A method for treating wastewater containing copper nitrate and copper sulfate in high-purity copper industry

Abstract

This invention relates to the field of environmental engineering technology and discloses a method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry. The method involves filtering the copper nitrate and copper sulfate wastewater into reaction tanks A and B respectively, adding flocculants, monitoring the pH value of the reaction tanks during the reaction process using online monitoring instruments, and separately adding hydrogen peroxide to reaction tank A to break down the complexed copper and convert it into Cu. 2+ The supernatant is used as effluent and treated by diffusion dialysis. Activated carbon adsorption and reverse osmosis separation are used to further remove residual copper ions. The sludge is washed eight times with circulating water. Based on sludge stabilization, the sludge is converted into organic fertilizer through composting. Bioleaching technology uses microorganisms or their metabolites to leach valuable metals from the sludge through interaction with the metals. The treated wastewater is neutralized and then discharged into a comprehensive wastewater pond. The recovered copper is electrolyzed to produce copper products with 98% purity.

Description

Technical Field

[0001] This invention relates to the field of environmental engineering technology, specifically to a method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry. Background Technology

[0002] In the high-purity copper industry, wastewater containing copper nitrate and copper sulfate is a common pollutant. If this wastewater is discharged directly without treatment, it will severely pollute water bodies, impacting the ecological environment and human health. Therefore, developing effective treatment methods is crucial. Currently, the main treatment methods for this type of wastewater include chemical precipitation, electrolysis, adsorption, and ion exchange. Among these, chemical precipitation is widely used due to its mature technology and low cost.

[0003] While existing treatment methods reduce the burden of environmental pollution, chemical treatment methods, which involve adjusting the pH to precipitate copper ions into copper hydroxide followed by solid-liquid separation to remove the precipitate, generate large amounts of sludge containing heavy metals. Improper handling of this sludge can lead to secondary pollution. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry. This method has the advantage of low sludge content of heavy metals, thus solving the problem of high sludge content of heavy metals in traditional chemical treatment methods.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry, comprising the following steps:

[0008] Step 1, Pretreatment: Filter the copper nitrate and copper sulfate wastewater separately, and collect the filtrates into reaction tanks A and B respectively;

[0009] Step 2: Add flocculant: Add flocculant to the reaction tank of copper nitrate and copper sulfate;

[0010] Step 3: Optimize the pH value of the reaction tank: Monitor the pH value of the reaction tank during the reaction process using online monitoring instruments and adjust the pH value in real time;

[0011] Step 4: Complex Breaking: Hydrogen peroxide is added to reaction tank A to break the complex of copper and convert it into Cu. 2+ The supernatant is used as the effluent;

[0012] Step 5: Conversion: The copper nitrate and copper sulfate wastewater from reaction tanks A and B are treated by diffusion dialysis technology respectively;

[0013] Step Six, Deep Treatment: Activated carbon adsorption and reverse osmosis separation technology are used to further remove residual copper ions;

[0014] Step 7: Sludge stabilization treatment: Stabilize the sludge generated from the advanced treatment process.

[0015] Step 8, Sludge Washing: The sludge is washed 8 times using circulating water;

[0016] Step 9, Sludge Composting: Based on sludge stabilization, sludge is converted into organic fertilizer through composting technology;

[0017] Step 10, Heavy Metal Recovery: Using bioleaching technology, valuable metals are leached out by the interaction between microorganisms or their metabolites and metals in the sludge.

[0018] Step 11, Final Treatment: The treated wastewater is neutralized and then discharged into the integrated wastewater pond;

[0019] Step 12, Recycling: The recycled copper is electrolyzed to produce copper products with 98% purity.

[0020] Preferably, in step one, the pretreatment involves filtering the copper nitrate and copper sulfate wastewater separately to obtain copper nitrate filtrate and copper sulfate filtrate. The copper nitrate filtrate is collected in reaction tank A, and the copper sulfate filtrate is collected in reaction tank B.

[0021] Preferably, in step two, flocculants are added: 15% polyaluminum chloride is added to reaction tank A, and 20% polyacrylamide is added to reaction tank B.

[0022] Preferably, in step three, the pH value of the reaction tank is optimized as follows: when the pH of reaction tank A is <6, 20% sodium hydroxide is added for adjustment; when the pH of reaction tank A is >9, 10% hydrochloric acid is added for adjustment; when the pH of reaction tank B is <6, 10% potassium hydroxide is added for adjustment; and when the pH of reaction tank A is >9, 5% sulfuric acid is added for adjustment.

