JP2002105598A - High-purity iron, method for producing the same, and high-purity iron target - Google Patents

Abstract

(57) [Problem] To provide high-purity iron with a reduced content of impurities such as copper, a method for producing the same, and a high-purity iron target. SOLUTION: Iron containing impurities such as copper is dissolved in a hydrochloric acid solution to prepare an aqueous solution of iron chloride having a hydrochloric acid concentration of 0.1 to 6 kmol / m ³ . Next, iron is put into the iron chloride aqueous solution, and the mixture is stirred while blowing an inert gas to make copper contained in the iron chloride aqueous solution into monovalent ions and iron into divalent ions. Subsequently, an aqueous solution of iron chloride is poured into a column filled with an anion exchange resin. At this time, monovalent copper is adsorbed on the anion exchange resin, but divalent iron is not adsorbed on the anion exchange resin. Therefore, copper can be separated from the aqueous iron chloride solution. Thereafter, the aqueous iron chloride solution is evaporated to dryness and oxidized, and heated in a hydrogen atmosphere to produce iron.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-purity iron having a reduced content of impurities such as copper, a method for producing the same, and a high-purity iron target.

[0002]

2. Description of the Related Art VLSI (very large scale integrated)
2. Description of the Related Art Semiconductor devices such as d circuit) and ULSI (ultra LSI) have a structure in which various metal thin films are provided on a silicon (Si) wafer, for example. In recent years, magnetic random access memory (Magnetic random access memory)
The use of iron (Fe) as a material for ory (MRAM) has been studied. However, if harmful impurities are contained in iron, it may cause malfunction or deterioration of the semiconductor device, which is not preferable. For example, copper (Cu) has a high diffusion rate in silicon and causes a short circuit, and radioactive elements such as uranium (U) or thorium (Th) have a high possibility of causing a malfunction, and include alkali metals or alkaline earth metals. Causes deterioration of characteristics.

[0003] Further, as an environmental semiconductor material proposed to construct a new engineering to deal with environmental problems or resource depletion problems in the future, iron silicide (F) has been proposed.
eSi ₂ ). The content of impurities allowed in iron silicide as an environmental semiconductor is based on gallium arsenide (GaAs) or cadmium telluride (Cd
Like compound semiconductors represented by Te), the number is very small compared to semiconductor devices called VLSI or ULSI. When an unnecessary impurity level is formed by a small amount of impurities, the semiconductor characteristics are immediately deteriorated. Therefore, iron as a raw material is required to have high purity.

However, the quality of crude iron currently traded worldwide is about 98% to 99.8%. Such crude iron includes transition metals such as nickel (Ni), cobalt (Co) or chromium (Cr), oxygen (O),
Various impurities are contained, including gaseous elements such as nitrogen (N) or sulfur (S). Therefore, in order to use iron as a material for semiconductor devices or environmental semiconductors, it is necessary to remove these impurities from crude iron and to purify the iron. In addition to iron, iron is considered to be very promising as a material for a magnetic recording medium or a magnetic recording head by utilizing the properties of a ferromagnetic metal. Purification of iron is indispensable for utilization in these.

Various methods for removing impurities from crude iron have been studied so far, for example, separation of metal elements by wet treatment such as solvent extraction, ion exchange or electrolytic purification, and dry hydrogen gas (H ₂ ) Removal of gaseous elements such as oxygen or nitrogen by treatment, or floating zone melting and purification.

[0006]

However, in solvent extraction, there is a problem that it is difficult to control the extraction and back extraction, and it is difficult to stably purify iron industrially. In ion exchange, almost all metal impurities can be separated,
There is a problem that it is difficult to remove copper and the content does not change before and after purification. In the electrolytic refining, there is a problem that it is necessary to control the pH range of the electrolytic solution, and it is difficult to remove nickel or copper. Floating zone melting and refining has been reported to be applied to metals that have been purified to some extent and to further increase the purity, and has actually been reported to have a large refining effect (Yukio Ishikawa, Koji Mimura, Minoru Isshiki, Material Engineering of Tohoku University) Research Institute Bulletin, 51 (1995), 10-18), it is difficult to produce a large amount of high-purity iron at low cost because it is difficult to increase the size and it is not a method that can produce it stably. There was a problem. Therefore, development of a method of easily and stably purifying iron, particularly a method of removing copper has been desired.

