Comprehensive treatment method for acidic copper-containing wastewater based on iron-based material

Abstract

The application provides a comprehensive treatment method for acid copper-containing wastewater based on iron-based materials, and belongs to the technical field of acid copper-containing wastewater treatment. The method comprises the following steps: preparing an iron-based material containing micron-sized zero-valent iron powder and mineral functional powder, and placing the iron-based material in a weakly acidic basic aqueous solution with a pH of 4.0-6.0; after mechanical stirring, an iron-based material activation suspension is obtained; the acid copper-containing wastewater is sequentially subjected to iron removal, copper recovery and neutralization treatment; the iron-based material activation suspension is added in the copper recovery treatment stage to adjust the ORP value to 0-50 mv; and the obtained copper recovery underflow is partially refluxed to the copper recovery reaction tank. Through the comprehensive action of the technical means such as optimization of the composition of the iron-based material system, improvement of the treatment method of the iron-based material, and regulation of the underflow reflux mode, the reaction rate is improved, the high copper recovery rate and copper grade are ensured, the reagent consumption and waste residue production are reduced, and the efficient treatment of the acid copper-containing wastewater is realized.

Description

Technical Field

[0001] This invention relates to the field of acidic copper-containing wastewater treatment technology, and specifically to a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials. Background Technology

[0002] Mining and non-ferrous metal smelting processes generate large amounts of acidic copper-containing wastewater. This type of wastewater is characterized by large volume and fluctuating copper ion concentrations. If it is not effectively treated, it will have an impact on the environment.

[0003] Since copper in these acidic copper-containing wastewaters is a valuable substance, its efficient recovery is a current research focus. Currently, copper is often recovered through sulfidation. However, sulfiding agents easily produce highly toxic and odorous hydrogen sulfide gas during the reaction, posing a safety hazard. In the existing technology, patent CN120903783A provides a comprehensive treatment method for acidic mining wastewater. In the copper recovery process, a reducing agent is first added to adjust the ORP to a specific range, and then a reducing iron powder system is added. This utilizes the displacement reaction of the reducing iron powder to reduce copper ions to elemental copper for recovery, avoiding the safety risks of hydrogen sulfide generation from the sulfidation method. However, this method still suffers from problems in practical applications, such as long reaction time, low reaction rate, low copper recovery rate, large reagent dosage, and large waste residue generation.

[0004] In view of this, it is necessary to optimize the existing comprehensive treatment methods for acidic copper-containing wastewater in order to solve the above problems. Summary of the Invention

[0005] In view of the technical problems existing in the background art, this application provides a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials. Through the combined effect of optimizing the composition of the iron-based material system, improving the treatment method of iron-based materials, and regulating the underflow reflux mode, the method can improve the reaction rate while ensuring a high copper recovery rate and copper grade, and reduce the amount of reagents and waste residue generated, thus having significant economic, environmental and social benefits.

[0006] This application provides a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials, including the following steps: Iron-based materials containing micron-sized zero-valent iron powder and mineral functional powders were prepared; the iron-based materials were placed in a weakly acidic basic aqueous solution with a pH of 4.0~6.0, and mechanically stirred to obtain an activated suspension of the iron-based materials. The acidic copper-containing wastewater is subjected to iron removal treatment to obtain iron-removed underflow and iron-removed overflow; the iron-removed underflow is dewatered by pressure filtration to obtain first filter residue and first filter liquid; The iron-removed overflow and the first filtrate are fed into the copper recovery reaction tank. The iron-based material activation suspension is added to adjust the ORP value to 0-50mv, resulting in a copper-recovering turbid liquid. The copper-recovering turbid liquid is then subjected to flocculation and solid-liquid separation treatments to obtain a copper-recovering underflow and a copper-recovering overflow. A portion of the copper-recovering underflow is returned to the copper recovery reaction tank, while the other portion is dewatered by pressure filtration to obtain a second filter residue and a second filtrate. The copper overflow and the second filtrate are neutralized to obtain a neutralized underflow and a neutralized overflow; the neutralized underflow is then dehydrated by pressure filtration to obtain a third filter residue and a third filtrate.

[0007] As a further improvement to this application, the method for preparing the iron-based material includes: Take micron-sized zero-valent iron powder with a particle size of 100~400 mesh, and perform particle size narrowing sieving to obtain micron-sized zero-valent iron powder with a particle size distribution index of <0.3; The micron-sized zero-valent iron powder with a particle size distribution index of <0.3 is mixed with mineral functional powder of 300~500 mesh to obtain iron-based materials.

