Element types F (mg / L) COD (mg / L) content 1506 320

[0132] This table shows that the COD value decreases significantly after the reaction with potassium permanganate. The lower the COD value, the more it helps in degradation and reduces wastewater treatment costs.

[0133] 4. Add the coagulant aid to the mixture and stir thoroughly. After stirring evenly, let it stand for 10-30 minutes to obtain the flocculent liquid. The reaction time is 3 minutes and the reaction temperature is 23℃. Filter the flocculent liquid to obtain a nickel-containing precipitate and a purified liquid. Detect the fluorine (F) content and COD value in the purified liquid. The values ​​are shown in the table below:

[0134] Element types F (mg / L) COD (mg / L) content 42.16 236

[0135] The data in the table shows that the fluorine recovery rate is 97.2%, which is greater than 90%, and can effectively improve the recovery of hydrogen.

[0136] Example 4

[0137] According to the method provided in Example 1, a third actual operation was performed on the sulfidation liquid of copper smelting process wastewater to recover fluorine and COD, and the recovery status of fluorine and COD was confirmed. The specific operation steps are as follows:

[0138] 1. The fluoride (F) content and COD value in the sulfidation liquid of copper smelting process wastewater were tested, and the values ​​are shown in the table below:

[0139] Element types F (mg / L) COD (mg / L) content 1436 1238

[0140] 2. Calculate the amount of potassium permanganate needed, as follows:

[0141] 21. The molar ratio of potassium permanganate added to sodium fluorosilicate in the sulfidation solution of copper smelting wastewater is 5:1. Knowing the proportion of the molar mass of sulfur (F) in sodium fluorosilicate to the total molar mass of sodium fluorosilicate, the molar mass of sodium fluorosilicate (M_Na2SiF6) is 188.07 g / mol. Since the chemical formula of sodium fluorosilicate is Na2SiF6, it can be seen that there are 6 F atoms in each molecule. Therefore, the total molar mass ratio of F in sodium fluorosilicate is:

[0142] Ratio = 6 * M(F) / M_Na2SiF6

[0143] =6 * 19.00 / 188.07

[0144] =114.00 / 188.07

[0145] = 0.606 (approximately equal to)

[0146] Calculate the total content of sodium fluorosilicate:

[0147] m_Na2SiF6 = F content / F ratio

[0148] =1436mg / L / 0.606

[0149] ≈2371.54mg / L

[0150] Calculate the amount of potassium permanganate (n_KMnO4) required for the reaction:

[0151] n_KMnO4=a*n_Na2SiF6

[0152] =3*(m_Na2SiF6 / M_Na2SiF6)

[0153] =3*(2371.54mg / L / 188.07g / mol)

[0154] ≈3*(2.37154g / L / 188.07g / mol)

[0155] ≈3*0.01261mol / L

[0156] ≈0.03783mol / L

[0157] Calculate the required mass of potassium permanganate (m_KMnO4):

[0158] m_KMnO4=n_KMnO4*M_KMnO4

[0159] = 0.03783 mol / L * 158.04 g / mol

[0160] ≈5.987g / L;

[0161] 3. Potassium permanganate was added to the sulfidation solution of copper smelting process wastewater at a ratio of 5.987 g / L. The mixture was heated and stirred until fully mixed and homogeneous to obtain a mixed solution. The reaction temperature was 100℃ and the reaction time was 3 hours. The fluorine (F) content and COD value in the reaction solution were measured, and the values ​​are shown in the table below:

[0162] Element types F (mg / L) COD (mg / L) content 1324.9 306

[0163] This table shows that the COD value decreases significantly after the reaction with potassium permanganate. The lower the COD value, the more it helps in degradation and reduces wastewater treatment costs.

[0164] 4. Add the coagulant aid to the mixture and stir thoroughly. After stirring evenly, let it stand for 10-30 minutes to obtain the flocculent liquid. The reaction time is 1 minute and the reaction temperature is 25℃. Filter the flocculent liquid to obtain a nickel-containing precipitate and a purified liquid. Detect the fluorine (F) content and COD value in the purified liquid. The values ​​are shown in the table below:

[0165] Element types F (mg / L) COD (mg / L) content 33.12 276

[0166] The data in the table shows that the fluorine recovery rate is 97.5%, which is greater than 90%, and can effectively improve the recovery of hydrogen.

[0167] In summary, by first calculating the amount of potassium permanganate required for the reaction with sodium fluorosilicate in the sulfidation solution of copper smelting wastewater, then adding potassium permanganate to the sulfidation solution of copper smelting wastewater and heating and stirring to obtain a mixed solution, then adding a coagulant aid to the mixed solution and stirring to obtain a flocculent solution, and finally filtering the flocculent solution to obtain a nickel-containing precipitate and a purified solution, the introduction of potassium permanganate promotes the transformation of sodium fluorosilicate, removing fluoride-containing compounds from the system in the form of precipitates. The newly generated sodium permanganate can effectively degrade COD in wastewater, improving the efficiency and depth of defluorination while also helping to degrade COD, reducing wastewater treatment costs, and mitigating calcium ion deposition and scaling in the defluorination process. Furthermore, the operation method of this invention is simple, the process is simple and reliable, and it is easy to industrialize, thus having significant economic and social benefits.