The present invention has been made in view of the above problems, and a first object of the present invention is to provide a high-purity iron and a high-purity iron target having a reduced content of copper as an impurity.

A second object of the present invention is to provide a method for producing high-purity iron, which can easily and stably produce high-purity iron.

[0009]

The high-purity iron according to the present invention has a purity of 99.99% by mass or more and a concentration of copper as an impurity of 50% by mass or less.

Another high-purity iron according to the present invention has a residual resistance ratio of 3000 or more and a concentration of copper as an impurity of 50 mass ppb or less.

In the method for producing high-purity iron according to the present invention, iron contained in an aqueous solution of iron chloride is converted into divalent ions, copper contained as impurities is converted into monovalent ions, and the concentration of hydrochloric acid is adjusted to 0.1.
The method includes a step of adjusting the concentration within a range of 1 kmol / m ^{3 to} 6 kmol / m ³ and separating monovalent copper from the aqueous solution of iron chloride with an ion exchange resin.

Another method for producing high-purity iron according to the present invention comprises:
Iron contained in the aqueous solution of iron chloride is defined as divalent ions, and the concentration of hydrochloric acid is adjusted within a range of 0.1 kmol / m ³ or more and 6 kmol / m ³ or less, and zinc, gallium, niobium, technetium, ruthenium, rhodium, palladium, At least one impurity selected from the group consisting of silver, cadmium, indium, tin, antimony, tellurium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, thallium, lead and bismuth, by an anion exchange resin It includes a step of separating from an aqueous solution of iron chloride.

The high-purity iron target according to the present invention has a purity of 99.99% by mass or more and a concentration of copper as an impurity of 50% by mass or less.

Another high-purity iron target according to the present invention is:
The residual resistance ratio is 3000 or more, and the concentration of copper as an impurity is 50 mass ppb or less.

In the high-purity iron and the high-purity iron target according to the present invention, the copper concentration is highly purified to 50 mass ppb or less.

In the method for producing high-purity iron according to the present invention, iron is a divalent ion and copper is a monovalent ion, and the concentration of hydrochloric acid is adjusted. Thereby, monovalent ion copper is adsorbed on the anion exchange resin, whereas divalent ion iron is not adsorbed,
Copper is easily and stably separated from the aqueous iron chloride solution.

In another method for producing high-purity iron according to the present invention, iron is used as divalent ions and the concentration of hydrochloric acid is adjusted. Thus, zinc, gallium, niobium, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, tellurium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold,
At least one impurity from the group consisting of mercury, thallium, lead and bismuth is adsorbed on the anion exchange resin, whereas divalent iron is not adsorbed and these impurities are removed from the aqueous iron chloride solution. Easy and stable separation.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

The high-purity iron and high-purity iron target according to one embodiment of the present invention have a purity of 99.99% by mass or more, preferably 99.999% by mass or more, or a residual resistance ratio of 3000 or more, The concentration of copper as an impurity is 5
It is less than 0 mass ppb.

Here, the purity (ie, chemical purity) is:
All quantifiable impurity concentrations were determined using currently available analytical instruments and methods, and were subtracted from 1. (Ishiki, K. Mimura, Bulletin of the Japan Institute of Metals, 31 (1992), 8)
80-887). For example, using glow discharge mass spectroscopy (Glow Discharge Mass Spectroscopy) as an analytical instrument, measuring 70 or more quantifiable impurities and measuring 1
Is determined by subtracting For gaseous elements such as oxygen, nitrogen or hydrogen, if necessary, use appropriate methods such as non-dispersive infrared absorption method, thermal conductivity method, or melting in an inert gas and then separating them in a column to measure thermal conductivity. The method is applied.