[0023] Preferably, the conditions for breaking the network in step four are:

[0024] S1.1 Control the pH of the solution between 6 and 9;

[0025] S1.2. While using hydrogen peroxide, add 80mg and 40mg of polyacrylamide.

[0026] Preferably, the conversion process in step five is as follows:

[0027] S2.1 Pretreatment steps: Use diffusion dialysis equipment to filter copper nitrate and copper sulfate waste liquid;

[0028] S2.2 Operation process: Sulfur dioxide is used as a reducing agent for copper nitrate and copper sulfate filtrate to reduce copper sulfate to copper. The pH value of copper nitrate and copper sulfate filtrate in reaction tanks A and B is controlled between 6 and 9. The ambient temperature is set at 20-30℃, the standing time is 2 hours, and the acidity of the influent is 5g / L.

[0029] S2.3 Separation: After the reduction reaction is completed, the mixed products in the reaction tank are processed by separating the copper by installing a diffusion dialysis device at the outlet.

[0030] Preferably, in step six, the deep treatment involves: adding activated carbon at a ratio of 3 to reaction tank A to adsorb residual copper ions, then using reverse osmosis separation technology to further remove the copper ions adsorbed by the activated carbon; and in reaction tank B, passing copper sulfate wastewater through a reactor containing ion exchange resin at a flow rate of 10 meters per second.

[0031] Preferably, in step seven, the sludge stabilization treatment involves: when the pH of reaction tanks A and B is >9, the sludge generated from the advanced treatment is subjected to a stabilization method using a combination of calcium oxide and magnesium salts in a 5:1 ratio, which is then uniformly mixed with the sludge and added to reaction tanks A and B.

[0032] Calcium oxide reacts with water:

[0033] CaO + H₂O → Ca(OH)₂ + Heat

[0034] Calcium hydroxide reacts with carbon dioxide:

[0035] Ca(OH)2 + CO2 → CaCO3 + H2O + heat

[0036] Preferably, in step ten, the bioleaching process involves maintaining the water temperature in reaction tanks A and B between 30-35°C and the pH value between 6-9. A combination of *Thiobacillus ferrooxidans*, *Thiobacillus thiooxidans*, and *Aspergillus niger* in a ratio of 3:1:2 is introduced into the reaction tanks to interact with copper ions in the sludge. Simultaneously, 50% oxygen is introduced into the bottom of reaction tanks A and B, and the stirring paddle is turned on for 2-4 hours.

[0037] Preferably, in step eleven, the final treatment involves adding 20% ​​sodium hydroxide, 10% hydrochloric acid, 10% potassium hydroxide, or 5% sulfuric acid to the treated wastewater to neutralize the wastewater discharged from reaction tanks A and B. When the pH value of the neutralization treatment is between 7 and 8, the wastewater is discharged into a comprehensive wastewater tank or municipal sewage network.

[0038] Compared with the prior art, the present invention provides a method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry, which has the following beneficial effects:

[0039] 1. This invention optimizes the pH value of the reaction tank. When the pH of reaction tank A is <6, 20% sodium hydroxide is added for adjustment; when the pH of reaction tank A is >9, 10% hydrochloric acid is added for adjustment; when the pH of reaction tank B is <6, 10% potassium hydroxide is added for adjustment; when the pH of reaction tank B is >9, 5% sulfuric acid is added for adjustment. The above adjustment process can be assisted by the automatic feeding equipment of the reaction tank to ensure that the pH value in the reaction tank is at the optimal state, thereby assisting the subsequent sludge treatment.

[0040] 2. This invention combines calcium oxide and magnesium salt in a 5:1 ratio and mixes them evenly with sludge. The mixture is then added to reaction tanks A and B for chemical treatment. This process effectively stabilizes the sludge, achieving both solidification and sterilization. It also improves storage and transportation conditions, prevents secondary pollution, and the stabilized sludge meets the requirements for recycling, such as for use in cement clinker, building materials, garden soil, and soil conditioners, thus realizing the resource utilization of sludge. Attached Figure Description

[0041] Figure 1 This is a flowchart of the process of the present invention; Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Please see Figure 1 A method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry includes the following steps:

[0044] Step 1, Pretreatment: Filter the copper nitrate and copper sulfate wastewater separately, and collect the filtrates into reaction tanks A and B respectively;

[0045] Step 2: Add flocculant: Add flocculant to the reaction tank of copper nitrate and copper sulfate to enhance the precipitation effect of copper ions, form larger precipitates, and thus improve the efficiency of solid-liquid separation.

