A high-efficiency copper removal and recycling system for copper cyanide complex wastewater

Abstract

The utility model relates to a kind of copper cyanide complex wastewater high-efficiency copper removal and recycling system, including 1# stirring barrel, 2# stirring barrel and 3# stirring barrel connected in turn by pipeline, the 3# stirring barrel is connected by pipeline and pump in the feed inlet of hydrocyclone, overflow outlet of the hydrocyclone is sequentially connected with 4# stirring barrel, 5# stirring barrel and 6# stirring barrel by pipeline, the discharge outlet of the 6# stirring barrel is connected by pipeline in the feed inlet of weak magnetic separator;1# pH meter is installed in the 1# stirring barrel, heating device is installed in the 2# stirring barrel, 2# pH meter is installed in the 4# stirring barrel.The closed-loop system of the utility model can efficiently remove and recover copper in copper cyanide complex wastewater, and wastewater is treated and then reused for cyanide leaching operation, which can significantly reduce the consumption of sodium cyanide and improve the leaching rate of gold and silver, and truly realize wastewater zero discharge and copper resource full recovery.

Description

Technical Field

[0001] This utility model belongs to the field of mining wastewater resource utilization technology, specifically relating to a high-efficiency copper removal and recycling system for copper-cyanide complexed wastewater. Background Technology

[0002] During the cyanide leaching process of gold and silver oxide ores, since the copper content in the raw ore is 0.2% to 0.3%, copper reacts with sodium cyanide to form a large amount of copper-cyanide complex (Cu(CN)3). 2- / Cu(CN)4 3- The copper concentration in the tailings remains in the wastewater, causing it to accumulate to over 2000 mg / L during the recycling process. Reusing this high-concentration copper-cyanide complex wastewater presents the following problems: the copper-cyanide complex consumes sodium cyanide, increasing sodium cyanide consumption by 2-3 times; simultaneously, the copper-cyanide complex forms an adsorption layer on the surfaces of gold and silver, reducing the leaching rate of gold and silver by 5-10%, and leading to system salinity accumulation and equipment corrosion.

[0003] However, traditional methods for treating high-cyanide and high-copper wastewater, such as acidification, sodium sulfide precipitation, and iron salt co-precipitation, all have numerous drawbacks. Acidification requires lowering the pH to below 2, which releases highly toxic HCN gas, posing extremely high safety risks and causing severe equipment corrosion. Sodium sulfide precipitation easily produces colloidal copper sulfide sludge, making solid-liquid separation difficult, and excessive sulfur ion residue leads to sulfur accumulation in the reclaimed water system. Iron salt co-precipitation generates large amounts of hazardous waste, and its disposal costs are high.

[0004] To address the aforementioned problems, this utility model proposes a novel high-efficiency copper removal and recycling system for copper-cyanide complex wastewater. The aim is to solve the problem of recycling high-concentration copper-cyanide complex wastewater, achieving copper recovery and wastewater recycling, and promoting cleaner production and near-zero emissions in mines. Utility Model Content

[0005] This invention provides a highly efficient copper removal and recycling system for copper-cyanide complex wastewater. Based on the properties of copper-cyanide complexes, the system precisely controls the pH value and utilizes critical acidification-selective crystallization technology to convert the copper-cyanide complexes in the solution into CuCN crystals. After recovering CuCN copper concentrate using a hydrocyclone separator, further deep copper removal is achieved through gradient activation with a composite sulfiding agent. This is combined with magnetic seed trapping and weak magnetic separation technology to separate high-density CuS particles, thereby efficiently removing copper from the solution while reducing sulfur enrichment. This transforms high-concentration copper-cyanide complex wastewater into recyclable wastewater, solving the problems associated with the reuse of high-concentration copper-cyanide complex wastewater.

[0006] Specific technical solutions:

[0007] A highly efficient copper removal and recycling system for copper-cyanide complex wastewater includes three mixing tanks connected in series via pipelines: a #1 mixing tank, a #2 mixing tank, and a #3 mixing tank. The #3 mixing tank is connected to the inlet of a hydrocyclone via a pipeline and a pump. The overflow outlet of the hydrocyclone is connected in series with mixing tanks #4, #5, and #6 via pipelines. The outlet of the #6 mixing tank is connected to the inlet of a weak magnetic separator via a pipeline. A #1 pH meter is installed inside the #1 mixing tank, a heating device is installed inside the #2 mixing tank, and a #12 pH meter is installed inside the #4 mixing tank.