[0008] As a further improvement of this application, in the iron-based material, the mass of the mineral functional powder accounts for 5% to 30% of the mass of the micron-sized zero-valent iron powder.

[0009] As a further improvement to this application, the mineral functional powder includes at least one of quartz powder, kaolin, and montmorillonite.

[0010] As a further improvement of this application, the weakly acidic basic aqueous solution is obtained by diluting the acidic copper-containing wastewater; the mass ratio of the weakly acidic basic aqueous solution to the iron-based material is 5~10:1.

[0011] As a further improvement of this application, the mechanical stirring time is 0.5~4.0h.

[0012] As a further improvement of this application, the reflux ratio of the copper undercurrent is 40%~70%.

[0013] As a further improvement of this application, the iron removal treatment includes: adjusting the pH value of the acidic copper-containing wastewater to 3.3~3.6 and reacting for 0.25~0.5h to obtain an iron-removed turbid liquid; adding a flocculant to the iron-removed turbid liquid, and performing solid-liquid separation after sufficient flocculation.

[0014] As a further improvement of this application, the neutralization treatment includes: adjusting the pH value of the copper overflow and the second filtrate to 8.2~8.8 and reacting for 0.75~1.2h to obtain a neutralized turbid liquid; adding a flocculant to the neutralized turbid liquid, and performing solid-liquid separation after sufficient flocculation.

[0015] As a further improvement of this application, the concentration of copper ions in the acidic copper-containing wastewater is not less than 300 mg / L.

[0016] The beneficial effects of this application include: This application provides a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials. It employs a combined physical and chemical treatment technology, sequentially removing iron, recovering copper, and neutralizing the wastewater. This ensures that the target heavy metals in the final neutralized overflow and second filtrate meet emission standards, achieving comprehensive treatment of the acidic copper-containing wastewater. Furthermore, by rationally designing the composition of the iron-based materials and activating them, combined with appropriate bottom sludge recirculation, this application significantly improves the reaction rate of the copper recovery stage, effectively shortens the reaction time, and achieves a synergistic improvement in copper grade and recovery rate with lower reagent dosages. Simultaneously, it reduces waste generation, demonstrating significant economic, environmental, and social benefits, and providing a new approach for the comprehensive treatment of acidic copper-containing wastewater.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0019] Figure 1 This is a schematic flowchart of the comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials provided in the embodiments of this application. Detailed Implementation

[0020] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0022] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0023] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] To address the technical problems of existing comprehensive treatment methods for acidic copper-containing wastewater, such as long reaction time, low reaction rate, low copper recovery rate, large reagent dosage, and large waste residue generation, this application provides a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials. Through the combined effect of optimizing the composition of the iron-based material system, improving the treatment method of the iron-based material, and controlling the underflow reflux mode, this method improves the reaction rate while ensuring a high copper recovery rate and copper grade, and reduces the amount of reagents and waste residue generation, resulting in significant economic, environmental, and social benefits.

[0026] Please refer to Figure 1 This application provides a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials, comprising the following steps: Iron-based materials containing micron-sized zero-valent iron powder and mineral functional powders were prepared. The iron-based materials were placed in a weakly acidic basic aqueous solution with a pH of 4.0~6.0 and mechanically stirred to obtain an activated suspension of iron-based materials. The acidic copper-containing wastewater is treated to remove iron, resulting in an iron-removed underflow and an iron-removed overflow. The iron-removed underflow is then dewatered by pressure filtration to obtain the first filter residue and the first filter liquid. The iron-removed overflow and the first filtrate are fed into the copper recovery reaction tank. An iron-based material activation suspension is added to adjust the ORP value to 0-50mv, resulting in a copper-recovering turbid liquid. The copper-recovering turbid liquid is then subjected to flocculation and solid-liquid separation treatments to obtain a copper-recovering underflow and a copper-recovering overflow. A portion of the copper-recovering underflow is returned to the copper recovery reaction tank, while the other portion is dewatered by pressure filtration to obtain a second filter residue and a second filtrate. The copper overflow and the second filtrate are neutralized to obtain neutralized underflow and neutralized overflow; the neutralized underflow is dewatered by pressure filtration to obtain third filter residue and third filtrate.

[0027] In the technical solution of this application embodiment, a combination of physical and chemical treatment technologies is adopted. By sequentially removing iron, recovering copper, and neutralizing acidic copper-containing wastewater, the target heavy metals in the final neutralized overflow and second filtrate meet the emission standards, thereby achieving comprehensive treatment of acidic copper-containing wastewater.

