Resourceful treatment system for copper-containing wastewater in copper foil production

Abstract

The utility model relates to a resourceful treatment system for copper-containing wastewater in copper foil production. The resourceful treatment system comprises a pretreatment unit, a membrane separation unit, a nanofiltration unit, a concentrated water recycling unit and a rotational flow electrolysis unit which are connected in sequence, the membrane separation unit comprises a multi-stage permeable membrane device, and the nanofiltration unit comprises a multi-stage nanofiltration membrane device; the copper foil production copper-containing wastewater is pretreated by the pretreatment unit and then is separated by the membrane separation unit to obtain copper-containing concentrated water; and then the copper-containing concentrated water is filtered by a nanofiltration unit and then electrolyzed by a rotational flow electrolysis unit. The device disclosed by the utility model realizes high-efficiency recovery of copper resources and near-zero discharge of wastewater, and has a good application prospect.

Description

Technical Field

[0001] This utility model belongs to the field of industrial wastewater treatment technology, and specifically relates to a resource-based treatment system for copper-containing wastewater from copper foil production. Background Technology

[0002] Direct discharge of concentrated wastewater from conventional RO treatment wastes copper resources and fails to meet the requirement of copper ≤0.5mg / L in the "Emission Standard of Pollutants for Copper, Nickel and Cobalt Industries" (GB 25467-2010). The single chemical precipitation method generates large amounts of copper-containing sludge (hazardous waste code: HW22), resulting in high disposal costs. Direct electrolysis for copper extraction from low-concentration wastewater (Cu...) is a better option. 2+ When the concentration of copper is <500 mg / L, the current efficiency is less than 40%, resulting in excessive energy consumption. Therefore, a new method for treating copper-containing wastewater needs to be developed. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to provide a resource-based treatment system for copper-containing wastewater from copper foil production, which achieves efficient recovery of copper resources and near-zero wastewater discharge.

[0004] This utility model provides a resource-based treatment system for copper-containing wastewater from copper foil production, comprising a pretreatment unit, a membrane separation unit, a nanofiltration unit, a concentrate reuse unit, and a cyclone electrolysis unit connected in sequence; the membrane separation unit includes a multi-stage permeate membrane device, and the nanofiltration unit includes a multi-stage nanofiltration membrane device; the copper-containing wastewater from copper foil production is pretreated by the pretreatment unit, then separated by the membrane separation unit to obtain copper-containing concentrate; subsequently, the copper-containing concentrate is filtered by the nanofiltration unit and then electrolyzed by the cyclone electrolysis unit.

[0005] Preferably, the pretreatment unit includes a bag filter.

[0006] Preferably, the multi-stage permeation membrane device uses a spiral wound polyamide membrane with a membrane housing pressure resistance ≥3MPa.

[0007] Preferably, the multi-stage nanofiltration membrane device uses a DK8040F nanofiltration membrane with a molecular weight cutoff of 200-300 Da.

[0008] Preferably, the concentrate reuse unit is equipped with an intelligent diversion valve.

[0009] Preferably, the cyclone electrolysis cell in the cyclone electrolysis unit adopts a coated titanium anode and a stainless steel cathode; the cyclone electrolysis process parameters are: pulse power supply frequency 50-100Hz, current density 400-450A / m2, and temperature 30-35℃.

[0010] Beneficial effects

[0011] (1) This invention achieves concentration through the synergistic effect of multi-stage RO and multi-stage nanofiltration, with RO preferentially retaining free Cu. 2+ Nanofiltration specifically concentrates complexed copper (such as Cu-EDTA) to stabilize the copper concentration in the electrolytic feed water at 25-30 g / L.

[0012] (2) The membrane combination of this invention increases the copper concentration in the electrolyte by 4-6 times and the current efficiency from 38% to 72%.

[0013] (3) The concentrated water reuse unit of this utility model is based on the diversion control of copper concentration feedback in real time, which reduces the load fluctuation of the electrolysis unit and realizes the dynamic balance of copper ion concentration in the sludge tank (maintaining 130-170mg / L).

[0014] (4) This utility model achieves efficient copper resource recovery and near-zero wastewater discharge, and has good application prospects. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the resource utilization system of this utility model; wherein, 1-pretreatment unit; 2-membrane separation unit; 3-nanofiltration unit; 4-cyclone electrolysis unit; 5-concentrate reuse unit.

[0016] Figure 2 This is a flow chart of the resource-based treatment process for copper-containing wastewater according to this utility model. Detailed Implementation

[0017] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0018] Example 1

[0019] like Figure 1 As shown, this embodiment provides a resource-based treatment system for copper-containing wastewater from copper foil production, including a pretreatment unit, a membrane separation unit, a nanofiltration unit, a concentrate reuse unit, and a cyclone electrolysis unit connected in sequence. The membrane separation unit includes a multi-stage permeate membrane device, and the nanofiltration unit includes a multi-stage nanofiltration membrane device. After pretreatment in the pretreatment unit, the copper-containing wastewater from copper foil production is separated by the membrane separation unit to obtain copper-containing concentrate. The copper-containing concentrate is then filtered by the nanofiltration unit and then electrolyzed by the cyclone electrolysis unit. In this embodiment, the multi-stage permeate membrane device is a three-stage permeate membrane device, meaning the copper-containing wastewater from copper foil production undergoes three permeate membrane separations. The multi-stage nanofiltration membrane device is a two-stage nanofiltration membrane device, meaning the copper-containing concentrate undergoes two nanofiltration membrane filtrations.

