CN205528097U - Processing system of nickeliferous waste water that anodic oxidation hole sealing produced - Google Patents

Abstract

The invention relates to a treatment system with small equipment investment, low treatment cost, which can completely remove nickel ions in waste water, and can effectively degrade and remove nickel-containing waste water produced by anodic oxidation sealing to remove organic pollutants. It includes nickel-containing wastewater collection tank, several liquid lifting pumps, network breaking pretreatment tank, several dosing pumps, Fenton reactor, coagulation reaction tank, flocculation reaction tank, sedimentation tank and ion exchange column. Through efficient pretreatment technology, it breaks the strongly complexed nickel to form free nickel, and breaks and destroys the molecular chains of organic matter that is difficult to oxidize and degrade, forming easy-to-handle small molecular compounds, and then further completely oxidizes through the Fenton reaction Organic matter, release the complexed nickel ions, and then use alkali and coagulant to remove the nickel ions in the wastewater again in the coagulation reaction link, and then precipitate most of the nickel ions through flocculation and precipitation reactions Down, the remaining nickel ions in the supernatant are adsorbed again by the cation resin exchanger.

Description

Treatment system for nickel-containing wastewater produced by anodic oxidation sealing

technical field

The utility model relates to a treatment method and equipment for nickel-containing wastewater, in particular to a treatment method for nickel-containing wastewater and a used treatment system for anodic oxidation sealing of the surface of an aluminum material.

Background technique

Aluminum alloy materials have excellent physical, chemical, mechanical and processing properties, and are widely used in aerospace, automotive, electronics, home appliances and other fields. However, the aluminum alloy material has low hardness and poor wear resistance, and abrasion damage often occurs. Therefore, the aluminum alloy often needs to undergo corresponding surface treatment before use.

The surface treatment process of aluminum alloy materials generally includes: degreasing, alkali etching, neutralization, anodizing, coloring and sealing. Anodic oxidation can form an oxide film on the surface of aluminum alloy, which can significantly improve the corrosion resistance of aluminum alloy, and improve the hardness and wear resistance of the aluminum alloy surface. However, the oxide film on the surface of the anodized aluminum alloy has a honeycomb microporous structure. These micropores have strong chemical activity and physical adsorption performance, and are easy to absorb corrosive media and pollutants in the atmosphere and affect the appearance. Seriously It will lead to corrosion of the oxide film and reduce the hardness and wear resistance of the aluminum alloy material. Therefore, proper hole sealing technology must be used to close the micropores in the oxide film, so that the oxide film can effectively protect the surface of the aluminum alloy.

At present, my country mainly uses low-temperature or medium-temperature oxide film sealant, which is a nickel-salt type sealant. Nickel metal ion, 0.3-0.5g/L surfactant, 0.2-0.6g/L hydration accelerator and 0.2-0.5g/L complexing agent. The nickel content in the waste water produced by this closed process is 0.1-1.8g/L, and the content of other additives is 0.3-1.2g/L.

Due to long-term exposure to nickel, mild cases can cause dermatitis, and severe cases may cause cancer. Therefore, my country has stepped up efforts to control nickel pollution. Since 2008, for areas with high land development density and weakened environmental carrying capacity, For example, some areas of the Pearl River Delta and the Yangtze River Delta strictly implement the special discharge limits of water pollutants specified in Table 3 of the National Standard of the People's Republic of China "Electroplating Pollutant Discharge Standards" (GB21900-2008), in which the total nickel content does not exceed 0.1 mg/L. In order to meet the requirements of environmental protection standards, most enterprises separate such nickel-containing wastewater from other wastewater and treat them separately.

