JPS5824515B2 - Closed System - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for closing a multilayer nickel plating process in which solid particles are suspended.

In the multilayer nickel plating process, a plating method using a nickel plating bath in which solid particles are suspended is used in order to improve the corrosion resistance of the object to be plated or to obtain a satin-like appearance.

That is, roughly as shown in the first diagram, the object to be plated M is a semi-bright nickel plating bath A, a bright nickel plating bath B,
After being transferred to the solid particle suspension nickel plating bath C, the washing tank D1. D2. Water washing is repeated in D3 and the product is transferred to chrome plating bath E.

In this case, as the object M to be plated is transferred, the liquid in the solid particle suspension nickel plating bath C is transferred to the next washing tank D1, and the liquid in this washing tank D1 is further transferred to the next washing tank D2, and the object is sequentially transferred to the next washing tank D2. It is being drawn out along with it.

In this way, normally this pumped-out liquid is finally brought into the chrome plating bath E, but in order to avoid having a negative effect on the chrome plating, water is supplied to the washing tank to ensure complete washing. A lot of repetition is being done.

The water that overflows from the washing tank naturally contains a large amount of nickel as well as suspended solid particles, so it is generally carried out to a wastewater treatment facility where it is coagulated and sedimented using chemicals. However, such methods require chemicals for treatment and also require treatment of the precipitated nickel sludge.

Usually, the basic liquid composition of the semi-bright nickel plating bath, bright nickel plating bath, and solid particle suspension nickel plating bath in the multilayer nickel plating is the same as shown below.

Nickel sulfate 300 &/l Nickel chloride
60 g/l boric acid 4
5 El/IJ Therefore, if the rinse water after solid particle suspension nickel plating can be returned to the previous plating bath, such as a semi-bright nickel plating bath, with the nickel content intact, valuable nickel metal can be reused. At the same time, it eliminates the need for expensive wastewater treatment equipment and associated treatment chemicals.
The process can be a closed loop.

However, the problem here is the following.

First, solid particles are suspended in solid particle suspension nickel plating baths, but in semi-bright nickel plating baths and bright nickel plating baths, if these solid particles are mixed in, it will have a negative effect on plating. These solid particles must be removed.

Possible methods for removing solid particles include sedimentation and filtration, but although these solid particles have fairly good sedimentation properties, they cannot be completely settled.On the other hand, filtration can completely remove them, but filtration Since there were a large number of solid particles to be removed, clogging occurred quickly, making it unsuitable for actual use.

Incidentally, if the pumped liquid from the solid particle suspended nickel plating bath is 10 II/hr, approximately 250 Vhr of solid particles must be removed.

The second problem is that although the basic liquid composition of each bath in this plating process is the same, the special additives such as brighteners are different, so the solid particles suspended in the nickel plating solution brought in during recovery water washing are The brightener component must be removed.

The third problem is that it is necessary to balance the amount of water generated by returning the entire amount of rinse water that is replenished with the amount of natural evaporation from the liquid surface of the plating bath before and after the semi-bright nickel plating bath. be.

An object of the present invention is to provide a method for solving the above-mentioned problems, effectively and appropriately recovering a nickel plating solution, and thereby closing a multilayer nickel plating process in which solid particles are suspended.

In the present invention, the first stage is a semi-bright nickel plating bath.

In a multi-layer nickel plating process in which solid particles are suspended, the second stage is a bright plating bath and the third stage is a solid particle suspended nickel plating bath, nickel-containing washing water containing suspended solid particles is made into microporous under pressure. While water is passed through a membrane or an ultrafiltration membrane to remove solid particles, the membrane-permeated water is brought into contact with an ion exchange resin to adsorb and remove the brightener in the water, and then the multilayer nickel plating process is carried out as it is or concentrated. A closed system method for a multilayer nickel plating process in which solid particles are suspended, characterized in that the solid particles are returned to a semi-bright nickel plating bath or a bright nickel plating bath.

Further, one embodiment of the present invention will be described with reference to FIG.
, bright nickel plating bath B, and solid particle suspension nickel plating bath C are sequentially transferred to the first washing tank D1 and the second washing tank D.
2. After passing through the third washing tank D3, it reaches the chrome plating bath E.

At this time, in order to reduce the amount of replenishment rinsing water, the rinsing tank is a multi-stage countercurrent rinsing tank, and the amount of water replenished from outside the system to the third tank D3 is the minimum amount that does not adversely affect the subsequent chrome plating. , preferably semi-bright nickel plating bath A
It is desirable to reduce the amount of water to the minimum amount commensurate with the amount lost by evaporation.

The rinsing water replenished to the third rinsing tank D3 is sent to the storage tank 1 via the second rinsing tank D2 and the first rinsing tank D1, but this rinsing water contains nickel, additives, and solid particles. include.

Next, the washing water in the storage tank 1 is sent under pressure by a pump 2 to an ultra filter 3 equipped with a microporous membrane or ultrafiltration membrane with pores of about 2.5 to 0.1 μm, where only solid particles are captured. The concentrated membrane permeate liquid 4 containing nickel and other additives is stored in a storage tank 5.

On the other hand, the concentrated liquid 6 that does not pass through the membrane is returned to the storage tank 1, but a part of it is sent to the concentration tank 7.

In the concentration tank 7, a certain amount of solid particles are precipitated by natural sedimentation, and if the supernatant liquid 8 with a reduced concentration is returned to the storage tank 1, the concentration of solid particles in the storage tank 1 can be kept constant.

