ANODE AND PROCESS FOR MANUFACTURING SAME
The present invention controls a temperature rise due to resistance in electrolysis, and prevents an anode from falling off A holding member is attached in surface contact with one side of an electrode plate made of a low melting metal or a low melting alloy having a melting point of not less than 100° C. and not more than 250° C., the holding member having a length equal to or longer than the length of said one side and being made of a metal or an alloy having a melting point higher than the melting point of the electrode plate.
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1. Field of the Invention
The present invention relates to an anode for electrolysis, and a process for manufacturing the same, and in particular, relates to an anode for electrolyzing a low melting metal or a low melting alloy, and a process for manufacturing the same. The present application claims priority based on Japanese Patent Application No. 2013-168271 filed in Japan on Aug. 13, 2013. The total contents of the Patent Application are to be incorporated by reference into the present application.
2. Description of Related Art
Electrolysis is the decomposition and purification of a substance by passing a direct current through an anode and a cathode in pairs in a state in which the anode and the cathode are immersed in an electrolytic solution or a fused salt, and thereby causing a chemical change in an electrode surface.
Examples of electrolysis techniques include hydrometallurgical reining and metal plating wherein a voltage is applied to a metal used as an anode, whereby the metal decomposed in the anode is deposited on a surface of the cathode in a high purity state, or a coating of the metal is formed.
On the other hand, adjustment of an electrolytic solution to obtain an appropriate pH makes it possible that, when a metal decomposed in an anode is dissolved in the electrolytic solution and moved to a cathode, before deposited on the cathode, the metal is precipitated as a hydroxide and thereby isolated (for example, see Patent Literature 1).
As disclosed in Patent Literature 2, in many cases, an anode for electrolysis is an anode 100 illustrated in
In electrolysis employing such anode 100, an exothermic phenomenon caused by electric resistance occurs between the projection 101 of the anode 100 and the electric supply unit 102. In the anode 100, this exothermic phenomenon is prevented as much as possible because the phenomenon leads to an energy loss. However, it is unable to entirely prevent the generation of heat.
Furthermore, this exothermic phenomenon does not cause a temperature rise to such an extent as to soften and melt an anode made of a common metal, such as copper. However, in the case where a low melting metal, such as tin or indium, or a low melting alloy is employed as the anode 100, when a high voltage or current is passed, there arise a problem that the anode 100 is softened and deformed due to the generation of heat, and a problem that the projection 101 is melted at a contact point between the projection 101 and the electric supply unit 102, the contact point having the highest temperature, whereby the anode 100 cannot support itself and falls off into an electrolytic bath.
For such problems, the anode 100 having a common integral form as illustrated in
Besides, Patent Literature 3 discloses a process wherein, as illustrated in
However, according to the process described in Patent Literature 3, the conductive connection jigs 105 and the electrode plate 103 are only in point contact with each other at the respective holes, and therefore, a temperature rise at contact portions cannot be controlled when a high voltage or current is passed, and consequently, when a low melting metal, such as tin or indium, is employed for the electrode plate 103 for an anode, the electrode plate 103 is softened and melted, and falls off
The process described in Patent Literature 4 has been often employed for an electrode on a cathode side, but such structure has been employed also for an anode. According to the process described in Patent Literature 4, as illustrated in
Patent Literature 1: Japanese Patent No. 2829556
Patent Literature 2: Japanese Patent Application Laid-Open No. H11-229171
Patent Literature 3: Japanese Patent No. 4911668
Patent Literature 4: Japanese Patent Application Laid-Open No. 2004-043846
BRIEF SUMMARY OF THE INVENTIONTherefore, the present invention is proposed in view of such actual circumstances, and an object of the present invention is to provide an anode and a process for manufacturing same, the anode being capable of controlling a temperature rise at a connection portion between an electrode plate made of a low melting metal or a low melting alloy and a holding member configured to hold the electrode plate and to electrically connect the electrode plate to an electric supply unit, and capable of achieving long hours of electrolysis without the electrode plate melting and falling off In particular, an object of the present invention is to provide an anode and a process for manufacturing the same, the anode being capable of achieving long hours of electrolysis without an electrode plate falling off even when a high voltage or current is passed through the electrode plate.
