Apparatus for electrolytic etching and dissolution and method for extracting metal compound particles
The object of the present invention is such that a surface exchange of metal fine particles by Cu ions, or the like is inhibited in order to prevent formation of Artificial CuS or the like, in extraction and analysis of the metal fine particles (inclusions and precipitates) in a metal material by electrolytic corrosion in a solvent-based electrolytic solution, without significantly changing conventional extraction and analysis methods, and such that the metal deposited on the cathode is actively attached to the cathode so that the deposited metal does not become a contamination source. An apparatus for electrolytic etching and dissolution and an extraction method for separation and extraction of metal compound particles in a metal material, wherein at least a part of the cathode comprises a material consisting of a metal M′ whose Δ defined by the following formula is 10 or more, and the apparatus comprises an electrolytic cell for containing an electrolytic solution comprising a chemical agent that forms a complex containing the metal M′ and a nonaqueous solvent, Δ = pKsp [ M ′ x ′ Ay ′ ] - pKsp [ MxAy ] = ( - log 10 Ksp [ M ′ x ′ Ay ′ ] ) - ( - log 10 Ksp [ MxAy ] ) .
1. An apparatus for electrolytic etching and dissolution, the apparatus comprising:
an electrolytic cell comprising an anode, a cathode and an electrolytic solution comprising a chemical agent and a nonaqueous solvent;
wherein the chemical agent comprises at least one of a polyethylene amine, ethylenediamine tetraacetic acid and cyclohexanediamine tetraacetic acid, and the nonaqueous solvent comprises at least one of methanol, ethanol and isopropyl alcohol;
wherein at least a part of the cathode comprises a metal element M′, the anode comprises a metal material including a different metal element M;
wherein the metal element M′ whose A is defined by the following formula is 10 or more:
Δ
=
pKsp
[
M
′
x
′
Ay
′
]
-
pKsp
[
MxAy
]
=
(
-
log
10
Ksp
[
M
′
x
′
Ay
′
]
)
-
(
-
log
10
Ksp
[
MxAy
]
)
wherein a solubility product of metal compound M′x′Ay′ is defined as Ksp[M′x′Ay′], and a solubility product of a metal compound to be extracted from the anode is MxAy, defined as Ksp[MxAy], the solubility product Ksp is a value in an aqueous solution at 25° C.; and
A consists of one or more of C, N, H, S, O, P, Se, Te and F for forming a compound with M or M′, and x, x′, y and y′ represent a composition ratio of the compound determined according to the valences of M, M′ and A; and
electrolytically etching the anode to extract the metal compound MxAy by electrifying between the anode and the cathode.
2. The apparatus of claim 1 , wherein the metal element M′ is at least one of Hg, Ag, Cu, Pb, Cd, Co, Zn and Ni.
3. The apparatus of claim 1 , wherein the metal compound MxAy is at least one of FeS and MnS.
4. The apparatus of claim 3 , wherein the metal element M′ is at least one of Hg, Ag, Cu, Pb, Cd, Co, Zn and Ni.
5. The apparatus of claim 1 , wherein the metal element M′ is provided to cover a surface of the cathode.
6. The apparatus of claim 1 , wherein the cathode consists of the metal element M′.
7. The apparatus of claim 6 , wherein the metal element M′ consists of 99.9% or more of copper by mass.
8. The apparatus of claim 1 , wherein the polyethylene amine of the chemical agent comprises triethylenetetramine.
9. The apparatus of claim 1 , wherein the apparatus further comprises a stirring means for the electrolytic solution.
10. The apparatus of claim 9 , wherein the stirring means is a gas bubble generator.
11. A method for extracting metal compound particles in a metal material, the method comprising:
providing an electrolytic cell comprising an anode, a cathode and an electrolytic solution comprising a chemical agent and a nonaqueous solvent;
wherein the chemical agent comprises at least one of a polyethylene amine, ethylenediamine tetraacetic add and cyclohexanediamine tetraacetic add, and the nonaqueous solvent comprises at least one of methanol, ethanol and isopropyl alcohol;
wherein at least a part of the cathode comprises a metal dement M′, the anode comprises the metal material including a different metal demerit M;
wherein the metal dement M whose A is defined by the following formula is 10 or more:
Δ
=
pKsp
[
M
′
x
′
Ay
′
]
-
pKsp
[
MxAy
]
=
(
-
log
10
Ksp
[
M
′
x
′
Ay
′
]
)
-
(
-
log
10
Ksp
[
MxAy
)
]
wherein a solubility product of metal compound M′x′Ay′ is defined as Ksp[M′x′Ay′], and a solubility product of a metal compound to be extracted from the anode is MxAy, defined as Ksp[MxAy], the solubility product Ksp is a value in an aqueous solution at 25° C.; and
A consists of one or more of C, N, H, S, O, P, Se, Te and F for forming a compound with M or M′, and x, x′, y and y represent a composition ratio of the compound determined according to the valences of M, M′ and A; and
electrolytically etching the anode to extract the metal compound MxAy by electrifying between the anode and the cathode.
12. The method of claim 11 , wherein the metal element M′ is at least one of Hg, Ag, Cu, Pb, Cd, Co, Zn and Ni.
13. The method of claim 11 , wherein the metal compound MxAy is at least one of FeS and MnS.
14. The method of claim 13 , wherein the metal element M′ is at least one of Hg, Ag, Cu, Pb, Cd, Co, Zn and Ni.
15. The method of claim 11 , wherein the metal element M′ is provided to cover a surface of the cathode.
16. The method of claim 11 , wherein the cathode consists of the metal element M′.
17. The method of claim 16 , wherein the metal element M′ consists of 99.9% or more of copper by mass.
18. The method of claim 11 , wherein the polyethylene amine of the chemical agent comprises triethylenetetramine.
19. The method of claim 11 , wherein the electrolytic solution is stirred during the electrolytic etching process.
20. The method of claim 19 , wherein the stirring is performed by a magnetic stirrer or a gas bubble generator.