[0046] Step 3: Optimize the pH value of the reaction tank: The pH value of the reaction tank is monitored by online monitoring instruments during the reaction process, and the pH value is adjusted in real time to ensure that copper ions precipitate to the maximum extent in the form of copper hydroxide. This not only improves the precipitation efficiency, but also reduces the problem of precipitate redissolving due to unsuitable pH value.

[0047] Step 4: Complex Breaking: Hydrogen peroxide is added to reaction tank A to break the complex of copper and convert it into Cu. 2+ The supernatant is used as the effluent;

[0048] Step 5: Conversion: The copper nitrate and copper sulfate wastewater from reaction tanks A and B are treated by filtration and diffusion dialysis technology, respectively.

[0049] Step Six, Deep Treatment: Activated carbon adsorption and reverse osmosis separation technology are used to further remove residual copper ions;

[0050] Step 7: Sludge stabilization treatment: The sludge produced from the advanced treatment is treated by stabilization method to convert the heavy metals in the sludge into a stable form, reducing their solubility and toxicity.

[0051] Step 8, Sludge Washing: The sludge is washed 8 times with circulating water to remove impurities and toxic substances, so as to facilitate subsequent treatment and utilization, and can effectively reduce the content of heavy metals in the sludge.

[0052] Step 9, Sludge Composting: Based on sludge stabilization, sludge is converted into organic fertilizer through composting technology. This method not only solves the sludge treatment problem, but also provides resources for agriculture.

[0053] Step 10, Heavy Metal Recovery: Using bioleaching technology, valuable metals are leached out by the interaction between microorganisms or their metabolites and metals in the sludge.

[0054] Step 11, Final Treatment: The treated wastewater is neutralized and then discharged into the integrated wastewater pond;

[0055] Step 12, Recycling: The recovered copper is electrolyzed to produce copper products with 98% purity, and nitric acid is converted into nitrogen fertilizer containing amide nitrogen and nitrate nitrogen. At the same time, other finished products in the wastewater are treated.

[0056] In step one, the pretreatment involves filtering the copper nitrate and copper sulfate wastewater separately to obtain copper nitrate filtrate and copper sulfate filtrate. The copper nitrate filtrate is collected in reaction tank A, and the copper sulfate filtrate is collected in reaction tank B.

[0057] Step 2: Add flocculants: Add 15% polyaluminum chloride (PAC) to reaction tank A and 20% polyacrylamide (PAM) to reaction tank B.

[0058] In step three, the pH value of the reaction tank is optimized as follows: when the pH of reaction tank A is less than 6, 20% sodium hydroxide is added for adjustment; when the pH of reaction tank A is greater than 9, 10% hydrochloric acid is added for adjustment; when the pH of reaction tank B is less than 6, 10% potassium hydroxide is added for adjustment; and when the pH of reaction tank A is greater than 9, 5% sulfuric acid is added for adjustment.

[0059] The advantages are: by optimizing the pH value of the reaction tank, when the pH of reaction tank A is <6, 20% sodium hydroxide is added for adjustment; when the pH of reaction tank A is >9, 10% hydrochloric acid is added for adjustment; when the pH of reaction tank B is <6, 10% potassium hydroxide is added for adjustment; when the pH of reaction tank B is >9, 5% sulfuric acid is added for adjustment. The above adjustment process can be assisted by the automatic feeding equipment of the reaction tank to ensure that the pH value in the reaction tank is at the optimal state, thereby assisting the subsequent sludge treatment.

[0060] The conditions for breaking the collaterals in step four are:

[0061] S1.1 Control the pH of the solution between 6 and 9;

[0062] S1.2. While using hydrogen peroxide, add 80mg and 40mg of polyacrylamide.

[0063] The conversion process in step five is as follows:

[0064] S2.1 Pretreatment step: Use diffusion dialysis equipment to filter copper nitrate and copper sulfate waste liquid. This step can effectively remove suspended matter or precipitate in the waste liquid and protect the normal operation of subsequent equipment.