At present, the commonly used methods for treating nickel-containing wastewater include chemical precipitation (that is, adjusting the pH value of nickel-containing wastewater with alkali, and adding metal replenishing agents to neutralize, coagulate, flocculate, and precipitate), ion exchange, adsorption, and electrolysis. Dialysis, evaporation concentration and reverse osmosis, etc. Among them, the ion exchange method and the adsorption method cannot effectively remove the macromolecules in the complex state; the electrodialysis method and the reverse osmosis method have high requirements on the membrane, which is easy to cause damage to the membrane; the evaporation concentration method has high requirements on the equipment and requires the use of a heat source. High energy consumption for processing.

Chinese patent CN201310706434.9 discloses an electroplating wastewater treatment system using a chemical precipitation method.

Chinese patent CN201010503812 adopts an anion-exchange resin to absorb nickel ions in an anode coloring wastewater treatment method.

The wastewater treated by the above two methods cannot continuously and stably meet the national first-level discharge standards, which will lead to hidden dangers of environmental pollution. The reason for nickel ions exceeding the standard is that the sealing solution contains complexing agents that can form stable complexes with nickel ions, such as acetic acid, ammonia water, fluoride ions, ethylenediaminetetraacetic acid, organic phosphates, etc. Once nickel ions are complexed with these complexing agents, they are very stable and cannot be removed by flocculation precipitation or ion exchange. Therefore, soluble complexed nickel can easily cause wastewater to exceed the standard.

Chinese patent CN102443709 discloses a pretreatment of electroplating nickel wastewater by using acidification method to break the complexation technology. Under strong acid conditions, commonly used complexes such as citric acid, ammonia water, oxalic acid, etc. lose or weaken the ability to complex with nickel ions, thereby The metal nickel in the complex state can be freed, and this method can release nickel ions from some weaker complexing agents, but the disadvantage of this method is that it cannot release organic phosphate complexing agents such as ethylenediamine tetramine Nickel complexed by sodium methylene phosphate. In addition, after the addition of acid, the subsequent process of resin adsorption of nickel ions will reduce the adsorption capacity and performance of the resin for nickel.

Chinese patent CN104528987 proposes a method of using Fenton oxidation technology to break nickel complexes to form free nickel. The method is based on the fact that hydroxyl radicals produced by Fenton oxidation and divalent iron ions have a certain redox ability to degrade the complex, thereby breaking the nickel in complex form to form free nickel. Although Fenton oxidation can effectively oxidize and degrade organic pollutants in water, the degradation and release efficiency of Ni-EDTA complex is low. Therefore, this method can only break the nickel complexes with weaker complexing ability, and the effect of breaking nickel complexes with stronger complexing ability is not obvious, and cannot achieve a sustained and stable nickel removal effect. Similarly, this method It is also easy to cause nickel discharge to exceed the standard.

Utility model content

The technical problem to be solved by the utility model is to provide a treatment system for nickel-containing wastewater produced by anodic oxidation sealing, which has small investment in equipment, low treatment cost, can completely remove nickel ions in wastewater, and can effectively degrade and remove organic pollutants at the same time .

In order to solve the above technical problems, the technical solution adopted by the utility model is:

The treatment system of nickel-containing wastewater produced by anodic oxidation sealing of the utility model includes nickel-containing wastewater collection tanks, several liquid lifting pumps, network-breaking pretreatment pools and several dosing pumps, and is characterized in that: it also includes Fenton Reactor, coagulation reaction tank, flocculation reaction tank, sedimentation tank and ion exchange column, wherein,

The complex-breaking pretreatment pool is used to break the strongly complexed nickel in the form of Ni-EDTA in the collection tank into free nickel and a small part of weakly complexed small molecules;

The Fenton reactor is used to oxidize and decompose the primary nickel-containing wastewater flowing into the decomplexation pretreatment tank to generate secondary wastewater in suspended matter containing small molecular organic matter and partial precipitates of nickel compounds;

The coagulation reaction tank is used to generate the secondary wastewater from the Fenton reactor into tertiary wastewater containing one or more mixtures of nickel hydroxide, nickel carbonate and nickel sulfide in the form of small particles and colloids;