[0028] Specifically, in the copper recovery process, this application pre-prepares an iron-based material containing micron-sized zero-valent iron powder and mineral functional powder, and then mechanically stirs it in a weakly acidic aqueous solution. This allows for the simultaneous physical polishing activation, chemical acidification activation, and particle dispersion stabilization of the zero-valent iron surface oxide film within the same reaction system, thereby efficiently activating the iron-based material. Furthermore, this process can be carried out under normal air conditions, with low environmental requirements. Based on this, by adding the activated suspension of the iron-based material prepared in this application to the copper recovery reaction tank, and adjusting the ORP value between 0 and 50 mV to control the amount of activated suspension added, compared to existing technologies, this not only eliminates the step of pre-adding a reducing agent to control the system ORP before adding the reduced iron powder system, shortening the process flow, but also effectively reduces the types and amounts of reagents used, and results in a faster reaction rate. Furthermore, by returning a portion of the copper recovery underflow to the copper recovery reaction tank, this application enables unreacted substances in the copper recovery underflow to return to the copper recovery reaction tank for further reaction, effectively improving the utilization rate of the reagents and reducing the amount of waste residue generated, and obtaining higher grade copper slag with a higher recovery rate.

[0029] Therefore, based on the combined effects of optimizing the composition of the iron-based material system, improving the treatment method of iron-based materials, and regulating the underflow reflux method in this application, the method provided by this application greatly improves the reaction rate in the copper recovery stage, effectively shortens the reaction time, and can achieve a synergistic improvement in copper grade and copper recovery rate with a lower reagent dosage, while reducing the amount of waste residue generated, providing a new approach for the comprehensive treatment of acidic copper-containing wastewater.

[0030] Furthermore, in some embodiments, the method for preparing the iron-based material includes: Take micron-sized zero-valent iron powder with a particle size of 100~400 mesh, and perform particle size narrowing sieving to obtain micron-sized zero-valent iron powder with a particle size distribution index of <0.3; Iron-based materials are obtained by mixing micron-sized zero-valent iron powder with a particle size distribution index of <0.3 with mineral functional powder of 300~500 mesh.

[0031] In the technical solution of this application embodiment, by performing particle size narrowing sieving on micron-sized zero-valent iron powder, micron-sized zero-valent iron powder with more uniform particle size is obtained, which is beneficial to improving the dispersion effect of micron-sized zero-valent iron in the iron-based material activation suspension. On this basis, this application selects mineral functional powder with a particle size of 300-500 mesh and mixes it with the narrowed micron-sized zero-valent iron powder, which enables it to efficiently grind the surface of the iron powder in the subsequent activation process, so as to remove the oxide film on the surface of the iron powder and achieve effective activation of the iron-based material.

[0032] Furthermore, in some embodiments, the mass of the mineral functional powder accounts for 5% to 30% of the mass of the micron-sized zero-valent iron powder in the iron-based material.

[0033] In the technical solution of this application embodiment, by adjusting the mass ratio between mineral functional powder and micron-sized zero-valent iron powder, it is possible to effectively activate the micron-sized zero-valent iron powder with an appropriate amount of mineral functional powder, and also to ensure that there is a sufficient amount of iron powder to react with copper ions in the wastewater, thereby achieving efficient treatment of wastewater with a lower total amount of reagents.

[0034] Furthermore, in some embodiments, the mineral functional powder includes at least one of quartz powder, kaolin, and montmorillonite. Preferably, the Mohs hardness of the quartz powder is ≥7, and the specific surface area of ​​the kaolin and montmorillonite is ≥20 m². 2 / g, in order to improve the activation effect on iron powder.

[0035] More preferably, in some embodiments, the mineral functional powder used is composed of quartz powder, kaolin, and montmorillonite in a mass ratio of (2~3):3:(1~2). Specifically, in this mineral functional powder, quartz powder can abrade the oxide film on the surface of iron powder while preventing iron powder agglomeration and improving fluidity; kaolin can isolate iron powder particles and prevent oxide caking; and montmorillonite can load and adsorb iron powder. Through nano-dispersion, interfacial electron channels, and inhibition of passivation, the reactivity of iron powder is improved. By controlling the ratio of the three components, it is beneficial to enable the components to work synergistically, forming an integrated system of grinding modification, stabilization protection, and activity enhancement to obtain a better activation effect.

[0036] Furthermore, in some embodiments, the weakly acidic basic aqueous solution is obtained by diluting acidic copper-containing wastewater; the mass ratio of the weakly acidic basic aqueous solution to the iron-based material is 5~10:1.

