CN108585104B - Treatment method of Ni-containing wastewater - Google Patents
Treatment method of Ni-containing wastewater Download PDFInfo
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- CN108585104B CN108585104B CN201810494523.4A CN201810494523A CN108585104B CN 108585104 B CN108585104 B CN 108585104B CN 201810494523 A CN201810494523 A CN 201810494523A CN 108585104 B CN108585104 B CN 108585104B
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/16—Nature of the water, waste water, sewage or sludge to be treated from metallurgical processes, i.e. from the production, refining or treatment of metals, e.g. galvanic wastes
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- Separation Of Suspended Particles By Flocculating Agents (AREA)
Abstract
The invention provides a treatment method of Ni-containing wastewater, which aims to solve the problem of environmental pollution caused by wastewater and waste residues containing heavy metal Ni ions. Firstly, measuring the content of Ni ions in Ni-containing wastewater, adjusting the pH value of the Ni-containing wastewater to be not less than 9, adding a heavy metal trapping agent with the Ni content of 4-8 times into the Ni-containing wastewater according to the content of the Ni ions in the wastewater, fully stirring, standing for 5-10 min, adding inorganic metal salt with the weight of 1-3 times that of the heavy metal trapping agent, fully stirring, and filtering after complete sedimentation. Compared with the traditional high molecular polymer flocculation process, the method has the advantages that the amount of the waste residues containing Ni can be reduced to be below 50 percent of the original amount, the treatment cost of dangerous waste products containing the waste residues containing Ni is greatly reduced for enterprises, the treated waste water can easily reach the limit value of the special discharge of the waste water containing Ni to be below 0.1mg/L (the discharge standard table 3 of electroplating waste water), and the hidden trouble that the waste water does not reach the standard after the treatment of the traditional process is eliminated.
Description
Technical Field
The invention relates to a treatment method of Ni-containing wastewater on an aluminum oxidation hole sealing production line.
Background
In the aluminum product surface treatment production line, after the aluminum anodic oxidation treatment, a hole sealing process is needed to increase the performances of corrosion resistance, fingerprint resistance and the like of an anodic oxide film. At present, the mainstream hole sealing process in the market is a process formula containing heavy metal Ni salt. The process has the advantages of high hole sealing speed, high hole sealing quality, long service life of the bath solution, low hole sealing cost and the like. But the waste water containing Ni and the waste residue after treatment brought by the application of the process bring great burden to production enterprises. Firstly, the problem of nickel-containing wastewater discharge. With the outstanding environmental protection problem in China, the emission limit standard of nickel-Ni-containing wastewater in the national electroplating pollutant emission standard GB21900-2008 is reduced to 0.1mg/L from the original 0.5mg/L (electroplating wastewater emission standard Table 3). The treatment difficulty of Ni-containing wastewater and the treatment cost are greatly increased. Secondly, a large amount of nickel-containing waste slag is brought after the Ni-containing waste water is treated. The nickel-containing waste residues are classified as dangerous waste products, cannot be treated together with common solid waste products, and generate non-negligible cost for special environment-friendly channel treatment. The nickel-containing wastewater and waste residue bring great expense burden and treatment technical problems to related enterprises, and the related enterprises urgently need professionals to develop new processes and methods to solve a series of production problems caused by the Ni-containing hole sealing process.
Aiming at the environmental problems caused by the Ni heavy metals, a method for drawing salary from the kettle bottom is the development and application of a novel nickel-free hole sealing process, and the nickel-free hole sealing process is used for replacing the traditional Ni-containing hole sealing process. The technicians in the field also develop various products of the aluminum anodic oxide film nickel-free hole sealing process. Including foreign German Hangao, Kaimeter, domestic Wuhan Material protection research institute Limited company and the like have respective nickel-free hole sealing products and have successful production and application. However, in the process of popularizing nickel-free products in recent years, short-plate understanding of the commonality of the nickel-free products is formed in the market: firstly, the hole sealing quality of the nickel-free process is unstable, and after the hole sealing quality reaches 30mg/dm required by national standard after being applied for a period of time2The weight loss requirement is within, the nickel-free process can only be applied to a production line with low hole sealing quality requirement and the thickness of the oxide film within 10 mu m. Secondly, the hole sealing temperature required by the nickel-free process is in the middle-high temperature range of 60-80 ℃, and enterprises with unsatisfied heating conditions are difficult to popularize and use. Therefore, in order to meet the quality requirements of customers, customers are not lost, and even though the huge cost of treating nickel-containing wastewater and waste residues is required, many production lines still use the original nickel-containing process.
