JP3258752B2 - Method and apparatus for recovering nickel mixed in plating solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous electroplating facility in which zinc plating and zinc nickel plating are alternately performed on a metal strip using an insoluble anode. The present invention relates to a method and an apparatus for removing and recovering nickel ions mixed (contaminated) into the inside.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for improved corrosion resistance in automobiles, home electric appliances and the like, and in addition to galvanized steel sheets conventionally used, there has been a remarkable demand for recently developed alloy-coated steel sheets such as zinc-nickel plated steel sheets. Showing an increase. To cope with such an increase in demand, a high-speed continuous electroplating method with a high current density that enables high-efficiency production has been adopted. It goes without saying that a method of using an insoluble anode such as an iridium type which does not need to be replaced and supplying the consumed metal ions to the plating solution is more advantageous.

An electrolytic solution such as sulfuric acid is usually used as a plating solution. Further, a method for replenishing metal ions such as zinc and nickel into the plating solution includes a method in which metal zinc or nickel is dissolved by directly contacting the plating solution, and a method in which a metal compound such as zinc oxide is dissolved. There is. At first glance, it seems to be more efficient to dissolve the powdered metal compound, but such powders are generally easily blocked (blocked) by the heat of reaction generated on the powder surface when poured into a liquid, and However, a method of directly dissolving powder or granular metallic zinc or metallic nickel is often adopted because of the drawback that the cured product hardly dissolves.

When zinc plating and zinc nickel plating are to be alternately performed on the same line, most of the equipment such as a plating cell and a plating solution circulation pipe in the line can be shared by the same equipment. The ions to be dissolved are only zinc ions in the case of zinc plating, and in the case of zinc nickel plating, both zinc ions and nickel ions are mixed, so there is not much problem when switching from zinc plating to zinc nickel plating. Conversely, when switching from zinc nickel plating to zinc plating, nickel ions mixed into the plating solution circulation system must be removed.

If metal zinc is excessively dissolved in a plating solution containing nickel ions, a substitution precipitation reaction occurs in which nickel is deposited instead of zinc because nickel is noble relative to zinc. JP-A-50-17335,
As disclosed in Japanese Patent Application Laid-Open No. 1-152300, this substitution precipitation reaction is conventionally used, and a large amount of powdered or granular metallic zinc is introduced into a plating solution to precipitate mixed nickel. That is being done. At this time, when nickel precipitates on the surface of the undissolved metallic zinc, the dissolution rate of zinc decreases, and when the deposited nickel adheres to the surface of the material to be plated, there are problems such as inferior quality such as pressing flaws. , After removing the precipitate through a filter, etc.
The procedure of starting zinc plating was taken. The solid metal material separated by the filter is a sludge state in which metal nickel as an impurity is mixed with undissolved metal zinc, and is usually disposed of as waste,
There is a problem that the nickel basic unit is reduced.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and solves the problem of sludge that has been conventionally discarded.
An object of the present invention is to provide a method for recovering nickel.

[0007]

Method for recovering mixed nickel plating solution of the present invention SUMMARY OF], the continuous intends rows galvanized or zinc-nickel plating metal strip using an insoluble anode electrical message
Cut Oite to come, from the zinc-nickel plating galvanized
When replacing , dissolve the metal zinc in the galvanizing solution ,
Nickel ions mixed in the zinc plating solution circulating path allowed out location <br/>換析, the precipitated metallic nickel was separated by solid-liquid separation means in a zinc plating solution circulating path together with the undissolved zinc metal zinc plating solution were charged into a zinc-nickel plating solution which pre recovered, characterized in that redissolved to the zinc-nickel plating solution.

Further, recovery system contamination nickel plating solution of the present invention, or galvanized metal strip using an insoluble anode
Other in-line intends continuous electroplating equipment zinc nickel plating, circulation pipe path connecting the the plating solution to dissolve the zinc metal zinc dissolving tank to replenish zinc ions (3) and a zinc plating solution circulating tank (6) a solid-liquid separation means for separating the sludge in the plating solution from the inner (5), and transfer means for transferring the separated sludge (7), an agitator for redissolved in zinc-nickel plating solution was charged the transported sludge And a re-dissolving tank ( 8 ) having ( 9 ).

[0009]

[Operation] As described above, when metal zinc is excessively dissolved in the plating solution, zinc is ionized and nickel loses electric charge and precipitates at the same time. That is, a reaction of Zn + Ni2 ⁺ → Zn2 ⁺⁺ Ni occurs. When switching from zinc nickel plating to zinc plating, this reaction is used to precipitate nickel mixed in the plating solution circulation system, and the precipitated nickel is captured by a filter. Most of the captured sludge is metallic zinc particles, into which precipitated nickel is mixed or adhered.

Slurry of 91% metallic zinc and 8% metallic nickel was treated with 35 g / l of zinc ions, 65 g / l of nickel ions, p
The solution was dissolved in a sulfuric acid plating solution having an H of 1.7 and a solution temperature of 50 ° C. with stirring, and the dissolution state was observed for each dissolution condition shown in Table 1.

