JPH04325692A - Method for recovering metal by electrolysis - Google Patents

Abstract

PURPOSE:To allow the execution of an electrolysis of a circulation type over a long period of time by forcing the electrolyte on the outer side of a bag containing a cathode and meshes of a specific size to flow convectionally at the time of executing an electrolysis with an ion exchange resin as a diaphragm and recovering the ionized metals in the liquid. CONSTITUTION:The cathode is put into the bag having the meshes or holes to the extent of allowing the free passage of the electrolyte and the electrolysis is executed at the time of recovering the metal ionized in the liquid to be electrolyzed by an electrolysis method in which the anode and cathode are parted by an ion exchange membrane. The dislodgment of the metal deposited on the cathode, the deposition and suspension of this metal in a cathode chamber and the consequent clogging of a conduit and pump connected to a storage tank, etc., are obviated in this way and the taking out of the deposited metal is facilitated. The straight washing of the recovered metal is possible. The electrolyte on the outer side of the above-mentioned bag is electrolyzed while this liquid flow is made to flow convectionally or is moved. The electrolytic conditions are stabilized in this way. The metallic ions are supplied near to the cathode where the metallic ion concn. in the electrolyte is low and the clogging of the meshes and holes of the bag is prevented. The ions exclusive of the metal are thus made to rapidly arrive at the neighborhood of the ion exchange membrane.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering ionized metals from an electrolytic solution using an ion exchange resin as a diaphragm.

0002

[Prior art and its problems] Conventionally, there has been a method in which an ion exchange membrane is used as a diaphragm, an electrolytic solution containing ionized metal is supplied to the cathode side, electrolysis is carried out, and the metal deposited on the cathode is taken out. It was done. However, when the amount of metal deposited on the cathode increases, the metal deposited on the cathode falls off.
The metal deposited at the bottom of the cathode chamber may take time to remove, or the fallen metal may become fine particles that become suspended and adhere to the ion exchange membrane, making it impossible to continue the electrolytic operation. A problem has arisen. moreover,
To perform electrolysis in a small electrolytic tank when there is a large amount of liquid to be electrolyzed, install a tank near the electrolytic tank to store the liquid to be electrolyzed, connect the storage tank to the cathode cell of the electrolytic tank with a conduit, and use a pump. When carrying out circulation type electrolysis in which the amount of liquid discharged from the cathode bath is supplied from the storage tank, if the metal deposited on the cathode falls off and floats, it may clog the pump and cause damage to the conduit. There is also the problem that it accumulates and cannot be circulated.

0003

OBJECTS OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the conventional method. The object of the present invention is to provide a method for recovering metals by electrolysis, which allows mold electrolysis to be carried out for a long time.

0004

[Means for Solving the Problems] The present invention provides a method for recovering metals ionized in an electrolytic solution using an electrolytic method in which an anode and a cathode are separated by an ion exchange membrane. Electrolysis is carried out by placing a cathode in a bag with holes or holes that allow the electrolysis to occur freely, and during electrolysis, the electrolytic solution outside the bag containing the cathode is carried out by convection or movement. This is a metal recovery method.

[0005] As for the bag having holes or holes large enough to allow the electrolytic solution to freely pass through, it is necessary to use a material that will not be corroded by the electrolytic solution, and materials made of various polymer resins can be used. be done. In addition, commercially available synthetic fiber filter cloths are easily available and easy to use, and can be used in a double layered manner to allow the electrolytic solution to freely pass through. Alternatively, a resin sheet with pores of approximately 0.3 to 0.5 microns may also be used, depending on the quality of the electrolytic solution and the state of the metal particles that precipitate and fall off. Although the cathode is placed in the bag for electrolysis, it is more preferable to hold the bag and the cathode in a state where they do not come into contact with each other.

[0006] During electrolysis, the electrolytic solution outside the bag containing the cathode is moved by convection to maintain stable electrolytic conditions, and the concentration of metal ions in the electrolytic solution is low near the cathode. This is because it has the effect of supplying metal ions to the membrane and preventing clogging of the openings and pores of the bag, as well as allowing ions other than metal to quickly reach the vicinity of the ion exchange membrane.

[0007] Examples related to the present invention will be described below, but the examples are not intended to limit the present invention.

[0008]

[Example] Using a cation exchange membrane (manufactured by Asahi Glass: CMV model), the electrolytic tank is separated into a cathode tank and an anode tank. Using a device consisting of a storage tank to which a discharge conduit is connected, a stannous chloride solution (Sn: 1
(containing 4 g/l), and 2.5 g/l in the anode tank.
mol dilute sulfuric acid, a DSE (insoluble metal electrode) was used as the anode, a titanium plate was used as the cathode, and the cathode was placed in a bag made of commercially available filter cloth (Tetron).The electrolytic conditions were 3V and 60A. I electrolyzed it. After 18 hours of electrolysis, the bag containing the cathode was taken out and washed with water to recover the metal tin. The tin concentration in the electrolyzed solution was 1 g/l, and no metal tin was floating in the solution or deposited in the cathode bath.

[0009]

[Conventional example] When electrolysis was carried out in the same manner as in the example without placing the cathode in a bag, the discharge conduit was clogged after 20 hours of electrolysis time, and the electrolytic solution flowed out from the electrolytic cell. Metallic tin was also deposited on the bottom of the cathode tank.

0010

Effects of the Invention As is clear from the above explanation, according to the method of the present invention, metals deposited on the cathode can be deposited on the cathode, especially when the metal ions in the circulating electrolytic solution are deposited on the cathode in the conventional method. Metals may fall off and accumulate in the cathode tank, or they may float and cause clogging of conduits connected to storage tanks, clogging of pumps, etc., and it may take time and effort to remove the deposited metals. In addition to being able to solve all of these problems, this method also has the effect of allowing metals recovered by electrolysis to be cleaned as they are, making it extremely useful industrially.

Claims (1)

[Claims] Claim 1: When recovering metals ionized in the electrolytic solution using an electrolytic method in which an anode and a cathode are separated by an ion exchange membrane, the electrolytic solution can freely pass through the metal or the metal. A metal recovery method by electrolysis, characterized in that electrolysis is carried out by placing a cathode in a bag with holes, and during electrolysis, the electrolytic solution outside the bag in which the cathode is placed is caused to flow or move.