The flocculation reaction tank is used to form the tertiary wastewater into a quaternary wastewater containing large colloidal particles of one or more mixtures of the nickel hydroxide, nickel carbonate and nickel sulfide;

The sedimentation tank is used to separate the fourth-stage wastewater flowing into it to generate the supernatant to be discharged and the precipitate containing one or more mixtures of the nickel hydroxide, nickel carbonate and nickel sulfide;

The sediment in the sedimentation tank is subjected to mud-water separation treatment, and the separated high-nickel-containing wastewater is pumped into the collection tank for recycling;

The ion exchange column is used for further adsorption treatment of the residual free nickel in the supernatant.

The device used in the decontamination pretreatment pool is any one or combination of multiple micro-electrolysis devices, three-dimensional electrolysis devices or photocatalytic degradation devices.

The coagulant used in the coagulation reaction tank is polyacrylamide.

The cationic resin used in the ion exchange column includes but not limited to strong acid type or weak acid type.

Compared with the prior art, the treatment system of the utility model breaks the strongly complexed nickel to form free nickel through the complex-breaking pretreatment technology, and at the same time breaks and destroys the molecular chains of organic substances that are difficult to oxidize and degrade, forming an easy-to-handle Then the organic matter is further thoroughly oxidized through the Fenton reaction, and the complexed nickel ions are released, and then the nickel ions in the inorganic state are formed into large colloids by adding liquid alkali and a small amount of coagulant in the coagulation reaction link Granular nickel hydroxide/nickel carbonate/nickel sulfide removes the nickel ions in the wastewater again, and then precipitates most of the nickel ions through flocculation and precipitation reactions. After removing the sediment, the supernatant The residual free nickel ions in the supernatant are adsorbed by pumping into the cationic resin exchanger through the filtration system. On the one hand, the method of the utility model can make the discharge of anodic oxidation sealing nickel-containing wastewater continuously and stably meet the national first-level discharge standard, and eliminate the risk of nickel pollution; on the other hand, it can effectively oxidize the organic pollutants in the nickel-containing wastewater , decomposition and removal. The utility model can thoroughly solve the problem that the nickel-containing waste water of anodic oxidation sealing cannot reach the standard continuously and stably.

Description of drawings

Fig. 1 is the schematic flow sheet of processing method in the utility model.

Fig. 2 is a structural schematic diagram of the processing system of the present invention.

detailed description

As shown in Figure 1, the utility model process is as follows:

Step S1, using the nickel-containing wastewater collection tank to collect the nickel-containing wastewater and pumping the nickel-containing wastewater into the network-breaking pretreatment tank.

Step S2, adding acid to the network-breaking pretreatment tank until the pH value in the network-breaking pre-treatment tank is between 2.0-5.0, and the reaction time is 60-90 minutes; after the network-breaking pretreatment, it is difficult to degrade in wastewater The structure of the complex is changed, and the treated primary wastewater flows into the Fenton reactor.

In step S3, ferrous sulfate and hydrogen peroxide are successively added to the Fenton reactor. During the Fenton reaction, the pH value of the incoming water is controlled to be between 2.0-6.0, and the process produces a large amount of hydroxyl radicals. The organic matter in the primary wastewater is oxidized and decomposed, and the reaction time is 15min-90min (preferably, the reaction time is 60min-90min). After that, the secondary wastewater containing the suspended matter is discharged into the coagulation reaction pool.

The ferrous sulfate accounts for 0.01%-0.6% of the weight of the nickel-containing wastewater; the hydrogen peroxide accounts for 0.05%-2.0% of the weight of the nickel-containing wastewater.

Step S4, adding caustic soda/soda ash/soluble sulfide to the coagulation reaction tank, adjusting the pH value of the secondary wastewater to between 9.0-13.0; then adding a little coagulant to react to form a large amount of new The resulting small particles and colloids including nickel hydroxide, nickel carbonate or nickel sulfide or their mixtures, the reaction time is 25min-40min, after that, the tertiary wastewater with a large number of small particles and colloids after this treatment is discharged into Flocculation reaction tank. The coagulant is preferably polyacrylamide.

