JPH0726221B2 - Method for producing electrolytic iron - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing electrolytic iron in which iron is used as an anode in a liquid electrolyte and high-purity iron is electrodeposited on the cathode.

[Conventional technology]

Electrolytic iron has much less impurities than ordinary mild steel or pure iron, so it has been prized in fields requiring high quality such as magnetic materials, electronic materials, alloy materials, and base metal materials for testing and research.

However, along with recent technological innovations, ultra-purification and ultra-low content of specific elements have been demanded in special fields, and non-metal elements other than metal elements, which have hitherto been influenced by the selection method of the anode. For example, chlorine, nitrogen, oxygen,
Inclusion of elements such as hydrogen has become a problem. The mixing source of these elements is the electrolytic solution component, and although the mixing mechanism has not been clarified yet, it is considered that the gas generated on the cathode surface or the electrolytic solution may be entrapped.

[Problems to be solved by the invention]

The present invention uses iron in an electrolytic solution as an anode, and in the case of producing electrolytic iron by electrodepositing high-purity iron on the cathode, chlorine, nitrogen, oxygen, hydrogen, etc. which are mixed into the high-purity iron. The purpose is to minimize the amount of the element.

[Means for solving problems]

As a result of intensive studies for achieving the above-mentioned objects, the inventors of the present invention have shown that chlorine, nitrogen, oxygen, and hydrogen elements in electrolytic iron are applied by applying ultrasonic waves toward the cathode surface where iron ions are discharged and electrodeposited. The present invention has been completed by finding that the content can be considerably reduced. That is, the present invention, a cathode and a mild steel in an electrolytic cell containing an electrolytic solution, an anode made of pure iron or the like is placed in opposition, in a method for producing electrolytic iron to obtain high-purity iron on the cathode by electrolysis, It is a method for producing electrolytic iron in which electrolysis is performed while applying ultrasonic waves to the cathode surface from an ultrasonic oscillator arranged in an electrolytic solution.

Conventionally, in addition to the technology of electrolyzing by placing a plate-shaped anode and a cathode in an electrolytic solution so as to face each other, a plate-shaped anode is placed opposite to a rotating drum type with a horizontal rotating shaft supported as the cathode. A technique is also known in which electrolysis is performed while rotating the cathode. Further, a method of using a rotating drum type having a vertical rotation axis or a rotating disk type having a horizontal or vertical rotation axis as the cathode and performing electrolysis while rotating the cathode is also conceivable. In any of these cases, it is possible to exert the effect of the present invention by applying ultrasonic waves to the cathode surface to give vibration or disturbance to the electrolytic solution on the cathode surface.

It is desirable that the ultrasonic waves strike the entire surface of the cathode. Therefore, when a plurality of cathode plates and an anode plate are arranged in parallel, it is preferable to use a plurality of ultrasonic oscillators so that the ultrasonic waves hit the entire surface of each cathode plate.
On the other hand, in the case of the rotating drum type cathode, if ultrasonic waves are applied toward one generatrix of the drum, the ultrasonic waves will hit the entire curved surface of the drum, and generally 1 One ultrasonic oscillator will be enough. However, this does not exclude the use of a plurality of ultrasonic oscillators for the rotating drum type cathode so that the ultrasonic waves are applied to the entire width of the cathode or are evenly applied.

Generally, ultrasonic waves with a frequency of 10 to 75 kHz are used. The energy of the ultrasonic oscillator should be determined by the size of the cathode, the amount of electrolyte, the distance between the ultrasonic oscillator and the cathode, and the like.

The material of the cathode may be any material that is a conductor and inert to the electrolytic solution, and pure iron, stainless steel, titanium, platinum, etc. can be used, but stainless steel is preferable from the viewpoint of good handleability and cost. preferable.

The anode is usually made of iron, but if the grade of iron is poor, it is necessary to clean it in a separate series, and a grade of steel material (SS material) or better is good, generally mild steel or pure iron is used. .

As the electrolytic solution, known ones can be used, for example, sodium sulfate, potassium sulfate, a sulfuric acid acidic aqueous solution of a water-soluble sulfate such as ammonium sulfate, sodium chloride,
Aqueous hydrochloric acid aqueous solution of water-soluble hydrochloride such as potassium chloride or ammonium chloride can be used.

[Action]

Although the mechanism of action of the method of the present invention is not always clear,
When hydrogen gas generated on the cathode surface is desorbed, an electrolytic solution or gas is caught in electrolytic iron and contains elements such as chlorine, but by applying ultrasonic waves on the cathode surface according to the present invention, the cathode surface It is considered that the gas existing in the iron is removed as soon as possible, and the entrainment of the electrolytic solution and the gas into the electrolytic iron is prevented.

〔Example〕

Referring to FIG. 1, in a electrolytic bath 1, a stainless steel rotating drum supported by a vertical rotating shaft 2 is used as a cathode 3.
Then, a large number of vertically supported iron anodes 4 were placed around the cathode 3 in opposition to the cathode 3, and electrolysis was performed while rotating the cathode 3. Then, during electrolysis, the nozzle 6 of the commercially available ultrasonic oscillator 5 was arranged in the electrolytic solution 1 in the direction of the generatrix of the cathode drum 3, and ultrasonic waves were applied to the cathode surface.

The electrolysis conditions were as follows.

Cathode: Stainless steel, diameter 1m, length 2m Anode: Mild steel Electrolyte: FeCl ₂ 1.0 mol / l NH ₄ Cl 2.0 mol / l pH 4.0 Concentration 70 ℃ Bath HCl Voltage: 3.5V Current density: 3.4A / dm ² Cathode rotation speed: 5 rpm Ultrasonic oscillator: 10 kHz, 100 W Thus, thickness 6.7 mm and thickness 10.5 mm on the curved surface of the cathode drum
After the electrolytic solution 7 was electrodeposited on, the drum surface was hit with a hammer to collect electrolytic iron fragments. As shown in FIG. 1, electrolytic iron pieces collected from positions (1) to (4) along the generatrix of the surface of the cathode drum were chemically analyzed. The results are shown in Tables 1 and 2 below. For comparison, the results of chemical analysis of electrolytic iron obtained under the same conditions without applying ultrasonic waves are also shown for comparison.

From the above results, it is clear that the element contents of Cl, N, O and H in electrolytic iron can be greatly reduced by applying ultrasonic waves to the cathode surface.

〔The invention's effect〕

According to the present invention, in the production of electrolytic iron, it is possible to reduce the content of elements such as chlorine, nitrogen, oxygen and hydrogen in the electrolytic iron and provide electrolytic iron of high purity.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining the manner of electrolyzing iron according to the method of the present invention. 1 ... Electrolyte, 2 ... Rotating shaft, 3 ... Cathode drum, 4 ...
… Anode, 5 …… Ultrasonic oscillator, 7 …… Electroplated iron.

Claims (2)

[Claims] 1. A cathode and mild steel in an electrolytic cell containing an electrolytic solution,
In the method of producing electrolytic iron, which is placed in opposition to an anode made of pure iron or the like and electrolyzes to obtain high-purity iron on the cathode, electrolysis is performed by applying ultrasonic waves on the cathode surface from an ultrasonic oscillator placed in an electrolytic solution A method for producing electrolytic iron, which comprises: 2. The method for producing electrolytic iron according to claim 1, wherein ultrasonic waves having a frequency of about 10 to 75 kHz are applied to the cathode.