[0037] In the technical solution of this application embodiment, a weakly acidic basic aqueous solution for activating iron-based materials can be obtained by diluting the acidic copper-containing wastewater with tap water or recycled production water. This not only efficiently activates the iron-based materials but also provides a new utilization method for both the acidic copper-containing wastewater and the recycled production water, improving resource utilization. Furthermore, by controlling the pH value of the weakly acidic basic aqueous solution and its mass ratio to the iron-based materials, this application facilitates the thorough acidification and activation of micron-sized zero-valent iron powder in the iron-based materials.

[0038] Furthermore, in some embodiments, the mechanical stirring time is 0.5 to 4.0 hours.

[0039] In the technical solution of this application embodiment, by controlling the mechanical stirring time, it is possible to ensure that the surface of micron-sized zero-valent iron is fully polished by the mineral functional powder during the mechanical stirring process, and to ensure that the micron-sized zero-valent iron is fully chemically acidified and activated by the weakly acidic basic aqueous solution. At the same time, it promotes the full dispersion of particulate matter in the suspension, so as to obtain an activated suspension of iron-based materials with high activity.

[0040] Furthermore, in some embodiments, after adding an iron-based material to activate the suspension and adjusting the ORP value to 0-50 mV, the precipitation of copper ions can be completed in 10-20 minutes. The reaction time is short and the reaction efficiency is high.

[0041] Furthermore, in some embodiments, the step of flocculating the copper-collecting turbid solution includes: flocculating at a concentration of 1~5 g / m³. 3 The amount of nonionic flocculant (preferably nonionic polyacrylamide) added to the copper-collecting turbid liquid is increased to ensure sufficient flocculation.

[0042] Furthermore, in some embodiments, the reflux ratio of the copper bottom current is 40% to 70%.

[0043] In the technical solution of this application embodiment, by making the copper recovery underflow return to the copper recovery reaction tank with a larger reflux ratio, the utilization rate of the reagent can be effectively improved, the amount of waste residue generated can be reduced, and the copper recovery rate and grade can be improved.

[0044] Furthermore, in some embodiments, the iron removal treatment includes: adjusting the pH value of the acidic copper-containing wastewater to 3.3~3.6 and reacting for 0.25~0.5h to obtain an iron-removed turbid liquid; adding a flocculant to the iron-removed turbid liquid, and performing solid-liquid separation after sufficient flocculation.

[0045] In the technical solution of this application embodiment, by adjusting the pH value of acidic copper-containing wastewater, heavy metal ions (mainly iron and arsenic) in the wastewater can be precipitated, and iron ions in the wastewater can be effectively removed through subsequent flocculation and solid-liquid separation operations. More specifically, in some embodiments, the pH value is adjusted as follows: acidic copper-containing wastewater is input into an iron removal reaction tank, and a first pH value adjuster is added to adjust the pH value of the acidic copper-containing wastewater to 3.3~3.6. The first pH value adjuster is preferably lime and / or carbide slag. In some embodiments, the flocculant added to the iron removal turbid liquid is a nonionic flocculant (preferably nonionic polyacrylamide), and the amount of the flocculant added is preferably 1~5 g / m³. 3 .

[0046] Furthermore, in some embodiments, after solid-liquid separation to obtain iron-removed underflow and iron-removed overflow, a portion of the iron-removed underflow is recycled back to the iron removal reaction tank, and the remaining iron-removed underflow is subjected to pressure filtration and dewatering treatment. The recycling ratio of the iron-removed underflow is preferably 2% to 10%.

[0047] In the technical solution of this application embodiment, a small portion of the iron removal underflow is returned, while the rest of the iron removal underflow is filtered. Compared with the prior art method of inputting a portion of the iron removal underflow into the copper slag filtration system, this method is more conducive to improving the copper grade in the copper slag and thus obtaining higher economic value.

[0048] Furthermore, in some embodiments, the neutralization treatment includes: adjusting the pH of the copper overflow and the second filtrate to 8.2-8.8 and reacting for 0.75-1.2 hours to obtain a neutralized turbid liquid; adding a flocculant to the neutralized turbid liquid, and performing solid-liquid separation after sufficient flocculation.

