JPS62161982A - Manufacture of electrolytic iron - Google Patents

Abstract

PURPOSE:To manufacture high purity and quality electrolytic iron free from unevenness while preventing generation of hydrogen and slime, by using nonaq. solvent bath contg. dissolved ferrous salt as electrolyte, at manufacturing electrolytic iron in electrolysis apparatus having anode and cathode. CONSTITUTION:Anode made of soft steel, pure iron, etc., and cathode made of stainless steel, etc., are used and electrolyte contg. dissolved ferrous salt such as FeCl2, FeSO4, Fe(NO3)2 is used to electrodeposit high purity electrolytic iron on cathode by electrolytic process. In this case, nonaq. solvent such as alcohol or the like of methanol, ethanol, propanol and dimethyl formamide are used as solvent for ferrous salt at preparing electrolyte by dissolving ferrous salt. Since electrolyte is not aq. soln., hydrogen is not generated during electrolytic refining and hydroxide slime of ferric ion is not formed by oxidation of ferrous ion, thus, extremely high purity electrolytic iron free from surface unevenness is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing electrolytic iron, and more specifically, to a method for producing electrolytic iron in which electrolysis is carried out using a non-aqueous solvent as a solvent for an electrolytic solution.

Electrolytic iron contains far fewer impurities than ordinary mild steel or pure iron, so it is used in fields that require high quality, such as magnetic materials, electronic materials, alloy materials, and base metal materials for testing and research.

(Prior Art) Conventionally, electrolytic iron has been produced using an electrolyte aqueous solution as an electrolytic bath. That is, for example, an acidic sulfuric acid aqueous solution of a water-soluble sulfate such as sodium sulfate, potassium sulfate, or ammonium sulfate, or sodium chloride or potassium chloride. The electrolytic bath is made by adding a ferrous salt to an acidic hydrochloric acid solution of a water-soluble hydrochloride such as ammonium chloride.In the electrolytic bath, raw iron such as mild steel or pure iron is used as an anode. Electrolysis is performed using stainless steel or other materials placed opposite each other as cathodes.

[Problem that the invention seeks to solve]

When producing electrolytic iron using an aqueous electrolytic bath, there are the following two problems. Firstly, since iron is a metal less noble than hydrogen, hydrogen is generated when an iron salt aqueous solution is electrolyzed. Second, ferrous ions in the electrolytic bath are oxidized by air to become ferric ions, which become hydroxides and float in the bath as slime.

To prevent the generation of ferric hydroxide (slime), r
+) (Although it is possible to lower the bath temperature and current density, hydrogen generation occurs and productivity deteriorates. When hydrogen generation occurs, the electrodeposited surface becomes extremely uneven or rough, turning into a black powder. In addition, floating slime affects the impurity content. Therefore, although 11 different electrolytic bath compositions, electrolytic conditions, and degassing methods have been proposed since ancient times, it is impossible to avoid these phenomena. .The range of electrolytic conditions that simultaneously satisfy an appropriate electrodeposition thickness and impurity content is narrow, and very strict control is required.

[Means for solving problems]

In order to solve the above problems, the present inventors discovered that hydrogen generation and slime generation can be prevented by using a non-aqueous solvent instead of water as the solvent in the electrolytic bath, and the present invention I was able to complete it.

That is, the present invention provides an electrolytic iron method in which a raw iron anode and a cathode are placed opposite each other in a nonaqueous solvent bath in which a ferrous salt is dissolved, and high-purity iron is electrodeposited on the cathode by electrolysis. It's in the manufacturing method.

Various solvents such as alcohols, ethers, and ketones can be used as nonaqueous solvents, but in addition to alcohols such as methanol, ethanol, propatool, methyl cellosohab, and cellosolve, dimethyl formamide and dimethyl sulfoxide are also usable. A preferred solvent.

The electrolyte is a primary salt suitable for these non-aqueous solvents, for example,
Ferrous chloride (FeCl z), ferrous sulfate (FeSO4
), ferrous nitrate (Fe(No:+) z) is dissolved and used.

Other electrolytic conditions are the same as those for the aqueous electrolyte.

[For production]

Since the electrolyte is a non-aqueous solvent, hydrogen is not generated during electrolysis, and hydroxide is not generated even when ferrous iron ions are oxidized, so no slime is generated.

〔Example〕

An experiment was conducted to confirm the effectiveness of electrolysis using an electrolyte solution containing alcohol as a solvent. Figure 1 shows the experimental equipment. In the figure, l is a container containing the electrolyte 2,
In this electrolyte 2, a mild steel anode 3 and a 9 cm x 13 cm
A cathode 4 made of a stainless steel plate of 1.5 m was placed oppositely and sealed.

Preparations were made so that the gas generated in the container 1 could be collected from above the container 1 via the rubber tube 5 into the measuring cylinder 6 on top of the liquid (alcohol).

Ethanol as electrolyte (azeotropic mixture with water content of 5%)
Ferrous chloride (FeC12) was dissolved in and used.

When the current-voltage curve during electrolysis was determined, as shown in FIG. 2, it passed approximately through the origin and showed a directly proportional relationship. Further, the calculated value obtained from the current consumption and the Nff1 of the anode were very close to each other. Therefore, from these facts, it is considered that an ideal electrolytic reaction occurred in which iron was eluted at the anode and iron was precipitated at the cathode.

Electrolysis was carried out for 48 hours at an average interelectrode voltage of 6 cm and an average current density of 1.7 A/drd, but no bubbles were generated in the measuring cylinder. No slime was observed in the bath. Elemental analysis of the electrodeposited iron thus obtained revealed that it was highly pure iron with a very small amount of impurities as shown in the table below.

Table 2 (Unit: ppm) [Effects of the Invention] According to the present invention, generation of hydrogen and slime can be prevented by changing the solvent of the electrolytic bath from water to a non-aqueous solvent. As a result, high-quality electrolytic iron with high purity and less unevenness on the surface can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an experimental apparatus for examining the effects of the present invention, and FIG. 2 is a graph showing the current-voltage curve of electrolysis in the method of the present invention. ■... Container, 2... Electrolyte, 3...
Anode, 4... Cathode, 5... Rubber tube,
6... Graduated cylinder.

Claims (1)

[Claims] 1. A method for producing electrolytic iron, which comprises placing a raw iron anode and a cathode opposite each other in a non-aqueous solvent bath in which a ferrous salt is dissolved, and electrolyzing to electrodeposit high-purity iron onto the cathode.