An anode that achieves the above-mentioned object according to the present invention is characterized in that a holding member is attached in surface contact with the vicinity of one side of at least one major surface of an electrode plate, the electrode plate being made of a low melting metal or a low melting alloy having a melting point of not less than 100° C. and not more than 250° C., the holding member having a length equal to or longer than the length of said one side and being made of a metal or an alloy having a melting point higher than the melting point of the electrode plate.
A process for manufacturing an anode that achieves the above-mentioned object according to the present invention is characterized in that a low melting metal or a low melting alloy having a melting point of not less than 100° C. and not more than 250° C. is cooled and solidified in a mold; a solidified low melting metal or a solidified low melting alloy is taken out of the mold to obtain an electrode plate; and a holding member is attached in surface contact with the vicinity of one side of at least one major surface of the obtained electrode plate, the holding member having a length equal to or longer than the length of said one side and being made of a metal or an alloy having a melting point higher than the melting point of the electrode plate, whereby an anode is manufactured.
According to the present invention, a holding member is attached in surface contact with the vicinity of one side of at least one major surface of an electrode plate, the holding member having a length equal to or longer than the length of said one side, whereby a temperature rise caused by electric resistance between the electrode plate and the holding member is controlled to prevent the electrode plate from melting, and furthermore, even when the electrode plate is somewhat softened by resistance heating, the entire vicinity of one side of at least one major surface of the electrode plate is held, whereby the electrode plate is prevented from falling off and long hours of electrolysis is achieved. Furthermore, according to the present invention, even when a high voltage or current is passed, the attachment of the holding member in surface contact with the electrode plate makes it possible to control a temperature rise caused by electric resistance, and thereby to prevent the electrode plate from melting, and thus, long hours of electrolysis is achieved.
Furthermore, according to the present invention, an anode is efficiently manufactured in such a manner that the use of a low melting metal or a low melting alloy having a melting point of not less than 100° C. and not more than 250° C. for an electrode plate allows the metal or the alloy to be easily melted, and, by cooling, solidifying, and casting the molten metal or the molten alloy, an electrode plate is obtained, and only by the attachment of a holding member in surface contact with the vicinity of one side of at least one major surface of the obtained electrode plate, a temperature rise caused by electric resistance at a connection portion between the electrode plate and the holding member is controlled, whereby the electrode plate is prevented from melting, and furthermore, the electrode plate is prevented from falling off when softened by resistance heating.
Hereinafter, an anode to which the present invention is applied, and a manufacture of said anode will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following detailed description unless otherwise specified.
<1. An Anode>
An anode 1 illustrated in
The electrode plate 2 is made of a low melting metal or a low melting alloy having a melting point of not less than 100° C. and not more than 250° C., and formed in the shape of, for example, a square or rectangular plate. Examples of the low melting metal include tin and indium, and examples of the low melting alloy include an alloy of indium and tin (for example, In-9.6 wt % Sn), and an alloy of indium and gallium (for example, In-6.3 wt % Ga).
The thickness of the electrode plate 2 is suitably determined in consideration of, for example, the prevention of the electrode plate 2 from falling off the holding member 3 due to the own weight of the electrode plate 2, and the fact that the thickness of the anode 1 becomes thinner as electrolysis proceeds. For example, the thickness of the electrode plate 2 is preferably not less than 2 mm and not more than 15 mm. An electrode plate 2 having a thickness of not more than 2 mm is not preferable because such thin thickness sometimes causes the electrode plate 2 to be broken when handled, and furthermore, causes pitting corrosion of the anode 1 for electrolysis to easily occur. On the other hand, an electrode plate 2 having a thickness of not less than 15 mm is not preferable because such thickness causes the electrode plate 2 to be heavy in weight and thereby easily fall off and be handled with difficulties, and furthermore, when the anode 1 becomes thinner as electrolysis proceeds, the distance between electrodes becomes larger and voltage remarkably rises.