[0008] Furthermore, preferably, the No. 1 stirring tank is equipped with a sulfuric acid addition pipe, and the sulfuric acid addition pipe is equipped with a No. 1 flow meter and a No. 1 solenoid valve.

[0009] Furthermore, preferably, a sodium hydroxide addition pipe is installed on the No. 4 mixing tank, and a No. 2 flow meter and a No. 2 solenoid valve are installed on the sodium hydroxide addition pipe.

[0010] Furthermore, preferably, the discharge port of the weak magnetic separator is connected to the cyanide leaching system via a pipeline.

[0011] Furthermore, preferably, the hydrocyclone is selected with an operating pressure of 0.3 to 0.5 MPa.

[0012] Furthermore, preferably, the weak magnetic separator uses a magnetic field strength of 0.5T.

[0013] The beneficial effects of this utility model are:

[0014] This invention utilizes a closed-loop system of "critical acidification selective crystallization – cyclone-enhanced crystallization – composite sulfide agent gradient activation – magnetic seed-enhanced separation." By precisely controlling key parameters such as pH, temperature, and pressure, it accurately triggers the directional dissociation of copper-cyanide complexes, inducing highly selective nucleation and growth of CuCN crystals. Subsequently, a cyclone classifier achieves rapid crystal separation, and a composite sulfide agent gradient activation combined with magnetic seed coupling technology further transforms residual copper into easily magnetically separated dense CuS particles, while simultaneously performing deep desulfurization. The entire closed-loop system efficiently removes and recovers copper from copper-cyanide complex wastewater. After treatment, the wastewater can be reused in cyanide leaching operations, significantly reducing sodium cyanide consumption and increasing gold and silver leaching rates. This truly achieves zero wastewater discharge and full copper resource recovery, meeting the green goals of "low sulfur, low slag, and high recovery," resulting in significant economic, environmental, and social benefits.

[0015] Furthermore, compared to traditional acidification methods, this invention utilizes critical acidification for selective crystallization, avoiding the need to lower the pH value below 2. This prevents the release of highly toxic hydrogen cyanide (HCN) gas and severe equipment corrosion, significantly improving safety. Compared to conventional sulfide precipitation, this invention employs a combined system of "composite sulfide agent gradient activation - magnetic seed enhanced separation," completely solving industry problems such as the difficulty in settling and filtering copper sulfide colloids, uncontrollable sulfur pollution, and the lack of value in sludge. Simultaneously, it prevents excessive S²⁻ from entering the recycle water, thus avoiding sulfur accumulation and the formation of SCN. - Or H2S. Attached Figure Description

[0016] Figure 1 This is an equipment diagram of a high-efficiency copper removal and recycling system for copper-cyanide complex wastewater according to this utility model.

[0017] In the diagram: 1-1# mixing tank; 2-2# mixing tank; 3-3# mixing tank; 4- hydrocyclone; 5-4# mixing tank; 6-5# mixing tank; 7-6# mixing tank; 8- weak magnetic separator; 9- cyanide leaching system; 101-1# pH meter, 102-2# pH meter; 11- sulfuric acid addition tube; 12- heating device; 13- sodium hydroxide addition tube; 141-1# flow meter, 142-2# flow meter; 151-1# solenoid valve, 152-2# solenoid valve. Detailed Implementation

[0018] To make the technical problems and solutions solved by this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present utility model and are not intended to limit the present utility model.

[0019] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0020] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] like Figure 1 As shown, this utility model provides a high-efficiency copper removal and recycling system for copper-cyanide complex wastewater, including a No. 1 mixing tank 1, a No. 2 mixing tank 2, and a No. 3 mixing tank 3 connected in series via pipes. The No. 3 mixing tank 3 is connected to the inlet of a hydrocyclone 4 via a pipe and a pump. The overflow port of the hydrocyclone 4 is connected in series via pipes to a No. 4 mixing tank 5, a No. 5 mixing tank 6, and a No. 6 mixing tank 7. The outlet of the No. 6 mixing tank 7 is connected to the inlet of a weak magnetic separator 8 via a pipe. The outlet of the weak magnetic separator 8 is connected to a cyanide leaching system 9 via a pipe.