In view of the immaturity and the difficult popularization of the nickel-free technology for replacing the nickel-containing technology, enterprises can only seek a way of reducing the production cost from a way of solving waste water and waste residue containing Ni. The traditional technology and method for adding the high molecular polymer flocculant can meet the standard requirement of a special discharge table 3 of 0.1mg/L of Ni-containing wastewater. For example, one or a combination of polymeric flocculant such as polyaluminum chloride (PAC) and Polyacrylamide (PAM) is added. However, the addition of the traditional flocculating agent brings two problems: firstly, the flocculation effect is not outstanding, the standard can be barely maintained by adding excessive flocculating agent, and the risk of exceeding the standard exists at any time; secondly, the treated flocs are more, filter-pressing waste residues are more, all the waste residues are divided according to dangerous waste products, and the treatment cost is overhigh. And the screen is often clogged with excess flocs, requiring frequent cleaning or replacement of the screen filter element. Therefore, related enterprises are seeking for a treatment technology and a method for Ni-containing wastewater, which can easily pass the limit discharge standard of Ni ions and can reduce the amount of waste residues.
Disclosure of Invention
The invention aims to solve the technical problem of providing a Ni-containing wastewater treatment method which can enable Ni ions in wastewater to reach the discharge standard of 0.1mg/L and reduce the content of waste residues.
The technical scheme of the invention can be realized by the following technical measures:
a treatment method of Ni-containing wastewater comprises the following steps:
step (1), determining the content of Ni ions in the Ni-containing wastewater;
step (2), adjusting the pH value of the Ni-containing wastewater to be not less than 9;
adding a heavy metal trapping agent with the Ni content of 4-8 times into the Ni-containing wastewater according to the content of Ni ions in the wastewater, fully stirring, and standing for 5-10 min, wherein the heavy metal trapping agent is a heavy metal adsorption aerogel capable of adsorbing Ni;
and (4) adding inorganic metal salt with the weight 1-3 times that of the heavy metal trapping agent, fully stirring, and filtering after complete sedimentation.
Preferably, the heavy metal trapping agent is RS type heavy metal aerogel produced by cleaning and environmental protection science and technology limited.
Preferably, the inorganic metal salt is a divalent metal inorganic salt.
Preferably, the inorganic metal salt is one or more of Mg, Zn, Ca, Cu, Ti and Co metal salts.
Preferably, the divalent metal inorganic salt is a water-soluble chloride salt or sulfate salt.
Preferably, the inorganic metal salt is MgSO4。
Preferably, in the step (1), the volume V of the Ni-containing wastewater is measured, and then the concentration C of Ni ions in the wastewater treatment tank is analyzed by chemical ETDA complex titration, and the content of Ni ions is equal to C × V.
Preferably, step (2) uses sodium hydroxide to adjust the pH of the Ni-containing wastewater.
Preferably, the pH value of the Ni-containing wastewater is adjusted to 9-11 in the step (2).
Compared with the prior art, the invention has the following beneficial effects:
the heavy metal collecting agent is prepared by taking an aerogel compound as a heavy metal collecting agent, matching divalent inorganic non-polymeric metal salt with a specific proportion, adding an organic polymer flocculant and recycling repeatedly, wherein the wastewater after primary filter pressing treatment can easily reach the 0.1mg/L special discharge standard of heavy metal Ni ions, and the weight of nickel-containing waste residues after filter pressing can be obviously reduced, so that the treatment cost of dangerous waste products containing Ni waste residues in enterprises is greatly reduced, the environmental discharge pressure is reduced, and the production benefit of the enterprises is increased.
Detailed Description
In order that the invention may be more readily understood, specific embodiments thereof will be described further below.
Example 1
Taking the wastewater in a rinsing bath on a 10L aluminum profile anodic oxide film surface hole sealing process line, and measuring the concentration of Ni ions in the wastewater containing Ni to be 15.4mg/L by using an EDTA (ethylene diamine tetraacetic acid) complexometric titration method, wherein the amount of the Ni ions is 154 mg.
The pH of 10L of nickel-containing wastewater was adjusted to 9.0 with caustic soda flakes (sodium hydroxide).
Adding 50ml of 20g/L prepared heavy metal trapping agent (RS-300 type heavy metal aerogel produced by cleaning environmental protection science and technology limited) water solution into wastewater, stirring, standing for 5min, adding 40ml of 50g/L prepared MgSO4And (4) uniformly stirring the coagulant aid, and filtering after complete sedimentation.
After filtering, measuring the Ni ion concentration in the filtrate by using a Shanghai Mei spectral Dada V-1800 type spectrophotometer method, treating filter residues in a 60 ℃ oven for 10min, drying to be semi-dry, and weighing (simulating filter pressing and airing the waste residue containing Ni).
Example 2
The same Ni-containing wastewater as in example 1 was used except that pH of the nickel-containing wastewater was adjusted to 7 with caustic soda flakes.
Example 3
The same Ni-containing wastewater as in example 1 was used except that pH of the nickel-containing wastewater was adjusted to 11 with caustic soda flakes.