[0065] S2.2 Operation process: Sulfur dioxide is used as a reducing agent for copper nitrate and copper sulfate filtrate to reduce copper sulfate to copper. The pH value of copper nitrate and copper sulfate filtrate in reaction tanks A and B is controlled between 6 and 9. The ambient temperature is set at 20-30℃, the standing time is 2 hours, and the acidity of the influent is 5g / L.

[0066] S2.3 Separation: After the reduction reaction is completed, the mixed products in the reaction tank are processed by separating the copper by installing a diffusion dialysis device at the outlet.

[0067] In step six, further treatment is carried out: activated carbon at a ratio of 3 is added to reaction tank A to adsorb residual copper ions, and then reverse osmosis separation technology is used to further remove the copper ions adsorbed by the activated carbon. In reaction tank B, copper sulfate wastewater is passed through a reactor containing ion exchange resin at a flow rate of 10 meters per second.

[0068] Step 7: Sludge stabilization treatment: When the pH of reaction tanks A and B is >9, the sludge generated from the advanced treatment is stabilized using a combination of calcium oxide and magnesium salts in a 5:1 ratio. This mixture is then uniformly added to reaction tanks A and B. When calcium oxide is used, it reacts chemically with the water in the sludge to produce calcium hydroxide and release heat. This helps to evaporate some of the water and increase the solids content. The chemical reaction formula is as follows:

[0069] Calcium oxide reacts with water:

[0070] CaO + H₂O → Ca(OH)₂ + Heat

[0071] Calcium hydroxide reacts with carbon dioxide:

[0072] Ca(OH)₂ + CO₂ → CaCO₃ + H₂O + Heat

[0073] In the chemical formula, the above chemical reaction helps to reduce the volume of sludge, and the heat generated also helps to evaporate some of the water, thereby increasing the solids content of the treated sludge. At the same time, the increased alkalinity and temperature make this treatment method effective in sterilization, ensuring the safety of the treated sludge during the disposal process.

[0074] The advantages are: through the treatment of the above chemical reagents, the sludge can be effectively stabilized, and at the same time, the purpose of solidification and sterilization can be achieved. It can also improve storage and transportation conditions, avoid secondary pollution, and the stabilized sludge meets the requirements of recycling and reuse, such as in cement clinker, building materials, garden soil and soil conditioner, thus realizing the resource utilization of sludge.

[0075] Step 10: Bioleaching process: When the water temperature in reaction tanks A and B is maintained between 30-35℃ and the pH value is between 6-9, a combination of ferrooxidizing thiobacillus, thiooxidizing thiobacillus, and Aspergillus niger in a ratio of 3:1:2 is added to the reaction tank to interact with copper ions in the sludge. At the same time, 50% oxygen is introduced into the bottom of reaction tanks A and B, and the stirring paddle is turned on for 2-4 hours.

[0076] Step 11 Final Treatment: Add 20% sodium hydroxide, 10% hydrochloric acid, 10% potassium hydroxide or 5% sulfuric acid to the treated wastewater to neutralize the wastewater discharged from reaction tanks A and B. When the pH value of the neutralization treatment is between 7 and 8, it is discharged into the comprehensive wastewater tank or municipal sewage network. For high ammonia nitrogen copper sulfate wastewater, ammonia nitrogen solidification, copper ion collection and sulfate separation can be adopted.

