JPH03277800A - Method and device for supplying metal ion - Google Patents

Abstract

PURPOSE:To control the dissolution of contained impurities and to supply a stabilized plating soln. by obliquely arranging many metallic pieces contg. a metal and a metal nobler than the former in a dissolving tank away from one another and injecting a plating soln. from the lower part toward the upper part. CONSTITUTION:A metal ion is supplied to the plating soln. with the concn. of metal ions reduced in Zn-Fe alloy plating. When the metal ion is supplied, one or more metallic pieces 13 contg. Zn and Fe and the Pb, Cd, etc., nobler than the Zn and Fe as impurities 16 and inclined to horizontal are arranged in the dissolving tank 12 away from one another. The piece 13 is arranged through a horizontal shelf 14 having a through hole 18 and an inclined rack 15 having a through hole 19 on the shelf. A plating soln. 3 is then supplied from the injection port 7 from the lower part toward the upper part. Consequently, the base Zn and Fe are selectively dissolved, and the plating soln. contg. the ions is supplied to a plating device through an outlet 8. In this case, the flow velocity of the ion-contg. plating soln. in the tank 12 is preferably made lower than the settling velocity of the impurity particles.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method and apparatus for supplying metal ions to electroplating.

<Prior Art> In recent years, demand for Zn-based plated steel sheets, mainly for automobile steel sheets, has rapidly increased. As a Zn-based meh, Zn
, Zn-Fe, Zn-Ni, Zn-Mn, etc.

Insoluble materials such as PB, PT, etc. are often used as the anode material.

Carbonates of plating metals or dissolution of plating metals are used as a method of supplying metal ions consumed by plating. In the case of carbonates, the melting speed is fast and the equipment is simple, but the cost (material cost) is high. In the case of metals, the cost (material cost) is low, but the slow reaction rate and shape (solid) require large and complex melting equipment, making the melting method difficult.

Highly efficient metal melting equipment includes a stirring tank shown in Figure 7;
! There is a fluidized tank shown in Figure 48.

<Problems to be Solved by the Invention> When the metal 1 is dissolved in the stirring tank 2, the plating solution 3 flows, for example, in the direction of arrow A in FIG. 7 due to the rotation of the stirring blade 4. As the metal 1, for example, Zn or Fe
When melting a base metal such as, impurities 5 (
(Ni, PB, etc.) dissolves and becomes impurity ions. The generation of impurity ions cannot be suppressed by changing any dissolution conditions such as stirring speed.

In addition, when the base metal 1 is filled into the fluidizing tank 6 and melted, the plating solution 3 is shown in FIG. I] A6 is charged from the lower injection lower, discharged from the upper discharge port 8,
For example, it flows in the direction of arrow B. The gold 741 base metal comes into contact with the plating solution 3 and dissolves, and the impurities 5 in this base metal also become ions.

The generation of impurity 5 ions cannot be suppressed by changing any dissolution conditions such as the flow rate of the plating solution 3.

In this way, both the stirring tank and the fluidized tank have good dissolution efficiency, but
It has the disadvantage that impurities contained in the metal are completely dissolved and mixed into the plating solution.

The present invention provides a method and apparatus for supplying metal ions that can suppress the dissolution of impurities in the metal and supply a stable plating solution when dissolving the metal with H'' ions in the plating solution. It is an object.

Means for Solving the Problems> The reaction in which metal is dissolved by H1 ions in the plating solution is expressed by the following equation, taking the case of Zn as an example.

Zn+2H” = Zn”+H2t Impurities in this metal (Pb, Cd, etc.) are the metal (Zn) to be dissolved
It is a metal (noble metal) that has a small ionization tendency compared to .

Therefore, the dissolution of impurity metals (Pb, Cd, etc.) coexisting with the metal begins after Zn (base metal), which has a tendency to ionize, is completely dissolved.

Therefore, in order to dissolve and suppress impurities (Pb, Cd, etc.), it is essential to constantly maintain contact with metals that have a strong ionization tendency, such as Zn and Fe.

