KR20030041039A - Apparatus and method for maintaining the concentration of the ferrous ion for the electroplating process - Google Patents

Abstract

PURPOSE: An apparatus and a method for maintaining ferrous ions suitable for electroplating process by preventing oxidation of the ferrous ions in electroplating solution for electroplating process and reducing the oxidized ferrous ions are provided. CONSTITUTION: The apparatus for maintaining ferrous ions suitable for electroplating process comprises a storage tank(104) in which electroplating solution is stored; an inert gas supply means for supplying inert gas into the storage tank; and a reduction tank(102) for reducing ferric ions inside the electroplating solution supplied from the storage tank into ferrous ions by electrochemical reduction, wherein the apparatus further comprises a chloric acid supply tank(103) for supplying chloric acid to maintain acidity of the electroplating solution supplied into the reduction tank to 2.1 to 2.5, and wherein the reduction tank comprises an agitation means for agitating the electroplating solution. The method for maintaining ferrous ions suitable for electroplating process comprises the steps of forming an inert gas atmosphere by supplying an inert gas into the storage tank; and reducing ferric ions existing in the electroplating solution exposed to the inert gas atmosphere into ferrous ions by electrochemical reduction, wherein the acidity of the electroplating solution is maintained to 2.1 to 2.5 before reducing the ferric ions.

Description

Apparatus and method for maintaining the concentration of the ferrous ion for the electroplating process

In the present invention, the electroplating operation of zinc (Zn) and iron (Fe) is finished and the electroplating solution having an alloy component of zinc-iron at rest until the next operation reacts with oxygen in the atmosphere to produce ferric ions (Fe ^The present invention relates to an apparatus and a method capable of preventing the production of ⁺³ ), and more particularly, ferric ions produced in an alloying solution to improve the electroplating efficiency of an electroplating solution having an alloy component of zinc-iron. (Fe ⁺³⁾ to ferrous ions in the electrolyte to relate (Fe ⁺²⁾ or pure iron ions (Fe ⁺⁾ iron ions suitable for holding an electroplating process capable of reducing the apparatus and maintenance method.

In general, the plating solution for electroplating is mainly composed of an alloy component of zinc (Zn) -iron (Fe), hydrochloric acid (HCl), iron (Fe), ferrous ions (Fe ⁺² ), ferric ions (Fe ⁺³⁾ ), Potassium chloride (KCl), zinc (Zn), zinc ions (Zn ⁺² ) and other solution products. The quality of this plating solution is strictly controlled because it is directly related to the quality of electroplating reaction and electroplating steel sheet.

On the other hand, when the plating solution of the zinc-iron alloy is stored for a long time, the iron (Fe) component reacts with dissolved oxygen (O) and hydrochloric acid (HCl) in the plating solution absorbed as a solution in the air as shown in the following equation (1). Is oxidized.

Fe ₂ + 3 / 2O ₂ + 6HCl = 2FeCl ₃ + 3H ₂ O ‥‥‥‥‥‥ (1)

In addition, the product represented by Formula (1), that is, ferric chloride (FeCl ₃ ) is present as sludge in the plating solution.

The sludge produced in this way should not be removed from the plating process because it does not help anymore, but rather stains the plated steel plate during the plating process, causing stains and sticking to various plating facilities. Therefore, the filtration equipment must be operated to remove the sludge of the electroplating solution, and the filtered sludge is acidic, so it must be disposed of by a separate neutralization treatment.

On the other hand, since the ferrous ions are oxidized to ferric ions by dissolved oxygen and present as sludge, the total iron ion concentration of the electroplating solution is reduced. That is, as the storage period of the electroplating solution becomes longer, the concentration of ferric ions increases due to oxidation, while the concentration of ferric ions decreases. As a result, the iron content deposited on the surface of the plated steel sheet during electroplating is reduced. You don't get as much as you expect.

The present invention has been made in order to solve the conventional problems as described above, in order to improve the plating efficiency of the electroplating process and also to improve the quality of the electroplating steel sheet after the plating process of the zinc-iron alloy is finished until the next operation It prevents iron ions from being oxidized by dissolved oxygen in the electroplating solution, and the ferric ions (Fe ⁺³ ) and ferrous ions (Fe ⁺² ) by electrolytic reduction of ferric ions (Fe ⁺³ ) and sludge present in the electroplating solution. The present invention provides an iron ion concentration maintaining apparatus and a method suitable for an electroplating process that can increase the concentration of iron ions participating in the plating process by reducing to).

1 is a block diagram showing an iron ion holding device according to the present invention;

2 is a block diagram showing a nitrogen supply means of the iron ion maintaining device according to the present invention;

Figure 3 is a schematic view showing a reducing tank of the iron ion maintaining apparatus according to the present invention;

Figure 4 is a block diagram showing a current collector of the iron ion holding device according to the present invention.