Example 4
The same Ni-containing wastewater as in example 1 was used except that 20ml of 20g/L RS-300 scavenger was added and 40ml of 50g/L MgSO was added in the flocculation treatment4A coagulant aid.
Example 5
The same Ni-containing wastewater as in example 1 was used except that 50ml of 20g/L RS-300 scavenger was added and no coagulant aid was added during the flocculation treatment.
Example 6
The same Ni-containing wastewater as in example 1 was used except that 50ml of 20g/L RS-300 scavenger was added and 10ml of 50g/L MgSO was added in the flocculation treatment4A coagulant aid.
Example 7
The same Ni-containing wastewater as in example 1 was used except that 50ml of 20g/L RS-300 scavenger was added and 70ml of 50g/L MgSO was added in the flocculation treatment4A coagulant aid.
Example 8
The agent of the invention is applied to the treatment case of sealing the Ni-containing wastewater tank liquor in the actual production. The method takes a tin-free Xiamen photoelectric aluminum product company Limited as an enterprise implementation object, and the treatment process comprises the following steps:
site 20m3Ni-containing wastewater in wastewater treatment tank is gathered to 15m3The Ni ion content in the nickel-containing wastewater tank is measured to be 10 mg/L-15 mg/L on site by adopting a complex titration method. Adjusting the pH value of the wastewater tank to about 10 by using caustic soda flakes each time; adding 40L of 20g/LRS-300 heavy metal trapping agent aqueous solution each time according to the Ni ion content of 4-8 times, fully stirring with air, reacting and settling for 5min, and adding 32L of 50g/LMgSO according to the RS-300 amount of 1-3 times each time4Coagulant aid, fully air stirring for 15 min.
Index detection and analysis: after 15min of sedimentation reaction is finished, starting a filter press for filter pressing, and measuring the Ni ion concentration of the wastewater after each filter pressing by using a spectrophotometer; and calculating the total weight of the Ni-containing filter residues for 10 times.
Example 9
The same Ni-containing wastewater as in example 4 was used, except that in the flocculation treatment, 40L of 20g/L RS-300 aqueous solution was added at a time in an amount of 4-8 times the Ni ion content, the mixture was stirred with air for 5min, and 8L of 50g/LMg was added at a time in an amount of 0.5 times the RS-300 amount2SO4Coagulant aid, fully air stirring for 15 min.
Comparative example 1
The same Ni-containing wastewater as in example 1 was used except that 20ml of a 50g/L polyaluminum chloride (PAC) solution was added for flocculation.
Comparative example 2
The same Ni-containing wastewater as in example 1 was used except that 20ml of 50g/L polyaluminum chloride (PAC) solution was added and 10ml of 0.1g/L Polyacrylamide (PAM) solution was added during flocculation treatment.
Comparative example 3
The same Ni-containing wastewater as in example 1 was used except that 50ml of 20g/L of a sulfur-containing compound trapping agent (the component is a conventional dithiocarbamate derivative) was added and 30ml of 50g/L of FeSO was added during flocculation treatment4Coagulant aid, stirring to react for 5min, and finally adding 10ml of 0.1g/L polyacrylamide solution.
Comparative example 4
The same procedures and steps as in example 9 were carried out except that in the flocculation treatment, only the conventional flocculant polyaluminum chloride (PAC) was used. In order to prevent the content of heavy metal Ni in water from exceeding the standard after filter pressing, excessive polyaluminium chloride is generally added to reduce the risk of exceeding the standard.
Table 1 compares the results of the experiments obtained in examples 1 to 10 and comparative examples 1 to 3.
| Rate of sedimentation | Whether Ni ion reaches the standard (0.1mg/L and below) | Weight of filter residue/g | |
| Example 1 | Fast-acting toy | Reach the standard | 1.352 |
| Example 2 | Fast-acting toy | Does not reach the standard | 1.320 |
| Example 3 | Fast-acting toy | Reach the standard | 1.403 |
| Example 4 | Fast-acting toy | Does not reach the standard | 1.886 |
| Example 5 | Slow | Does not reach the standard | 2.789 |
| Example 6 | Is quicker | Does not reach the standard | 1.739 |
| Example 7 | Is quicker | Does not reach the standard | 2.684 |
| Example 8 | Fast-acting toy | Reach the standard (10 times), do not reach the standard (0 times) | 18.5kg (cumulative 10 times) |
| Example 9 | Is quicker | Reach the standard (2 times), do not reach the standard (8 times) | 25.5kg (cumulative 10 times) |
| Comparative example 1 | Slow | Does not reach the standard | 2.450 |
| Comparative example 2 | Slow | Does not reach the standard | 2.780 |
| Comparative example 3 | Is quicker | Does not reach the standard | 2.833 |
| Comparative example 4 | Slow | Reach standard (8 times), not reach standard (2 times) | 52.5kg (cumulative 10 times) |
From table 1, the following conclusions can be drawn:
the indexes of the filter residue weight of the examples 1, 2 and 3 (using the combined medicament and the addition amount of the invention) and the comparative examples 1, 2 and 3 (the traditional treatment medicament) are obviously different, the filter residue weight in a laboratory is reduced to about 50 percent of that of the traditional method, and the weight of the filter residue in field production (examples 9 and 10) is only about 35 percent of that of the original filter residue due to the excessive addition method of the polyaluminium chloride.