Low melting metal or low melting alloy, which forms the electrode plate 2, has the characteristic of becoming softer as the metal or the alloy has a higher purity or temperature is higher. Therefore, the electrode plate 2 obtained by molding a low melting metal or a low melting alloy into the shape of a plate is kept being hung in an electrolytic solution by a holding member 3 that has a large contact area with a holding member attaching surface 2a, and is attached thereto, the holding member attaching surface 2a being positioned in the upper side of the electrode plate 2 at the time of an installation to an electrolysis apparatus.
The holding member 3 is attached to the holding member attaching surface 2a of the electrode plate 2, holds the electrode plate 2 in an electrolytic solution in electrolysis, and electrically connects the electrode plate 2 to an electric supply unit provided in an electrolysis apparatus.
The holding member 3 has a melting point higher than the melting point of the electrode plate 2, and is made of a metal or an alloy having high electrical conductivity. The use of a metal or an alloy having a melting point higher than the melting point of the electrode plate 2 makes it possible that, even when resistance becomes higher at a contact portion between the electrode plate 2 and the holding member 3 and temperature rises accordingly, the falling of the electrode plate 2 due to the melting of the holding member 3 prior to that of the electrode plate 2 is prevented. Examples of the metal that forms the holding member 3 include silver, copper, and gold, and examples of the alloy that forms the holding member 3 include an alloy of said metals, and among them, in terms of cost, copper is preferably employed because of its inexpensiveness.
Furthermore, the holding member 3 is preferably such that a metal or an alloy having a high melting point and high electrical conductivity is employed as a core material, and coated with a metal having an ionization tendency low enough not to cause corrosion by an electrolytic solution. Examples of the metal for the coating include noble metals, such as platinum, and titanium in order to prevent formation of a non-conducting film on the core material due to corrosion or the like, and among them, in terms of cost, titanium is preferably employed because of its inexpensiveness. In the case where corrosion resistance against an electrolytic solution is not highly required, a metal having high electric conductivity and wear resistance is more preferably selected.
Coating of the core material can be performed by a common process, such as welding processing, plating, or cladding. Also there is no problem about a partial coating on only a portion having a risk of corrosion. In the case where there is no risk of corrosion or the like by an electrolytic solution, a core material with no coating may be employed alone as the holding member 3.
The shape of the holding member 3 is not particularly limited as long as the holding member 3 can be attached in surface contact with the vicinity of one side of at least one major surface of the electrode plate 2, that is, the holding member attaching surface 2a, and is capable of holding the electrode plate 2 and electrically connecting the electrode plate 2 to an electric supply unit.
Examples of the holding member 3 include a member illustrated in
The electrode plate holding member 4 has a structure in which the lower end portion of the electrode plate holding member 4 is connected to the electrode plate 2 via the conductive connecting member 6, and, to hook or hang the electrode plate 2 on or from an electric supply unit, the upper end portion of the electrode plate holding member 4 projects like an arm in the horizontal direction. This projecting portion serves as an electric supply connection portion 4a to be electrically connected to an electric supply unit. The electric supply connection portion 4a may be formed in the shape of a bar or a plate extending in the lateral direction. The form of the electric supply connection portion 4a is preferably a structure that allows a contact area with the electric supply unit to be sufficiently secured, and prevents the distance between anodes and cathodes from being too large when the anodes and the cathodes are arranged alternately (refer to
The conductive connecting member 6 is formed in the shape of a plate that has a length equal to or longer than the length of the holding member attaching surface 2a of the electrode plate 2 so as to at least bring the conductive connecting member 6 into contact with the entirety of the holding member attaching surface 2a of the electrode plate 2 formed in the shape of a plate and that has a width enough to make an integral connection between the electrode plate 2 and the electrode plate holding member 4 by a bolt 5. A metal having excellent electric conductivity is preferably employed for the conductive connecting member 6. Since this conductive connecting member 6 is connected in surface contact with the electrode plate 2, even when temperature rises at a connection portion between the electrode plate 2 and the conductive connecting member 6 due to electric resistance, heat diffuses, whereby the electrode plate 2 can be prevented from melting, and even when a high voltage or current is passed, the electrode plate 2 can be prevented from melting. Furthermore, even if temperature rises due to electric resistance and the electrode plate 2 is somewhat softened, the electrode plate 2 can be prevented from falling off because the entirety of the holding member attaching surface 2a of the electrode plate 2 is connected to the conductive connecting member 6.
