EP0611838A1 - Apparatus for the electrolytic recovery of silver - Google Patents
Apparatus for the electrolytic recovery of silver Download PDFInfo
- Publication number
- EP0611838A1 EP0611838A1 EP94200310A EP94200310A EP0611838A1 EP 0611838 A1 EP0611838 A1 EP 0611838A1 EP 94200310 A EP94200310 A EP 94200310A EP 94200310 A EP94200310 A EP 94200310A EP 0611838 A1 EP0611838 A1 EP 0611838A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cathode
- cell
- contact surface
- electrolytic cell
- anode
- 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.)
- Granted
Links
Images
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
Definitions
- the present invention relates to an apparatus for the electrolytic recovery of silver from solutions containing silver, in particular used photographic solutions such as fixing and bleach-fixing solutions.
- Electrolytic silver recovery from used photographic solutions is a common way to extend the life of such solutions.
- An apparatus is known from German patent specification DE 4007906-C1 (Kodak AG) for the electrolytic recovery of silver from solutions containing silver, the apparatus comprising an electrolytic cell, an anode and a removable cathode positioned within the cell and encircling the anode and electrical connectors outside the cell for the cathode and the anode.
- the cell includes an electrically conductive contact surface which defines an aperture in the side of the cell.
- the cathode is in the form of a graphite foil carried on a backing of polymeric material.
- Clamping means in the form of a bolt pass through the aperture and through a hole in the cathode to clamp the cathode against the contact surface to complete an electrical connection from the cathode to the cathode connector.
- the cathode electrical connection is of vital importance since the electrode is the basis for the cathodic reactions which are most important in a de-silvering apparatus.
- the electrical connection should make sure that enough current can flow to the cathode, without causing a significant ohmic voltage drop between the cathode connector and the cathode itself.
- the reason for this is that the controlling of the current is usually done by means of the potential on this cathode as one pole and a reference electrode or the anode as the other pole.
- the potential on the cathode is in the range of some hundred millivolts and should be measured with fair accuracy.
- the potential between the cathode and the reference electrode is about 400mV.
- the potential should be measured with an accuracy of some millivolts.
- any ohmic resistance between the cathode and the electrical current supply will cause a measurement fault.
- the arrangement disclosed in DE 4007906 may provide a secure electrical connection between the cathode and its exterior connector, the contact surface is small and in use lies below the level of the electrolyte in the cell. This may lead to leakage if the bolt is not tightened sufficiently or to damage to the cathode if it is over-tightened. In any case, contact between the contact surface and the electrolyte may result in corrosion of the contact surface and ultimate build-up of the electrical resistance therein.
- a further electrolytic recovery apparatus with removable cathode is disclosed in US-A-3,985,634.
- the electrical contact with the cathode is established through a conductor which enters with a lip in sliding contact with the upper edge of a cylindrical cathode as the lid of the apparatus is clamped on the housing.
- Reliable electrical contact is obtained by a tab and corresponding screw that apply extra pressure on the contact place of lip with cathode edge.
- This construction has the same disadvantage as the apparatus described hereinbefore, namely an electrical contact with limited contact surface. Also the protruding tab of the lid is vulnerable and the presence of an electrical connection on the lid reduces the convenience of manipulation.
- Still another recovery apparatus is disclosed in CH-A-647,005. Electrical contact with a cylindrical removable cathode occurs through elastic fingers protruding from the lid of the apparatus. The contact surface is limited and deformation of the contact fingers by uncareful manipulation of the lid may impede the successful use on the long run.
- an apparatus for the electrolytic recovery of silver from solutions containing silver comprising an electrolytic cell, an anode and a removable cathode positioned within the cell and encircling the anode and electrical connectors outside the cell for the cathode and the anode, the cell including an electrically conductive contact surface, clamping means being provided to clamp a deformable portion of the cathode against the contact surface to complete an electrical connection from the cathode connector to the cathode, is characterised thereby that the electrically conductive contact surface is positioned to define an upper circular opening of the electrolytic cell through which the cathode may be removed, and that the clamping means comprises a removable lid for closing said circular upper opening of the electrolytic cell, the lid having a frusto-conical lower end engaging the upper edge of the cathode for clamping it against the electrically conductive contact surface.