The residual resistance ratio is one index indicating the purity of a high-purity metal.
The ratio between the specific resistance at 98K and the specific resistance at 4.2K is taken. Since the specific resistance has a relationship with the resistance value (electrical resistance) as shown in Expression 2, the residual resistance ratio can be converted as shown in Expression 3, and if the volume change due to temperature can be ignored, , 298K and the ratio at 4.2K. Since iron is a ferromagnetic metal, when measuring resistance, it is necessary to suppress the influence of geomagnetism, demagnetization conditions, or the magnetic field due to the measurement current. Normally, a measurement is performed by applying a vertical magnetic field of about 60 kA / m. (Seiichi Takagi, Materia,
33 (1994), 6-10).

[0022]

RRR = ρ _298K / ρ _4.2K RRR; Residual resistance ratio ρ _298K ; Specific resistance at 298K (Ωm) ρ _4.2K ; Specific resistance at 4.2K (Ωm)

[0023]

Ρ = R × (S / L) ρ; specific resistance (Ωm) R; resistance value (Ω) S; cross-sectional area (m ² ) perpendicular to current direction L; length (m)

[0024]

(Equation 3) RRR: Residual resistance ratio R _298K , S _298K , L _298K ; Resistance value, sectional area, length at _298K R _4.2K , S _4.2K , L _4.2K ; Resistance value, sectional area, length at 4.2K

The high-purity iron and the high-purity iron target are used, for example, as materials for semiconductor devices, magnetic recording media, magnetic recording heads or devices using environmental semiconductors. The term “environmental semiconductor” refers to a semiconductor substance that is abundant on the earth and composed of environmentally friendly materials. Examples thereof include iron silicide (FeSi ₂ ) and calcium silicide (Ca ₂ Si). Reru (Environmental Semiconductor Research Group website (http: //kan.engjm.s
aitama-u.ac.jp/SKS/index2.html)).

Such a high-purity iron and a high-purity iron target can be manufactured as follows.

FIGS. 1 and 2 show the steps of manufacturing the high-purity iron according to the present embodiment. First, iron containing impurities such as copper is dissolved in a hydrochloric acid solution to prepare an iron chloride (FeCl ₂ or FeCl ₃ ) aqueous solution (step S10).
1). At this time, the concentration of hydrochloric acid is 0.1 kmol / m ³ or more and 6
Adjust within the range of kmol / m ³ or less.

Next, as shown in FIG. 3, this aqueous solution of iron chloride M is put into a container 12 together with a metal 11 such as iron, and an inert gas 13 such as nitrogen gas (N ₂ ) or argon gas (Ar) is blown therein. Simultaneously, the iron chloride aqueous solution M and the metal 11 are sufficiently brought into contact with each other by, for example, stirring with the stirrer 14 (step S102). As a result, copper contained in the aqueous solution of iron chloride M reacts, for example, as shown in Chemical formula 1, and changes from divalent ions to monovalent ions or metallic copper. Further, iron contained in the iron chloride aqueous solution M reacts, for example, as shown in Chemical formula 2 to convert from trivalent ions to divalent ions. Note that the reaction formula shown in Chemical formula 1 does not completely proceed to the right, and a small amount of monovalent copper ions remains in the aqueous iron chloride solution.

[0029]

Embedded image [CuCl ₂ ] ⁰ + Fe (solid) → [FeC
l ₂ ] ⁰ + Cu (solid)

2 [FeCl ₆ ] ^3- + Fe (solid) → 3 [FeCl ₄ ] ^2-

Here, the inert gas 13 is blown into the aqueous solution of iron chloride M in order to drive out oxygen dissolved in the aqueous solution of iron chloride M. Does not proceed if oxygen is dissolved in The blowing of the inert gas 13 is performed by using an aqueous solution of iron chloride M and metal 1
1 and may be performed at the same time as stirring, or may be performed before the metal 11 is added to the aqueous iron chloride solution M.