When supplying metal ions by chemical dissolution, in order to suppress the dissolution of impurity ions contained in the metal, it is necessary to use Zn, Fe, etc., which have a greater ionization tendency than impurity ions, as much as possible.
All you have to do is make contact (formation of a corrosion battery).

That is, as shown in FIG. 5, in the plating solution 3 in the container 9, there are metal pieces 10 of metals with a strong ionization tendency, such as Zn and Fe, and metal pieces 11 of nobler metals, such as Ni and Pb. These metal pieces 10 exist independently of each other.
．． 11 is gradually dissolved in plating solution 3 and z n
2 +Fe2+ and N i ", pb" ions.

On the other hand, as shown in FIG.
When the metal piece 11 of 0 and Nt% pb is in contact, Ni
% pb metal piece 11 is not dissolved in the plating solution 3, and only metal pieces 10 of base metals such as Zn and Fe are dissolved to form Zn''Fe2.

The present invention has been made based on the above findings.

That is, according to the present invention, in order to achieve the above object,
In electroplating, a metal is charged into a dissolution tank as a source of the metal ions in a plating solution with a reduced concentration of metal ions, and the plating solution is brought into contact with the solution to dissolve the metal,
When supplying metal ions, the metal includes the metal to be supplied and a metal more noble than this metal, and the metal is placed in the melting tank in one or more layers with an inclination to the horizontal direction. There is provided a method for supplying metal ions, characterized in that the metal ions are arranged in layers separated by a predetermined interval, and the plating solution is injected from the bottom to the top of the melting tank.

Here, it is preferable that the flow rate of the plating solution in the dissolution tank is set to be equal to or lower than the sedimentation rate of impurity particles generated when the metal is dissolved by the injected plating solution.

Further, according to the present invention, a metal ion supply device for electroplating includes a dissolving tank having a plating solution injection port below, and a horizontal shelf having a through hole provided in the dissolving tank.
a pedestal for mounting plated metal consisting of one or more pedestals having one end fixed on the horizontal shelf and having a through hole arranged at an angle with respect to the horizontal shelf; There is provided a metal ion supply device characterized in that it has a plating solution discharge port provided above the upper end of the pedestal.

Here, it is preferable that the surface of the pedestal has a protrusion.

The present invention will be explained in more detail below.

The metal used in the present invention serves as a supply source of a plating solution with a reduced metal ion concentration in electroplating, and is Zn.
, Fe can be mentioned as a representative example, but it is not limited to this.

An example of a melting tank 12 for melting these metals is shown in FIG. 1.

This dissolving tank 12 may be of any type as long as the plating solution 3 is injected from the bottom to the top of the tank to dissolve the metal pieces 13 filled in the tank.

In the present invention, the metal pieces 13 are arranged in the melting tank 12 at a predetermined interval in one or more layers, inclined with respect to the horizontal direction. That is, when the metal piece 13 is rod-shaped or elongated plate-shaped, it is arranged so that one end in the longitudinal direction thereof faces down and the other end faces diagonally upward. It is preferable to provide a horizontal shelf 14 in the melting tank 12 and provide an inclined pedestal 15 on which the metal piece 13 is placed.

The angle of inclination of the metal piece 13 can be appropriately selected depending on the type and shape of the metal, the flow rate of the plating solution 3 in the melt 4!12, and the like.

The shape and dimensions of the metal piece 13 are not specified. In other words, they can be stacked on an inclined shelf with appropriate gaps.
As long as the shape does not move easily with the liquid flow, it can be arbitrarily selected depending on the type of metal, the composition of the solution, the amount of ions to be supplied, and the supply rate.

In this way, when the plating solution 3 is blown into the melting tank 12 from below, impurities 16 are scattered in the metal piece 13 (base material) to be melted at the beginning of melting, as shown in FIG. Since the impurities 16 are melted in this state, a corrosion cell is formed within the base material 13, and the impurities 16 are not dissolved.

However, after the base metals such as Zn and Fe constituting the base material 13 are almost completely dissolved, the impurities 16 become fine particles 17 and begin to float in the liquid. The second state
As shown in the figure.