Step S5, adding a flocculant to the flocculation reaction tank to form large colloidal particles including the nickel hydroxide/nickel carbonate/nickel sulfide, the reaction time is 30min-40min, after that, the belt after this treatment The fourth-stage wastewater with large colloidal particles is discharged into the sedimentation tank.

Step S6, after the fourth-grade wastewater is settled in the sedimentation tank for 150min-230min, the supernatant therein is directly pumped to a filter system, and a small amount of suspended matter in the supernatant is filtered by the filter system, and then the supernatant is The remaining final waste water in the clear liquid is sent to the ion exchange column to further remove the residual nickel ions in the waste water; the sediment containing the nickel hydroxide/nickel carbonate/nickel sulfide in the sedimentation tank is subjected to mud-water separation treatment, The separated waste water with high nickel content is pumped into the collection tank for recycling.

Step S7, using a cationic resin (preferably a high-efficiency chelating resin) to exchange the free nickel ions existing in the water body in the ion exchange column to perform ion exchange on the supernatant, and discharge the waste water that meets the standard discharged through the ion exchange column; Among them, the nickel ion content is less than 0.1mg/L, and the COD is less than 80mg/L.

As shown in Figure 2, the method of the present utility model selects following treatment device to carry out for use:

The anodic oxidation sealing nickel-containing wastewater treatment equipment 200 includes a sealing nickel-containing wastewater collection tank 210, a first lift pump 211, a network-breaking pretreatment pool 220, a first pH detector 221, a first dosing pump 222, a Fenton Reactor 230, mechanical agitator 231, second dosing pump 232, third dosing pump 233, coagulation reaction tank 240, second pH detector 241, fourth dosing pump 242, fifth dosing pump 243, Flocculation reaction tank 250, sixth dosing pump 251, sedimentation tank 260, second lift pump 261, pneumatic diaphragm pump 262, filter press 263, ion exchange column 270, filter 271, backwash pump 272 and control system 280.

Specifically, the sealing nickel-containing wastewater collection tank 210 is used to collect the sealing nickel-containing wastewater, such as the cleaning water and sealing waste liquid of the anodizing sealing workshop can flow into the sealing nickel-containing wastewater collection tank 210 through a dedicated pipeline. In the sealing nickel-containing wastewater collection tank 210, a liquid level detector is provided to detect the liquid level in the sealing nickel-containing wastewater collection tank 210, when the liquid level of the nickel-containing wastewater flowing in exceeds the preset value of the liquid level detector , the liquid level detector sends a signal to the control system 280, and the control system 280 sends an instruction to the first lift pump 211 to make the first lift pump 211 run after receiving the signal. The first lift pump 211 pumps the nickel-containing waste water into the network-breaking pretreatment pool.

The sealed nickel-containing wastewater tank 210 is connected to the network-breaking pretreatment tank 220 through the first lift pump 211, and the first lift pump 211 is used to transport the wastewater in the sealed nickel-containing wastewater tank 210 to the network-broken pre-treatment tank. The conveying speed can be controlled by adjusting the first lift pump 211 , so as to control the reaction time of the nickel-containing wastewater in the network-breaking pretreatment tank 220 . Wherein the device used in the network breaking pretreatment pool is any one or combination of multi-element micro-electrolysis device, three-dimensional electrolysis device or photocatalytic degradation device.

The first pH detector 221 and the first dosing pump 222 are connected to the decontamination pretreatment tank 220 . Wherein the first pH detector 221 is used to detect the pH value of the waste liquid in the decontamination pretreatment tank 220 . The first dosing pump 222 is used to add liquid acid such as sulfuric acid solution to the decontamination pretreatment tank 220 until the first pH detector 221 detects that the pH value in the decontamination pretreatment tank 220 is between 2-5. The reaction time of the nickel-containing wastewater in the network-breaking pretreatment tank 220 is 60-90 minutes, and the reaction time can be regulated by the flow rate and the volume of the network-breaking pretreatment tank. The nickel-containing wastewater then enters the Fenton reactor 230 .