The metal 11 preferably has a large surface area, such as a powder. This is because copper and iron can be sufficiently reacted by increasing the contact area with the aqueous solution of iron chloride M. Metals other than iron can be used as the metal 11, but iron is preferred. Iron chloride aqueous solution M
This is for the purpose of preventing other impurities from being mixed in as much as possible.

Here, after adjusting the hydrochloric acid concentration of the aqueous solution of iron chloride M, the aqueous solution of iron chloride M is brought into contact with the metal 11 to convert iron into divalent ions and copper into monovalent ions. After the iron chloride aqueous solution M is brought into contact with the metal 11 to convert iron into divalent ions and copper into monovalent ions, the hydrochloric acid concentration of the iron chloride aqueous solution M may be adjusted.

Subsequently, as shown in FIG. 4, a column 22 filled with an anion exchange resin 21 is prepared, and an aqueous solution of iron chloride M is poured into the column 22 from a storage tank 23, and sufficiently mixed with the anion exchange resin 21. Contact (step S10)
3). The flow rate of the aqueous solution of iron chloride M is preferably about 1 hour (1 bed volume (s) / hour) so that the amount of the resin volume flows over 1 hour so that the aqueous solution of iron chloride M sufficiently contacts the anion exchange resin 21. Here, since iron is a divalent ion and copper is a monovalent ion, monovalent copper ions are adsorbed on the anion exchange resin 21 and divalent iron ions are adsorbed on the anion exchange resin 21 at all. But eluted from the column 22. FIG. 5 shows the change in the metal ion concentration (elution curve) in the eluate at this time. In FIG. 5, the horizontal axis represents the elution volume, and the vertical axis represents the concentration standardized by the maximum concentration of metal ions. Thus, it can be seen that the peaks of the elution curves of divalent iron and monovalent copper have no overlapping portions at all, and that copper can be completely separated from the aqueous iron chloride solution. That is,
In the recovery tank 24, an aqueous solution of iron chloride M from which copper has been separated is recovered.

Incidentally, zinc (Zn), gallium (Ga), niobium (Nb), technetium (T
c), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), indium (In), tin (Sn), antimony (Sb),
Tellurium (Te), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), mercury (H
g), thallium (Tl), lead (Pb) and bismuth (Bi), when at least one impurity is contained, as shown by zinc and tin in FIG. By S103, these impurities are also adsorbed on the anion exchange resin 21 together with the copper, and the iron chloride aqueous solution M
Separated from

After separating copper, lithium (Li), beryllium (Be), sodium (N
a), magnesium (Mg), aluminum (Al),
Silicon (Si), phosphorus (P), potassium (K), calcium (Ca), scandium (Sc), titanium (T
i), vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr), cesium ( Cs),
Barium (Ba), lanthanoids, hafnium (H
f), when at least one impurity from the group consisting of francium (Fr), radium (Ra) and actinoids is contained, for example, a hydrogen peroxide solution is added to an aqueous solution of iron chloride M to oxidize. Then, iron is changed from divalent ions to trivalent ions (step S104). Note that since this oxidation occurs naturally even when left as it is, it is not necessary to actively perform the oxidation step.

Thereafter, the concentration of hydrochloric acid in the aqueous solution of iron chloride M was adjusted to 2
It is adjusted within the range of kmol / m ³ or more and 11 kmol / m ³ or less, and the iron chloride aqueous solution M is sufficiently brought into contact with the anion exchange resin 21 as shown in FIG. 4 (step S10).
5). Thereby, trivalent iron is adsorbed on the anion exchange resin 21, and lithium, beryllium, sodium,
Magnesium, aluminum, silicon, phosphorus, potassium, calcium, scandium, titanium, vanadium,
Chromium, manganese, cobalt, nickel, rubidium,
Strontium, yttrium, zirconium, cesium, barium, lanthanoids, hafnium, francium, radium and actinoids are eluted without adsorbing to the anion exchange resin 21.