- the provision of the contact surface in an upper part of the electrolytic cell enables this surface to be above the level of the electrolyte in the cell in use, thus reducing the risk of leakage and corrosion.
- the upper opening has a dimension which is sufficient to enable the removal of the cathode from the cell.
- the clamping means for clamping the deformable portion of the cathode to the contact surface may comprise a removable lid for closing the circular upper opening of the electrolytic cell.
- a removable lid for closing the circular upper opening of the electrolytic cell.
- the lid and the electrolytic cell may be provided with cooperating screw-threaded portions.
- the deformable portion of the cathode is deformed to the extent necessary to press it firmly against the contact surface where it is held securely by pressure from the clamping surface of the lid.
- a seal may be provided between the lid and the electrolytic cell in the vicinity of the opening to prevent leakage of the electrolyte from the cell, that is to maintain an air space above the surface of the electrolyte, the contact surface being located in this air space.
- the cathode is preferably in sheet form and ideally has a frusto-conical cross-section, with its larger radius end uppermost, that is towards the circular upper opening of the electrolyte cell. This configuration enables easy removal of the cathode even after a silver deposit has built up there-on after use.
- the upper, larger radius of the frusto-conical cathode preferably corresponds closely to the inner radius of the contact surface.
- Usable cathode materials include stainless steel, silver and silver alloys, the non-silver containing materials being preferred from the point of view of costs, while the silver containing materials cause fewer starting-up problems.
- the deformable portion of the cathode may be elastically or non-elastically deformable.
- the cathode is in sheet form and the deformable portion is comprised by a castellated upper edge of the cathode. This may be achieved by providing a number of longitudinal incisions extending from the upper edge of the cathode, defining between them a number of tabs which can be bent outwardly by the clamping means to lie against the contact surface.
- the electrolytic cell is suitably formed of electrically non-conductive material and may be generally cylindrical, although other shapes are possible. A cylindrical shape to the cell enables the cathode to be positioned near to the wall of the cell.
- the cell will be provided with inlet and outlet ports for the electrolyte liquid.
- the electrolytic cell further comprises a reference electrode.
- a reference electrode may conveniently be positioned adjacent the outlet port of the cell.
- the reference electrode may be a calomel type electrode or an Ag/AgCl type electrode.
- a suitable electrode has been disclosed in our co-pending application EP 92203439.2 filed 11 November 1992 and entitled "pH Sensitive Reference Electrode in Electrolytic Desilvering".
- the contact surface is formed by a steel ring connected to the cathode connector. This connection should be a permanent connection. Usually the anode will be permanently connected to the exterior anode connector.
- the material used for the anode is less critical, although platinated titanium is usually used.
- the anode may be in the form of a rod, located at the axis of the electrolytic cell, where this is in cylindrical form. In any case, the anode is encircled by the cathode.
- the apparatus comprises an electrolytic cell 10, formed of electrically non-conductive material such as PVC, and comprising a base 15, sides 16 and an upper portion 17.
- An electrolyte inlet port 18 is provided towards the bottom of the cell and an electrolyte outlet port 19 is provided towards the top of the cell.
- An anode 20, in the form of a platinised titanium rod, is secured to the base of the cell by means of a bolt 21 which acts as an electrical connector for the anode.
- a reference electrode 50 protrudes into the outlet port 19 of the cell.
- the upper part 17 of the cell is in the form of a neck portion having an opening 12 defined by a stainless steel ring 22 having an inwardly directed annular contact surface 11.
- the contact surface 11 is frusto-conically shaped, having its narrower radius downwards.
- the stainless steel ring 22 is permanently fixed to one end of a bolt 31 which extends through the wall of the cell and provides a connector for the cathode 30.
- a sealing ring 14 Positioned in the neck of the cell, below the level of the annular ring 22, is a sealing ring 14.
- the apparatus further comprises a lid 40 so shaped as to fit into the neck portion of the cell.