[0077] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry, characterized in that, Includes the following steps: Step 1, Pretreatment: Filter the copper nitrate and copper sulfate wastewater separately, and collect the filtrates into reaction tanks A and B respectively; Step 2: Add flocculant: Add flocculant to the reaction tank of copper nitrate and copper sulfate; Step 3: Optimize the pH value of the reaction tank: Monitor the pH value of the reaction tank during the reaction process using online monitoring instruments and adjust the pH value in real time; Step 4: Complex Breaking: Hydrogen peroxide is added to reaction tank A to break the complex of copper and convert it into Cu. 2+ The supernatant is used as the effluent; Step 5: Conversion: The copper nitrate and copper sulfate wastewater from reaction tanks A and B are treated by diffusion dialysis technology respectively; Step Six, Deep Treatment: Activated carbon adsorption and reverse osmosis separation technology are used to further remove residual copper ions; Step 7: Sludge stabilization treatment: Stabilize the sludge generated from the advanced treatment process. Step 8, Sludge Washing: The sludge is washed 8 times using circulating water; Step 9, Sludge Composting: Based on sludge stabilization, sludge is converted into organic fertilizer through composting technology; Step 10, Heavy Metal Recovery: Using bioleaching technology, valuable metals are leached out by the interaction between microorganisms or their metabolites and metals in the sludge. Step 11, Final Treatment: The treated wastewater is neutralized and then discharged into the integrated wastewater pond; Step 12, Recycling: The recycled copper is electrolyzed to produce copper products with 98% purity; In step one, the pretreatment involves filtering copper nitrate and copper sulfate wastewater separately to obtain copper nitrate filtrate and copper sulfate filtrate. The copper nitrate filtrate is collected in reaction tank A, and the copper sulfate filtrate is collected in reaction tank B. The bioleaching process in step ten is as follows: When the water temperature in reaction tanks A and B is maintained between 30-35℃ and the pH value is between 6-9, a combination of *Thiobacillus ferrooxidans*, *Thiobacillus thiooxidans*, and *Aspergillus niger* in a ratio of 3:1:2 is added to the reaction tank to interact with copper ions in the sludge. At the same time, 50% oxygen is introduced into the bottom of reaction tanks A and B, and the agitator is turned on to stir for 2-4 hours.

2. The method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry according to claim 1, characterized in that: In step two, flocculants are added: 15% polyaluminum chloride is added to reaction tank A, and 20% polyacrylamide is added to reaction tank B.

3. The method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry according to claim 1, characterized in that: In step three, the pH value of the reaction tank is optimized as follows: when the pH of reaction tank A is less than 6, 20% sodium hydroxide is added for adjustment; when the pH of reaction tank A is greater than 9, 10% hydrochloric acid is added for adjustment; when the pH of reaction tank B is less than 6, 10% potassium hydroxide is added for adjustment; and when the pH of reaction tank A is greater than 9, 5% sulfuric acid is added for adjustment.

4. The method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry according to claim 1, characterized in that: The conditions for breaking the network in step four are as follows: S1.1 Control the pH of the solution between 6 and 9; S1.

2. While using hydrogen peroxide, add 80mg and 40mg of polyacrylamide.

5. The method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry according to claim 1, characterized in that: The conversion process in step five is as follows: S2.1 Pretreatment steps: Use diffusion dialysis equipment to filter copper nitrate and copper sulfate waste liquid; S2.2 Operation process: Sulfur dioxide is used as a reducing agent for copper nitrate and copper sulfate filtrate to reduce copper sulfate to copper. The pH value of copper nitrate and copper sulfate filtrate in reaction tanks A and B is controlled between 6 and 9. The ambient temperature is set at 20-30℃, the standing time is 2 hours, and the acidity of the influent is 5g / L. S2.3 Separation: After the reduction reaction is completed, the mixed products in the reaction tank are processed by separating the copper from the mixed acid solution by installing a diffusion dialysis device at the outlet.

6. The method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry according to claim 1, characterized in that: In step six, the deep treatment involves adding activated carbon at a ratio of 3 to reaction tank A to adsorb residual copper ions, followed by reverse osmosis separation technology to further remove the copper ions adsorbed by the activated carbon. In reaction tank B, copper sulfate wastewater is passed through a reactor containing ion exchange resin at a flow rate of 10 meters per second.

7. The method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry according to claim 1, characterized in that: In step seven, the sludge stabilization treatment involves stabilizing the sludge produced from the advanced treatment when the pH in reaction tanks A and B is greater than 9. A combination of calcium oxide and magnesium salts in a 5:1 ratio is used, and the mixture is uniformly added to reaction tanks A and B. Calcium oxide reacts with water: CaO + H₂O → Ca(OH)₂ + Heat Calcium hydroxide reacts with carbon dioxide: Ca(OH)2 + CO2 → CaCO3 + H2O + heat 8. The method for treating wastewater containing copper nitrate and copper sulfate from the high-purity copper industry according to claim 1, characterized in that: The final treatment in step eleven involves adding 20% ​​sodium hydroxide, 10% hydrochloric acid, 10% potassium hydroxide, or 5% sulfuric acid to the treated wastewater to neutralize the wastewater discharged from reaction tanks A and B. When the pH value of the neutralization treatment is between 7 and 8, the wastewater is discharged into the integrated wastewater tank or the municipal sewage network.

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