A process for connecting the electrode plate 2 to the holding member 3 is such that, as illustrated in
Furthermore, as illustrated in
Even in the case where the electrode plate 2 illustrated in
In the electrode plate 2 illustrated in
The holding member 3 illustrated in
The holding member 3 is not limited to a member illustrated in
In the anode 1 having the above-mentioned configuration, even in the case where the electrode plate 2 is made of a low melting metal or a low melting alloy, the electrode plate 2 is in surface contact with the holding member 3, for example, with the conductive connecting members 6 illustrated in
<2. A Process for Manufacturing the Anode>
As to a process for manufacturing the anode 1, first, a process for manufacturing the electrode plate 2 will be described. The electrode plate 2 is manufactured by casting by the use of a mold that fits the shape of the electrode plate 2.
Specifically, the electrode plate 2 to be used for the anode 1 illustrated in
Besides graphite carbon, polytetrafluoroethylene and high melting metals can be employed for the mold 10 in terms of heat resistance. However, polytetrafluoroethylene is not preferably employed because polytetrafluoroethylene has low heat conductivity, and accordingly, it takes much time to melt a metal. High melting metals are not preferably employed because the wettability between a molten low melting metal or low melting alloy and the high melting metals is higher, and accordingly, when the metal or alloy is cooled and solidified and then removed from the mold, the metal or alloy has difficulties in being removed from the mold. Hence, graphite carbon is preferably employed as a material having excellent heat conductivity, causing less deformation due to thermal expansion, and having an excellent release property. The size of the mold 10 is determined by the thickness and the length and width of the electrode plate 2. In the depression 10a of the mold 10, an angle may be provided so as to make the inner wall widen from the bottom toward the opening in order that a cooled and solidified electrode plate 2 can be more easily removed.
In casting by the use of the above-mentioned mold 10, a through-hole 7 through which a bolt 5 for attaching a holding member 3 passes is formed in a holding member attaching surface 2a of an electrode plate 2 on which the holding member 3 is attached. For example, a process for forming the through-hole 7 is such that, as illustrated in
With being parallel to the mold 10 and without being suspended above the mold 10, the fixing plate 13 covers an opening portion of the mold 10. Furthermore, the fixing plate 13 has a structure by which, every time casting is carried out, accuracy of position is securely maintained so that the fixing plate 13 appropriately covers the mold 10. Therefore, as illustrated in
This accuracy maintaining member 14 is fit into the fixing plate 13 so as to slide along the outer surface of the mold 10 when the mold 10 is covered with the fixing plate 13. The accuracy maintaining member 14 is formed to have the same height as the height of the mold 10, thereby allowing accuracy of the height of the fixing plate 13 to be maintained, and furthermore, the accuracy maintaining member 14 is formed to have the same length as the length of the fixing plate 13, thereby allowing accuracy of position of a passing hole 12 for passing the bar 11 therethrough to be maintained by aligning an end portion 14a of the accuracy maintaining member 14 with a corner portion 10b of the mold 10. The structure of the accuracy maintaining member 14 is not limited to the above-mentioned structure as long as high accuracy of position is maintained.
As the bar 11 to form the through-hole 7, there is preferably employed a bar that is heat resistant and has poor wettability with metal so as to be easily removed even after the solidification of a low melting metal or a low melting alloy. For example, a bar 11 made of polytetrafluoroethylene is preferably employed.
As to the size of the bar 11, the bar 11 needs to have a length sufficient for penetrating the electrode plate 2 to be cast and needs to have a diameter equal to the diameter of the bolt 5. The number of the bars 11 and intervals between the bars 11 to be inserted are made to match the number and the position of the bolts 5.
