CA1187838A - Coated metal anode for the electrolytic recovery of metals - Google Patents
Coated metal anode for the electrolytic recovery of metalsInfo
- Publication number
- CA1187838A CA1187838A CA000370725A CA370725A CA1187838A CA 1187838 A CA1187838 A CA 1187838A CA 000370725 A CA000370725 A CA 000370725A CA 370725 A CA370725 A CA 370725A CA 1187838 A CA1187838 A CA 1187838A
- Authority
- CA
- Canada
- Prior art keywords
- rods
- anode
- anode according
- current supply
- supply rail
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
- C25C7/02—Electrodes; Connections thereof
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrolytic Production Of Metals (AREA)
- Electrodes For Compound Or Non-Metal Manufacture (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A coated metal anode for the electrolytic recovery of metals is disclosed, whereby the working surface of this anode is represented by rods which are arranged in a plane in spaced, parallel relationship to each other and which are electrically connected to a current supply rail. To provide a coated metal anode of the identified type, which ensures an operation with acceptable current density and which permits with a simple constructive assembly an economic deposit of metal with high purity on the opposite disposed cathode, the total surface area FA of all the rods and the sur-face area Fp assumed by the total arrangement of all the rods fulfills the relationship 6 ? FA / Fp ? 2.
A coated metal anode for the electrolytic recovery of metals is disclosed, whereby the working surface of this anode is represented by rods which are arranged in a plane in spaced, parallel relationship to each other and which are electrically connected to a current supply rail. To provide a coated metal anode of the identified type, which ensures an operation with acceptable current density and which permits with a simple constructive assembly an economic deposit of metal with high purity on the opposite disposed cathode, the total surface area FA of all the rods and the sur-face area Fp assumed by the total arrangement of all the rods fulfills the relationship 6 ? FA / Fp ? 2.
Description
L;~Y~'7~
~ he invention relates to a coated metal anode for the electro]y-tic recovery of metals, the working surface of which is represented by rods which are arranged in a plane in spaced, parallel relationship to each other, and which are electrically connected to a current supply rail.
In the field of the electrolytic recovery of metals, especially non-ferric metals, from acidic solu-tions containing the metal to be recovered, anodes of iron or iron alloy should be replaced by other metal anodes. The core of each of these metal anodes consists of a valve metal, such as e~g. titanium, whereas the coating is formed of e.g. platinum or platinum oxide. The essential advantage of the metal anodes in question is to be seen in the saving of electric energy as compared to the conventional iron or graphite anodes. The saving of energy results from the larger surface obtainable with metal anodes, the high activity of the coating and the stability of form, which permit a considerable re-duction in anode voltage. A further operational economyis achieved with metal anodes in that the cleaning and neutralization of the electrolyte is simplified, as the coating of the metal anodes Cl, NO3 or free H2SO4 is not destroyed. An additional economy in costs results from the fact that with the use of metal anodes, it is not necessary to add expensive additives, e.g. cobalt, to the electrolyte, as is necessary with the use of iron anodes. Furthermore, the contamination of the electro-lyte and the recovered metal by iron, which is unavoid-able in the case of iron anodes, is no longer applicable.
Finally, the metal anodes permit an increase in current density and thus in productivity.
In a known metal anode of the given type (German application DE-OS 24 04 167 filed January 29, 1974, pub-35 lished August 1, 1974 in the name of Diamond Shamrock ~A~
~ ... :i
~ he invention relates to a coated metal anode for the electro]y-tic recovery of metals, the working surface of which is represented by rods which are arranged in a plane in spaced, parallel relationship to each other, and which are electrically connected to a current supply rail.
In the field of the electrolytic recovery of metals, especially non-ferric metals, from acidic solu-tions containing the metal to be recovered, anodes of iron or iron alloy should be replaced by other metal anodes. The core of each of these metal anodes consists of a valve metal, such as e~g. titanium, whereas the coating is formed of e.g. platinum or platinum oxide. The essential advantage of the metal anodes in question is to be seen in the saving of electric energy as compared to the conventional iron or graphite anodes. The saving of energy results from the larger surface obtainable with metal anodes, the high activity of the coating and the stability of form, which permit a considerable re-duction in anode voltage. A further operational economyis achieved with metal anodes in that the cleaning and neutralization of the electrolyte is simplified, as the coating of the metal anodes Cl, NO3 or free H2SO4 is not destroyed. An additional economy in costs results from the fact that with the use of metal anodes, it is not necessary to add expensive additives, e.g. cobalt, to the electrolyte, as is necessary with the use of iron anodes. Furthermore, the contamination of the electro-lyte and the recovered metal by iron, which is unavoid-able in the case of iron anodes, is no longer applicable.