The mechanical stirrer 231 , the second dosing pump 232 and the third dosing pump 233 are connected with the Fenton reactor 230 . Wherein the mechanical agitator 231 is used to stir the nickel-containing waste water in the Fenton reactor 230 evenly, and the second dosing pump 232 and the third dosing pump 233 add quantitative ferrous sulfate and hydrogen peroxide to the Fenton reactor 230 respectively , thereby undergoing Fenton oxidation degradation. The nickel-containing wastewater passing through the Fenton reactor 230 flows into the coagulation reaction tank 240 .

The second pH detector 241 , the fourth dosing pump 242 and the fifth dosing pump 243 are connected to the coagulation reaction tank 240 . Wherein the second pH detector 241 is used to detect the pH value of the waste liquid in the coagulation reaction tank 240 . The fourth dosing pump 242 is used to add a liquid such as sodium hydroxide solution to the coagulation reaction tank 240 until the second pH detector 241 detects that the pH value in the coagulation reaction tank 24 is between 10-11. The fifth dosing pump 243 is used for adding a coagulant such as polyacrylamide (PAM) into the coagulation reaction tank 240 . The nickel-containing wastewater passing through the coagulation reaction tank 240 flows into the flocculation reaction tank 250 .

The sixth dosing pump 251 is connected with the flocculation reaction tank 250 . The sixth dosing pump 251 is used to add flocculant to the flocculation reaction tank 250 . The nickel-containing wastewater flows into the sedimentation tank 260 through the flocculation reaction tank 250 .

The second lift pump 261 and the pneumatic diaphragm pump 262 are connected with the sedimentation tank 260 . Wherein the second lift pump 261 is used to transport the supernatant waste liquid in the sedimentation tank 260 to the filter 271 for filtering. The pneumatic diaphragm pump 262 transports the sediment in the sedimentation tank 260 to the filter press 263 for mud-water separation. The waste liquid separated by the filter press 263 flows into the sealed nickel-containing waste water tank 210 again.

The filter 271 is used to filter out a small amount of suspended solids in the supernatant wastewater from the sedimentation tank 260, so as to ensure that the wastewater discharge meets the standard. Waste water passing through the filter 271 flows into the ion exchange column 270 .

The ion exchange column 270 is filled with high-efficiency chelating resin, which is used to adsorb and remove nickel ions that have not been completely precipitated, so as to further ensure that the wastewater meets the standard. The backwash pump 272 is connected to the ion exchange column 270 . Among them, the backwash pump 272 is used to regenerate the ion exchange column 270 to obtain high-concentration nickel-containing water, which can be used as a resource. In addition, the regenerated high-concentration nickel-containing water can also flow into the sealed nickel-containing waste water tank 210 .

The method of the utility model preferably adopts the following treatment system to treat nickel-containing wastewater.

The system includes: sealing nickel-containing wastewater collection tank, first lift pump, network breaking pretreatment tank, first pH detector, first dosing pump, second dosing pump, third dosing pump, Fenton reaction device, mechanical agitator, coagulation reaction tank, second pH detector, fourth dosing pump, fifth dosing pump, flocculation reaction tank, sixth dosing pump, sedimentation tank, second lift pump, filter, Pneumatic diaphragm pump, filter press, ion exchange column, backwash pump: among them,

The sealing nickel-containing wastewater collection tank is used to collect the sealing nickel-containing wastewater;

The first lift pump is placed between the sealing nickel-containing wastewater collection tank and the network-breaking pretreatment tank, and is used to pump the nickel-containing wastewater in the sealing nickel-containing wastewater into the network-breaking pretreatment pool;