- the lid 40 is formed of electrically non-conductive material such as PVC.
- the lower portion of the lid 40 has a frusto-conically shaped clamping surface 42, shaped to correspond to the shape of the annular contact surface 11.
- the upper part of the lid 40 has a thread 41 which engages with a thread 13 in the neck portion of the cell.
- the cathode 30, formed for example of stainless steel sheet having a thickness of 100 ⁇ m, is wrapped around into a frusto-conical configuration.
- the upper radius R1 is marginally larger than the lower radius R2 by a factor of 1.05.
- Castellations 33 are formed at the upper edge of the cathode by the provision of incisions 34 extending longitudinally away from that edge.
- the castellations or tabs 33 together form a deformable upper edge portion 32 of the cathode, the sheet material of which the cathode is formed being sufficiently resilient to allow the castellations to bend outwardly in response to outwardly directed force.
- the cathode 30 is located in the cell 10 with its bottom edge supported by a cathode support ledge 35 in the cell. In this position the deformable upper edge portion 32 of the cathode lies adjacent the stainless steel ring 22.
- the frusto-conical contact surface 42 on the lid bears against the castellations 33 of the cathode 30, causing these castellations to bend outwardly against the annular surface 11 of the ring 22. Tightening of the lid caused the castellations to be clamped firmly by the lid against the annular contact surface 11, thereby establishing good electrical contact there-between.
- the sealing ring 14 bears against the outer surface of the lid 40, thereby forming a tight seal.
- Electrolyte liquid is now fed into the cell by way of the inlet port 18, fills the cell and exits by way of the outlet port 19.
- the effect of the sealing ring 14 is to prevent the electrolyte level rising above the level of the outlet port 19, so maintaining an air space above the liquid and preventing contact between the liquid and the annular contact surface 11. The risk of corrosion of the latter is thereby reduced.
- the cell is then operated under usual conditions, during which a silver deposit builds up on the cathode 30, primarily on the inside surface thereof. After a period of time determined by the required amount of deposited silver, the operator unscrews the lid 40 and lifts the cathode 30 out of the cell. Due to the frusto-conical cross-section of the cathode, the sides of the cathode will not foul against the ring 22, even when some small amount of silver deposit has built up on the outside surface thereof. The silver deposit is then removed from the cathode, which may then be re-used as desired or replaced by another of similar construction for the de-silvering of a further batch of electrolyte.
Landscapes
- 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)
Abstract
Description
- The present invention relates to an apparatus for the electrolytic recovery of silver from solutions containing silver, in particular used photographic solutions such as fixing and bleach-fixing solutions.
- Electrolytic silver recovery from used photographic solutions is a common way to extend the life of such solutions. An apparatus is known from German patent specification DE 4007906-C1 (Kodak AG) for the electrolytic recovery of silver from solutions containing silver, the apparatus comprising an electrolytic cell, an anode and a removable cathode positioned within the cell and encircling the anode and electrical connectors outside the cell for the cathode and the anode. In this apparatus the cell includes an electrically conductive contact surface which defines an aperture in the side of the cell. The cathode is in the form of a graphite foil carried on a backing of polymeric material. Clamping means in the form of a bolt pass through the aperture and through a hole in the cathode to clamp the cathode against the contact surface to complete an electrical connection from the cathode to the cathode connector.
- In an electrolytic cell, the cathode electrical connection is of vital importance since the electrode is the basis for the cathodic reactions which are most important in a de-silvering apparatus. The electrical connection should make sure that enough current can flow to the cathode, without causing a significant ohmic voltage drop between the cathode connector and the cathode itself. The reason for this is that the controlling of the current is usually done by means of the potential on this cathode as one pole and a reference electrode or the anode as the other pole. The potential on the cathode is in the range of some hundred millivolts and should be measured with fair accuracy.