Finally, the metal anodes permit an increase in current density and thus in productivity.
In a known metal anode of the given type (German application DE-OS 24 04 167 filed January 29, 1974, pub-35 lished August 1, 1974 in the name of Diamond Shamrock ~A~
~ ... :i
2-Technologies, Zurich), the working surEace is repre-sented by vertically arranged rods which are spaced from each other in the ver-tical plane and are in parallel relationship to each other. The most essent:ial feature of this known anode is that the anode surface opposing the cathode is 1.5 to 20 times smaller than the opposing cathode surface and the anode is operated with a current density which is 1.5 to 20 times greater than the cathode current density. Thus, supposedly, in an econo~ical manner, a relatively pure metal deposit of the desired crystalline structure and purity should be obtained on the cathode. The economy with which the known anode should operate should evidently be seen in the fact that on account of the reduced area of the anode as compared to the cathode, the requirement of material for the pro-duction of the anode is reduced and thus expensive material saved. The reduction in costs is paid for dearly, however, by considerable disadvantages during production, as follows:
The considerably reduced surface of the known anode as compared to the cathode, and the resultant neces-sity to work with high current densities, cause the course and uniformity of the current paths in the cell to be very difficult to control. However, a non-uniform dis tribution and a course of current paths which is not precisely foreseeable result in a non-uniform deposit of the metal on the cathode.
Since the known anode works with a high current density, the anodic portion of the cell voltage is high.
This results in the substantial disadvantage of a high energy requirement for the cells equipped with such an anode.
The large current density and the reduced con-ductor cross-section of the known anode on account of the reduced surface and thus of the small volume cause a large inner IR drop, which results in a Eurther increase of -the necessary electric ener~y. In order to elimin-ate this disadvantage, the known anodes require a plur-ality of current supply rai]s of complicated construction, which considerably increase the construction costs.
In the known anodes, the rods are formed with a xound profile, i.e. they have a circular cross-section.
~ Thus, a considerable portion of the surface of the rods -~ ` which bear the active coating liesin the current shadow region of the cathode. This portion of the surface of the rods contributes vexy little to the working surface of the anode. Thus, the known anode has only a low effici-ency due to the reduced utili~ation of the coating, i.e.
the working surface of the anode.
Furthermore, the known anode has the disadvantage that the sensitive and expensive coating on the round rods is relatively freely accessible with the consequence that the coating can easily be destroyed mechanically, e.g. when the anode or cathode is being built in or out.
During the assembly and disassembly of the known anodes, also the necessary current supply rails, which extend partly parallel to and partly perpendicular to the rods, have a disadvantageous effect, as they increase the width of the construction so that the danger of damage of both the anode and also the cathode when withdrawing e.g. the anode from the cell is increased.
Furthermore, in the case of the known anodes, no sufficient measures have been taken to form a rigid rod construction so that there is the possibility that the rods will arch out beyond the plane of arrangement re-sulting in a contact with the cathode and thus a short-circuit.
As compared thereto, it is the object of the invention to provide a coated metal anode of the above-given type, which effects a compromise meeting all the demands between a material-saving cons-truction on the one hand and an operation with acceptable current den-si-ty on the other hand, and which permits, with a simple, constructive assembly, an economic deposit of metal with high purity on the oppositely disposed cathode.
This object is solved in the case of a coated metal anode of the above-described type in that the total surface area of all the rods FA and the surface area F
assumed by the entire arrangement of all the rods fulfills the relationship 6 ~ FA / Fp > 2.
The solution according to the invention is pro-vided by an anode which, on the one hand, offers a large working surface and nevertheless, on the other hand, can be produced with the smallest possible requirement of material. The large working surface permits an operation of the anode according to the invention with relatively small current densities, even upon large application of voltage. This guarantees an economic deposit of the desired metal with great purity on the cathode. The saving in energy is achieved primarily by the reduction of the anodic portion of the cell voltage obtained as compared to the known solutions.
The large surface of the anode according to the invention leads also to a large conductor total cross-section of the rods and thus causes only a relativelysmall inner voltage drop of the electrical current when flowing through the rods from the current supply rail to the ends of the rods remote therefrom. For this reason, besides the main current supply rail, no further current supply rails are necessary, so that the anode construction according to the invention is not only relatively small, but also material, and thus production costs are saved.
In the anode according to the invention, the rods are arranged vertically in the usual manner. The surface assumed by the rods corresponds approximately with the '~
.~#~
surface of the cathode facing the anode. Precise]y on account oE the last-mentioned measure, a uniform, easlly controllable distribution of the current paths between anode and cathode results.