<Description of Symbols for Major Parts of Drawings>

100: control panel

100a: nitrogen supply controller

100b: hydrochloric acid supply controller

101: nitrogen tank

102: reduction tank

103: hydrochloric acid tank

104: storage tank

202, 302: on-off valve

205a: drive motor

303: Rotating Motor

305 electrode

In order to achieve the above object, according to the present invention, in order to prevent the oxidation of iron ions in the electroplating solution for the electroplating process and to reduce the oxidized iron ions to maintain the iron ions suitable for the electroplating process is the electroplating A storage tank in which the solution is stored, an inert gas supply means for supplying an inert gas to the storage tank, and a reduction tank for reducing ferric ions in the electroplating solution supplied from the storage tank to ferrous ions by electrolytic reduction. It is characterized by.

According to another embodiment of the present invention, a method for maintaining the iron ion concentration of the electroplating solution stored in the storage tank to be suitable for the electroplating process, the step of supplying an inert gas to the storage tank to form an inert atmosphere and And reducing the ferric ions present in the electroplating solution exposed to the inert atmosphere by electrolytic reduction.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention.

According to the present invention, in order to maintain the iron ion concentration in the electroplating solution stored in the storage tank 104 suitable for the electroplating process, dissolved oxygen present in the electroplating solution is removed. That is, the iron ion holding device according to the present invention has an inert gas supply means for supplying an inert gas to the storage tank (104). The inert gas is composed of argon (Ar) or nitrogen (N ₂ ) and the like, and the inert gas is limited to nitrogen in the following description.

That is, referring to FIG. 2, the inert gas supply means includes a nitrogen tank 101 and a nitrogen supply line 101a for supplying nitrogen in the nitrogen tank 101 to the storage tank 104, and the storage tank. A nitrogen injection nozzle 204 is installed at the discharge end of the nitrogen supply line 101a located in the 104. The nitrogen supply line 101a includes a first opening / closing valve 202 for controlling the amount of nitrogen supplied from the nitrogen tank 101 and a pressure gauge 203 for measuring the pressure of nitrogen supplied from the nitrogen tank 101. Is installed.

The inert gas supply means further includes a nitrogen supply amount controller 100a for adjusting the opening degree of the first opening / closing valve 202 according to the pressure value of nitrogen measured by the pressure gauge 203.

Therefore, by opening the first opening / closing valve 202 by the nitrogen supply amount controller 100a to supply nitrogen from the nitrogen tank 101 to the storage tank 104 and to keep the inside of the storage tank 104 in an inert atmosphere, The absorption of atmospheric oxygen into the electroplating solution in the storage tank 104 is also prevented and the dissolved oxygen in the electroplating solution is removed.

At this time, the storage tank 104 is provided with circulation means for circulating the electroplating solution to increase the removal rate of dissolved oxygen from the electroplating solution in the storage tank (104). The circulation means has a circulation line 104b arranged to extend outward from the storage tank 104 to form a circulation trajectory and a circulation pump 205b installed in the circulation line 104b. Therefore, the electroplating solution discharged from the storage tank 104 by the operation of the circulation pump 205b flows back into the storage tank 104 along the circulation line 104b.

In addition, the iron ion maintaining apparatus according to the present invention further comprises a reducing means for reducing the iron ions in the electroplating solution.

That is, referring to FIG. 3, the reduction means has a reduction tank 102 in which the electroplating solution in the storage tank 104 flows in and is reduced. A lid 102a is provided at an upper portion of the reduction tank 102, and a stirring means for agitating the electroplating solution contained in the accommodation space of the reduction tank 102 is installed at the lid 102a. The stirring means comprises a rotating shaft 303a and a rotating motor 303 for rotating the rotating shaft 303a, which are installed to penetrate the cover 102a and the stirring blade 303b is installed at the lower portion.

In addition, the reduction means is an electrode 305 is fixed to the cover 102a to be immersed in the electroplating solution accommodated in the receiving space of the reduction tank 102 and the electrode 305 through the conducting wire 304 It has a control panel 100 that is connected to the electricity supply.

The electroplating solution in the storage tank 104 is introduced into the receiving space of the reduction tank 102 along the solution supply line 104a by the operation of the driving pump 205a. By supplying power to the electrode 305 from the control panel 100 through the conduction wire 304, the iron ions in the electroplating solution introduced into the receiving space of the reduction tank 102 by the electrolytic reduction is reduced. That is, electrons are released to the electroplating solution introduced into the receiving space of the reduction tank 102 from the electrode 305 due to the power supply, and iron ions in the electroplating solution are reduced by receiving the electrons emitted. Such a reduction reaction of iron ions is represented by the following formula (2) to formula (4).

^{Fe +2 + 2e - = Fe ‥‥‥‥‥} (2)

^{Fe +3 + 3e - = Fe ‥‥‥‥‥} (3)

^{Fe +3 + e - = Fe +2} ‥‥‥‥‥ (4)

At this time, the stirring means to agitate the electroplating solution in the reduction tank 102 so that the above-described reduction of iron ions can be carried out extensively.

The reducing tank 102 is provided with a level gauge (not shown) for measuring the level of the electroplating solution flowing into the receiving space, the lower portion of the reducing tank 102 to discharge the electroplating solution to the storage tank 104 Discharge line 102a for is connected. The discharge line 102a is provided with a third open / close valve 102a for controlling the discharge of the electroplating solution.

The reducing means further includes a hydrochloric acid tank 103 for supplying hydrochloric acid to the reducing tank 102 along the hydrochloric acid supply line 103a to adjust the acidity (pH) of the electroplating solution in the reducing tank 102. Include. The hydrochloric acid supply line 103a is provided with a second opening / closing valve 302 for adjusting the amount of hydrochloric acid supplied. In addition, the reduction tank 102 is provided with a pH detector 306 for detecting the acidity of the electroplating solution in the receiving space. The second opening / closing valve 302 and the pH detector 306 are connected to the hydrochloric acid supply controller 100b to enable transmission and reception of electric signals.

On the other hand, it is preferable to maintain the acidity (pH) of the electroplating solution to 2-3 in order to improve the electrical conductivity of the electroplating solution and to reduce the power ratio when performing the electrolytic reduction as described above in the reduction tank 102 Do. In particular, according to a preferred embodiment of the present invention, the acidity of the electroplating solution is maintained at 2.1 to 2.5 to improve the electrical conductivity while minimizing the amount of sludge present in the electroplating solution.

Therefore, if the acidity of the electroplating solution in the reduction tank 102 measured by the pH detector 306 is not maintained in an appropriate state, the hydrochloric acid supply controller adjusts the opening degree of the second opening / closing valve 302 to make the hydrochloric acid tank. The amount of hydrochloric acid supplied to the reduction tank 102 is adjusted along the hydrochloric acid supply line 103a from 103.

As a result, the sludge in the form of ferric ions (Fe ^{+ 3} ) or ferric chloride (FeCl ₃ ) present in the electroplating solution while the acidity of the electroplating solution was maintained at 2.1 to 2.5 is represented by the following formula (5). Dissolve together.

4FeCl ₃ + HCl + 2Fe = 6FeCl ₂ + 1 / 2H ₂ (g) ‥‥‥‥‥‥ (5)

Referring to FIG. 4, the control panel 100 for supplying power to the electrode 305 includes a nitrogen supply amount controller 100a and a hydrochloric acid supply amount controller 100b. The front of the control panel 100 is provided with a meter and switch suitable for power supply and control of the on-off valve. That is, reference numeral 500 is a positive current gauge of the DC power supply, 501 is a negative current gauge of the DC power supply, 502 is a current recorder of the DC power supply, 503 is a current regulator of the DC power supply, 504 is a system mode switch, 505 is the system power switch, 506 is a switch for the circulation pump of the storage tank, 507 is the first drive pump operation switch, 508 is the second open / close valve operation switch, 509 is the first open / close valve operation switch, and 510 is A third open / close valve controller, and 511 is an energization controller.

Hereinafter, the operation of the iron ion holding device suitable for the electroplating solution according to the present invention.

First, the electroplating solution generated by the zinc-iron alloying operation is collected and stored in the storage tank 104. By selecting the system mode switch 504 of the control panel 100 as the operation mode and manipulating the system power switch 505, the iron ion maintaining device according to the present invention operates according to the built-in program.

That is, in the state in which the electroplating solution is stored in the storage tank 104, the nitrogen supply amount controller 100a receives a signal from the pressure gauge 203 to start calculation, so that a reference pressure of 1.5 kg ± 0.3 kg is supplied to the nitrogen supply line 101a. The opening degree of the first opening / closing valve 202 is adjusted. Nitrogen in the nitrogen tank 101 is supplied to the storage tank 104 to maintain the interior of the storage tank 104 in an inert atmosphere, thereby preventing the electroplating solution from contacting the atmosphere, thereby oxidizing iron ions in the electroplating solution. Prevent it.

At this time, the circulation pump 205b is operated to circulate the electroplating solution along the circulation line 104b to discharge dissolved oxygen dissolved in the electroplating solution.

In addition, in order to reduce sludge in the ferric ion (Fe ⁺³ ) and ferric chloride (FeCl ₃ ) states present in the oxidized state in the electroplating solution, the nitrogen supply amount controller 100a of the control panel 100 is a driving motor ( 205a) is started. By the operation of the driving motor 205a, the electroplating solution in the storage tank 104 is supplied to the reduction tank 102 along the solution supply line 104a. At this time, the level gauge installed in the reduction tank 102 so that the appropriate amount of the electroplating solution is supplied to the reduction tank 102 measures the level of the electroplating solution accommodated in the receiving space of the reduction tank 102, The measured value is provided to the nitrogen supply amount controller 100a. The nitrogen supply amount controller 1001 recognizes the water level in the reduction tank according to the measured value provided from the water level meter and controls the operation of the driving motor 205a to adjust the level of the electroplating solution in the reduction tank 102.

When the electroplating solution of the proper level flows into the reduction tank 102, the pH meter 306 measures the acidity (pH) of the electroplating solution introduced into the reduction tank 102 and displays the measured value in the control panel 100. To the hydrochloric acid supply controller 100b. The hydrochloric acid supply amount controller 100b adjusts the opening degree of the second opening / closing valve 302 to maintain the acidity of the electroplating solution in a range of 2.3 ± 0.2 according to the measured value provided from the pH measuring instrument 306. The amount of hydrochloric acid supplied to the reduction tank 102 is controlled.

At this time, as the acidity (pH) of the electroplating solution is lower, the amount of sludge of the ferric ion component present in the electroplating solution decreases, but the electrical conductivity is lowered and the power consumption is increased. Therefore, the acidity of the electroplating solution is to be maintained in the range of 2.3 ± 0.2.

As such, in the state in which the acidity of the electroplating solution is maintained at an appropriate value, the ferric ion (Fe ^{+ 3} ), ie, ferric chloride (FeCl ₃ ) -type sludge in the electroplating solution is dissolved according to the reaction formula of the above formula (5). do.

As described above, when the acidity adjustment of the electroplating solution is completed, the energization controller 511 of the control panel 100 applies a direct current to the electrode 305 in the reduction tank 102 to reduce the iron ions in the electroplating solution. Supply. At this time, the energization controller 511 operates the current regulator 503 of the DC power supply so that the polarity of the current supplied to the electrode 305 is alternately changed, and the anode current gauge 500 of the DC power supply and the DC power supply are alternately changed. The cathode current gauge 501 measures the amount of anode current and cathode current and these measured values are recorded by the current recorder 502 of the direct current power source.

In the reduction tank 102 by the current supply as described above, the reduction reaction of iron ions occurs according to the reaction formulas shown in the formulas (2) to (4).

When the electrolytic reduction reaction is completed in the reduction tank 102, the third opening and closing valve is opened to discharge the electroplating solution to the storage tank 104.

The process as described above is performed until the electroplating solution stored in the storage tank 104 is used in the electroplating process.

According to the present invention, the quality of the electroplated steel sheet can be improved by appropriately maintaining the iron ion concentration in the electroplating solution stored for a long time.

The foregoing is merely illustrative of the preferred embodiments of the present invention and those skilled in the art to which the present invention pertains recognize that modifications and variations can be made to the present invention without departing from the spirit and gist of the invention as set forth in the appended claims. shall.

Claims (5)

In the device for maintaining the iron ion suitable for the electroplating process by preventing the oxidation of the iron ion in the electroplating solution for the electroplating process and reducing the oxidized iron ion, A storage tank in which the electroplating solution is stored; Inert gas supply means for supplying an inert gas to the storage tank; An iron ion holding device suitable for an electroplating process, comprising a reduction tank for reducing ferric ions in the electroplating solution supplied from the storage tank to ferrous ions by electrolytic reduction. The method of claim 1, And an hydrochloric acid supply tank for supplying hydrochloric acid to maintain the acidity of the electroplating solution supplied to the reduction tank at 2.1 to 2.5. The method of claim 1, The reduction bath is suitable for the iron ion holding device, characterized in that the stirring means for stirring the electroplating solution is provided. In the method for maintaining the iron ion concentration of the electroplating solution stored in the storage tank suitable for the electroplating process, Supplying an inert gas to the storage tank to form an inert atmosphere; A method for maintaining iron ions suitable for an electroplating process, comprising the steps of reducing ferric ions present in an electroplating solution exposed to an inert atmosphere by electrolytic reduction. The method of claim 4, wherein A method for maintaining iron ions suitable for an electroplating process, wherein the acidity of the electroplating solution is maintained at 2.1 to 2.5 before reducing the ferric ions.