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

Definitions

• the means relates to a method of manufacturing an electrically conductive plate, provided with a protection device, which plate finds particular application as a cathode for the refining of metals.
• an electrolytic cell containing the material in the form of an ionic solution, at least one conductive plate is immersed which is polarized and on which plate is formed a deposit obtained by migration of certain ions on the plate.
• a conductive plate has at its upper part means for suspending it in the electrolytic bath, means for allowing its manipulation and means for electrical connection to a current line.
• the plate After a determined electrolysis time, the plate is covered on both sides with a layer of electrolysed material.
• the layers of material are recovered by detaching these layers.
• the device for protecting the plate comprises at least one of the protective elements which are, on the one hand, a protective element, hereinafter called a strip made of an electrically insulating material, possibly split in several sections lining at least the side edges of the plate and which prevents the deposition of material on the edges and, therefore, the connection by a material bridge of the layers of material deposited on both sides and, on the other hand , at least one other protective element below called insert made of an insulating material, housed in the thickness of the plate, in a predetermined area of this plate which generally is located in the upper part of this plate and will be partially covered by the layer of material to allow priming peeling off said layer of material using a generally wedge-shaped tool.
• a protective element hereinafter called a strip made of an electrically insulating material, possibly split in several sections lining at least the side edges of the plate and which prevents the deposition of material on the edges and, therefore, the connection by a material bridge of the layers of material deposited on both sides and, on the other hand
• this second protective element called insert facilitates the insertion of the tool behind the layer of material and prevents the said tool from damaging or scratching the conductive plate which would then be unusable.
• This connection must, on the one hand, be watertight to prevent the formation of material deposits between the plate and the protective element and, on the other hand, be sufficiently resistant mechanically to guarantee good impact resistance in particular during the initiation of detachment.
• the conductive plate is pierced with a plurality of holes and the battens are fixed with plastic rivets.
• Conductive plates having anchors are also known from documents DE-A-3219300 and US-A-
• the insert fixing operations must be carried out by a separate process.
• a zone is determined for each protection element which, when the corresponding element is fixed on the plate, will be covered with said protection element, - in each of the zones thus determined, at least one orifice is pierced through the conductive plate and , then, each protective element is fixed to the conductive plate so that the two parts each adjoining one of the two faces of the plate are interconnected by bridges of material passing through the aforementioned holes and for this,
• two main half-molds are constituted, each comprising at least indirectly means for positioning the plate as well as at least in a predetermined location to correspond on the plate to the areas which will be covered by the protective element at least one molding half-shell and,
• the said protective element is molded onto the plate, which is why:. the two half-molds are moved aside, the conductive plate is positioned between the half-molds,
• One of the results which the invention aims to obtain is a method of manufacturing a conductive plate of the aforementioned type which overcomes in particular the problems mentioned above.
• FIG. 1 a front view of a conductive plate
• FIG. 2 a section along II-II of FIG. 1,
• - Figure 4 a simplified view of the means for implementing the method
• - Figure 5 a view of a detail of the unfinished plate.
• the conductive plate 1 used for refining a material such as zinc, has, conventionally, the shape of a rectangular parallelepiped and has in its upper part means 2 for its suspension in an electrolytic cell, its manipulation and its electrical connection in order to polarize it.
• This conductive plate is provided with a protection device.
• This protective device consists of at least one of the protective elements (4, 5) that are on the one hand, a protective element (4), hereinafter called a strip made of an electrically insulating material, possibly split in several sections lining at least the side edges of the plate and which prevents the deposition of material on the edges and, therefore, the connection by a material bridge of the layers of material deposited on both sides and, on the other hand , at least one other protective element (5) hereinafter called an insert consisting of an insulating material, housed in the thickness of the plate, in a predetermined area of this plate which generally is located in the upper part of this plate and will be partially covered by the layer of material to allow to initiate the detachment of said layer of material using a generally wedge-shaped tool.
• the insert is housed in the plate so that the visible faces 6 of this insert are coplanar with the two faces 7 of the plate.
• a zone 8, 9, 10 is determined for each protection element which, when the corresponding protection element is fixed to the plate, will be covered with said protection element, which zones are called lateral 8 , 9 for the battens and upper 10 for the insert,
• Each protective element 4, 5 is fixed on the conductive plate 1 so that the parts of the protective element adjoining the faces of the plate are interconnected by members 4a, 5a fitting into the aforementioned holes.
• the material constituting the batten is different from that used for the insert but, in all cases, the material used for the manufacture of the protective elements is electrically insulating and chemically resistant to the ionic solution.
• the conductive plate is made of aluminum but its composition may be different, in particular in the case of any other type of metal production by electrolytic deposition.
• the conductive plate is made of aluminum but its composition may be different, in particular in the case of any other type of metal production by electrolytic deposition.
• two main half-molds 11, 12 are constituted, each comprising at least indirectly means for positioning the plate as well as at least at a predetermined location to correspond on the plate to the zones which will be covered by the protective element at least one half-shell 13, 14 of molding and, - said protective element is molded on the plate, which is why:
• thermoplastic material is injected,. the thermoplastic material is at least partially cooled,
• the insert and / or the battens are therefore produced by the injection molding technique. According to the invention:
• thermoplastic material specific to the corresponding protective element is injected into each half-shell by controlling for each injection point at least the injection speed, the pressure and the temperature of the injected material.
• the closing pressure is adapted for each group of half-shells.
• the material intended for producing the insert is injected at low speed and under low pressure to avoid, on the one hand, the deformation of the core and, on the other hand, the appearance of grooming at the periphery.
• the material intended for the insert is injected into the center of the corresponding half-shell and, in order to tend towards an equal distribution of the material over the entire surface of the insert, the holes drilled in the core are distributed according to a size going decreasing towards the outside.
• a central hole 17a is produced in the core and around it, distributed over at least one circle, a series of peripheral holes 17b of smaller diameters than the central hole 17a.
• edges of the counterbore in which the insert is housed are chamfered.
• the means for implementing the method include: - two half-molds 11, 12, each comprising means for positioning the plate and as many half-shells 13, 14 as there are protective elements 4, 5 to realize, means 19 for controlling the closing pressure of each group of half-shells.
• the means further comprise at least two independent injection groups with their means for controlling the injection speed, pressure and temperature.
• each injection nozzle of each injection group is connected to each injection point of the half-shells by a thermoregulated hot channel 21.
• At least the half-shells for the overmolding of the battens have a lip 30 which extends slightly outside the volume which will be filled with the molding material, which lips under the effect of the closing pressure penetrate slightly. in the conductive plate and thus avoid, on the one hand, having to rectify the plate before molding and, on the other hand, the cloth of the material.
• the conductive plate thus obtained is remarkable in that the protective elements are molded onto the plate which, in the covered areas, has holes for anchoring the material.
• the insert it is further characterized in that it is provided in a predetermined area with two counterbores 15 each accommodating a fraction of the insert and the depth of which preserves a core 16 whose thickness is sufficient to provide mechanical rigidity to the mechanical stresses usually exerted by a wedge-shaped tool.
• the core is traversed by a central hole 17a and comprises a plurality of other holes 17b which, distributed over the entire section, are of decreasing size going towards the outside .
• the edges of the counterbore housing the insert has a chamfer 24.
• this chamfer increases the seal at the insert when the material is removed during cooling.
• the orifices of the core are distributed at a predetermined angular pitch and, for example, are distributed in two concentric circles at an angular pitch of 45 °, the orifices of a circle being angularly offset about 22 ° 5 compared to those of the other circle.
• the area of material preserved from the core is greater than the sum of the areas of the cutouts.
• the depth of the counterbore is two millimeters
• - the thickness of the core is three millimeters
• the central hole is twenty millimeters in diameter
• thermoplastic used for the insert is preferably polypropylene loaded with 30% glass fiber.
• thermoplastic used for the battens is, for example, an unfilled polypropylene.
• the use of a bi-injection machine allows the complete covering of a cathode to be carried out in a single operation
• the use of a dimensioned hydraulic closing machine makes it possible to use the cathode as an insert and to ensure an adjustable and constant locking force in order to respond to variations in thickness and small surface irregularities of the cathode as well as to control any creep of the aluminum plate used as an insert
• thermoplastic injection process makes it possible to apply the material very intimately on the aluminum plate in order to avoid infiltration of zinc during electrolysis which have the effect of tearing off the battens and the protective insert over time; moreover, the molding operation makes it possible to follow all the surface irregularities and to drown the hanging holes by making them integral with the batten,
• the injection process does not require precise machining in the bores determining the protective insert as well as for the perforated holes ensuring the good behavior of the battens
• the injection process also makes it possible to choose different thermoplastics of low density, charged or uncharged, colored or non-colored, - the injection process gives a lifetime of the thermoplastic equipment close to that of the cathode with as benefits :