[0022] A pH meter 101 is installed inside mixing tank 1, a heating device 12 is installed inside mixing tank 2, and a pH meter 102 is installed inside mixing tank 4. A sulfuric acid addition tube 11 is installed on mixing tank 1, and a flow meter 141 and a solenoid valve 151 are installed on the sulfuric acid addition tube 11. A sodium hydroxide addition tube 13 is installed on mixing tank 4, and a flow meter 142 and a solenoid valve 152 are installed on the sodium hydroxide addition tube 13.

[0023] The mixing tanks 1, 2, and 3 are positioned with a certain elevation difference, as are the hydrocyclones 4, 4, 6, and 7. This ensures that the wastewater in the entire system can flow by gravity to the next stage, reducing the power supply required. In addition, the hydrocyclone 4 is selected with an operating pressure of 0.3–0.5 MPa, and the weak magnetic separator 8 is selected with a magnetic field strength of 0.5 T.

[0024] It should be noted that all of the above-mentioned equipment are existing equipment, and this application only relates to the application of these existing equipment, and does not involve any improvement to their structure. For example, the heating device 12 can be an existing vertical heating tube, and the weak magnetic separator 8 can be an existing permanent magnet drum magnetic separator.

[0025] Working principle:

[0026] (1) When treating copper-cyanide complex wastewater, the wastewater is pumped into No. 1 stirring tank 1. 5% dilute sulfuric acid is added to No. 1 stirring tank 1 through sulfuric acid addition pipe 11. When the pH value detected by No. 1 pH meter 101 is 4.0-4.5, the addition is stopped. After stirring and mixing, the valve at the outlet of No. 1 stirring tank 1 is opened, and the solution flows by gravity to No. 2 stirring tank 2. At this time, the heating device 12 in No. 2 stirring tank 2 is started to heat the solution temperature to 40℃. After reacting in No. 2 stirring tank for 2 hours, the copper-cyanide complex is directionally recombined to generate insoluble CuCN crystals. The valve at the outlet of No. 2 stirring tank 2 is opened, and the insoluble CuCN crystals flow by gravity with the solution to No. 3 stirring tank 3.

[0027] During this process, when the solution pH drops to 4.0–4.5, low CN - Concentration disrupts the stability of high-coordination copper-cyanide complexes, prompting them to dissociate towards lower coordination numbers. When low-coordination complexes dominate, the extremely low solubility of CuCN becomes the core driving force for directional crystallization, i.e., the copper-cyanide complex ([Cu(CN)3)). 2- [Cu(CN)4] 3- The copper-cyanide complex undergoes directional recombination, generating insoluble crystals CuCN·xH2O (white powder). When the pH of the solution is greater than 5, the copper-cyanide complex does not dissolve; when the pH of the solution is less than 3.5, HCN volatilizes in large quantities, and CuCN dissolution intensifies. Therefore, precise pH control is crucial. This application utilizes a combination of a pH meter 101, a flow meter 141, a solenoid valve 151, and a PLC controller to precisely regulate the pH of the wastewater (the specific control process is conventional and will not be elaborated here). Simultaneously, combined with heating and stirring, the copper-cyanide complex undergoes directional dissociation at its critical point of pH 4.0–4.5, while maintaining the HCN volatilization rate below the nucleation rate to avoid gaseous loss. This drives the selective crystallization of thermodynamically stable CuCN, completing the critical acidification-selective crystallization of the copper-cyanide complex wastewater.

[0028] (2) The crystallization mixture in the No. 3 stirring tank 3 is then pumped into the hydrocyclone 4 for solid-liquid separation. The CuCN crystals are discharged from the bottom sand outlet and are dried to obtain CuCN copper concentrate. The overflow liquid flows by gravity to the No. 4 stirring tank 5.

[0029] In this process, due to the problems that CuCN crystals are prone to deformation under pressure, easy to clog the filter cloth pores, and the residence time cannot be too long, and given that the separation efficiency of the conical hydrocyclone is highly compatible with the physical properties of the crystals, and that the equipment has advantages such as corrosion resistance, strong wear resistance, and low operating costs, the conical hydrocyclone (operating pressure selected as 0.3~0.5MPa) is selected for separation.

[0030] (3) Add 10% NaOH to the No. 4 mixing tank 5 to adjust the pH value of the overflow liquid to 8.5-9.0. After stirring and mixing, open the valve of the discharge port of the No. 4 mixing tank 5 to allow the solution to flow by gravity into the No. 5 mixing tank. Then add the composite sulfiding agent (prepared by mixing sodium sulfide and triethanolamine in a molar ratio of 1:0.05). The consumption of the added agent is 75mg / L. After stirring and reacting for 2 hours, the fine CuCN particles and dissolved low-coordinated copper cyanide complex in the overflow liquid react to generate insoluble CuS crystals, achieving the dual purpose of deep copper removal and reducing sulfur enrichment.