FIG. 6 shows the change in the metal ion concentration (elution curve) in the eluate at this time. FIG. 6 shows a comparison of aluminum, silicon, phosphorus, titanium, manganese, cobalt and chromium with iron as a representative of the impurities described above. The horizontal axis and the vertical axis are the same as in FIG. in this way,
The peaks of the elution curves of these impurities and iron of trivalent ions have almost no overlapping portions, indicating that these impurities and iron can be substantially separated.

Also, zinc, gallium,
Niobium, molybdenum (Mo), technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, tellurium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, thallium, lead, bismuth and polonium (Po)
If at least one impurity from the group consisting of is contained, these impurities are also adsorbed on the anion exchange resin 21 together with iron in step S105.

In this case, iron is replaced with an anion exchange resin 21.
After adsorption, the concentration is 0.1 kmol / m ³ or more 2
Iron is eluted from the anion exchange resin 21 by flowing a hydrochloric acid solution of kmol / m ³ or less, and zinc, gallium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, adsorbed on the anion exchange resin together with iron. Iron is separated from cadmium, indium, tin, antimony, tellurium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, thallium, lead, bismuth, and polonium (step S106). The change in the metal ion concentration (elution curve) in the eluate at this time is also shown in FIG. FIG. 6 compares molybdenum and zinc with iron as a representative of the impurities described above. Thus, it can be seen that the peaks of the elution curves of these impurities and the iron of the trivalent ion do not substantially overlap, and that these impurities and iron can be substantially separated.

However, here, in step S103, zinc, gallium, niobium, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, tellurium, tantalum, tungsten, rhenium, osmium, iridium, platinum, Money,
Since mercury, thallium, lead and bismuth are separated from the aqueous solution of iron chloride M together with copper, in step S106, mainly molybdenum and polonium are separated from iron.

After eluting the iron, the obtained aqueous solution of iron chloride M is evaporated to dryness and oxidized to obtain iron oxide (step S107). Thereafter, the iron oxide is heated in a hydrogen atmosphere at a temperature of 500K or more and less than 1800K (Step S108). However, in order to perform the reduction promptly, 100
It is preferable to heat at a temperature of 0K or more. Thereby, iron oxide reacts as shown in Chemical formula 3 to obtain iron.

[0042]

Embedded image 3Fe ₂ O ₃ + H ₂ = 2Fe ₃ O ₄ + H ₂ O Fe ₃ O ₄ + H ₂ = 3FeO + H ₂ O Fe ₃ O ₄ + 4H ₂ = 3Fe + 4H ₂ O FeO + H ₂ = Fe + H ₂ O

After reacting the iron oxide, the obtained iron is
Melting by a plasma arc using a plasma generating gas containing active hydrogen to remove at least one impurity from the group consisting of oxygen, nitrogen, carbon (C), sulfur, halogen, alkali metal and alkaline earth metal. (Step S
109). Thereby, high-purity iron and a high-purity iron target according to the present embodiment can be obtained.

As described above, according to the high-purity iron and the high-purity iron target of the present embodiment, the copper concentration is reduced to 50 mass pp.
Since it can be set to b or less, for example, even when used for a semiconductor device, a short circuit does not occur, and the characteristics of the semiconductor device can be improved. Further, it can be used for devices such as a magnetic recording medium and a magnetic recording head, and their characteristics can be improved. Furthermore, when used as a material of a compound semiconductor such as iron silicide, unnecessary impurity levels due to trace impurities that cause deterioration of characteristics are not formed, and excellent characteristics can be obtained.

According to the method for producing high-purity iron according to the present embodiment, iron is a divalent ion, copper is a monovalent ion, and the concentration of hydrochloric acid is 0.1 kmol / m ³ or more and 6 kmol / m ^3.
After the adjustment within the range of ³ or less, the aqueous solution of iron chloride was brought into contact with the anion exchange resin, so that copper could be easily separated from the aqueous solution of iron chloride. Therefore, high-purity iron having a low copper concentration and a high-purity iron target can be easily and stably obtained.