An especially advantageous configuration of the anQde ~ac~ording to the invention is to be seen in the ~c~-~t the'rods have an essentially rectangular cross-section and are arranged in such a manner that the larger ~ e~ ~ ~ the cross-section of the rods extends perpen-dicular to the arrangement plane assumed by the rods.
Due to this measure, a large portion of the work-ing surface oE the anode, i.e. the rods or their coating, respectively, lies perpendicular to the arrangement plane of the rods of the anode, or the surface of the cathode facing the anode, respectively. This results in a series of advantages. One advantage is that the portion of the working surface which lies in the current shadow reyion of the cathode is relatively small. Thus, already geo-metrically a large effective surface results. This causes an optimal utilization of the coatiny, and thus a very large physical surface of the anode of the invention.
Moreover, a large portion of the coating, namely that on the surfaces of the rods perpendicular to the arrangement plane of the anode, is protected from a mechanical de-struction, so that not only can the anode according tothe invention be built in and out without any problems, but also the cathode can be withdrawn from and re~inserted into the cell without difficulty. The anode structure according to the invention also reduces the danger of short-circuits and mechanical destructions due to a for-mation of dendrites on the cathode surface.
It has proven to be advantageous to provide a ratio of the short side to the long side of the rectangular cross-section of the rods which amounts to 1:2 to 1:10.
In this respect, it is especially advantageous to provide a width B
~ ~ ~ 7~
of t.he rods measu.red parallel to the arrangement p]ane which amounts to about 0.5 mm to about 2.5 mm. This measure contributes no-t only to the desired state of the surface ratio, but also permits the use of convention-al profiles for the rods and thus a construction favour~able to costs and further, a practical production of the anode.
It is also advantageous with respect to the named aspects that the depth T of the rods measured perpendi-cular to the anode plane ~ amounts to about 5 mm to25 mm.
It has also proven to be expedient tha-t the ratio of the width of one of each rods to the distance of two adjacent rods is 1:4 to 1:6. In this respect, it is especially recommendable if the clear distance A between two adjacent rods amounts to A 7 2 mm. This construction of the anode of the invention permits a good circulation of the electroly-te between the rods.
An especially advantageous constructive configur-ation of the anode of -the invention is to be seen in the fact that the rods lie in a plane with the current supply rail, connect with their one face end to the current sup-ply rail, and both the electrical and mechanical con-nection of the rods with the current supply rail takes place via at least one connecting strip extending parallel to the latter, the one marginal region of which is con-nected with the current supply rail and the other marginal region of which is connected with the rods. This solution ensures with a large geometrical surface not only a large mechanical strength of the anode of the invention, but simultaneously a configuration of the electrical connection of the component parts of the anode of the invention in such a manner that at the contact ~ones the current den-sity or current load always assumes acceptable values and thus the drop of voltage in the contact zones is slight, ~7--even in -the event of long operating t.imes. The attained mechanical strength of the anode of the invention simplifies not only the installa-tion and removal of same, but also reduces the danger of short circuits due to an arching out of the anode struc-ture with -the consequence of a contact with the ca-thode.
An especially preferred embodiment of this solution is that on both sides of the current supply rail or the rods, respectively, one connecting strip respectively is arranged. By means of this measure, the current density in the contact zones between the individual component parts of the anode according to the invention can be kept especially low.
It is expedient if the connecting strips are secured to the current supply rails by screw connecti.ons.
This provides an especially simple exchangeability of the anode arrangement of the invention. It is further pos-sible with this measure to introduce the anode according to the invention instead of e.g. an iron anode using the same current supply rail in a cell already provided.
Accordingly, it is especially economical and simple to exchange the conventional iron anodes with a coated metal anode according to the invention.
According to the invention, the screw connection is constructed such that the contact area between the connecting strip or strips and the current supply rail is selected to be so large that the reduction of the contact area caused by-the bores of the screw connection have no substantial effect on the current density or current l.oad in the contact area.
Whereas expediently the connecting strips are screwed together with the current supply rail, it is advantageous that the rods are connected to the connecting strips by means of spot-welding. This permits an especially economical connection of the rods to the connecting strips.
7~
~8 In order to increase the mechanical strength of the anode structure of the inven-tion, it is moreover advantageous that the rods are connected with each other by a plurallty of crossbars. This especially applies if the successive crossbars are arranged alternatively on the one and on the other side of the rods. In -this respect, it is expedient that the crossbar be secured to the rods by means of spot-welding. The crossbars should be integrated extensively into the rod structure so that no projecting edges are formed which would cause an especially rapid formation of dendrite by the ca-thode.