In the embodiment 1, the Ni ion content of the waste water after filter pressing of 3 reaches the special discharge requirement (below 0.1 mg/L). Using the conventional agent (comparative example 4), the treated Ni ion content was low and there was a risk of about 20% failure by adding excessive flocculant.
Examples 4, 5, 6 and 7 used the combination of the present invention, but the treatment results of Ni-containing wastewater did not reach the standards. The 80% treatment results of the field example (example 9) were not achieved, mainly because the heavy metal trap and the inorganic coagulant aid needed to be in the proper ranges to achieve synergistic results. When the coagulant aid is not in a proper proportion, the RS-300 flocculation effect is poor, and the phenomenon that the settled flocs are large and scattered occurs, namely the flocs with water and other metal ions are more (the content of Al ions in the wastewater is high), so that the Ni ion content does not reach the standard and the waste residues are more.
The adjustment of the pH before addition of the drug is also a critical step, and good treatment results can only be ensured when the pH is adjusted to 9 or more (examples 1, 2 and 3).
Inorganic salt coagulant aids such as MgSO4，MgCl2The flocculation sedimentation speed can be accelerated, the sedimentation effect of the catching agent is improved, the addition amount of the catching agent is reduced, and the purpose of reducing the weight of filter residue is achieved (examples 1 and 5). And the coagulant aid is required to be added and used according to the proportion required by the specification.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (7)
1. A treatment method of Ni-containing wastewater is characterized by comprising the following steps:
step (1), determining the content of Ni ions in the Ni-containing wastewater;
step (2), adjusting the pH value of the Ni-containing wastewater to 9-11;
adding a heavy metal trapping agent with the Ni content of 4-8 times into the Ni-containing wastewater according to the Ni ion content in the wastewater, fully stirring, and standing for 5-10 min, wherein the heavy metal trapping agent is RS300 type heavy metal aerogel;
and (4) adding inorganic metal salt with the weight 1-3 times that of the heavy metal trapping agent, fully stirring, and filtering after complete sedimentation.
2. The method for treating Ni-containing wastewater according to claim 1, wherein the inorganic metal salt is a divalent metal inorganic salt.
3. The method for treating Ni-containing wastewater according to claim 2, wherein the inorganic metal salt is one or more of Mg, Zn, Ca, Cu, Ti and Co.
4. The method for treating Ni-containing wastewater according to claim 2, wherein the divalent metal inorganic salt is a water-soluble chloride salt or sulfate salt.
5. The method for treating Ni-containing wastewater according to claim 1, wherein the inorganic metal salt is MgSO4。
6. The method for treating Ni-containing wastewater according to claim 1, wherein in step (1), the volume V of the Ni-containing wastewater is measured, and then the concentration C of Ni ions in the wastewater treatment tank is analyzed by chemical ETDA complexation titration, and the content of Ni ions is equal to C x V.
7. The method for treating Ni-containing wastewater according to claim 1, wherein the pH of the Ni-containing wastewater in the step (2) is adjusted by using sodium hydroxide.
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| US4072605A (en) * | 1975-11-28 | 1978-02-07 | Automated Medical Systems, Inc. | Method of obtaining a precipitate of metallic ions from solutions containing low concentrations of metal salts |
| DE10022867A1 (en) * | 2000-05-10 | 2001-11-22 | Kronos Titan Gmbh & Co Ohg | Precipitation of nickel and lead ions from iron(II) salt solution, from e.g. lixiviation of cyclone dust from titanium dioxide production by chloride process, involves using excess alkali sulfide and filtration after dwell |
| CN1289413C (en) * | 2005-03-31 | 2006-12-13 | 苏州市环境工程有限责任公司 | Technique for processing reclamation of industrial wastewater from printing electronic circuit board |
| CN102020374A (en) * | 2009-09-23 | 2011-04-20 | 上海轻工业研究所有限公司 | Method for recycling waste water of lead-acid storage battery |
| CN107159089A (en) * | 2017-05-17 | 2017-09-15 | 太原科技大学 | A kind of heavy metal ion porous magnetic haydite sorbent preparation method |
| CN107570118A (en) * | 2017-11-07 | 2018-01-12 | 苏州清控环保科技有限公司 | A kind of preparation method and applications of sulfur doping graphene aerogel |
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