Further, since iron is made a divalent ion, zinc, gallium, niobium, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, tellurium, tantalum, tungsten, rhenium, osmium are used. , Iridium, platinum, gold, mercury, thallium, lead and bismuth can be easily separated together with copper from the aqueous iron chloride solution together with copper. Therefore, high-purity iron and a high-purity iron target can be easily and stably obtained.

[0047]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described with reference to FIGS. In the following examples, the signs and symbols used in the above-described embodiment are used as they are.

First, scrap iron was used as a raw material, and this was added to a hydrochloric acid solution having a concentration of 2 kmol / m ^{3 with} an iron concentration of 0.179 kM.
mol / m ³ (10 g / dm ³ )
An aqueous solution M of iron chloride (FeCl ₃ ) was prepared (step S).
101). Next, as shown in FIG. 3, powdered iron 11 was put into the aqueous iron chloride solution M, and stirred while blowing in an inert gas to convert copper into monovalent ions and iron into divalent ions ( Step S102). Subsequently, as shown in FIG. 4, the aqueous solution of iron chloride M was brought into contact with the anion exchange resin 21 to adsorb copper and separated from the aqueous solution of iron chloride M (step S103).

After separating the copper, an aqueous solution of hydrogen peroxide was added to the aqueous solution of iron chloride M to convert iron into trivalent ions (step S).
104). Then, the hydrochloric acid concentration of the aqueous solution of iron chloride M was increased to 5 k.
mol / m ³ , an aqueous solution of iron chloride M was brought into contact with the anion exchange resin 21 to adsorb iron and separated from impurities such as lithium (step S105). Then, concentration 1km
Iron was eluted from the anion exchange resin 21 with an ol / m ³ hydrochloric acid solution to separate it from impurities such as molybdenum (step S106).

After eluting the iron from the anion exchange resin 21, the obtained aqueous solution of iron chloride M is evaporated to dryness and oxidized,
Iron oxide was obtained (Step S107). Thereafter, the obtained iron oxide was placed in a hydrogen atmosphere at 1073K (800
C) to obtain iron (Step S108). After obtaining iron, the iron is melted by a plasma arc containing active hydrogen to remove impurities such as oxygen (step S109),
High purity iron was obtained.

The purity of the obtained high-purity iron is determined by glow discharge mass spectrometry to determine the purity.
The residual resistance ratio was determined. Table 1 shows the results. As shown in Table 1, the copper concentration was as low as 50 mass ppb or less, the purity was 99.9997%, and the residual specific resistance was as high as 5500.

[0052]

[Table 1]

That is, iron is a divalent ion, copper is a monovalent ion, and the hydrochloric acid concentration is 0.1 kmol / m ^3.
It has been found that by adjusting the concentration to 6 kmol / m ³ or less, copper can be easily separated from the aqueous solution of iron chloride, and high-purity iron with a reduced copper concentration of 50 mass ppb or less can be easily obtained.

As described above, the present invention has been described with reference to the embodiments and examples. However, the present invention is not limited to the above embodiments and examples, and can be variously modified. For example, in the above embodiments and examples, iron contained in the aqueous iron chloride solution is divalent ion and copper is a monovalent ion, the hydrochloric acid concentration of the aqueous iron chloride solution is adjusted, and the aqueous iron chloride solution is converted into an anion exchange resin. Contact was made to adsorb and separate copper, but after adjusting the ionic valence of iron and copper, iron and copper were adsorbed on an anion exchange resin, and the concentration was 0.1 k
Copper may be separated from the aqueous iron chloride solution by eluting the iron with a hydrochloric acid solution of not less than 6 mol / m ^{3 and not} more than 6 kmol / m ³ .