- For example, where an Ag/AgCl reference electrode is used, the potential between the cathode and the reference electrode is about 400mV. When the unit is to perform optimally, meaning employing the maximum current without causing side reactions to occur, the potential should be measured with an accuracy of some millivolts. As a result any ohmic resistance between the cathode and the electrical current supply will cause a measurement fault. While the arrangement disclosed in DE 4007906 may provide a secure electrical connection between the cathode and its exterior connector, the contact surface is small and in use lies below the level of the electrolyte in the cell. This may lead to leakage if the bolt is not tightened sufficiently or to damage to the cathode if it is over-tightened. In any case, contact between the contact surface and the electrolyte may result in corrosion of the contact surface and ultimate build-up of the electrical resistance therein.
- A further electrolytic recovery apparatus with removable cathode is disclosed in US-A-3,985,634. In this apparatus the electrical contact with the cathode is established through a conductor which enters with a lip in sliding contact with the upper edge of a cylindrical cathode as the lid of the apparatus is clamped on the housing. Reliable electrical contact is obtained by a tab and corresponding screw that apply extra pressure on the contact place of lip with cathode edge. This construction has the same disadvantage as the apparatus described hereinbefore, namely an electrical contact with limited contact surface. Also the protruding tab of the lid is vulnerable and the presence of an electrical connection on the lid reduces the convenience of manipulation.
- Still another recovery apparatus is disclosed in CH-A-647,005. Electrical contact with a cylindrical removable cathode occurs through elastic fingers protruding from the lid of the apparatus. The contact surface is limited and deformation of the contact fingers by uncareful manipulation of the lid may impede the successful use on the long run.
- It is an object of the present invention to provide an electrolytic cell in which a secure electrical connection can be assured between the cathode and its exterior connector over a large surface and without the risk of leakage or the build-up of resistive corrosion.
- In accordance with the present invention, an apparatus for the electrolytic recovery of silver from solutions containing silver, the apparatus comprising an electrolytic cell, an anode and a removable cathode positioned within the cell and encircling the anode and electrical connectors outside the cell for the cathode and the anode, the cell including an electrically conductive contact surface, clamping means being provided to clamp a deformable portion of the cathode against the contact surface to complete an electrical connection from the cathode connector to the cathode, is characterised thereby that the electrically conductive contact surface is positioned to define an upper circular opening of the electrolytic cell through which the cathode may be removed, and that the clamping means comprises a removable lid for closing said circular upper opening of the electrolytic cell, the lid having a frusto-conical lower end engaging the upper edge of the cathode for clamping it against the electrically conductive contact surface.
- The provision of the contact surface in an upper part of the electrolytic cell, in particular an annular contact surface, enables this surface to be above the level of the electrolyte in the cell in use, thus reducing the risk of leakage and corrosion. The upper opening has a dimension which is sufficient to enable the removal of the cathode from the cell. By providing the contact surface at this opening, a large contact surface can be assured, reducing the risks of a resistive connection occurring.
- The clamping means for clamping the deformable portion of the cathode to the contact surface may comprise a removable lid for closing the circular upper opening of the electrolytic cell. Thus, as the lid is put securely in place after the insertion of the cathode into the cell, the deformable portion of the cathode is forced against the contact surface. This may be achieved in particular by the lid being provided with a clamping surface, corresponding in shape to the contact surface, so as to clamp the deformable portion of the cathode there-between.
- To firmly secure the lid in the opening of the cell, the lid and the electrolytic cell may be provided with cooperating screw-threaded portions. In this manner, as the lid is screwed into the upper opening, the deformable portion of the cathode is deformed to the extent necessary to press it firmly against the contact surface where it is held securely by pressure from the clamping surface of the lid. A seal may be provided between the lid and the electrolytic cell in the vicinity of the opening to prevent leakage of the electrolyte from the cell, that is to maintain an air space above the surface of the electrolyte, the contact surface being located in this air space.
- The cathode is preferably in sheet form and ideally has a frusto-conical cross-section, with its larger radius end uppermost, that is towards the circular upper opening of the electrolyte cell. This configuration enables easy removal of the cathode even after a silver deposit has built up there-on after use. The upper, larger radius of the frusto-conical cathode preferably corresponds closely to the inner radius of the contact surface. Usable cathode materials include stainless steel, silver and silver alloys, the non-silver containing materials being preferred from the point of view of costs, while the silver containing materials cause fewer starting-up problems.