[0049] In the technical solution of this application embodiment, after iron removal and copper recovery, the remaining heavy metal ions (iron, arsenic, lead, manganese, nickel, etc.) in the wastewater can be precipitated by adjusting the pH value of the copper recovery overflow and the second filtrate during the neutralization stage. These precipitates can then be effectively removed through subsequent flocculation and solid-liquid separation operations. This process does not require the addition of an oxidant, and compared to existing technologies, it effectively reduces costs while ensuring treatment effectiveness. More specifically, in some embodiments, the pH value is adjusted by inputting the copper recovery overflow and the second filtrate into the neutralization reaction tank and adding a second pH adjuster to adjust the pH value to 8.2-8.8. The second pH adjuster is preferably lime and / or carbide slag. In some embodiments, the flocculant added to the neutralized turbid liquid is a nonionic flocculant (preferably nonionic polyacrylamide), and the amount of flocculant added is preferably 1-15 g / m³. 3 .

[0050] Furthermore, in some embodiments, after solid-liquid separation to obtain neutralized underflow and neutralized overflow, a portion of the neutralized underflow is recycled back to the neutralization reaction tank, and the remaining neutralized underflow is subjected to pressure filtration and dewatering treatment. The recycling ratio of the neutralized underflow is preferably 70% to 90%.

[0051] Furthermore, in some embodiments, the concentration of copper ions in the acidic copper-containing wastewater is not less than 300 mg / L.

[0052] In the technical solution of this application embodiment, the acidic copper-containing wastewater is rich in copper ions, so it is necessary to efficiently recover these valuable copper ions and achieve a synergistic improvement in copper recovery rate and grade.

[0053] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0054] Example 1 This embodiment provides a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials. The acidic copper-containing wastewater contains high concentrations of heavy metals such as copper and iron, with copper concentrations of approximately 885 mg / L, iron concentrations of approximately 1978.2 mg / L, arsenic concentrations of approximately 4.4 mg / L, and manganese concentrations of approximately 33 mg / L. The process flow diagram is shown below. Figure 1 As shown, the specific steps include the following: S1, Activation of iron-based materials Preparation of iron-based materials: Micron-sized zero-valent iron powder with a particle size range of 100-200 mesh was collected and subjected to particle size narrowing sieving to obtain micron-sized zero-valent iron powder with a particle size distribution index (PDI) < 0.3. Quartz powder with a Mohs hardness ≥ 7 and a specific surface area ≥ 20 m² was also collected. 2 Kaolin and montmorillonite, each weighing approximately 100g, were dried and sieved to 300-500 mesh. Then, quartz powder, kaolin, and montmorillonite were mixed in a mass ratio of 2:3:1 to obtain pretreated mineral functional powder. Micron-sized zero-valent iron powder with a PDI < 0.3 was mixed with the pretreated mineral functional powder to obtain an iron-based material. In the iron-based material, the mass of the mineral functional powder accounted for 20% of the mass of the micron-sized zero-valent iron powder.

[0055] Activation treatment: Under normal air conditions, clean water and acidic copper-containing wastewater are mixed in an iron-based material activation tank. The pH of the mixture is adjusted to 5.0 by adjusting the ratio of the two. Then, iron-based materials are added to the mixture at a liquid-to-solid ratio of 10:1. At the same time, mechanical stirring is turned on and stirred at 50 rpm for 2.0 hours to fully activate the iron-based materials and obtain an activated suspension of iron-based materials.

[0056] S2, Iron removal Acidic copper-containing wastewater is fed into an iron removal reaction tank. Lime is added as the first pH adjuster to adjust the pH to 3.5, causing heavy metal ions (mainly iron and arsenic) to precipitate. After 0.5 hours of reaction, the iron ion concentration in the wastewater decreases to approximately 200 mg / L, yielding an iron-removed turbid liquid. This turbid liquid is then fed into an iron removal thickener at a concentration of 1.5 g / m³. 3 A nonionic polyacrylamide with a molecular weight of 10-12 million is added to the iron removal turbid liquid as a nonionic flocculant. After sufficient flocculation, the liquid is separated into solid and liquid components by an iron removal thickener, yielding an iron removal overflow and an iron removal underflow in sludge form. 10% of the iron removal underflow is recycled to the iron removal reaction tank, while the remaining underflow is dewatered by a first filter press, yielding a first filter residue and a first filter liquid. The first filter residue, i.e., the iron removal slag, meets the requirements for general industrial solid waste and is stored in compliance with regulations.