Functionally, this aim can be achieved especially simply if the crossbars are ~lattened on their outwardly lying surfaces so that these surfaces either do not arch beyond the outline of the anode rods, or only to an insignificant extent.
Advantageously, the core of the rods is formed of valve metal, especially titanium, whereas the coating is formed of platinum metal and/or platinum metal oxide and/or an electrically conductive, non-stoichiometric oxide and/
or a base metal and/or its oxide and/or mixtures of the above substances.
An embodiment of the coated metal anode according to the invention is explained in more detail on the basis of the enclosed drawings. These show:
Fig. 1 a plan view of the arrangement plane of the anode according to the invention, Fig. 2 an end view of the arrangement according to the invention, Fig. 3 an enlarged representation of the detail III of Fig. 2, and Fig. 4 an enlarged representation of the detail IV of Fig. lo As shown by Fig. 1, a cell tank represented only schematically is indicated with 1. On bearing blocks 2 _9_ at the opening edge of the cel] tank 1, a current supply rail 3 is positioned, which is connected v.ia a contact rail 5 to the source of current. The current rail 3 bears a series of rods 4, which represents the working surface of -the anode. The rods with the length LS have a rectangular cross-section with the width B and the depth T. In this respect, the rods are orientated such that their depth T extends perpendicular to -the arrangement plane of Fig. 1. The surface area sssumed by the arrange-ment of the rods is defined by the length of the rods LSand by the distance LG of the outer sides of the two outer rods of the anode structure. The rods 4 are arranged with a clear distance A to each other.
The electrical and mechanical connection of the current supply rail, comprised e.g. of copper, with the rods 4/ comprised e.g. of coated titanium, is best shown by Fig. 3. According to same, the current supply rails
The considerably reduced surface of the known anode as compared to the cathode, and the resultant neces-sity to work with high current densities, cause the course and uniformity of the current paths in the cell to be very difficult to control. However, a non-uniform dis tribution and a course of current paths which is not precisely foreseeable result in a non-uniform deposit of the metal on the cathode.
Since the known anode works with a high current density, the anodic portion of the cell voltage is high.
This results in the substantial disadvantage of a high energy requirement for the cells equipped with such an anode.
The large current density and the reduced con-ductor cross-section of the known anode on account of the reduced surface and thus of the small volume cause a large inner IR drop, which results in a Eurther increase of -the necessary electric ener~y. In order to elimin-ate this disadvantage, the known anodes require a plur-ality of current supply rai]s of complicated construction, which considerably increase the construction costs.
In the known anodes, the rods are formed with a xound profile, i.e. they have a circular cross-section.
~ Thus, a considerable portion of the surface of the rods -~ ` which bear the active coating liesin the current shadow region of the cathode. This portion of the surface of the rods contributes vexy little to the working surface of the anode. Thus, the known anode has only a low effici-ency due to the reduced utili~ation of the coating, i.e.
the working surface of the anode.
Furthermore, the known anode has the disadvantage that the sensitive and expensive coating on the round rods is relatively freely accessible with the consequence that the coating can easily be destroyed mechanically, e.g. when the anode or cathode is being built in or out.
During the assembly and disassembly of the known anodes, also the necessary current supply rails, which extend partly parallel to and partly perpendicular to the rods, have a disadvantageous effect, as they increase the width of the construction so that the danger of damage of both the anode and also the cathode when withdrawing e.g. the anode from the cell is increased.
Furthermore, in the case of the known anodes, no sufficient measures have been taken to form a rigid rod construction so that there is the possibility that the rods will arch out beyond the plane of arrangement re-sulting in a contact with the cathode and thus a short-circuit.
As compared thereto, it is the object of the invention to provide a coated metal anode of the above-given type, which effects a compromise meeting all the demands between a material-saving cons-truction on the one hand and an operation with acceptable current den-si-ty on the other hand, and which permits, with a simple, constructive assembly, an economic deposit of metal with high purity on the oppositely disposed cathode.
This object is solved in the case of a coated metal anode of the above-described type in that the total surface area of all the rods FA and the surface area F
assumed by the entire arrangement of all the rods fulfills the relationship 6 ~ FA / Fp > 2.
The solution according to the invention is pro-vided by an anode which, on the one hand, offers a large working surface and nevertheless, on the other hand, can be produced with the smallest possible requirement of material. The large working surface permits an operation of the anode according to the invention with relatively small current densities, even upon large application of voltage. This guarantees an economic deposit of the desired metal with great purity on the cathode. The saving in energy is achieved primarily by the reduction of the anodic portion of the cell voltage obtained as compared to the known solutions.