- The deformable portion of the cathode may be elastically or non-elastically deformable. We prefer that the cathode is in sheet form and the deformable portion is comprised by a castellated upper edge of the cathode. This may be achieved by providing a number of longitudinal incisions extending from the upper edge of the cathode, defining between them a number of tabs which can be bent outwardly by the clamping means to lie against the contact surface.
- The electrolytic cell is suitably formed of electrically non-conductive material and may be generally cylindrical, although other shapes are possible. A cylindrical shape to the cell enables the cathode to be positioned near to the wall of the cell. The cell will be provided with inlet and outlet ports for the electrolyte liquid.
- Usually the electrolytic cell further comprises a reference electrode. This may conveniently be positioned adjacent the outlet port of the cell. The reference electrode may be a calomel type electrode or an Ag/AgCl type electrode. A suitable electrode has been disclosed in our co-pending application EP 92203439.2 filed 11 November 1992 and entitled "pH Sensitive Reference Electrode in Electrolytic Desilvering".
- The contact surface is formed by a steel ring connected to the cathode connector. This connection should be a permanent connection. Usually the anode will be permanently connected to the exterior anode connector.
- The material used for the anode is less critical, although platinated titanium is usually used. The anode may be in the form of a rod, located at the axis of the electrolytic cell, where this is in cylindrical form. In any case, the anode is encircled by the cathode.
- The invention will now be further described, purely by way of example, by reference to the accompanying drawings in which:
- Figure 1 shows, partly in cross-section, an apparatus according to the invention;
- Figure 2 shows, in cross section, the upper part of the electrolytic cell of the apparatus shown in Figure 1;
- Figure 3A is an exploded view of the upper portion of the apparatus shown in Figure 1;
- Figure 3B corresponds to Figure 3A, in the assembled position; and
- Figure 4 is a perspective view of the cathode used in the apparatus shown in Figures 1 to 3.
- As shown in Figure 1, the apparatus comprises an
electrolytic cell 10, formed of electrically non-conductive material such as PVC, and comprising abase 15, sides 16 and anupper portion 17. Anelectrolyte inlet port 18 is provided towards the bottom of the cell and anelectrolyte outlet port 19 is provided towards the top of the cell. - An
anode 20, in the form of a platinised titanium rod, is secured to the base of the cell by means of abolt 21 which acts as an electrical connector for the anode. Areference electrode 50 protrudes into theoutlet port 19 of the cell. - As is shown more clearly in Figure 2, the
upper part 17 of the cell is in the form of a neck portion having anopening 12 defined by astainless steel ring 22 having an inwardly directedannular contact surface 11. Thecontact surface 11 is frusto-conically shaped, having its narrower radius downwards. Thestainless steel ring 22 is permanently fixed to one end of abolt 31 which extends through the wall of the cell and provides a connector for thecathode 30. Positioned in the neck of the cell, below the level of theannular ring 22, is a sealingring 14. - As can seen in Figures 1, 3A and 3B, the apparatus further comprises a
lid 40 so shaped as to fit into the neck portion of the cell. Thelid 40 is formed of electrically non-conductive material such as PVC. The lower portion of thelid 40 has a frusto-conically shaped clampingsurface 42, shaped to correspond to the shape of theannular contact surface 11. The upper part of thelid 40 has athread 41 which engages with athread 13 in the neck portion of the cell. - Referring in particular to Figure 4, the