[0020] In one specific embodiment, the pretreatment unit includes a bag filter with a particle size of 50 μm.

[0021] In one specific embodiment, the multi-stage permeation membrane device uses a spiral wound polyamide membrane with a membrane shell pressure resistance ≥3MPa, capable of withstanding 5% copper sulfate and 5% sulfuric acid, and a water production rate of 60%-70%. NaOH is added for pH adjustment, and the pH is controlled between 5.0 and 6.5.

[0022] In one specific embodiment, the multi-stage nanofiltration membrane device uses a DK8040F nanofiltration membrane with a molecular weight cutoff of 200-300 Da, which preferentially separates Cu-EDTA complexes.

[0023] In one specific implementation, the concentrate reuse unit is equipped with an intelligent diversion valve to monitor the liquid level of the sludge tank in real time. When the liquid level is below the set range, the concentrate addition valve is opened to replenish the sludge tank, and the remaining concentrate is used for cyclone electrolysis to extract copper.

[0024] In one specific embodiment, the cyclone electrolysis cell in the cyclone electrolysis unit uses a coated titanium anode and a stainless steel cathode; the cyclone electrolysis process parameters are: pulse power supply frequency 50-100Hz, current density 400-450A / m2, and temperature 30-35℃. Electrolyzed copper foil (purity ≥99.8%) is stripped and recycled, and the concentration of the electrolyzed liquid is controlled at 3-5g / L before being discharged into a comprehensive wastewater treatment pond for comprehensive treatment before being discharged.

[0025] like Figure 2 As shown, this embodiment also provides a method for the resource-based treatment of copper-containing wastewater from copper foil production, including the following steps:

[0026] Copper-containing wastewater from copper foil production is pretreated in a pretreatment unit, then separated in a membrane separation unit to obtain copper-containing concentrate. The copper-containing concentrate is then filtered by a nanofiltration unit and electrolyzed by a cyclone electrolysis unit.

[0027] As an example, the influent water quality of copper-containing wastewater in this embodiment is as follows:

[0028] Project Name pH value copper ions electrical conductivity COD Copper-containing wastewater 2.0～3.0 500mg / L 3000μs / cm 120mg / L

[0029] Process operation:

[0030] The three-stage RO system achieves a 65% permeable rate, reduces conductivity to 3000 μS / cm, and maintains a pH of 6.0–7.5. After precision filtration, the water is supplied under constant pressure. The RO concentrate is then nanofiltration to remove Cu. 2+The concentration is between 25 and 30 g / L. It is divided into two streams. One stream of high-concentration water is used to replenish the evaporation water in the wastewater tank and is used to meet the production needs. The copper ions are directly reused in the system production. The other stream of high-concentration water is subjected to cyclone electrolysis. After cyclone electrolysis, the Cu2+ concentration is reduced to 5 mg / L and then discharged in compliance with the standards.

[0031] The indicators are as follows:

[0032] index This utility model Traditional chemical precipitation method Increase Copper recovery rate ≥98.5％ 82％-88％ +12％ Cost per ton of water treatment 3.5-4.2 yuan / ton 6.0-7.5 yuan / ton -40％ sludge production 0.15kg / m3 0.8-1.2 kg / m³ -85％ Copper concentration in effluent ≤0.3mg / L ≤1.5mg / L -80％

Claims

1. A resource-based treatment system for copper-containing wastewater from copper foil production, characterized in that: The system includes a pretreatment unit, a membrane separation unit, a nanofiltration unit, a concentrate reuse unit, and a cyclone electrolysis unit connected in sequence. The membrane separation unit includes a multi-stage permeate membrane device, and the nanofiltration unit includes a multi-stage nanofiltration membrane device. Copper-containing wastewater from copper foil production is pretreated by the pretreatment unit and then separated by the membrane separation unit to obtain copper-containing concentrate. Subsequently, the copper-containing concentrate is filtered by the nanofiltration unit and then electrolyzed by the cyclone electrolysis unit.

2. The resource-based treatment system for copper-containing wastewater from copper foil production according to claim 1, characterized in that: The pretreatment unit includes a bag filter.

3. The resource-based treatment system for copper-containing wastewater from copper foil production according to claim 1, characterized in that: The multi-stage permeation membrane device uses spiral wound polyamide membranes with a membrane housing pressure resistance ≥3MPa.

4. The resource-based treatment system for copper-containing wastewater from copper foil production according to claim 1, characterized in that: The multi-stage nanofiltration membrane device uses a DK8040F nanofiltration membrane with a molecular weight cutoff of 200-300 Da.

5. The resource-based treatment system for copper-containing wastewater from copper foil production according to claim 1, characterized in that: The concentrate reuse unit is equipped with an intelligent diversion valve.

6. The resource-based treatment system for copper-containing wastewater from copper foil production according to claim 1, characterized in that: The cyclone electrolysis cell in the cyclone electrolysis unit uses a coated titanium anode and a stainless steel cathode.

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