In the case where the electrode plate 2 is manufactured using such mold 10 or the like, when a low melting metal or a low melting alloy is heated to the melting point thereof or higher in the mold 10 and a state is created where the low melting metal or the low melting alloy is sufficiently melted and spreads in the mold 10, the fixing plate 13 in a state where the bar 11 passes through the passing hole 12 is made to cover the mold 10 so that the bar 11 faces a portion at which the through-hole 7 is to be formed, and the bar 11 is inserted into the molten metal. Then, the metal is cooled and solidified by still standing in the state where the bar 11 is inserted thereinto. Then, the bar 11 is removed from the passing hole 12, and a solidified metal is removed from the mold 10, whereby an electrode plate 2 having the through-hole 7 formed therein is obtained. In this process for manufacturing the electrode plate 2, the mold 10 is preferably heated until the bar 11 is inserted in order to maintain the molten state of the low melting metal or the low melting alloy.
Then, a through-hole 8 is formed in an end portion of the electrode plate holding member 4, the end portion being to be connected to the conductive connecting member 6, and through-holes 9 configured to pass the bolts 5 therethrough are formed at positions of the conductive connecting member 6 so as to face the through-hole 7 of the electrode plate 2 and the through-hole 8 of the electrode plate holding member 4. Examples of a process for forming the through-holes 8 and 9 include cutting using a common drill.
Next, the holding member 3 is attached to the holding member attaching surface 2a of the electrode plate 2 obtained as mentioned above, whereby an anode 1 is manufactured. The electrode plate 2 and the electrode plate holding member 4 are made to butt against each other, and a butted portion is sandwiched from both sides thereof by the two conductive connecting members 6, and the bolts 5 are made to pass through the through-holes 7, 8, and 9 of the electrode plate 2, the electrode plate holding member 4, and the conductive connecting member 6, respectively, and the bolts 5 are tightened with nuts to unite the electrode plate 2 and the holding member 3, whereby the anode 1 is obtained.
The process for manufacturing the anode 1 in the case of employing a holding member 3 illustrated in
The process for manufacturing the anode 1 that includes the electrode plate 2 having the through-hole 7 was described above, and next, a process for manufacturing an anode 1 that includes an electrode plate 2 having a groove portion 7a will be described.
An electrode plate 2 having a groove portion 7a can be manufactured using a mold 15 illustrated in
In the manufacture of the electrode plate 2, a low melting metal or a low melting alloy is heated to the melting point thereof or higher in the mold 15, and the low melting metal or the low melting alloy is sufficiently melted and spreads in the mold 15, and then, the metal is cooled and solidified. Then, a solidified metal is removed from the mold 15 to obtain an electrode plate 2 having the groove portion 7a formed therein.
According to this process for manufacturing the electrode plate 2, a through-hole 7 does not need to be formed as mentioned above, and therefore, a low melting metal or a low melting alloy as an electrode material does not need to be melted and maintained in the mold 15, and hence, the low melting metal or the low melting alloy may be melted in another container, and then poured into the depression 15a of the mold 15 to obtain the electrode plate 2.
Since the projection portion 15b to form the groove portion 7a is formed in the mold 15, the electrode plate 2 having the groove portion 7a formed therein can be manufactured only by melting a low melting metal or a low melting alloy in the mold 15 and cooling and solidifying the metal, or by pouring a molten low melting metal or a molten low melting alloy into the mold 15 and cooling and solidifying the metal. Thus, the electrode plate 2 having the groove portion 7a formed therein can be more easily and more efficiently manufactured than the electrode plate 2 having the through-hole 7 formed therein.
In the case of employing the electrode plate 2 having the groove portion 7a formed therein, an anode 1 may be obtained in such a manner that, first, the bolt 5 is passed through the through-holes 8 and 9 of the electrode plate holding member 4 and the conductive connecting member 6, and the bolt 5 is loosely tightened with a nut, and then, the electrode plate 2 is inserted so that the bolt 5 fits into the groove portion 7a of the electrode plate 2, and then, the bolt 5 is firmly tightened with a nut, whereby the electrode plate 2 and the holding member 3 are united.
