JPS5823155B2 - Pyrolin Sandometsuki Haisuino Shiyorihouhou - Google Patents

Description

Detailed Description of the Invention The present invention relates to a method for treating copper pyrophosphate plating wastewater. Generally, copper pyrophosphate plating is widely used together with copper sulfate plating as a cyanide-free copper plating. Washing wastewater contains copper ions, so it is necessary to remove copper ions before discharge.

As one method for removing copper from such copper pyrophosphate plating wastewater, a basic anion exchange resin is used to treat the copper pyrophosphate plating wastewater, and the strongly basic anion exchange resin is regenerated with a neutral salt and an eluent is used. A method for electrolytically recovering copper from copper is proposed in Japanese Patent Application Laid-Open No. 48-68485.

However, since this method uses a strongly basic anion exchange resin, its adsorption power for copper pyrophosphate ions is weak, and when the space velocity (SV) is increased in the column method, leakage of copper ions increases, resulting in a reduction in mass exchange capacity. becomes smaller,
Since the capacity of the ion exchange column must be increased, the installation area of the equipment becomes larger and the cost of the equipment increases.In addition, the overnight regeneration operation becomes complicated, and the elution time in the elution process becomes longer. Since the amount of liquid increases, there are some practical problems, such as requiring a long time to electrolytically recover copper from the eluent as the frequency of regeneration of the anion exchange resin increases.

Generally, ion exchange resin has a diameter of about 300 to 1200μ.
They are spherical particles, and the ion diffusion mechanism is different between the spherical surface and the inside, and the rate distribution of the exchange reaction is wide.In the case of ion adsorption, the through-flow exchange capacity decreases as the liquid passing rate increases, and the processing capacity tends to decrease. On the other hand, there are problems in that the amount of eluent increases and the elution time becomes longer.

The present inventors investigated a method of treating copper pyrophosphate plating wastewater using an ion exchange resin, and found that the above-mentioned drawbacks could be overcome if a fibrous and weakly basic anion exchanger was used. This has led to the present invention.

That is, the present invention involves a process in which wastewater discharged from a copper pyrophosphate plating process is treated with weakly basic anion exchange fibers having polyethylene polyamino groups to adsorb copper ions to the weakly basic anion exchange fibers, A method for treating copper pyrophosphate plating wastewater comprising a step of treating basic anion exchange fibers with an eluent to elute copper ions, or a step of electrolytically recovering copper ions in the eluent using an insoluble anode and a cathode. be.

The weakly basic anion exchange fibers having polyethylene polyamino groups used in the present invention are obtained by crosslinking polystyrene fibers and then chloromethylating them to introduce polyethylene polyamide 7 groups.Novolak fibers are crosslinking with formalin and then chloromethylating them to introduce polyethylene polyamino groups. It can be obtained by methods such as introducing polyethylene polyamide 7 groups into vinyl chloride or vinylidene chloride fibers, or introducing polyethylene polyamino groups into acrylic fibers made from a vinyl chloride-acrylonitrile copolymer.

As for the polyethylene polyamino group to be introduced.

General formula -NH (CH2CH2NH) It is represented by nH, and n is 1 to 8, preferably 2 to 5. If n exceeds 9, it becomes difficult to obtain a pure polyethylene polyamino group and the viscosity becomes high, causing problems in handling. There is.

The single fiber diameter of the weakly basic anion exchange fiber of the present invention is 5
-150μ Preferably 20-100μ, if it is less than 5μ, there is a disadvantage that flow resistance increases and liquid permeability decreases.
As with particles of ion exchange resin exceeding 150μ, the rate distribution of ion exchange reactions becomes large between the fiber surface and inside.
The distribution of ion adsorption and elution is broadened, which is undesirable.

In the present invention, waste water from a copper pyrophosphate plating process is treated by contacting weakly basic anion exchange fibers having polyethylene polyamino groups in an appropriate shape to convert copper ions into weakly basic anion exchange fibers.

Let it absorb.

By this treatment, copper ions are adsorbed not only as [Cu(P20□) 2 ) 6-] but also as clear 1-1 on the weakly basic anion exchange fiber.

Treatment methods include turning it into cotton and putting it into wastewater, packing it into a column and passing water through it, or using appropriate support.

Any method can be used, such as using a filter pre-coated on the body, passing water through a fabric-like filter, or continuously immersing the body in a fabric-like filter.