The large surface of the anode according to the invention leads also to a large conductor total cross-section of the rods and thus causes only a relativelysmall inner voltage drop of the electrical current when flowing through the rods from the current supply rail to the ends of the rods remote therefrom. For this reason, besides the main current supply rail, no further current supply rails are necessary, so that the anode construction according to the invention is not only relatively small, but also material, and thus production costs are saved.
In the anode according to the invention, the rods are arranged vertically in the usual manner. The surface assumed by the rods corresponds approximately with the '~
.~#~
surface of the cathode facing the anode. Precise]y on account oE the last-mentioned measure, a uniform, easlly controllable distribution of the current paths between anode and cathode results.
An especially advantageous configuration of the anQde ~ac~ording to the invention is to be seen in the ~c~-~t the'rods have an essentially rectangular cross-section and are arranged in such a manner that the larger ~ e~ ~ ~ the cross-section of the rods extends perpen-dicular to the arrangement plane assumed by the rods.
Due to this measure, a large portion of the work-ing surface oE the anode, i.e. the rods or their coating, respectively, lies perpendicular to the arrangement plane of the rods of the anode, or the surface of the cathode facing the anode, respectively. This results in a series of advantages. One advantage is that the portion of the working surface which lies in the current shadow reyion of the cathode is relatively small. Thus, already geo-metrically a large effective surface results. This causes an optimal utilization of the coatiny, and thus a very large physical surface of the anode of the invention.
Moreover, a large portion of the coating, namely that on the surfaces of the rods perpendicular to the arrangement plane of the anode, is protected from a mechanical de-struction, so that not only can the anode according tothe invention be built in and out without any problems, but also the cathode can be withdrawn from and re~inserted into the cell without difficulty. The anode structure according to the invention also reduces the danger of short-circuits and mechanical destructions due to a for-mation of dendrites on the cathode surface.
It has proven to be advantageous to provide a ratio of the short side to the long side of the rectangular cross-section of the rods which amounts to 1:2 to 1:10.
In this respect, it is especially advantageous to provide a width B
~ ~ ~ 7~
of t.he rods measu.red parallel to the arrangement p]ane which amounts to about 0.5 mm to about 2.5 mm. This measure contributes no-t only to the desired state of the surface ratio, but also permits the use of convention-al profiles for the rods and thus a construction favour~able to costs and further, a practical production of the anode.
It is also advantageous with respect to the named aspects that the depth T of the rods measured perpendi-cular to the anode plane ~ amounts to about 5 mm to25 mm.
It has also proven to be expedient tha-t the ratio of the width of one of each rods to the distance of two adjacent rods is 1:4 to 1:6. In this respect, it is especially recommendable if the clear distance A between two adjacent rods amounts to A 7 2 mm. This construction of the anode of the invention permits a good circulation of the electroly-te between the rods.
An especially advantageous constructive configur-ation of the anode of -the invention is to be seen in the fact that the rods lie in a plane with the current supply rail, connect with their one face end to the current sup-ply rail, and both the electrical and mechanical con-nection of the rods with the current supply rail takes place via at least one connecting strip extending parallel to the latter, the one marginal region of which is con-nected with the current supply rail and the other marginal region of which is connected with the rods. This solution ensures with a large geometrical surface not only a large mechanical strength of the anode of the invention, but simultaneously a configuration of the electrical connection of the component parts of the anode of the invention in such a manner that at the contact ~ones the current den-sity or current load always assumes acceptable values and thus the drop of voltage in the contact zones is slight, ~7--even in -the event of long operating t.imes. The attained mechanical strength of the anode of the invention simplifies not only the installa-tion and removal of same, but also reduces the danger of short circuits due to an arching out of the anode struc-ture with -the consequence of a contact with the ca-thode.
An especially preferred embodiment of this solution is that on both sides of the current supply rail or the rods, respectively, one connecting strip respectively is arranged. By means of this measure, the current density in the contact zones between the individual component parts of the anode according to the invention can be kept especially low.
It is expedient if the connecting strips are secured to the current supply rails by screw connecti.ons.
This provides an especially simple exchangeability of the anode arrangement of the invention. It is further pos-sible with this measure to introduce the anode according to the invention instead of e.g. an iron anode using the same current supply rail in a cell already provided.
Accordingly, it is especially economical and simple to exchange the conventional iron anodes with a coated metal anode according to the invention.
According to the invention, the screw connection is constructed such that the contact area between the connecting strip or strips and the current supply rail is selected to be so large that the reduction of the contact area caused by-the bores of the screw connection have no substantial effect on the current density or current l.oad in the contact area.
Whereas expediently the connecting strips are screwed together with the current supply rail, it is advantageous that the rods are connected to the connecting strips by means of spot-welding. This permits an especially economical connection of the rods to the connecting strips.