[0011]

[Table 1]

As can be seen from Table 1, in Experiment 1, there is undissolved part, in Experiment 2, it is completely melted. In Experiment 4, there is undissolved part, and in Experiment 5, it is completely dissolved. In the case of this combination of sludge and plating solution, the sludge should be 20 g or less per liter of plating solution,
It can be seen that if the solution is stirred for 15 seconds or more, it is completely dissolved. This is an example, but the conditions for complete dissolution can be determined by conducting a simple preliminary experiment in accordance with the composition of the plating solution or sludge to be dissolved in the same manner.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a part of a continuous electroplating line for alternately performing zinc plating and zinc nickel plating of a steel strip according to an embodiment of the present invention. 1 is a metal zinc powder storage hopper, 2 is a cutting device, 3 is a zinc dissolving tank, 4 is a stirrer, 5 is a filter, 6 is a zinc plating solution circulation tank, 7
Is a transfer means, 8 is a re-dissolution tank, 9 is a stirrer, 10 is a zinc-nickel plating solution circulation tank, 51 is a discharge path, and 52 is a sludge carrier.

[0014] end is operation of zinc-nickel plating, is switched to galvanized, with zinc-nickel plating solution was used is collected in the zinc nickel plating solution circulating tank 10 until then, the zinc plating solution circulating tank 6, illustrated The plating cell in the line not to be connected is connected. The zinc plating solution circulation tank 6 is provided with a zinc dissolution tank 3 for dissolving metal zinc, and the metal zinc powder is introduced into the plating solution in the zinc dissolution tank 3 through the cutting device 2 from the metal zinc powder storage hopper 1. Charged and dissolved. Therefore, by circulating the plating solution between the zinc dissolving tank 3 and the zinc plating solution circulation tank 6 as shown by the arrow, zinc ions can be replenished in the plating solution.

When the operation of the plating line is switched from zinc nickel plating to zinc plating, even if the plating solution is recovered, the zinc nickel plating solution is mixed in the plating cells and piping. When a large amount of metallic zinc is newly introduced into the plating solution using the tank 3, nickel is precipitated by the substitution reaction and is captured together with undissolved metallic zinc by the solid-liquid separating means 5 such as a filter in the circulation circuit. . Conventionally, the trapped sludge was discharged out of the system as shown by the dashed arrow 51 here and discarded by the sludge carrier 52.In this embodiment, the trapped sludge is transferred to a slurry pipe, a conveyor, or the like. The sludge composition is transferred to the re-dissolution tank 8 by means 7 and charged therein, and while being stirred by the stirrer 9, both the sludge metal zinc and metal nickel are re-dissolved in the zinc nickel plating solution to be used next time.

The plating solution containing the re-dissolved nickel ions may be stored in the re-dissolving tank 8, but may be circulated between the zinc-nickel plating solution circulation tank 10 as shown in FIG. . The re-dissolution tank 8 may be provided independently, but may also be used as a dissolution tank for replenishing the zinc-nickel plating solution with ions. As the solid-liquid separation means 5, in addition to the above-described filter, a settling tank, a cyclone, or the like can be used. Further, the sludge may be separated at any position as long as it is in the middle of a pipe connecting the zinc dissolution tank 3 and the zinc plating solution circulation tank 6. In addition, the transfer means 7
The separated sludge may not necessarily be continuously transferred, but may be transferred in a batch manner.

[0017]

According to the present invention, the precipitated nickel is recovered, redissolved in the zinc nickel plating solution to be used next time, and used as an ion source. It has an excellent effect of reducing waste.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Metal zinc powder storage hopper 2 Cutting device 3 Zinc dissolution tank 4 Stirrer 5 Solid-liquid separation means 6 Zinc plating solution circulation tank 7 Transfer means 8 Remelting tank 9 Stirrer 10 Zinc nickel plating solution circulation tank 52 Sludge transport vehicle

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) C25D 21/18 C22B 23/00 C25D 5/12 C25D 7/06 C25D 21/14

Claims (2)

(57) [Claims] 1. A galvanizing metal strip using an insoluble anode or
Others Te placed <br/> to come continuous electric plating intends rows zinc-nickel plating, fly switching from zinc-nickel plating galvanizing
In case, to dissolve the zinc metal in a zinc plating solution, zinc plating
Nickel ions are substituted deposit to be mixed into the gas-liquid circulation path, the precipitated metallic nickel was separated by solid-liquid separation means in a zinc plating solution circulating path together with the undissolved zinc metal zinc plating solution, previously recovered zinc-nickel A method for recovering nickel mixed in a plating solution , wherein the method is introduced into a plating solution and redissolved in the zinc-nickel plating solution. 2. A galvanizing metal strip using an insoluble anode or
Other in-line intends continuous electroplating equipment zinc nickel plating, circulation pipe path connecting the the plating solution to dissolve the zinc metal zinc dissolving tank to replenish zinc ions (3) and a zinc plating solution circulating tank (6) a solid-liquid separation means for separating the sludge in the plating solution from the inner (5), and transfer means for transferring the separated sludge (7), an agitator for redissolved in zinc-nickel plating solution was charged the transported sludge An apparatus for collecting nickel contained in a plating solution, comprising: a re-dissolution tank ( 8 ) having ( 9 ).