[0057] S3, Copper Collection The iron-removed overflow and the first filtrate obtained in step S2 are fed into the copper recovery reaction tank, and the activated suspension of the iron-based material obtained in step S1 is added to the copper recovery reaction tank to adjust the ORP value to 25mv (at this point, the actual amount of iron powder in the iron-based material is about 1.2 times the theoretical amount of iron replacing copper), so that heavy metal ions (mainly copper) are chemically precipitated. After reacting for 0.25 hours, the copper ion concentration in the liquid phase is below 1 mg / L, resulting in a copper-recovered turbid solution. The copper-recovered turbid solution is fed into a copper-recovering thickener at a concentration of 1.5 g / m³. 3 Nonionic polyacrylamide was added to the copper-collecting turbid liquid at a specified dosage. After thorough flocculation, the liquid was separated into solid and liquid components using a copper-collecting thickener, yielding a copper-collecting overflow and a copper-collecting underflow in sludge form. 40% of the copper-collecting underflow was recycled to the copper-collecting reaction tank, while the remaining underflow underwent dewatering treatment using a second filter press, yielding a second filter residue and a second filter liquid. The copper content in the second filter residue was 56.74%, which can be sold as copper slag.

[0058] S4, Neutralization The copper-collected overflow and second filtrate obtained in step S3 are fed into the neutralization reaction tank. Lime is added as a second pH adjuster to adjust the pH to 8.5, causing the remaining heavy metal ions (mainly iron, arsenic, lead, manganese, nickel, etc.) in the wastewater to precipitate. After reacting for 1 hour, a neutralized turbid liquid is obtained. The neutralized turbid liquid is fed into a neutralization thickener at a concentration of 10 g / m³. 3 Nonionic polyacrylamide is added to the neutralized turbid liquid at a specified dosage. After thorough flocculation, the liquid is separated into solid and liquid components using a neutralization thickener, yielding a neutralization overflow and a neutralization underflow in sludge form. 80% of the neutralization underflow is recycled back to the neutralization reaction tank, while the remaining underflow undergoes dewatering treatment using a third filter press, yielding a third filter cake and a third filter liquid. The target heavy metals in the neutralization overflow and the third filter liquid meet the Class I discharge standards of the "Integrated Wastewater Discharge Standard" (GB 8978-1996) and the direct discharge limits specified in the "Emission Standard of Pollutants for Copper, Cobalt, and Nickel Industries" (GB 25467-2010), and are discharged in compliance with standards. The third filter cake meets the standards for general industrial solid waste and is stored in compliance with regulations.

[0059] The influent and effluent water quality of this embodiment were tested, and the results are shown in Table 1.

[0060] Table 1. Water quality of influent and effluent In Table 1, pH value is dimensionless, and the units of the other indicators in the table are "mg / L". The indicators such as pH, Cu, Pb, Zn, Cd, Cr, As, Ni, Mn, COD, and ammonia nitrogen in this table meet the requirements of the Class I standard of the "Integrated Wastewater Discharge Standard" (GB 8979-1996), and sulfate meets the standard in the "Surface Water Environmental Quality Standard" (GB 3838-2002).

[0061] As can be seen from Table 1, after comprehensive treatment of acidic copper-containing wastewater based on iron-based materials provided in this embodiment, the effluent quality meets the corresponding requirements, and the recovery rate of valuable copper reaches 95.8%, with the grade of the recovered copper slag reaching 56.74%, thus achieving efficient recovery of valuable copper from acidic copper-containing wastewater.

[0062] Examples 2-8 and Comparative Examples 1-4 Examples 2-8 and Comparative Examples 1-4 each provide a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials. Compared with Example 1, the only difference is the change in the composition of the iron-based material in step S1; the remaining steps are the same as in Example 1 and will not be repeated here. The specific composition of the iron-based material in each example and comparative example is shown in Table 2.

[0063] Table 2 Composition of iron-based materials In the table above, Comparative Example 3 represents the addition of no mineral functional powder.

[0064] After treating the acidic copper-containing wastewater in Example 1 according to the methods provided in Examples 2-8 and Comparative Examples 1-4, the copper recovery rate, copper slag grade, reagent dosage, and slag production were tested and compared with those in Example 1. The results are shown in Table 3. Specifically, the reagent dosage refers to the ratio of the actual amount of iron powder added to the theoretical amount of iron powder used in the iron-based material; the slag production refers to the total mass of the first and third filter press residues. The meanings of reagent dosage and slag production in the following text are consistent with those here and will not be repeated.