According to the above-mentioned process for manufacturing the anode 1, the use of a low melting metal or a low melting alloy having a low melting point of not less than 100° C. and not more than 250° C. for the electrode plate 2 allows the metal or the alloy to be easily melted; and the molding of a molten low melting metal or a molten low melting alloy by the use of a mold allows an electrode plate 2 to be obtained; only by the attachment of the holding member 3, for example, the conductive connecting member 6 in
Furthermore, according to the process for manufacturing an anode 1, in the case where an anode 1 illustrated in
In the case where an anode 1 having a configuration illustrated in
Hereinafter, specific examples to which the present invention is applied will be described, but the present invention is not limited to these examples.
Example 1In Example 1, an anode illustrated in
An indium electrode plate having a thickness of 4 mm, a length of 27 cm, and a width of 27 cm was produced by melting and casting using a mold (refer to
The mold was produced by making a depression portion having a depth of 15 mm, a length of 27 cm, and a width of 27 cm in a carbon graphite block having a thickness of 30 mm, a length of 30 cm, and a width of 30 cm. A fixing plate was produced in such a manner that a carbon graphite block having a length of 65 mm, a width of 35 mm, and a height of 35 mm was shaved to be in the form of a plate having a length of 60 mm, a width of 30 mm, and a height of 30 mm. The dimension d (refer to
Using, for example, the mold produced as mentioned above, an indium electrode plate was cast as follows. The produced mold was put on a large sized hot plate manufactured by AS ONE Corporation (HP-A2234M, 30 cm×30 cm), and 2000-g indium metal was put into the mold. With this state kept, the hot plate was heated to approximately 300° C. and maintained. At the time when the indium metal completely melted, an end portion of the accuracy maintaining member attached to the fixing plate was aligned with one corner of the mold and placed thereon, and the bars made of Teflon (registered trademark) were deeply inserted into the respective four passing holes, and then, cooling was performed. After the indium metal cooled down to room temperature, the bars made of Teflon (registered trademark) were pulled out and the fixing plate was removed, and then, the mold was turned upside down. A solidified indium metal was smoothly released and removed from the mold. An obtained indium electrode plate had a thickness of approximately 4 mm.
Next, the indium electrode plate was attached to a holding member manufactured as follows. The holding member was a copper material having the same shape as that of a holding member illustrated in
Electrolysis was performed using the anode produced as mentioned above. An apparatus illustrated in
In the electrolysis apparatus 20, a 1 mol/L ammonium nitrate solution having a pH of 4.0 is in a regulating tank 27 that is provided to be adjacent to the electrolytic bath 23. The regulating tank 27 is connected to the electrolytic bath 23 via a circulating pump 28 to circulate the electrolytic solution 21. The regulating tank 27 comprises: a stirring rod 29 to stir the electrolytic solution 21; a pH electrode 30 to measure pH; a temperature control heater 31 to control and maintain the temperature of the electrolytic solution 21; and a cooler 32.
In the electrolysis apparatus 20 having such configuration, while an current was maintained so as to achieve a current density of 15 A/dm2, electrolysis was performed.
During the electrolysis, the contact temperature between the indium electrode plate and the conductive connecting member ranged from 50° C. to 80° C., and deformation of the indium electrode plate due to a temperature rise was not observed. In Example 1, indium hydroxide was generated in the electrolytic solution by electrolysis for 6 consecutive hours, and an obtained slurry was solid-liquid separated.
Example 2In Example 2, an anode illustrated in
An indium electrode plate having a thickness of 8 mm, a length of 349 mm, and a width of 260 mm was produced by melting and casting using a mold (refer to
The mold was produced in such a manner that a depression portion having a depth of 15 mm, a bottom length of 349 mm, and a bottom width of 260 mm was made on the inside of a carbon graphite block having a thickness of 30 mm, a length of 400 mm, and a width of 300 mm. More specifically, the inner wall of the mold was inclined so that the depression portion was 355 mm in length and 266 mm in width at a depth of 8 mm. Furthermore, in the mold, there were formed projection portions projected from one of the short sides of the mold. The projection portion had an angle so as to be 14 mm in width and 17 mm in length at the bottom of the depression portion of the mold, whereas 8 mm in width and 14 mm in length at a depth of 8 mm Three such projection portions were provided at regular intervals. The projection portion was shaped like the letter U in such a manner that one end portion of the projection portion, the one end being not connected to the short side of the mold, was made circular.