7~
~8 In order to increase the mechanical strength of the anode structure of the inven-tion, it is moreover advantageous that the rods are connected with each other by a plurallty of crossbars. This especially applies if the successive crossbars are arranged alternatively on the one and on the other side of the rods. In -this respect, it is expedient that the crossbar be secured to the rods by means of spot-welding. The crossbars should be integrated extensively into the rod structure so that no projecting edges are formed which would cause an especially rapid formation of dendrite by the ca-thode.
Functionally, this aim can be achieved especially simply if the crossbars are ~lattened on their outwardly lying surfaces so that these surfaces either do not arch beyond the outline of the anode rods, or only to an insignificant extent.
Advantageously, the core of the rods is formed of valve metal, especially titanium, whereas the coating is formed of platinum metal and/or platinum metal oxide and/or an electrically conductive, non-stoichiometric oxide and/
or a base metal and/or its oxide and/or mixtures of the above substances.
An embodiment of the coated metal anode according to the invention is explained in more detail on the basis of the enclosed drawings. These show:
Fig. 1 a plan view of the arrangement plane of the anode according to the invention, Fig. 2 an end view of the arrangement according to the invention, Fig. 3 an enlarged representation of the detail III of Fig. 2, and Fig. 4 an enlarged representation of the detail IV of Fig. lo As shown by Fig. 1, a cell tank represented only schematically is indicated with 1. On bearing blocks 2 _9_ at the opening edge of the cel] tank 1, a current supply rail 3 is positioned, which is connected v.ia a contact rail 5 to the source of current. The current rail 3 bears a series of rods 4, which represents the working surface of -the anode. The rods with the length LS have a rectangular cross-section with the width B and the depth T. In this respect, the rods are orientated such that their depth T extends perpendicular to -the arrangement plane of Fig. 1. The surface area sssumed by the arrange-ment of the rods is defined by the length of the rods LSand by the distance LG of the outer sides of the two outer rods of the anode structure. The rods 4 are arranged with a clear distance A to each other.
The electrical and mechanical connection of the current supply rail, comprised e.g. of copper, with the rods 4/ comprised e.g. of coated titanium, is best shown by Fig. 3. According to same, the current supply rails
3 and the rods 4 are arranged in a plane such that the upper end faces of the rods 4 border against the lower surface of the current supply rail 3. The connection of the current supply rail 3 with the rods 4 takes place via two connecting strips 6 arranged on both sides of the current supply rail and parallel thereto, whereby said strips 6 can also be of coated titanium. The connecting strips 6 are secured by means of screws 7a and nuts 7b to the current supply rail 3. The connection of the rods
4 with the connecting strips 6 takes place by welding spots 8. For the further stiffening of the anode structure, a plurality of crossbars 9, which are also of coated titanium, are connected to the rods 4 by spot welding.
In this respect, the successive crossbars 9 are arranged alternatively on the one or the other side oE the arrange-ment plane of the rods 4.
With the described construction, the rods 4 have a 35 length LS of 1170 mm, whereas their width B is 2 mm and .
-10~
their depth T l2 mm. The clear dis-tance A between two adjacent rods 4 is 8 mm. The entire length LG of the anode structure is 852 mm. 82 rods are provided.
The described anode is designed for a current of 600 A corresponding with an anode-side current density of 355 A/m (Fp). With a current of 600 A, merely an IR
drop of about 100 rnV occurs in the anode.
The anode construction is stiff and robust. This results not only from the described connection of the rods 4 with the current supply rail 3 by means of the connecting strips 6 and from the spot welding of the rods with these connecting strips 6, but also from the additional arrangement of the crossbars 9, which have a diameter of 4 mrn in the embodiment. In this manner, each lamella-like rod 4 is held by seven welding spots.
The anode is simple in construction, relatively inexpensive to produce on account of the smallest pos-sible amount of material, and has a very large geometrical surfaee. Without the current supply rail 3, it weighs about 12 kg. The total surface of the rods FA, to which the coating is applied, is about 3 m , inclusive of the contaets. The working surface of the anode, i.e. that which immerses in the electrolyte, is about 2.4 m2, which provides at 600 A a DA value (anodic current density) of about 250 A/m (FA~. The actual physical anode current density which results from the extremely large BET surfaee of the eoating amounts to only a few 5%o of the DA value.
Therefrom, and from the catalytic effectivity of the active components of the eoating, a constant, low oxygen voltage results at the anode according to the invention for a long period of operation.
The coating of the anode surface which projects from the bath serves for the protection against corrosion of the component parts of the anode consisting of titanium.