In addition, the solid particles that have settled in the concentration tank 7 are periodically taken out and returned to the solid particle suspended nickel plating bath C.

Next, since the liquid stored in the storage tank 5 contains additives in addition to nickel as described above, the liquid is passed through the ion exchange resin tower 10 by the pump 9.

The ion exchange resin used in this ion exchange resin tower 10 is a weakly basic anion exchange resin that selectively adsorbs brighteners.

Then, the treatment liquid 11 flowing out from the ion exchange resin tower 10
is returned to the storage tank 5, and at the same time, a portion is sent to the processing liquid storage tank 12, and then returned to the semi-bright nickel plating bath A or the bright nickel plating bath B by the pump 13.

In addition, in this process, the liquid temperature in the solid particle suspension nickel plating bath C is room temperature, and there is almost no evaporation of water, so returning the liquid to this bath is not desirable in terms of maintaining water balance.

On the other hand, the liquid temperature in semi-bright nickel plating bath A and bright nickel plating bath B is high at around 50°C, the surface area of the bath is large, and the amount of natural evaporation of water from the liquid surface is large.
It is possible to balance the amount of incoming processing liquid.

If the amount of natural evaporation is less than the amount of incoming processing liquid, for example, the amount of washing water due to increasing the make-up washing water supplied from outside the system or reducing the number of washing stages in the countercurrent washing tank. In the case of an increase in nickel plating bath A, the treatment liquid to be returned to the semi-bright nickel plating bath A may be concentrated to the same amount as the natural evaporation amount.

In this case, concentration is performed using a concentrator 14 that uses atmospheric evaporation, vacuum evaporation, electrodialysis using an ion exchange membrane, reverse osmosis, or the like.

Moreover, the fresh water collected at the same time in these concentration means can be reused as washing water.

As described above, according to the present invention, valuable components can be effectively and appropriately recovered without discharging nickel-containing washing water containing suspended solid particles from the multilayer nickel plating process in which solid particles are suspended. It can be reused, making the process completely closed and eliminating the need for wastewater treatment equipment.

Next, an example of the present invention will be shown in which the pumping amount is [Ol/br] during multi-stage countercurrent water washing in three tanks.

The third washing tank is supplied with washing water at a rate of 100 rpm or less,
This washing water was sent to the storage tank via the second washing tank and the first washing tank, but the composition of the sent liquid was Ni1Of! /L solid particles 2
．． It was 5g/11.

This liquid was supplied to an ultrafilter equipped with an ultrafiltration membrane, and the results were as shown in the following table.

Note: SS stands for suspended solid particles.The SS concentration in the needle tank in the table above is 25 g/11, which indicates the steady state concentration in the storage tank by returning a portion of the concentrate to the storage tank. Yes, and the amount of liquid supplied indicates the amount of liquid supplied to the ultra filter.

As is clear from the table above, the composition of the permeated liquid was such that the Ni content remained unchanged, and 88% (suspended solid particles) were completely removed.

In addition, as mentioned above, the amount of washing water supplied to the washing tank and sent to the storage tank is about 10M/brr, 7 l/m1n), whereas the amount of permeated liquid (processed liquid amount) is 2A/m2.
Since there is in, the processing capacity is sufficient.

Note that the amount of permeate through the ultrasonic membrane decreases over time due to membrane surface contamination, and when the amount of permeate becomes less than the amount of make-up water flowing in, physical cleaning of the membrane by flushing can be used to ensure sufficient performance. was able to recover.

Furthermore, when the permeate from which the solid particles had been removed was passed through a column filled with Diaion WA30 (trade name of a weakly basic anion exchange resin) at 5V=5, no additives were found in the effluent. Only traces were detected, and most of the nickel salts and boric acid were adsorbed to the resin, and nickel salts and boric acid were not reduced at all.

When the effluent from the ion exchange treatment reached approximately 250 times the resin capacity, the third additive relative to the stock solution leaked into the effluent.

All the liquid that had flowed up to that point was collected in one place and the concentration of each component was analyzed, and the results are shown in the table below.

This treatment solution could be directly returned to the semi-bright nickel plating bath.

The ion exchange resin was regenerated with 10% caustic soda and 5% sulfuric acid and used again, but the adsorption capacity of the resin was almost completely reproduced.

[Brief explanation of the drawing]

FIG. 1 is a system explanatory diagram of a multilayer nickel plating process in which solid particles are suspended in general, and FIG. 2 is a system explanatory diagram showing one embodiment of the present invention. M: object to be plated, A: semi-bright nickel plating bath, B: bright nickel plating bath, C: solid particle suspension nickel plating bath, Do, D2. D3: Washing tank, E: Chrome plating bath,
1; storage tank, 3; ultra filter, 5; storage tank, 10;
Ion exchange resin tower, 12; treated liquid storage tank, 14; concentrator.

Claims (1)

[Claims] 1 In a multilayer nickel plating process in which solid particles are suspended, the first stage is a semi-bright nickel plating bath, the second stage is a bright plating bath, and the third stage is a solid particle suspended nickel plating bath. The nickel-containing washing waste water is passed under pressure through a microporous membrane or an ultrafiltration membrane to remove solid particles, while the membrane-permeated water is brought into contact with an ion exchange resin to adsorb and remove the brightener in the water. A closed system method for a multilayer nickel plating process in which solid particles are suspended, characterized in that the solid particles are returned as is or after being concentrated to a semi-bright nickel plating bath or a bright nickel plating bath in the multilayer nickel plating process.