Then, a 2-L stainless-steel pot was put on a large sized hot plate manufactured by
AS ONE Corporation (HP-A2234M, 30 cm×30 cm), and 5000-g indium metal was put into the pot. With this state kept, the hot plate was heated to approximately 300° C. and maintained to completely melt the indium metal. This molten indium was poured into the above-mentioned mold. Then, the indium metal was left standing at room temperature for 15 minutes to be cooled and solidified, and then, the mold was turned upside down. The solidified indium metal was smoothly released and removed from the mold. Three groove portions were formed without problems in one side of an electrode plate, and thus, an indium electrode plate having a thickness of 8 mm, a length of 349 mm, and a width of 260 mm was obtained.
The attachment to the holding member was performed in the same manner as in Example 1, except that the number of attachment bolts was decreased from four to three. Furthermore, electrolysis was performed in the same manner as in Example 1.
In Example 2, indium hydroxide was generated by electrolysis for 12 hours, and an obtained slurry was solid-liquid separated.
<Example 3>In Example 3, there was produced an anode including an electrode plate obtained by changing the U-shaped groove portion in Example 2 to a triangular V-shaped groove portion. Other conditions were the same as in Example 2.
Also in Example 3, indium hydroxide was generated by electrolysis for 12 hours, and an obtained slurry was solid-liquid separated.
[Comparative Example]In Comparative Example, an anode 40 made of indium metal and having a width of 27 cm, a length of 40 cm, and a thickness of 4 mm was formed, the anode 40 having a portion 40a laterally projecting by 6.5 cm to the left and by 6.5 cm to the right in the upper part of the anode 40 as illustrated in
Immediately after the start of the electrolysis, the temperature around a contact point between the projection 40a of the anode 40 and the electric supply unit 41 began to rise gradually, and, 30 minutes later, just before the temperature reached 150° C., indium was softened and melted, whereby the anode 40 falls off, and accordingly, the electrolysis had to be terminated at this point.
From the above-mentioned Examples and Comparative Example, it is understood that, in the case where an electrode plate is made of a material having a low melting point, such as indium, and the electrode plate is in surface contact with a holding member as described in Examples 1 to 3, the electrode plate can be prevented from melting, and accordingly, electrolysis is enabled to be performed for long hours.
On the other hand, it is understood that, in the case where a contact area between the electrode plate and the electric supply unit is small as described in Comparative Example, a material having a low melting point, such as indium, melts, whereby electrolysis time is shorter, and accordingly, metal cannot be sufficiently deposited.
REFERENCE SIGNS LIST1: anode
2: electrode plate
2a: holding member attaching surface
3: holding member
4: electrode plate holding member
5: bolt
6: conductive connecting member
7: through-hole
7a: groove portion
8: through-hole
9: through-hole
10: mold
10a: depression portion
10b: corner portion
11: bar
12: through-hole
13: fixing plate
14: accuracy maintaining member
14: end portion
15: mold
15a: depression portion
15b: projection portion
20: electrolysis apparatus
21: electrolytic solution
22: liquid dispersing plate
23: electrolytic bath
24: anode
25: cathode
26: lead
27: regulating tank
28: circulating pump
29: stirring rod
30: pH electrode
31: heater
32: cooler
Claims
1. An anode, wherein a holding member is attached in surface contact with a vicinity of one side of at least one major surface of an electrode plate, the electrode plate being made of a low melting metal or a low melting alloy having a melting point of not less than 100° C. and not more than 250° C., the holding member having a length equal to or longer than a length of said one side and being made of a metal or an alloy having a melting point higher than the melting point of the electrode plate.
2. The anode according to claim 1,
- wherein the holding member comprises: an electrode plate holding member configured to hold the electrode plate; and conductive connecting members configured to electrically connect the electrode plate to the electrode plate holding member and formed in a shape of a plate, and
- wherein sides of a connection portion at which the electrode plate and the electrode plate holding member are connected are sandwiched by the two conductive connecting members, and tightening of a bolt passing through the electrode plate, the electrode plate holding member, and the two conductive connecting members so as to unite the electrode plate, the electrode plate holding member, and the two conductive connecting members allows the electrode plate and the electrode plate holding member to be electrically connected via the conductive connecting members.