3S The relatively small current load of the current `.~
3~3 supply rail 3 consistincJ of copper of abou-t 0.8 A/mm with a current of 600 A at the anode permits the pro-vision of nine bores 3a in the current supply rail 3 over a length LG of 852 mm. Each bore 6a in the con-necting strip 6 has an individual current of about 33 A.On account of this small individual current in the con-tact zones and the good contact coating, the voltage drop in these regions remains constant for long periods of operation.
-; ; s:, .
In this respect, the successive crossbars 9 are arranged alternatively on the one or the other side oE the arrange-ment plane of the rods 4.
With the described construction, the rods 4 have a 35 length LS of 1170 mm, whereas their width B is 2 mm and .
-10~
their depth T l2 mm. The clear dis-tance A between two adjacent rods 4 is 8 mm. The entire length LG of the anode structure is 852 mm. 82 rods are provided.
The described anode is designed for a current of 600 A corresponding with an anode-side current density of 355 A/m (Fp). With a current of 600 A, merely an IR
drop of about 100 rnV occurs in the anode.
The anode construction is stiff and robust. This results not only from the described connection of the rods 4 with the current supply rail 3 by means of the connecting strips 6 and from the spot welding of the rods with these connecting strips 6, but also from the additional arrangement of the crossbars 9, which have a diameter of 4 mrn in the embodiment. In this manner, each lamella-like rod 4 is held by seven welding spots.
The anode is simple in construction, relatively inexpensive to produce on account of the smallest pos-sible amount of material, and has a very large geometrical surfaee. Without the current supply rail 3, it weighs about 12 kg. The total surface of the rods FA, to which the coating is applied, is about 3 m , inclusive of the contaets. The working surface of the anode, i.e. that which immerses in the electrolyte, is about 2.4 m2, which provides at 600 A a DA value (anodic current density) of about 250 A/m (FA~. The actual physical anode current density which results from the extremely large BET surfaee of the eoating amounts to only a few 5%o of the DA value.
Therefrom, and from the catalytic effectivity of the active components of the eoating, a constant, low oxygen voltage results at the anode according to the invention for a long period of operation.
The coating of the anode surface which projects from the bath serves for the protection against corrosion of the component parts of the anode consisting of titanium.
3S The relatively small current load of the current `.~
3~3 supply rail 3 consistincJ of copper of abou-t 0.8 A/mm with a current of 600 A at the anode permits the pro-vision of nine bores 3a in the current supply rail 3 over a length LG of 852 mm. Each bore 6a in the con-necting strip 6 has an individual current of about 33 A.On account of this small individual current in the con-tact zones and the good contact coating, the voltage drop in these regions remains constant for long periods of operation.
-; ; s:, .
Claims (16)
1. A coated metal anode for the electrolytic recovery of metals, the working surface of which is represented by rods which are arranged in a plane in spaced, parallel relationship to each other, and which are electrically connected to a current supply rail, wherein: said rods lie in a plane with the current supply rail, so as to create a substantially planar rectangular, surface for the anode; said rods are connected to said current supply rail at one end face; both the electrical and mechanical connection of each rod with said current supply rail takes place by means of at least one connecting strip extending parallel to said rods; one marginal region of said connecting strip is connected with said current supply rail and another marginal region is connected with said rods; and the total surface area of all the rods FA and the surface area Fp assumed by the total arrangement of all the rods fulfills the relation-ship 6 ? FA / Fp ? 2.
2. The anode according to claim 1, wherein said rods have a substantially rectangular cross-section and are arranged in such a manner that the larger dimension of the cross-section of said rods extends perpendicular to the arrangement plane assumed by said rods.
3. The anode according to claim 2, wherein the ratio of the short side of the rectangular cross-section of said rods to the long side thereof is 1 : 2 to 1 : 10.
4. The anode according to claims 2 and 3, wherein the width of said rods, measured parallel to-the arrange-ment plane, is about 0.5 mm to about 2.5 mm.
5. The anode according to claim 1, wherein the depth of said rods, measured perpendicular to the anode plane, is about 5 mm to 25 mm.
6. The anode according to claim 1, wherein the ratio of the width of each of said rods to the center to center distance between two adjacent rods is 1:4 to 1:6.
7. The anode according to claim 1, wherein the clear distance A between two adjacent rods is A ? 2 mm.
8. The anode according to claim 1, wherein on each side of said current supply rail or said rods, respectively, one connecting strip is respectively arranged.
9. The anode according to claim 1, wherein said connecting strip is secured to said current supply rail by screw connections.
10. The anode according to claim 9, wherein the contact area between said connecting strip or strips and said current supply rail is selected to be so large that the reduction of the contact area caused by the bores of said screw connection has no substantial effect on the current density or current load, respectively, in said contact area.