The fine particles 17 are mainly composed of impurities 16. These are raised by the plating solution 3 blown in from below the dissolution tank 12, but immediately descended by their own weight, and the base material 1
3 (base metal), the plating metal in the base material is preferentially dissolved, and the elution of the impurity 16 can be suppressed to an extremely small amount.

The flow rate of the plating solution 3 in the dissolution tank 12 is such that the flow rate of the plating solution 3 in the dissolution tank 12 is
It is preferable to adjust the injection of the plating solution so that the sedimentation rate is lower than that due to the own weight of the particles 7 (impurity particles), since the fine particles 17 can easily descend and adhere to the inclined surface of the metal piece 13.

The fine particles 17 deposited on the inclined surface of the inclined metal piece 13 (base material) are periodically (for example, once or twice a day) dissolved in the dissolving tank 12.
If the liquid is removed, rinsed with plating solution or water, treated with a solid-liquid separator, etc., the separated liquid is collected or treated with a wastewater treatment system, and the sludge is disposed of in a landfill, it becomes a stable metal. Can dissolve ions.

Next, the metal ion supply device of the present invention will be explained based on an embodiment shown in FIG.

The apparatus of the present invention is constructed with a dissolution tank 12, a horizontal shelf 14 provided in the dissolution tank 12, and a pedestal 15 as main elements.

The dissolution tank 12 has a lower plating solution injection lower part and a plating solution outlet 8 above the upper end of the pedestal 15, and may be generally used as a fluidized tank. The number of injection lowers is not limited to two as shown in FIG. 1, and one or more injection lowers may be provided.

The horizontal shelf 14 is for placing the metal 13 and spouting the plating solution 3 onto the metal 13, and has a through hole 18 opening in the thickness direction on its entire surface. The inner diameter of the through hole 18 is not limited, and may be, for example, 10 to 100 mm. The material may be any material as long as it is not corroded by the plating solution, and if the molten metal is Zn or Fe, typical examples include rubber-lined steel, FRP, etc.

One end of the pedestal 15 is fixed to the upper surface of the horizontal shelf 14, and the pedestal 15 is arranged to stand upright with an inclination to the horizontal plane.

Although the method of fixing the pedestal 15 to the horizontal shelf 14 is not limited, it is preferable to fix it removably in consideration of cleaning and the like. Also,
The upper end may be fixed using an appropriate method. The number of frames 15 is not limited, and when two or more frames 15 are provided, it is preferable that they are arranged parallel to each other as shown in FIG.

The angle of inclination of the pedestal 15 can be appropriately selected depending on the type and shape of the molten metal, melting conditions, etc.

The frame 5 has a through hole 1 opening in the thickness direction on its entire surface.
It has 9. The inner diameter of the through hole 19 is not limited, for example, 5~
10mm is sufficient.

Furthermore, it is preferable to provide a protrusion 20 on the surface of the pedestal 15 as shown in FIG. 3 and place the metal piece 13 on the protrusion 20, since the flow velocity of the plating liquid 3 in the dissolution tank 12 is evened out. . The height of the protrusion 20 is not limited.

When the metal piece 13 is placed on the mount 15 using the metal ion supply device of the present invention and the plating solution 3 is injected from the injection lower into the molten AlT 12, the plating solution 3 is deposited on a horizontal shelf as shown in FIG. A main flow of the plating solution 3 ejected from the through holes 18 of 14 and indicated by the arrow C is formed between the mount 15 and the metal piece 13, and from this main flow C, tributaries shown by the arrows pass through the through holes 19 of each mount 15. It branches and comes into contact with the metal piece 13.

At this time, the impurity fine particles 17 generated or attached to the surface of the metal piece 13 move by the tributaries as shown by arrow E and descend again, and are always in contact with the surface of the metal piece 13. As a result, it does not dissolve in the plating solution 3.

<Example> The present invention will be specifically explained below based on Examples.