[0168] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater, characterized in that: Includes the following steps: S1. Calculate the amount of potassium permanganate required to react with sodium fluorosilicate based on the total sodium fluorosilicate content in the sulfidation liquid of copper smelting process wastewater. S2. Add potassium permanganate to the sulfidation liquid of copper smelting process wastewater, heat and stir, and after thorough mixing and uniform reaction, obtain a mixed liquid. The reaction conditions for adding potassium permanganate to the sulfidated copper smelting wastewater are: reaction temperature of 70-100℃ and reaction time of 3-12h. S3. Add the coagulant aid to the mixture and mix thoroughly. After stirring evenly, let it stand for 10-30 minutes to obtain the flocculent liquid. The coagulant is set as polyacrylamide with a molecular weight of 8 million to 18 million; S4. Filter the flocculant to obtain a nickel-containing precipitate and a purified liquid.

2. The method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater according to claim 1, characterized in that: In step S1, the amount of potassium permanganate used is calculated as follows: A1. Determine the molar mass of sodium fluorosilicate, M_Na2SiF6; A2. Calculate the amount of substance n_Na2SiF6 of sodium fluorosilicate by dividing the total content of sodium fluorosilicate by the molar mass, with the total content in grams. A3. Determine the molar ratio a of potassium permanganate and sodium fluorosilicate based on the chemical reaction equation; A4. Calculate the amount of potassium permanganate required: n_KMnO4=a*n_Na2SiF6; A5. Determine the molar mass of potassium permanganate, M_KMnO4; A6. Calculate the required mass of potassium permanganate: m_KMnO4 = n_KMnO4 * M_KMnO4.

3. The method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater according to claim 2, characterized in that: In step S2, the molar ratio of the amount of potassium permanganate added to the sodium fluorosilicate content in the sulfidation liquid of copper smelting process wastewater is 1.5-5:

1.

4. The method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater according to claim 3, characterized in that: When potassium permanganate reacts with the sulfidation liquid of copper smelting process wastewater, the potassium permanganate reacts with the organic matter in the wastewater, oxidizing the organic matter into carbon dioxide and water.

5. The method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater according to claim 4, characterized in that: The mixture is subjected to flocculation reaction after the addition of coagulant. The amount of coagulant added to each L of vulcanized liquid is 1-5 mL, and the mass fraction of the coagulant is 0.1%-0.5%. The flocculation reaction conditions are: reaction time of 1-5 min and reaction temperature of 20-25℃.

6. The method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater according to claim 5, characterized in that: When adding the coagulant, the coagulant is pumped into the mixture, and then the mixture is rapidly stirred at a stirring rate of 400-800 r / min using a stirring device to ensure that the coagulant is evenly dispersed in the liquid. After stirring for 1-5 minutes, the stirring speed is reduced to 200-300 r / min, and the mixture is slowly stirred for 1-5 minutes. After stirring, the mixture is allowed to stand for 10-30 minutes to allow sufficient time for the flocs to settle to the bottom of the container.

7. The method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater according to claim 6, characterized in that: In step S4, the precipitate needs to be subjected to nickel recovery, and the specific operation is as follows: B1. Mix the nickel-containing precipitate with hydrochloric acid or nitric acid solution to dissolve the nickel and obtain a leachate; B2. Filter the leachate through a filtration device to obtain insoluble residue and clear liquid; B3. Use sodium hydroxide or potassium hydroxide to precipitate the nickel in the clear liquid, so that the nickel is precipitated as nickel hydroxide, and obtain the precipitated nickel compound. B4. Calcining the precipitated nickel compound at high temperature converts it into nickel oxide or metallic nickel.

8. The method for removing fluoride and COD from the sulfidation liquid of copper smelting process wastewater according to claim 7, characterized in that: The purified liquid needs to undergo further purification treatment. The specific purification steps are as follows: C1. Use activated carbon filtration equipment to filter the solution and remove organic matter, heavy metal ions or pigments to obtain the filtrate. C2. Use a reverse osmosis device to perform reverse osmosis on the filtrate to remove dissolved solids and obtain reverse osmosis solution; C3. Sterilize the reverse osmosis solution using an ultraviolet disinfection device to obtain the treated solution; C4. If the treated liquid meets the emission standards, it is returned to the process for recycling; if the treated liquid does not meet the emission standards, it is returned to C1.

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