The treated effluent may be discharged as is or may be reused as washing water.

The weakly basic anion exchange fiber with copper ions adsorbed thereon is treated with an eluent such as hydrochloric acid, sulfuric acid, or aqueous ammonia to elute the copper ions and regenerate it.

If necessary, an electrolytic reaction is performed using an eluent such as platinum, titanium, lead peroxide, etc. as an insoluble anode and platinum, aluminum, stainless steel, etc. as an insoluble cathode to recover copper.

According to the present invention, unlike a granular strongly basic anion exchange resin, the anion exchanger used has a single fiber diameter of 150 mm.
Since it is a fibrous weakly basic anion exchanger with polyethylene polyamino groups of less than μ, the rate distribution of the ion exchange reaction on the fiber surface and inside the fiber is negligible, and copper ions can be adsorbed and eluted quickly. be exposed.

In addition, in the electrolytic recovery of copper from the eluent, the method using a strongly basic anion exchange resin requires a long time for electrolysis because the elution time in the elution process is long and the concentration of copper ions in the eluent is low. On the other hand, in the present invention, elution can be performed in a short time, so that electrolytic recovery can be performed at the same time as elution, and the electrolytic reaction can be carried out efficiently.

The present invention will be explained below with reference to Examples.

Example □ A copper pyrophosphate plating solution was prepared according to the following formulation and diluted 100 times with distilled water to obtain artificial wastewater containing 300 ppm of pot ions.

Copper pyrophosphate 83°8f/A (30f as Cu
? /IJ) Potassium pyrophosphate 3
47? /1 ammonia water (28%)
1 ml/1 On the other hand, a weakly basic anion exchange fiber was produced as follows.

A single acrylic fiber with a diameter of 50μ made of a copolymer of 52% by weight of vinyl chloride and 48% by weight of acrylonitrile was heated in a solution of triethylenetetramine, washed with water, and cut into 2mm lengths to obtain triethylenetetramino groups. A weakly basic anion exchange fiber WAF of CI type was obtained.

The anion exchange capacity of this WAF is 6.1 me in OH type.
q/,? (dry fiber).

This WAF 31.2 & (dry fi in OH type)
ber conversion) into an acrylic resin column with an inner diameter of 2 cm and a length of 80 cIrL at a packing density of 0.24,9/l717! !
and the above-mentioned copper pyrophosphate plating wastewater at a space velocity of 5
At V20, the liquid was passed through, copper ions in the effluent were detected, and the flow rate and mass exchange capacity were determined.

For comparison with this WAF, commercially available ion exchange resins and chelate resins were passed in the same manner, and the flow rate and flow exchange capacity were determined.

These results are shown in Table 1.

From the results shown in Table 1, it is clear that WAF adsorbs copper ions extremely efficiently and has the best performance.

The copper ions adsorbed on this WAF were removed using a 10% sulfuric acid aqueous solution.
00ml to obtain an eluent with a copper ion concentration of 20.09/l.

Pour this eluent into a beaker of 307711 and place it on a platinum plate (3
0mi x 30mm x 0.3 mm) were used as negative and positive poles, and electrolyzed at a current density of 2 people/drri'' and a liquid temperature of 25°C to form copper i9.
9.99% recovery was achieved.

The current efficiency was 95% up to a copper recovery rate of 80%.

- Copper ions adsorbed on the strongly basic anion exchange resin were similarly eluted with 350 ml of 1O ammonium sulfate aqueous solution,
An eluent with a copper ion concentration of 2.59/l was obtained.

This eluent was placed in a beaker with 500 mA of t, and electrolyzed with a platinum plate as an electrode at a current density of IA/di'' and a liquid temperature of 25° C., and 99.99% of copper i was recovered.

The current efficiency was 90% up to 80% copper recovery.

As described above, the weakly basic anion exchange fiber used in the present invention has far superior adsorption and elution of copper ions compared to ordinary ion exchange resins and chelate resins, and it is clear that the fiber functions are well exhibited. I know that there is.

Claims (1)

[Claims] 1 Process of treating the wastewater discharged from the copper pyrophosphate plating process with a weakly basic anion exchange fiber having a polyethylene polyamino group to adsorb and remove copper ions in the wastewater, and a process of adsorbing and removing the copper ions in the wastewater. A method for treating copper pyrophosphate plating wastewater, which comprises a step of eluting copper ions treated with an eluent.