In the above-described embodiment and examples,
Although the method of removing impurities other than copper has also been specifically described, it may be removed by another method. Furthermore, although impurities such as zinc are separated from the aqueous solution of iron chloride together with copper by changing iron into divalent ions, copper may be separated by another method.

[0056]

As described above, according to the high-purity iron according to claim 1 or claim 2 or the high-purity iron target according to claim 12 or claim 13, the concentration of copper is reduced to 50 mass ppb. Since the following can be achieved, for example, there is an effect that characteristics of a semiconductor device can be improved without causing a short circuit even when used in a semiconductor device. Further, it can be used for devices such as a magnetic recording medium and a magnetic recording head, and their characteristics can be improved. Furthermore, when used as a material of a compound semiconductor such as iron silicide, unnecessary impurity levels due to trace impurities that cause deterioration of characteristics are not formed, and excellent characteristics can be obtained.

Further, any of claims 3 to 10
According to the method for producing high-purity iron according to item (1), iron is divalent iron.
ON, copper as monovalent ion, hydrochloric acid concentration 0.1kmol
/ M ^ThreeMore than 6kmol / m^ThreeAdjust within the following range
So that copper is adsorbed on the anion exchange resin and
It can be easily separated from the aqueous iron solution. Therefore, copper
Low concentration of high purity iron and high purity iron target easily
This has the effect that it can be obtained stably.

[0058] Further, according to the manufacturing method of the high purity iron according to claim 6 or claim 11, the iron with a divalent ion, in the range of hydrochloric acid concentration of 0.1 kmol / m ³ or more 6kmol / m ³ or less Therefore, impurities such as zinc can be adsorbed on the anion exchange resin and easily separated from the aqueous iron chloride solution. Therefore, there is an effect that high-purity iron and a high-purity iron target can be easily and stably obtained.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a process of manufacturing high-purity iron and a high-purity iron target according to one embodiment of the present invention.

FIG. 2 is a flowchart illustrating a manufacturing process following FIG. 1;

FIG. 3 is a view for explaining one manufacturing process shown in FIG. 1;

FIG. 4 is a view for explaining another manufacturing process shown in FIG. 1;

FIG. 5 is a characteristic diagram showing a change in metal ion concentration in an eluate of an anion exchange resin.

FIG. 6 is another characteristic diagram showing a change in metal ion concentration in the eluate of the anion exchange resin.

[Explanation of symbols]

11 metal, 12 container, 13 inert gas, 14 stirrer, 21 anion exchange resin, 22 column, 2
3: Storage tank, 24: Recovery tank, M: Iron chloride solution.

Continued on the front page (72) Inventor Masahito Uchikoshi 2-1-1-15 Meigetsu, Tagajo City, Miyagi Prefecture Inside Fine Material Co., Ltd. (72) Inventor Norio Yokoyama 2-1-1-15 Meigetsu, Tagajo City, Miyagi Prefecture Fine Material Stock In-house (72) Inventor Tamas Kekeshi 11-10, Lingyashita, Aoba-ku, Aoba-ku, Sendai, Miyagi Prefecture 1-303 Chisan Mansion Hirosegawa (72) Inventor: Minoru Isshiki 3-2-14 F, Hori, Tashiro-ku, Sendai-shi, Miyagi F Term (reference) 4K001 AA01 AA04 AA05 AA06 AA09 AA10 AA11 AA14 AA15 AA18 AA20 AA21 AA24 AA25 AA26 AA29 AA30 AA39 AA41 AA42 BA19 BA23 DB04 DB22 DB36 EA03 4K012 EA07 EA08 4K029 BA09 DC09

Claims (13)