3. The anode according to claim 2, wherein, in the electrode plate, a portion through which the bolt is passed comprises a through-hole or a groove portion.
4. The anode according to claim 1, wherein the electrode plate has a thickness of not less than 2 mm and not more than 15 mm The anode according to claim 1, wherein the low melting metal is indium or tin.
6. The anode according to claim 1, wherein the holding member is made of copper.
7. The anode according to claim 1, wherein a surface of the holding member is coated with a metal that is resistant to corrosion by an electrolytic solution for electrolysis.
8. A process for manufacturing an anode, wherein a low melting metal or a low melting alloy having a melting point of not less than 100° C. and not more than 250° C. is cooled and solidified in a mold, a solidified low melting metal or a solidified low melting alloy is taken out of the mold to obtain an electrode plate, and a holding member is attached in surface contact with a vicinity of one side of at least one major surface of the obtained electrode plate, whereby the anode is obtained, the holding member having a length equal to or longer than the length of said one side and being made of a metal or an alloy having a melting point higher than the melting point of the electrode plate.
9. The process for manufacturing the anode according to claim 8, further comprising:
- inserting a bar into a portion corresponding to the vicinity of the one side of the major surface of the electrode plate in a state in which a low melting metal or a low melting alloy in the mold is molten, and forming the electrode plate so that said inserted bar portion serves as a through-hole;
- forming a through-hole in an end portion of an electrode plate holding member being a constituent of the holding member and configured to hold the electrode plate;
- sandwiching side faces of a connection portion between the electrode plate and the electrode plate holding member by two conductive connecting members, the conductive connecting members being in a shape of a plate having a through-hole formed at a position facing the through-holes of the electrode plate and the electrode plate holding member, being a constituent of the holding member, and being configured to electrically connect the electrode plate to the electrode plate holding member; and
- passing a bolt through the through-hole of the electrode plate, the through-hole of the electrode plate holding member, and the through-holes of the two conductive connecting members, and tightening the bolt to unite the electrode plate, the electrode plate holding member, and the two conductive connecting members, and electrically connecting the electrode plate holding member to the electrode plate by the conductive connecting members.
10. The process for manufacturing the anode according to claim 8, wherein the mold is made of graphite carbon.
11. The process for manufacturing the anode according to claim 9, wherein the bar is made of polytetrafluoroethylene.
12. The process for manufacturing the anode according to claim 8, further comprising:
- forming the electrode plate by using the mold having a projection portion projected from an inner wall so that, around a perimeter of the electrode plate, the electrode plate has a groove portion formed by said projection portion;
- forming a through-hole in an end portion of an electrode plate holding member, the electrode plate holding member being a constituent of the holding member and being configured to hold the electrode plate;
- sandwiching side faces of a connection portion between the electrode plate and the electrode plate holding member by two conductive connecting members, the conductive connecting members being in a shape of a plate having a through-hole formed at a position facing the groove potion of the electrode plate and the through-hole of the electrode plate holding member, being a constituent of the holding member, and being configured to electrically connect the electrode plate to the electrode plate holding member; and
- passing a bolt through the groove portion of the electrode plate, the through-hole of the electrode plate holding member, and the through-holes of the two conductive connecting members, and tightening the bolt to unite the electrode plate, the electrode plate holding member, and the two conductive connecting members, and electrically connecting the electrode plate holding member to the electrode plate by the conductive connecting members.
Type: Application
Filed: Jul 23, 2014
Publication Date: Jul 14, 2016
Applicant: SUMITOMO METAL MINING CO., LTD. (Tokyo)
Inventors: Noriaki SUGAMOTO (Tokyo), Tatsuo KIBE (Tokyo), Tetsuro KAMO (Tokyo), Tsuyoshi IWASA (Tokyo), Tetsuji KAWAKAMI (Tokyo), Kou TAKADA (Tokyo), Toshio MORIMOTO (Tokyo)
Application Number: 14/909,830