cathode 30, formed for example of stainless steel sheet having a thickness of 100 µm, is wrapped around into a frusto-conical configuration. The upper radius R₁ is marginally larger than the lower radius R₂ by a factor of 1.05.Castellations 33 are formed at the upper edge of the cathode by the provision ofincisions 34 extending longitudinally away from that edge. The castellations ortabs 33 together form a deformableupper edge portion 32 of the cathode, the sheet material of which the cathode is formed being sufficiently resilient to allow the castellations to bend outwardly in response to outwardly directed force. - The
cathode 30 is located in thecell 10 with its bottom edge supported by acathode support ledge 35 in the cell. In this position the deformableupper edge portion 32 of the cathode lies adjacent thestainless steel ring 22. As the lid is screwed into place, by engagement of thethreads conical contact surface 42 on the lid bears against thecastellations 33 of thecathode 30, causing these castellations to bend outwardly against theannular surface 11 of thering 22. Tightening of the lid caused the castellations to be clamped firmly by the lid against theannular contact surface 11, thereby establishing good electrical contact there-between. - In the closed position of the lid, the sealing
ring 14 bears against the outer surface of thelid 40, thereby forming a tight seal. Electrolyte liquid is now fed into the cell by way of theinlet port 18, fills the cell and exits by way of theoutlet port 19. The effect of the sealingring 14 is to prevent the electrolyte level rising above the level of theoutlet port 19, so maintaining an air space above the liquid and preventing contact between the liquid and theannular contact surface 11. The risk of corrosion of the latter is thereby reduced. - The cell is then operated under usual conditions, during which a silver deposit builds up on the
cathode 30, primarily on the inside surface thereof. After a period of time determined by the required amount of deposited silver, the operator unscrews thelid 40 and lifts thecathode 30 out of the cell. Due to the frusto-conical cross-section of the cathode, the sides of the cathode will not foul against thering 22, even when some small amount of silver deposit has built up on the outside surface thereof. The silver deposit is then removed from the cathode, which may then be re-used as desired or replaced by another of similar construction for the de-silvering of a further batch of electrolyte.
Claims (8)
- An apparatus for the electrolytic recovery of silver from solutions containing silver, the apparatus comprising an electrolytic cell (10), an anode (20) and a removable cathode (30) positioned within the cell (10) and encircling the anode (20) and electrical connectors (21,31) outside the cell (10) for the cathode (30) and the anode (20), the cell (10) including an electrically conductive contact surface (11), clamping means (40) being provided to clamp a deformable portion (32) of the cathode (30) against the contact surface (11) to complete an electrical connection from the cathode connector (31) to the cathode (30), characterised in that the electrically conductive contact surface (11) is positioned to define an upper opening (12) of the electrolytic cell (10) through which the cathode (30) may be removed.
- An apparatus according to claim 1, wherein the clamping means comprises a removable lid (40) for closing the circular upper opening (12) of the electrolytic cell (10).
- An apparatus according to claim 2, wherein the lid (40) and the electrolytic cell (10) are provided with co-operating screw-threaded portions (41, 13).
- An apparatus according to any preceding claim, wherein the cathode (30) has a frusto-conical cross-section, with its larger radius end uppermost, towards the circular opening (12) of the electrolytic cell (10).
- An apparatus according to any preceding claim, wherein the deformable portion of the cathode (30) is comprised by a castellated upper edge thereof.
- An apparatus according to any preceding claim, wherein the electrolytic cell (10) is generally cylindrical.
- An apparatus according to any preceding claim, wherein the electrolytic cell (10) further comprises a reference electrode (50).
- An apparatus according to any preceding claim, wherein the contact surface (11) is formed by a steel ring (22) connected to the cathode connector (31).