[0065] Table 3 Comparison of detection results in Examples 1-8 and Comparative Examples 1-4 As shown in Table 3, reducing the iron powder mesh size, increasing the iron powder particle size distribution index, reducing the mineral powder mesh size, using too much or too little mineral powder, or adjusting the mineral powder composition all lead to increased reagent dosage, increased slag production, and decreased copper slag grade, negatively impacting copper recovery rate. While using only one of quartz powder, kaolin, or montmorillonite as the functional mineral powder can achieve some activation, its effect is far less than using a mixture of quartz powder, kaolin, and montmorillonite in a specific ratio. This application, by mixing quartz powder, kaolin, and montmorillonite in a mass ratio of (2~3):3:(1~2), facilitates synergistic effects among the three, forming an integrated system of grinding modification, stabilization protection, and activation enhancement, thereby achieving better activation results and synergistically improving copper recovery rate and copper slag grade while reducing reagent dosage and slag production.

[0066] Examples 9-13 and Comparative Examples 5-7 Examples 9-13 and Comparative Examples 5-7 each provide a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials. Compared with Example 1, the only difference is that the activation treatment conditions in step S1 are changed; the remaining steps are the same as in Example 1 and will not be repeated here. The activation treatment conditions in each example and comparative example are shown in Table 4.

[0067] Table 4 Activation Treatment Conditions In the table above, Comparative Example 5 indicates that only water was used for activation, without the addition of acidic copper-containing wastewater.

[0068] After treating the acidic copper-containing wastewater in Example 1 according to the methods provided in Examples 9-13 and Comparative Examples 5-7, the copper recovery rate, copper slag grade, reagent dosage and slag production were tested and compared with those in Example 1. The results are shown in Table 5.

[0069] Table 5 Comparison of detection results in Examples 1, 9-13 and Comparative Examples 5-7 As can be seen from Table 5, factors such as excessively high activation pH, excessively low liquid-to-solid ratio, and excessively short stirring time will reduce the activation effect of iron-based materials, thereby increasing the amount of reagent added and affecting the grade of copper slag and the amount of slag produced.

[0070] Comparative Examples 8-9 Comparative Examples 8 and 9 respectively provide a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials. Compared with Example 1, the only difference is that the pH value adjusted by the first pH value adjuster during iron removal in step S2 is changed. Comparative Examples 9 and 10 adjust the pH value to 4.0 and 3.0 respectively during iron removal. The remaining steps in Comparative Examples 8 and 9 are the same as those in Example 1, and will not be repeated here.

[0071] After treating the acidic copper-containing wastewater in Example 1 according to the methods provided in Comparative Examples 8-9, the copper recovery rate, copper slag grade, reagent dosage and slag production were tested and compared with those in Example 1. The results are shown in Table 6.

[0072] Table 6 Comparison of detection results in Example 1 and Comparative Examples 8-9 As can be seen from Table 6, if the pH value is adjusted too high during iron removal, the pH value for copper recovery in the next step will be too high, and the copper recovery rate will decrease significantly. If the pH value is adjusted too low during iron removal, iron removal will be incomplete, and iron ions and hydrogen ions will consume the reagents, which will lead to a significant increase in the amount of reagents added.

[0073] Comparative Examples 10-11 Comparative Examples 10 and 11 respectively provide a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials. Compared with Example 1, the only difference is that the ORP value adjusted by activating the suspension with iron-based materials during copper collection in step S3 is changed. In Comparative Examples 10 and 11, the ORP value is adjusted to 100mv and -50mv respectively during copper collection. The remaining steps in Comparative Examples 10 and 11 are the same as those in Example 1, and will not be repeated here.

[0074] After treating the acidic copper-containing wastewater in Example 1 according to the methods provided in Comparative Examples 10-11, the copper recovery rate, copper slag grade, and reagent dosage were tested and compared with those in Example 1. The results are shown in Table 7.

[0075] Table 7 Comparison of detection results in Example 1 and Comparative Examples 10-11 As can be seen from Table 7, if the ORP value is controlled too high during copper recovery, copper recovery will be incomplete and the copper recovery rate will be low; if the ORP value is controlled too low during copper recovery, the amount of reagent added will increase significantly and the copper recovery rate will also decrease.

[0076] Example 14 and Comparative Example 12 Example 14 and Comparative Example 12 respectively provide a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials. Compared with Example 1, the only difference is that the reflux ratio of the copper underflow during copper collection in step S3 is changed. The reflux ratios of the copper underflow in Example 14 and Comparative Example 12 are 70% and 10%, respectively. The remaining steps in Example 14 and Comparative Example 12 are the same as those in Example 1, and will not be repeated here.

[0077] After treating the acidic copper-containing wastewater in Example 1 according to the methods provided in Example 14 and Comparative Example 12, the copper recovery rate, copper slag grade, reagent dosage and slag production were tested and compared with those in Example 1. The results are shown in Table 8.