[0031] In this process, a composite vulcanizing agent (concentration of 10%) and a gradient vulcanization control mechanism are used to vulcanize S 2-The concentration is controlled at 50–100 mg / L to limit the CuS nucleation rate and promote crystal growth. Simultaneously, triethanolamine activates hi-2, which adsorbs onto the CuS crystal nuclei, forming a steric hindrance layer on the surface and preventing the aggregation of fine particles. Furthermore, the pH of the solution is controlled at 8.5–9.0 to avoid H2S formation and optimize CuS crystallinity. Compared to the traditional sodium sulfide precipitation method, this method solves the problems of difficult sedimentation of colloidal suspensions and excessive sulfur content. 2- Sulfur accumulation (SCN formation) occurs when water enters the return water system. - Issues such as H2S (or H2S) are addressed. Specifically, precise pH control is achieved through the combination of a pH meter 101 (2#), a flow meter 141 (2#), a solenoid valve 151 (2#), and a PLC controller.

[0032] (4) Open the valve at the outlet of the No. 5 mixing tank 6 to allow the crystallization mixture solution to flow by gravity into the No. 6 mixing tank 7. Then add the modified magnetic seed Fe3O4@SiO2-CH3. After stirring and reacting for 2 hours, open the valve at the outlet of the No. 6 mixing tank 7 to introduce the solution into the weak magnetic separator 8. Under the action of the weak magnetic field, the modified magnetic seeds attract each other and form chain aggregates. These chain aggregates trap and wrap CuS particles to form CuS magnetic flocs. The CuS magnetic flocs will be adsorbed on the surface of the magnetic drum and discharged from the concentrate end. After drying, CuS magnetic floc concentrate is obtained, while the separated purified tailings are recycled into the cyanide leaching system 9.

[0033] During this process, the magnetic seeds can also adsorb residual S² in the solution while adsorbing CuS particles. - This prevents CuS from accumulating in the solution, further reducing the sulfur content and avoiding secondary pollution. Furthermore, the formation of magnetic flocs and the magnetic separation process effectively remove excess moisture, reducing the water content of the CuS magnetic flocs and improving recovery efficiency and product quality.

[0034] Application examples

[0035] Taking the copper-cyanide complex wastewater (copper content 2000 mg / L) generated from the cyanidation leaching process of a gold and silver oxide ore as an example, the copper-cyanide complexation high-efficiency copper removal and recycling process described in this utility model is used for treatment. The specific implementation is as follows:

[0036] (1) Critical acidification-selective crystallization of copper-cyanide complex wastewater: Wastewater is pumped into No. 1 stirring tank 1. 5% dilute sulfuric acid is added to No. 1 stirring tank 1 through sulfuric acid addition pipe 11. When the value detected by No. 1 pH meter 101 is about 4.25, the addition is stopped. After stirring and mixing, the valve of the discharge port of No. 1 stirring tank 1 is opened, and the solution flows by gravity to No. 2 stirring tank 2. At this time, the heating device 12 in No. 2 stirring tank 2 is started to heat the solution temperature to 40℃. After reacting in No. 2 stirring tank for 2 hours, the copper-cyanide complex is directionally recombined to generate insoluble CuCN crystals. The valve of the discharge port of No. 2 stirring tank 2 is opened, and the insoluble CuCN crystals flow by gravity with the solution to No. 3 stirring tank 3.

[0037] (2) Cyclone-enhanced crystallization: The crystallization mixture in the No. 3 stirring tank 3 is then pumped into the hydrocyclone 4 for solid-liquid separation. CuCN crystals are discharged from the bottom sand outlet and are dried to obtain CuCN copper concentrate. The overflow liquid flows by gravity to the No. 4 stirring tank 5.

[0038] (3) Gradient activation of composite sulfide agent for deep copper removal: Add 10% NaOH to the No. 4 stirring tank 5, adjust the pH value of the overflow liquid to 8.5-9.0, stir and mix well, open the valve of the discharge port of the No. 4 stirring tank 5, and let the solution flow into the No. 5 stirring tank by gravity. Then add composite sulfide agent (prepared by mixing sodium sulfide and triethanolamine in a molar ratio of 1:0.05). The consumption of the added agent is 75mg / L. After stirring and reacting for 2 hours, the fine CuCN particles and dissolved low-coordinated copper cyanide complex in the overflow liquid react to generate insoluble CuS crystals, achieving the dual purpose of deep copper removal and reducing sulfur enrichment.