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Engineering & Computer Science (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)
• Battery Electrode And Active Subsutance (AREA)
• Electrolytic Production Of Metals (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Laminated Bodies (AREA)
• Secondary Cells (AREA)
• Nitrogen And Oxygen Or Sulfur-Condensed Heterocyclic Ring Systems (AREA)
• Thermistors And Varistors (AREA)
• Superconductors And Manufacturing Methods Therefor (AREA)
• Reinforced Plastic Materials (AREA)
• Chemically Coating (AREA)
• Manufacturing Of Printed Wiring (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=9433530

Family Applications (1)

Country Status (10)

Families Citing this family (2)

Family Cites Families (3)

• 1992
  • 1992-09-08 FR FR9210998A patent/FR2695411B1/fr not_active Expired - Fee Related
• 1993
  • 1993-08-16 KR KR1019940701483A patent/KR100199222B1/ko not_active Expired - Fee Related
  • 1993-08-16 ES ES93919387T patent/ES2114067T3/es not_active Expired - Lifetime
  • 1993-08-16 DE DE69316582T patent/DE69316582T2/de not_active Expired - Fee Related
  • 1993-08-16 JP JP6506923A patent/JP2821816B2/ja not_active Expired - Lifetime
  • 1993-08-16 EP EP93919387A patent/EP0611402B1/de not_active Expired - Lifetime
  • 1993-08-16 AU AU49639/93A patent/AU4963993A/en not_active Abandoned
  • 1993-08-16 WO PCT/FR1993/000812 patent/WO1994005833A1/fr not_active Ceased
  • 1993-08-16 AT AT93919387T patent/ATE162558T1/de not_active IP Right Cessation
• 1994
  • 1994-05-06 FI FI942121A patent/FI101982B/fi active

Non-Patent Citations (1)

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