11. The anode according to claim 1, wherein said rods are secured to said at least one connecting strip by means of spot-welding.
12. The anode according to claim 1, wherein said rods are connected together by at least one crossbar.
13. The anode according to claim 12, wherein successive crossbars are arranged alternately on respective sides of said rods.
14. The anode according to claim 12, wherein said at least one crossbar is secured to said rods by spot-welding.
15. The anode according to claim 1, wherein said rods have cores formed of valve metal, and coatings selec-ted from the group consisting of platinum, platinum oxide, an electrically conductive non-stoichiometric oxide, a base metal, a base metal oxide and mixtures of at least two of the above substances.
16. The anode according to claim 15, wherein said valve metal is titanium.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3005795.5 | 1980-02-15 | ||
| DE3005795A DE3005795C2 (en) | 1980-02-15 | 1980-02-15 | Coated metal anode for the electrolytic extraction of metals |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1187838A true CA1187838A (en) | 1985-05-28 |
Family
ID=6094754
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000370725A Expired CA1187838A (en) | 1980-02-15 | 1981-02-12 | Coated metal anode for the electrolytic recovery of metals |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS56127786A (en) |
| BE (1) | BE887491A (en) |
| CA (1) | CA1187838A (en) |
| DE (1) | DE3005795C2 (en) |
| FR (1) | FR2476150B1 (en) |
| SU (1) | SU1069633A3 (en) |
| ZA (1) | ZA81622B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9920443B2 (en) | 2010-12-23 | 2018-03-20 | Ge-Hitachi Nuclear Energy Americas Llc | Modular cathode assemblies and methods of using the same for electrochemical reduction |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3406823C2 (en) * | 1984-02-24 | 1985-12-19 | Conradty GmbH & Co Metallelektroden KG, 8505 Röthenbach | Coated valve metal anode for the electrolytic extraction of metals or metal oxides |
| DE3406777C2 (en) * | 1984-02-24 | 1985-12-19 | Conradty GmbH & Co Metallelektroden KG, 8505 Röthenbach | Coated valve metal anode for the electrolytic extraction of metals or metal oxides |
| JP2007312941A (en) * | 2006-05-24 | 2007-12-06 | Heiwa Corp | Prize-winning part of pachinko game machine |
| US8956524B2 (en) * | 2010-12-23 | 2015-02-17 | Ge-Hitachi Nuclear Energy Americas Llc | Modular anode assemblies and methods of using the same for electrochemical reduction |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE478511C (en) * | 1928-03-07 | 1929-06-27 | Siemens & Halske Akt Ges | Method and device for obtaining deposition products with the same physical properties in electrochemical processes |
| IT978581B (en) * | 1973-01-29 | 1974-09-20 | Oronzio De Nora Impianti | METALLIC ANODES WITH REDUCED ANODIC SURFACE FOR ELECTROLYSIS PROCESSES USING LOW DENSITY OF CATHODIC CURRENT |
| DE2313683C3 (en) * | 1973-03-20 | 1982-05-06 | Union Rheinische Braunkohlen Kraftstoff AG, 5000 Köln | Electrolytic cell |
| US4022679A (en) * | 1973-05-10 | 1977-05-10 | C. Conradty | Coated titanium anode for amalgam heavy duty cells |
| US4013525A (en) * | 1973-09-24 | 1977-03-22 | Imperial Chemical Industries Limited | Electrolytic cells |
-
1980
- 1980-02-15 DE DE3005795A patent/DE3005795C2/en not_active Expired
-
1981
- 1981-01-29 ZA ZA00810622A patent/ZA81622B/en unknown
- 1981-02-12 BE BE0/203774A patent/BE887491A/en unknown
- 1981-02-12 CA CA000370725A patent/CA1187838A/en not_active Expired
- 1981-02-13 JP JP2003281A patent/JPS56127786A/en active Pending
- 1981-02-13 SU SU813244705A patent/SU1069633A3/en active
- 1981-02-13 FR FR8102804A patent/FR2476150B1/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9920443B2 (en) | 2010-12-23 | 2018-03-20 | Ge-Hitachi Nuclear Energy Americas Llc | Modular cathode assemblies and methods of using the same for electrochemical reduction |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2476150A1 (en) | 1981-08-21 |
| DE3005795A1 (en) | 1981-08-20 |
| SU1069633A3 (en) | 1984-01-23 |
| ZA81622B (en) | 1982-03-31 |
| JPS56127786A (en) | 1981-10-06 |
| DE3005795C2 (en) | 1984-12-06 |
| BE887491A (en) | 1981-06-01 |
| FR2476150B1 (en) | 1985-09-27 |
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