The first pH detector and the first dosing pump are connected with the network-breaking pretreatment pool; the first pH detector is used to monitor the waste water information in the network-breaking pretreatment pool; the first dosing pump is used for Automatically adding acid to the decomplexation pretreatment tank until the first pH detector shows that the pH value is between 2-5;

The second dosing pump, the third dosing pump, and the mechanical stirrer are connected to the Fenton reactor; the mechanical stirrer is used to stir the waste liquid in the Fenton reactor evenly; the second dosing pump The drug pump is used to add ferrous sulfate to the Fenton reactor; the third drug addition pump is used to add hydrogen peroxide to the Fenton reactor;

The second pH detector, the fourth dosing pump, and the fifth dosing pump are connected to the coagulation reaction tank; the second pH detector is used to monitor the waste water information in the coagulation reaction tank; the fourth dosing pump The drug pump is used to automatically add caustic soda/soda ash/soluble sulfide to the coagulation reaction tank until the second pH detector shows that the pH value is between 10-11; A coagulant is added into the coagulation reaction tank;

The sixth dosing pump is used to add flocculant to the flocculation reaction tank;

The pneumatic diaphragm pump is used to transport the sediment in the sedimentation tank to the filter press;

The filter press is used to separate the sludge from the sediment;

The second lift pump is placed between the sedimentation tank and the filter, and is used to pump the supernatant in the sedimentation tank into the filter;

The filter is connected with the ion exchange column; the backwash pump is connected with the ion exchange column; the backwash pump is used to regenerate the ion exchange column.

Relevant parameters see the following table in five embodiments of the present utility model:

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Claims (4)

1. The utility model provides a processing system of nickeliferous waste water that anodic oxidation hole sealing produced, includes nickeliferous waste water collecting vat, a plurality of liquid elevator pumps, broken pretreatment tank and a plurality of platform dosing pumps, its characterized in that: also comprises a Fenton reactor, a coagulation reaction tank, a flocculation reaction tank, a sedimentation tank and an ion exchange column, wherein,

the complex breaking pretreatment pool is used for breaking and complexing the Ni-EDTA form strong complex state nickel in the collecting tank into free nickel and a small part of weak complex state small molecules;

the Fenton reactor is used for oxidizing and decomposing the primary nickel-containing wastewater flowing into the vein breaking pretreatment tank to generate secondary wastewater which is suspended matter and contains part of precipitates of micromolecular organic matters and nickel compounds;

the coagulation reaction tank is used for generating the secondary wastewater from the Fenton reactor into small-particle and colloidal tertiary wastewater containing one or a mixture of nickel hydroxide, nickel carbonate and nickel sulfide;

the flocculation reaction tank is used for forming the third-level wastewater into fourth-level wastewater containing large colloidal particles including one or a mixture of more of nickel hydroxide, nickel carbonate and nickel sulfide;

the sedimentation tank is used for separating the four-stage wastewater flowing into the sedimentation tank to generate a supernatant to be discharged and a sediment containing one or a mixture of several of the nickel hydroxide, the nickel carbonate and the nickel sulfide;

Carrying out mud-water separation treatment on the precipitate in the sedimentation tank, and pumping the separated high nickel-containing wastewater into a collection tank for recycling;

and the ion exchange column is used for further adsorbing the free nickel remained in the supernatant.

2. The system for treating nickel-containing wastewater generated by anodic oxidation hole sealing according to claim 1, characterized in that: the device used in the vein-breaking pretreatment tank is any one or combination of a multi-element micro-electrolysis device, a three-dimensional electrolysis device or a photocatalytic degradation device.

3. The system for treating nickel-containing wastewater generated by anodic oxidation hole sealing according to claim 1, is characterized in that: the coagulant used in the coagulation reaction tank is polyacrylamide.

4. The system for treating nickel-containing wastewater generated by anodic oxidation hole sealing according to claim 1, characterized in that: the ion exchange column uses cation resin, including but not limited to strong acid type or weak acid type.