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP19940200310 EP0611838B1 (en) | 1993-02-16 | 1994-02-04 | Apparatus for the electrolytic recovery of silver |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP93200427 | 1993-02-16 | ||
EP93200427 | 1993-02-16 | ||
EP19940200310 EP0611838B1 (en) | 1993-02-16 | 1994-02-04 | Apparatus for the electrolytic recovery of silver |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0611838A1 true EP0611838A1 (en) | 1994-08-24 |
EP0611838B1 EP0611838B1 (en) | 1996-10-23 |
Family
ID=26133660
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19940200310 Expired - Lifetime EP0611838B1 (en) | 1993-02-16 | 1994-02-04 | Apparatus for the electrolytic recovery of silver |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP0611838B1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0930380A1 (en) * | 1998-01-15 | 1999-07-21 | Agfa-Gevaert N.V. | Electrolytic cell with removable electrode and its operating method |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3985634A (en) * | 1975-01-27 | 1976-10-12 | Larson Kay R | Electrolytic silver recovery apparatus |
CH647005A5 (en) * | 1980-03-14 | 1984-12-28 | Ladislav Krivanek | Electrolytic unit for the recovery of silver |
US4840717A (en) * | 1988-08-24 | 1989-06-20 | Dzodin Milton A | Silver recovery cell |
-
1994
- 1994-02-04 EP EP19940200310 patent/EP0611838B1/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3985634A (en) * | 1975-01-27 | 1976-10-12 | Larson Kay R | Electrolytic silver recovery apparatus |
CH647005A5 (en) * | 1980-03-14 | 1984-12-28 | Ladislav Krivanek | Electrolytic unit for the recovery of silver |
US4840717A (en) * | 1988-08-24 | 1989-06-20 | Dzodin Milton A | Silver recovery cell |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0930380A1 (en) * | 1998-01-15 | 1999-07-21 | Agfa-Gevaert N.V. | Electrolytic cell with removable electrode and its operating method |
Also Published As
Publication number | Publication date |
---|---|
EP0611838B1 (en) | 1996-10-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
NO169537B (en) | PROCEDURE FOR EXPLOITING C3 + HYDROCARBONES FROM ENGINE FLOW | |
KR890000708B1 (en) | Electrolytic cell of the filter press type | |
US5378340A (en) | Apparatus for the electrolytic recovery of silver | |
KR890010284A (en) | Process for producing electrolyzer and electrolytic products for hypochlorite production. | |
EP0611838B1 (en) | Apparatus for the electrolytic recovery of silver | |
US5454924A (en) | Apparatus for the electrolytic recovery of silver from solutions containing silver | |
JPH09503616A (en) | Electrode connection device for storage battery | |
US6579429B2 (en) | Antifouling system for structure exposed to seawater and heat exchanger | |
EP0611839A1 (en) | Electrode | |
EP3976861B1 (en) | An electrode assembly for electrochemical processes | |
US5135633A (en) | Electrode arrangement for electrolytic processes | |
EP0833963B1 (en) | Diaphragm element for an electrolytic filter press assembly | |
US4072595A (en) | Anode seal assembly for electrolytic cells | |
US3975255A (en) | Inter-electrode spacing in diaphragm cells | |
GR3004171T3 (en) | ||
ES8302121A1 (en) | Method of generating halogen, an electrode-membrane assembly, an electrolytic cell and a semipermeable ion-exchange membrane for said method. | |
US5639362A (en) | Apparatus and method for de-silvering a silver-containing solution | |
US5344541A (en) | Silver recovery device | |
CA1129376A (en) | Electrodes for electrolytic recovery of metals | |
Van de Wynckel et al. | Apparatus for the electrolytic recovery of silver | |
JPH0892782A (en) | Apparatus for electrolytic recovery of silver from solution containing silver | |
SU1191493A1 (en) | Apparatus for hanging anode material in electrochemical solutions | |
JPS5847986Y2 (en) | Cathode electrode attachment/detachment mechanism for cylindrical electrolytic cell | |
JP2764125B2 (en) | Electrolytic apparatus having electrode protection function and electrode protection method | |
JPH0328368Y2 (en) |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): BE DE FR GB NL |
|
17P | Request for examination filed |
Effective date: 19950224 |
|
17Q | First examination report despatched |
Effective date: 19951215 |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): BE DE FR GB NL |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 19961023 Ref country code: BE Effective date: 19961023 |
|
REF | Corresponds to: |
Ref document number: 69400762 Country of ref document: DE Date of ref document: 19961128 |
|
ET | Fr: translation filed | ||
REG | Reference to a national code |
Ref country code: GB Ref legal event code: 746 Effective date: 19970207 |
|
NLV1 | Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act | ||
REG | Reference to a national code |
Ref country code: FR Ref legal event code: D6 |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20021210 Year of fee payment: 10 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20021212 Year of fee payment: 10 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20021216 Year of fee payment: 10 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20040204 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20040901 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20040204 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20041029 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |