JPS5945930A - Method for accelerating reduction of fe3+ ion - Google Patents

Abstract

PURPOSE:To remarkably accelerate a reductive reaction, by applying ultrasonic waves of a given frequency to a solution containing Fe<3+> ions dissolving a metal in the solution for reducing the Fe<3+> ions, and activating always the surface of the metal. CONSTITUTION:A metal is added to a solution containing Fe<3+> ions to reduce the Fe<3+> ions. In the process, ultrasonic waves of 10-500kHz are applied to the solution in dissolving the metal in the solution. Thus, the surface of the metal is always activated The fresh activated surface is always exposed, and the reductive reaction is remarkably accelerated by the method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a solution containing Fe3+ ions.
The method of reducing + ions efficiently at high speed can be applied to iron plating, production of divalent iron compounds, production of electrolytic iron, analysis of Ii'e ions, etc.

The present invention will be described in detail below, focusing on iron-based electroplating.

In general Cζ iron-based electroplating, iron and zinc, cadmium τ
Iron-based alloy plating containing one or more of 1-hum, 2-metal, cobalt, manganese, moly7denum, tin, etc. is widely used. During these plating processes, the Fe ion contained in the plating bath is oxidized by the oxygen present in the bath or by the oxygen generated by the generator generated at the anode, and by the electrical reaction on the surface of the anode (this also oxidizes the Fe'' - converts into ions.If the anode is a soluble electrode,
The i4 reaction or (oxidation caused by the oxygen in the generator is extremely
Because of its small size, its production rate is relatively small, or when an insoluble electrode is used, the production rate increases to 1 s (reaction, oxidation by oxygen in the generator is very noticeable, and its production rate increases to a large rl) + .

Formation of 1·e ions in the electrolyte 1. '+7 When the amount increases, (1) the electrolytic efficiency decreases by a large margin. This is because a reaction of Fe +e -F'e occurs on the surface of the 1;5 electrode, and a part of the electricity is consumed for precipitation, resulting in a loss of 1''L.

(2) The appearance of the deposits deposited on the cathode changes and the performance deteriorates. Although the pH on the surface of the cathode increases due to electrolysis, it is considered that even at a low pH (Q per 2), it already precipitates and is partially incorporated into the deposits.

(3) A precipitate is formed. 11/ When trivalent iron is added (a colored precipitate forms).

(4) Accelerates equipment corrosion. l'c 2” I:A
In the bath θ)l'e, there is almost no corrosion, but in the bath θ)l'e
When the ion count increases, corrosion of metal parts such as the mating tank, energizing bar, and rolls is promoted.

As mentioned above, unfavorable phenomena occur in plating, and in order to perform stable plating over a long period of time, it is necessary to use Fe.
In addition to suppressing the production of Fe,
We need to find a way to reduce this.

A method using iron and metals as alloy components has been proposed as a method for reducing Fe. Particularly when using an insoluble anode, it is necessary to replenish metal ions, and one method is to replenish them as salts such as sulfates, halogen ions, carbonates, and nitrates, but as the plating progresses, As a result, sulfate ions, halogen ions, carbonate ions,
Acid ions such as nitrate ions accumulate in the bath, which is undesirable.

On the other hand, if it is replenished as a metal, the problem caused by the accumulation of acid ions will be solved, which is preferable.

And if the metal is dissolved in the plating bath, \4e
-t n IrX -Me X n
-11z °----
(IIM e X n → M e 11 layer 1-nX-r
+r X”-Ie + nl'e =
Me"-1nl'c-・
(2) However, Me is an acid ion in Nationwide X. The reactions in (11, f2) and (31) above occur, hydrogen is generated, and the metal dissolves as a salt, and it also directly reacts with Fe, and itself becomes a Me ion. Fe
will be reduced to

However, in general, the dissolution reaction of a metal depends on its surface +11 and its surface activity, but the surface activity usually tends to decrease with time and become difficult to dissolve. 2) When using base metals such as zinc, cadmium, and manganese, it is thought that over time, iron ions will precipitate by substitution on the surface of the metal, and the surface of the iron mass will become passivated. The rate of dissolution gradually decreases.Furthermore, metals that are weaker than iron, such as nickel, molybdenum, and tin, are exposed to acid on their surfaces, forming a hydrated oxide film and becoming passivated. It is thought that this will gradually become difficult to reduce.

For the reasons mentioned above, the method of reducing Fe using metal is
It becomes impossible to keep the balance due to the slow return to income. In particular, when electrolyzing in a high-intensity bath of Fe2+ ions using an insoluble anode, the production reaction of F"e or Fe-
The reduction reaction of Fe 2 is exceeded and the balance becomes unbalanced, causing the above-mentioned problems.

The present inventors investigated various ways to keep the metal surface active at all times in the reduction method using the metal listed in -F, and found that it is possible to apply ultrasonic waves of 101<IrZ to 500KIIZ when melting the metal11. It was recognized that the reduction reaction of Fe-+Fe was greatly promoted by

This is thought to be because the film Cζ formed on the metal surface is destroyed by the ultrasonic waves, and a fresh and active film always emerges. Moreover, in the above-mentioned reaction (although the reason is unknown, it was found that hydrogen generation was suppressed and Fe was efficiently reduced to Fe at a high rate).

In this case, the metal that can be used is iron, 'llj Zi>
, cadmium, dinochelium, cobalt, mancuff, tin,
In other cases, molybdenum, o, > $5 < metals that are electrolytically deposited on the alloy plating itself is not deposited and is reduced ((aluminum It is preferable that the powder be in the form of a large powder, but it can also take the form of a linear, pathological, or cylindrical shape.

The high frequency to be applied is 101<117. From 50F
<11Z, preferably 151 (HZ to 50KIIZ
Good results can be obtained. ■ Below the old < IIZ, the sonic range (oxidation of the metal surface containing ζ or water-use oxide skin 1 to Δ is not sufficient to destroy Δ, and its effect is not recognized. On the other hand, 5
Above 00K H2, the vibration is too large and the melting itself (
This produces bubbles, and this also becomes ineffective in destroying the entire Dopa surface skin.

The application of the present invention is not limited to plating; for example, a method of preparing an Fc compound as a eutectic, lli IQ'#>
'), a method for producing the entire product, or a method for analyzing 1.゛C ions + (reducing all of the Fe to Fe and then titrating with a potassium permanganate solution). It is possible to do so.

What happens when the present invention is applied to iron plating based on the drawings below? (This will be explained in detail. Fig. 1 shows a Fe reduction device using ultrasonic waves. ■ A plating cell, 2 a pipe through which the plating solution flows, and 3 a reduction tank in which metal is removed from an opening 4. Fe is introduced into the metal-filled portion 3+, where it comes into contact with the plating barrier, and a reduction reaction of Fe occurs.In order to promote this reaction, ultrasonic waves are applied from the outside by an oscillator 5. Fe from which P has been reduced by the circulation pump is sent to the plating cell through piping 7.

At this time, the reduction rate of 1i'e varies depending on the metal ions in the plating bath, the concentration of components, the pH 1 temperature, the type and surface area of the metal added, the frequency and intensity of the applied ultrasonic waves, and the circulation speed of the plating bath. It is desirable to determine optimal conditions depending on the conditions.

The present invention will now be described in detail with reference to Examples.

Example 1 ZnSO4・71r201509/I as the basic component
t, (NH4)2 S O, + 309 / j2, F
Fe ions as e5(1,1 and F c2 (S O,1)3 are 1009 / , 1. Fe or 309 , / It 13111.5. Surface iI' ( 3 n?/g of zinc powder was added to the plating mh=looy+ and 4 g was added to perform reduction. At this time, 26 Kl (Z, 1.
Fig. 2 shows a comparison between cases in which 50W of ultrasonic sound was applied and cases in which it was not applied.

In Fig. 2, when A is applied with ultrasound, RI; is applied υ[1
1・゛c0〕reduction l
It shows that the lt speed will increase by a wide margin in February. History C
ζ What is distinctive is that in reaction B, 21% of the dissolved 11" and lead was consumed for hydrogen generation, whereas in reaction A, no hydrogen was generated and all of the dissolved zinc was consumed, e: l
It was consumed for the return of +.

Example 2 N1p (11·611□(1200y
/ i, (NH4)2 S 04 is 40y/no, Ii
"e S 04 and l'e (804)3 as Fe
is 409/, L Fe' is 202/note pH
Fe reduction was carried out using the apparatus shown in FIG. 1 using a 50 g plating bath at 2.5°0. At this time, the circulation speed of the plating bath was set to 517 minutes, and the reaction tank was 59 mmφ and 20
500g of 2.59/n/ iron powder in a 0mm cylinder
After filling, a P cloth was placed on the inlet and outlet sides to prevent the powder from flowing out of the yarn. At this time, 45KIIZ and 60
A comparison was made between applying and not applying 0W ultrasonic waves.

The results obtained are shown in Table 1. As can be seen from the table, Fe in the plating bath is significantly reduced by applying ultrasonic waves.

Table 1 Changes in FC in plating bath over time

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the reduction device for σ/e io'/ of the present invention. Fig. 2 is a diagram showing the effect of the application of ultrasonic θ on Fe ions θ). within 8%

Claims (1)

[Claims] 1+ using a metal in a solution containing Fe ions
When reducing 'e''+ ion to 1・e ion, l
A method for promoting Fe ion reduction, characterized in that it is carried out by applying ultrasonic waves of 0 KHz to 500 KHz.