(Example 1) Zn90g/j2. Ni and pb
Tr, the liquid temperature was 50° C., and the solution was injected from the injection lower of the dissolving tank 12 (with an inner diameter of 1 m) shown in FIG. Dissolution [12 has a horizontal shelf 14 (material FRP, thickness 5
mm, and the inner diameter of the through hole is 10 mm), and on top of it, stands 15 inclined at the angle with respect to the horizontal plane shown in Table 1 are installed at intervals of 50 m.
A metal Zn rod (outer diameter 10 mm, length 2 0 mm) was placed on top of the 20 layers arranged in parallel. Metallic Zn was dissolved at the plating solution flow rate shown in Table 1. A frame without through holes 19 was added (Example 2).

(Comparative example) Using the same plating solution and metal Zn rod as in the example, the solid-liquid ratio was 1:100 and the liquid temperature was 50°C in a stirring tank (with an inner diameter of 1 m), and the metal was coated at the stirring speed and time shown in Table 2. Zn was dissolved (Comparative Examples 1 to 5).

Zn metal was melted in the same manner as in Example 1 except that the stand 15 and horizontal shelf 14 of the melting tank used in Example 1 were removed at the plating solution flow rate and residence time shown in Table 3 (Comparative Examples 6 to 11
).

Tables 1 to 3 show the analysis results of the plating solution after dissolution, and the examples of the present invention all have a lower concentration of Ni, an impurity, than the comparative examples, and it is possible to supply a stable plating solution without reducing the dissolution rate. It shows.

Table <Effects of the Invention> Since the present invention is configured as described above, the metal ion supply method of the present invention allows stable dissolution of metal ions and dissolution of impurity ions without reducing the melting rate. Dissolution can be suppressed.

Further, according to the metal ion supply device of the present invention, it is possible to suppress the dissolution of impurities without reducing the dissolution rate of metal ions with a simple configuration, and to supply a stable tamping liquid.

[Brief explanation of drawings]

FIG. 1 is a schematic representation of the metal in the early stage of melting.
1 is a cross-sectional view of a metal ion supply device showing an example. FIG. 2 is a cross-sectional view of the apparatus of the present invention schematically showing the fall of impurity particles. FIG. 3 is a sectional view showing the protrusion of the pedestal. FIG. 4 is a schematic diagram showing the flow of impurity particles and plating solution near the horizontal shelf and the pedestal. FIG. 5 and FIG. 6 are diagrams explaining the basic principle of the present invention. FIG. 7 is a schematic diagram showing the dissolution of metal in a stirring tank. FIG. 8 is a schematic diagram showing the melting of metal in a conventional fluidized tank. Explanation of symbols 1... Metal, 2... Stirring tank, 3... Plating solution, 4... Stirring blade, 5... Impurities, 6... Fluidization tank, 7... Inlet, 8...Discharge port, 9...Container, 10.11...Metal piece, 12...Dissolution tank, (base material) 3...Metal piece 4...Horizontal shelf, 5... Xo, 6...Impurity, 7...Fine particles, 8.19...Through hole, 0...Protrusion

Claims (4)

[Claims] (1) In electroplating, a metal is charged into a dissolution tank as a supply source of the metal ions in a plating solution with a reduced concentration of metal ions, and the plating solution is brought into contact with the solution to dissolve the metal, and the metal ions are dissolved. When supplying, the metal includes the metal to be supplied and a metal more noble than the metal, and the metal is arranged in one or more layers in the melting tank with an inclination to the horizontal direction. A method for supplying metal ions, characterized in that the plating solution is injected from the bottom to the top of the dissolution tank, which are separated for a predetermined period of time. (2) The method for supplying metal ions according to claim 1, wherein the flow rate of the plating solution in the dissolution tank is lower than the sedimentation rate of impurity particles generated when the metal is dissolved by the injected plating solution. (3) In a metal ion supply device for electroplating, a dissolution tank having a plating solution injection port below, a horizontal shelf having a through hole provided in the dissolution tank, and one end fixed on the horizontal shelf, a pedestal for mounting plated metal consisting of one or two or more having through holes arranged at an angle with respect to the horizontal shelf; and a pedestal provided at least above the upper end of the pedestal in the melting tank. A metal ion supply device comprising a liquid discharge port. (4) The metal ion supply device according to claim 3, further comprising a projection on the surface of the pedestal.