[0078] Table 8 Comparison of detection results in Example 1, Example 14 and Comparative Example 12 As can be seen from Table 8, if the reflux rate of the copper underflow is too low during copper recovery, it will lead to a significant increase in the amount of reagent added and the amount of slag produced, and a significant decrease in the grade of copper slag.

[0079] In summary, this application provides a comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials, belonging to the technical field of acidic copper-containing wastewater treatment. The method includes: preparing an iron-based material containing micron-sized zero-valent iron powder and mineral functional powders; placing the iron-based material in a weakly acidic aqueous solution with a pH of 4.0-6.0; mechanically stirring to obtain an activated suspension of the iron-based material; sequentially treating the acidic copper-containing wastewater with iron removal, copper recovery, and neutralization; adding the activated suspension of the iron-based material during the copper recovery stage to adjust the ORP value to 0-50 mV; and recirculating a portion of the copper-recovered underflow to the copper recovery reaction tank. This application achieves a copper recovery rate of over 95% and a copper slag grade of over 56% through a combination of technical means, including optimizing the composition of the iron-based material system, improving the treatment method of the iron-based material, and controlling the underflow reflux mode. The amount of reagent required is only 1.2 times the theoretical value. This approach ensures a high copper recovery rate and copper grade while increasing the reaction rate, and reduces the amount of reagent used and the amount of waste slag generated, thus achieving efficient treatment of acidic copper-containing wastewater.

[0080] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials, characterized in that, Includes the following steps: An iron-based material containing micron-sized zero-valent iron powder and mineral functional powder is prepared. The iron-based material is placed in a weakly acidic basic aqueous solution with a pH of 4.0~6.0 and mechanically stirred to obtain an activated suspension of the iron-based material. In the iron-based material, the mass of the mineral functional powder accounts for 5%~30% of the mass of the micron-sized zero-valent iron powder, and the mineral functional powder is composed of quartz powder, kaolin, and montmorillonite in a mass ratio of (2~3):3:(1~2). The acidic copper-containing wastewater is subjected to iron removal treatment to obtain an iron-removed underflow and an iron-removed overflow; the iron-removed underflow is dewatered by pressure filtration to obtain a first filter residue and a first filter liquid; the iron removal treatment includes: adjusting the pH value of the acidic copper-containing wastewater to 3.3~3.6 and reacting for 0.25~0.5h to obtain an iron-removed turbid liquid; adding a flocculant to the iron-removed turbid liquid, and performing solid-liquid separation after sufficient flocculation; The iron-removed overflow and the first filtrate are fed into the copper recovery reaction tank. The iron-based material activation suspension is added to adjust the ORP value to 0-50mv, resulting in a copper-recovering turbid liquid. The copper-recovering turbid liquid is then subjected to flocculation and solid-liquid separation treatments to obtain a copper-recovering underflow and a copper-recovering overflow. A portion of the copper-recovering underflow is returned to the copper recovery reaction tank, while the other portion is dewatered by pressure filtration to obtain a second filter residue and a second filtrate. The copper overflow and the second filtrate are neutralized to obtain neutralized underflow and neutralized overflow; the neutralized underflow is dehydrated by pressure filtration to obtain third filter residue and third filtrate. The preparation method of the iron-based material includes: Take micron-sized zero-valent iron powder with a mesh size of 100-400 and perform particle size narrowing sieving to obtain micron-sized zero-valent iron powder with a particle size distribution index of <0.3; The micron-sized zero-valent iron powder with a particle size distribution index of <0.3 is mixed with mineral functional powder of 300~500 mesh to obtain iron-based materials.

2. The comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials according to claim 1, characterized in that, The weakly acidic basic aqueous solution is obtained by diluting the acidic copper-containing wastewater; the mass ratio of the weakly acidic basic aqueous solution to the iron-based material is 5~10:

1.

3. The comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials according to claim 1, characterized in that, The mechanical stirring time is 0.5~4.0h.

4. The comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials according to claim 1, characterized in that, The reflux ratio of the copper underflow is 40%~70%.

5. The comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials according to claim 1, characterized in that, The neutralization process includes: adjusting the pH of the copper overflow and the second filtrate to 8.2-8.8 and reacting for 0.75-1.2 hours to obtain a neutralized turbid liquid; adding a flocculant to the neutralized turbid liquid, and performing solid-liquid separation after sufficient flocculation.

6. The comprehensive treatment method for acidic copper-containing wastewater based on iron-based materials according to claim 1, characterized in that, The concentration of copper ions in the acidic copper-containing wastewater is not less than 300 mg / L.

Images