[0039] (4) Magnetic seed enhanced separation: Open the valve of the discharge port of the No. 5 stirring tank 6 to allow the crystallization mixed solution to flow by gravity into the No. 6 stirring tank 7. Then add the modified magnetic seed Fe3O4@SiO2-CH3. After stirring and reacting for 2 hours, open the valve of the discharge port of the No. 6 stirring tank 7 to introduce the solution into the weak magnetic separator 8. Under the action of the weak magnetic field, the modified magnetic seeds attract each other and form chain aggregates. These chain aggregates capture and wrap CuS particles to form CuS magnetic flocs. The CuS magnetic flocs will be adsorbed on the surface of the magnetic drum and discharged from the concentrate end. After drying, CuS magnetic floc concentrate is obtained, while the separated purified tailings are recycled into the cyanide leaching system 9.

[0040] After the above treatment, the copper content in the solution decreased from 2000 mg / L to 18 mg / L, with a copper removal rate as high as 99.1%, and a yield of 1.82 kg / m³ was obtained. 3 A CuCN copper concentrate with a copper grade of 61.5% and a yield of 2.1 kg / m³. 3 CuS magnetic flocculent copper concentrate with a copper grade of 43%.

[0041] To further verify the effectiveness of reusing the purified solution in the cyanide leaching process, compared with cyanide leaching of untreated high-concentration copper-cyanide complex wastewater, the sodium cyanide consumption decreased from 2.6 kg / t to 1.25 kg / t, and the gold leaching rate increased from 88.1% to 94.5% when using the purified solution for ore cyanide leaching. It is evident that the wastewater reuse process described in this invention significantly reduces the amount of sodium cyanide used and improves the gold leaching rate.

[0042] The present invention has been described in detail above through specific and preferred embodiments. However, those skilled in the art should understand that the present invention is not limited to the embodiments described above. Any modifications or equivalent substitutions made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A highly efficient copper removal and recycling system for copper-cyanide complexed wastewater, characterized in that, The system includes a No. 1 mixing tank (1), a No. 2 mixing tank (2), and a No. 3 mixing tank (3) connected in series via pipes. The No. 3 mixing tank (3) is connected to the inlet of a hydrocyclone (4) via pipes and a pump. The overflow outlet of the hydrocyclone (4) is connected in series via pipes to a No. 4 mixing tank (5), a No. 5 mixing tank (6), and a No. 6 mixing tank (7). The outlet of the No. 6 mixing tank (7) is connected to the inlet of a weak magnetic separator (8) via pipes. A No. 1 pH meter (101) is installed inside the No. 1 mixing tank (1), a heating device (12) is installed inside the No. 2 mixing tank (2), and a No. 12 pH meter (102) is installed inside the No. 4 mixing tank (5).

2. The efficient copper removal and recycling system for copper-cyanide complexed wastewater according to claim 1, characterized in that, The No. 1 mixing tank (1) is equipped with a sulfuric acid addition pipe (11), and the sulfuric acid addition pipe (11) is equipped with a No. 1 flow meter (141) and a No. 1 solenoid valve (151).

3. A high-efficiency copper removal and recycling system for copper-cyanide complex wastewater according to claim 1 or 2, characterized in that, The 4# mixing tank (5) is equipped with a sodium hydroxide addition pipe (13), and the sodium hydroxide addition pipe (13) is equipped with a 2# flow meter (142) and a 2# solenoid valve (152).

4. The efficient copper removal and recycling system for copper-cyanide complexed wastewater according to claim 3, characterized in that, The outlet of the weak magnetic separator (8) is connected to the cyanide leaching system (9) via a pipeline.

5. A high-efficiency copper removal and recycling system for copper-cyanide complex wastewater according to claim 1 or 4, characterized in that, The hydrocyclone (4) is selected with an operating pressure of 0.3 to 0.5 MPa.

6. A high-efficiency copper removal and recycling system for copper-cyanide complex wastewater according to claim 1 or 4, characterized in that, The weak magnetic separator (8) uses a magnetic field strength of 0.5T.

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