JPH0310093A - Electrolytic recovery device - Google Patents

Abstract

PURPOSE:To easily recover a noble metal from a waste plating soln. having a low content of the noble metal by concentrically hanging plural cylindrical cathodes having different diameters from the lower surface of a discoid mounting plate rotating at a high speed and fixing the cathodes so that plural cylindrical anodes are positioned between the surface of the cylindrical cathodes. CONSTITUTION:A driving shaft 42 with a discoid cathode mounting plate 41 freely detachably fixed to its lower end and capable of being rotated is positioned in a cylindrical electrolytic cell 1, and the cylindrical cathodes 43a, 43b and 43c with the diameters successively decreasing are fixed concentrically to the lower surface of the plate 41. Furthermore, the cylindrical anodes 51a, 52b and 53c with the diameters successively decreasing are concentrically fixed to the upper surface of a discoid anode mounting plate 52, and the plate 52 is fixed to the cell bottom so that the respective cylinders of the anodes 51a, 52b and 53c are positioned between the layers of the cathodes 43a, 43b and 43c. Under such a constitution, a waste plating soln. 11 having a low content of a noble metal is filled into the cell 1, the driving shaft 42 is rotated at a high speed, and electrolysis is carried out. Consequently, the noble metal is deposited and recovered with high recovery rate and efficiency.

Description

[Detailed Description of the Invention] [Summary] Regarding an electrolytic recovery device that recovers precious metals contained in plating waste liquid etc. of precious metal plating, high recovery can be achieved by widening the facing area of the cathode and anode and making the current distribution uniform. The purpose is to provide an apparatus that can obtain a good recovery precipitate at a high speed, and is equipped with a cathode inside an electrolytic cell and an anode opposite to the cathode, and has a low concentration in the solution filled in the electrolytic cell. It is an electrolytic recovery device that deposits metal on a cathode, and a disk-shaped cathode that rotates at high speed is installed with a plurality of cylindrical cathodes with different diameters concentrically hung on the bottom surface of the plate, and a plurality of cylindrical cathodes with different diameters. This configuration includes a plurality of cylindrical anodes fixed so as to be located between the cylindrical surfaces.

[Industrial application field]

The present invention relates to an electrolytic recovery device for recovering low-concentration precious metals contained in plating waste liquid and the like of precious metal plating.

In precious metal plating processes such as contact plating for electronic components, precious metal components are effectively recovered from the plating solution that adheres to the product after precious metal plating and is taken out of the plating bath.
We are trying to use resources effectively.

C. Prior Art] In a continuous plating device that continuously applies precious metal plating to workpieces connected in a strip shape, a predetermined precious metal plating is applied while the workpiece passes through a plating tank filled with a precious metal plating solution. The workpiece is then transported to the next stage for post-processing such as washing with water, but the workpiece sent out from the plating tank has precious metal plating solution attached to it, and if it is washed with water, the precious metal components contained in the attached plating solution will be removed. It leaks and results in a loss.

To prevent this, the cleaning water containing the plating solution is passed through a precious metal recovery process without being disposed of, and the precious metal is recovered as metal from the cleaning solution. Usually, the noble metal ion component contained in such waste liquid is at an extremely low concentration of 100 to 11,000 pp. In order to separate and recover metal components from this low-concentration metal solution, conventional methods have been to adsorb metals on adsorption resin or activated carbon, then incinerate these adsorbents in a roasting furnace, etc., and separate precious metals from the remaining ash. It was being collected. This method requires large-scale equipment and requires a large amount of adsorbent that cannot be reused, which has the drawback of increasing recovery costs.

Therefore, recently, a recovery method using an electrolytic recovery device that can be easily used continuously by being connected to a plating device has been used.

The conventional electrolytic recovery device has an electrolytic tank 1 as shown in Fig. 2.
A disk-shaped cathode 2 rotatably held by a drive shaft 22 covered with an insulating coating 22a and a cylindrical anode 3 surrounding the cathode 2 are provided in a solution such as plating waste liquid filled inside the While rotating the cathode 2 at high speed, the precious metal 12 was deposited on the surface of the cathode 2 by electrolysis, and the deposited precious metal was separated and recovered by peeling it off from the cathode 2.

[Problem to be solved by the invention]

In order to recover plating waste liquid with extremely low metal concentration at a practical recovery rate, it is desirable that the current density of the electrolytic current be as high as possible. However, in the conventional recovery device described above, the cylindrical anode is arranged around the disc-shaped cathode, so
The electrolytic current concentrates only on the periphery of the cathode near the anode, and the current density becomes too high, causing the deposited film to become porous and sooty, causing burns and making it impossible to handle it as a metal film, resulting in poor peeling from the cathode. becomes difficult to do.

Furthermore, since the entire surface of the cathode does not contribute to electrolysis, there is a problem in that the recovery efficiency and recovery rate cannot be increased compared to the outer shape.