[Claims] 1. A high-purity iron having a purity of 99.99% by mass or more and a concentration of copper as an impurity of 50% by mass or less. 2. A high-purity iron having a residual resistance ratio of 3000 or more and a concentration of copper as an impurity of 50 mass ppb or less. 3. The method according to claim 1, wherein iron contained in the aqueous solution of iron chloride is converted into divalent ions, copper contained as impurities is converted into monovalent ions, and the concentration of hydrochloric acid is 0.1 kmol / m ³ or more and 6 kmol / mole.
A method for producing high-purity iron, comprising the step of adjusting the concentration to within m ³ or less and separating monovalent copper from an aqueous solution of iron chloride with an ion exchange resin. 4. A process in which iron contained in an aqueous solution of iron chloride is converted into divalent ions and copper contained as an impurity is converted into monovalent ions, and the concentration of hydrochloric acid in the aqueous solution of iron chloride is 0.1 kmol / m ³ or more.
kmol / m ³ or less; adjusting iron to divalent ions, copper to monovalent ions and adjusting the concentration of hydrochloric acid, and then bringing the aqueous solution of iron chloride into contact with an anion exchange resin; 4. The method for producing high-purity iron according to claim 3, comprising a step of separating copper. 5. An iron chloride aqueous solution is blown with an inert gas, and the iron chloride aqueous solution is brought into contact with iron so that iron contained in the iron chloride aqueous solution is converted into divalent ions and copper is converted into monovalent ions. The method for producing high-purity iron according to claim 3, characterized in that: 6. Zinc, gallium, niobium, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, tellurium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, thallium, lead. 4. The method for producing high-purity iron according to claim 3, wherein at least one impurity selected from the group consisting of iron and bismuth is separated from the aqueous iron chloride solution together with copper. 7. An aqueous solution of iron chloride having a hydrochloric acid concentration of 2 kmol / m ³ or more and 11 k
mol / m ³ or less, an aqueous solution of iron chloride is brought into contact with an anion exchange resin to adsorb iron of trivalent ions, and lithium, beryllium, sodium, magnesium, aluminum, A group consisting of silicon, phosphorus, potassium, calcium, scandium, titanium, vanadium, chromium, manganese, cobalt, nickel, rubidium, strontium, yttrium, zirconium, cesium, barium, lanthanoids, hafnium, francium, radium, and actinoids 4. The method according to claim 3, further comprising a step of separating iron from at least one of the impurities, and a step of eluting the iron adsorbed on the anion exchange resin from the anion exchange resin with a hydrochloric acid solution. Production method of high purity iron. 8. The iron adsorbed on the anion exchange resin is eluted from the anion exchange resin with a hydrochloric acid solution having a concentration of 0.1 kmol / m ³ or more and 2 kmol / m ³ or less, and is adsorbed on the anion exchange resin together with iron. Zinc, gallium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, tin,
Claims: Separating iron from at least one impurity selected from the group consisting of antimony, tellurium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, thallium, lead, bismuth and polonium. Item 7. The method for producing high-purity iron according to Item 7. 9. The method according to claim 3, further comprising the steps of: producing iron oxide from an aqueous solution of iron chloride from which copper has been separated; and heating iron oxide in a hydrogen atmosphere to produce iron. Production method of high purity iron. 10. The obtained iron is melted by a plasma arc using a plasma generating gas containing active hydrogen, and oxygen, nitrogen, carbon, sulfur,
10. The method for producing high-purity iron according to claim 9, further comprising a step of removing at least one impurity from the group consisting of halogen, alkali metal and alkaline earth metal. 11. Iron contained in an aqueous solution of iron chloride is converted into divalent ions, and the concentration of hydrochloric acid is 0.1 kmol / m ³ or more and 6 kmo.
1 / m ³ or less, zinc, gallium, niobium, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony,
Including a step of separating at least one impurity from the group consisting of tellurium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, thallium, lead and bismuth from an aqueous solution of iron chloride by an anion exchange resin. A method for producing high-purity iron, characterized in that: 12. The purity is 99.99% by mass or more,
A high-purity iron target, wherein the concentration of copper as an impurity is 50 mass ppb or less. 13. A high-purity iron target having a residual resistance ratio of 3000 or more and a concentration of copper as an impurity of 50 mass ppb or less.