The present invention was created in view of the above problems, and is an electrolytic recovery device that can obtain good recovered precipitates at a high uniform rate by widening the facing area of the cathode and the anode and making the current distribution uniform. The purpose is to provide

[Means to solve the problem]

The above problem is solved by an electrolytic recovery device that includes a cathode inside an electrolytic cell and an anode facing the cathode, and deposits low-concentration metals in a solution filled in the electrolytic cell onto the cathode. The rotating disc-shaped cathode installation consists of a plurality of cylindrical cathodes with different diameters that are vertically installed concentrically on the bottom surface of the plate, and a plurality of cylindrical cathodes that are fixed to be located between the cylindrical surfaces of the plurality of cathodes. This problem is solved by the electrolytic recovery device of the present invention, which is characterized by having a cylindrical anode.

[Function] Since the entire surface of the cathode faces the anode at approximately the same distance, the current density becomes uniform, and good precipitates can be obtained on the entire cathode surface without causing burns due to local current concentration. In addition, since the cathode has a concentric multilayer structure, the surface area of the cathode can be increased without increasing the external size.
Even at the same precipitation rate, the overall recovery rate is improved.

〔Example〕

The present invention will be explained in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic cross-sectional view showing the electrolytic recovery apparatus of the present invention.

In the figure, 1 is a cylindrical electrolytic cell made of a corrosion-resistant material. Reference numeral 41 denotes a disk-shaped cathode mounting plate made of a conductive material, and is detachably fixed to the lower end of a metal drive shaft 42 which is rotated at a high speed of several 1100 orps by a drive means (not shown).

43a, 43b, and 43c are cylindrical cathodes with diameters decreasing in this order, and are made of corrosion-resistant stainless steel plates. A plurality of cathodes are arranged concentrically, and the cathode is attached to the bottom surface of the plate 42. is fixed.

Reference numerals 51a, 51b, and 51c are cylindrical anodes having smaller diameters in this order, and the lower end of the disk-shaped anode is fixed concentrically to the upper surface of the plate 52. Each cylinder of the anode is fixed to the bottom surface of the electrolytic cell 1 so as to be located between each of the plurality of layers of cathodes 43a, 43b, and 43c. By arranging the electrodes in this manner, the entire inner and outer surfaces of the cylindrical cathode face the anode at regular intervals, and this opposing area can be increased by increasing the number of layers.

Then, a solution 11 such as a plating waste solution containing a low concentration metal to be recovered is placed in the electrolytic tank 1 so that the liquid level is at the anode level 51a, b.
, C, the upper end of the cathode is placed between the lower surface of the plate 41, and one side of the power supply is connected to the drive shaft 42.
By connecting the + side of the anode to the plate 52 and supplying a predetermined electrolytic current, the low concentration metal in the solution is electrolytically deposited at a substantially uniform deposition rate on the entire surface of the cathode facing the anode. .

In this case, the high-speed rotation of the drive shaft 42 keeps the cathode in a concentric state, and since it rotates and stirs in the solution, the cathode surface is always replenished with the solution before collection having a predetermined metal concentration, resulting in high efficiency. metal is deposited on the cathode surface.

In addition, since the entire surface of the cathode faces the anode at an equal distance, the current distribution on the cathode surface is uniform, and even when a large current is passed, the current does not concentrate on a part of the cathode. A good precipitate is deposited over the surface at a high rate.

When a precipitate of a predetermined thickness is obtained, the plate is removed from the electrolytic bath and the precipitate is peeled off from the cathode surface to recover the precious metal in bulk.

〔Effect of the invention〕

As described above, the electrolytic recovery device of the present invention can obtain a good recovered precipitate with high recovery rate and efficiency by widening the facing area of the cathode and anode and making the current distribution uniform, and it is possible to obtain good recovered precipitates with high recovery rate and high efficiency. It becomes possible to reduce the cost of recovering precious metals, etc. from

(one

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an electrolytic recovery device of the present invention, and FIG. 2 is a schematic sectional view of a conventional electrolytic recovery device. In the figure, ■ - electrolytic cell, 11 - solution containing low concentration metal, 41 - cathode mounting plate, 42 - drive shaft, 43a+b+c '-'-
Cylindrical cathode, 51a, b, c
・−・Cylindrical anode, 52−
The anode mounting is on a board. 〉Z! , variable gp/) '1. A vine diagram showing the progress of decomposition and convergence.

Claims (1)

[Claims] An electrolytic cell (1) is provided with a cathode and an anode facing the cathode, and a low concentration metal in a solution (11) filled in the electrolytic cell (1) is applied to the cathode. An electrolytic recovery device for precipitation, comprising a plurality of cylindrical cathodes (43, 43b, 43c) with different diameters, which are vertically installed concentrically on the lower surface of a disk-shaped cathode mounting plate (41) that rotates at high speed; An electrolytic recovery device comprising a plurality of cylindrical anodes (51a, 51b, 51c) fixed so as to be located between the cylindrical surfaces of the plurality of cathodes.