Pin assembly of an electrode and method of manufacturing the same

Abstract

Disclosed are a pin assembly for providing current to an electrode, e.g. an inert or oxygen evolving anode, and its manufacturing method. The pin assembly is configured to be inserted into an electrode body of an electrode for providing an electric current to the electrode body. The pin assembly comprises a structural support member configured to mechanically support the electrode body, and a protective conductive member configured to embed the structural support member. The protective conductive member comprises at least one metal or alloy thereof adapted for conducting the electric current while protecting the structural support member against corrosion during a given period of time of use of the electrode. The pin assembly enables convenient electrical connection of the electrodes, combines electrical and thermal performance for optimizing cell efficiency, provides structural and corrosion durability for extending pin assembly life, and utilizes robust joining processes for high reliability.

What is claimed is: 
     
         1 . A pin assembly configured to be inserted into an electrode body of an electrode for providing an electric current to the electrode body, the pin assembly comprising:
 a structural support member configured to mechanically support the electrode body; and   a protective conductive member configured to embed the structural support member, the protective conductive member comprising at least one metal or alloy thereof adapted for conducting the electric current while protecting the structural support member against corrosion during a given period of time of use of the electrode;   wherein the protective conductive member is a tube fitting around the structural support member; and   wherein the tube is a bimetal tube having an upper section comprising a first metal and a lower section comprising a second metal, both first and second metals being conductive of said electric current.   
     
     
         2 . The pin assembly according to  claim 1 , wherein the structural support member is further configured to mechanically support a refractory component of the electrode, and wherein the structural support member comprises titanium, nickel, iron or an alloy thereof. 
     
     
         3 . The pin assembly according to  claim 1 , wherein the first metal of the upper section of the bimetal tube has a lower thermal conductivity than the second metal of the lower section. 
     
     
         4 . The pin assembly according to  claim 1 , wherein:
 the first metal of the bimetal tube comprises titanium, nickel, iron or an alloy thereof; and   the second metal of the bimetal tube comprises at least one of cobalt, copper or an alloy thereof.   
     
     
         5 . The pin assembly according to  claim 1 , wherein the structural support member comprises a pin longitudinally extending from a pin head, the pin being configured for passing through a central orifice of the tube, and wherein the pin head is configured to radially extend beyond an external surface of the lower section of the tube for connecting the pin head to a bottom end of the tube formed by the second metal. 
     
     
         6 . The pin assembly according to  claim 5 , further comprising a metallic form comprising a conductive metal or an alloy thereof, the metallic form comprising a stem longitudinally extending from a bottom end of a cup, wherein the cup is configured for wrapping around the pin head to form an interlocking connection between the form and the pin once the pin is inserted into the tube; and wherein the stem of the form is configured to be inserted into an orifice of the electrode body when the pin assembly is operatively connected to the electrode body, and wherein the cup and the stem of the form are optionally formed as one part. 
     
     
         7 . The pin assembly according to  claim 6 , wherein the metallic form comprises at least one of cobalt, copper or an alloy thereof. 
     
     
         8 . The pin assembly according to  claim 6 , wherein the cup has a circular lateral section with a cup diameter superior than a diameter of the pin head, the form is assembled over the pin head so that the cup extends over of the lower section of the bimetal tube such as to form a radial gap all around the pin head. 
     
     
         9 . The pin assembly according to  claim 6 , wherein the cup has an elliptic-like lateral section defining a major axis and a minor axis, the major axis being larger than a diameter of the pin head, the form is then assembled over the pin head so that the cup extends over of the lower section of the bimetal tube such as to form two opposites gaps between the pin head and the cup along the major axis. 
     
     
         10 . The pin assembly according to  claim 6 , wherein the cup once permanently connected around the pin head forms a shoulder, the electrode body being configured to be supported by the shoulder of the pin assembly when the pin assembly is operatively connected to the electrode. 
     
     
         11 . The pin assembly according to  claim 1 , wherein the protective conductive member is configured to form on its external surface a corrosion product adapted for being mechanically constrained without breaking or fracturing, wherein the constraining material comprises one of the following: sintered aluminum oxide tube, aluminum oxide powder, castable refractory, copper shot, inert anode material, or sintered tin oxide tube. 
     
     
         12 . The pin assembly according to  claim 1 , wherein the electrode is an anode, and wherein the anode is optionally an inert anode or oxygen evolving anode. 
     
     
         13 . An electrode assembly of an electrolytic cell for the production of aluminum, comprising:
 a plurality of electrodes, each of the plurality of electrodes comprising an electrode body connected to a pin assembly, the pin assembly being as defined in  claims 1 ; and   a distribution plate configured for operatively connecting each of the plurality of electrodes via its respective pin assembly for providing an electrical path to the electrodes.   
     
     
         14 . The electrode assembly according to  claim 13 , wherein each of the plurality of electrodes are an anode, wherein the anode are optionally inert or oxygen evolving anodes. 
     
     
         15 . A method for the manufacturing of an electrode comprising an electrode body and a pin assembly configured to be inserted in the electrode body of the electrode for providing an electric current to the electrode body, the method comprising:
 a) providing a structural support member configured to mechanically support the electrode body;   b) embedding the structural support member with a protective conductive member, the protective conductive member comprising at least one metal or alloy thereof adapted for conducting the electric current while protecting the structural support member against corrosion during a given period of time of use of the electrode; and   c) electrically connecting the pin assembly and the electrode body to form the electrode;   
       wherein the protective conductive member is a bimetal tube having an upper section comprising a first metal and a lower section comprising a second metal, both first and second metals being conductive of said electric current, step b) then comprising:
 fitting the bi-metal tube around the structural support member. 
 
     
     
         16 . The method according to  claim 15 , wherein the upper section has a lower thermal conductivity than the lower section, the method further comprising before step b), the step of connecting the upper section and the lower section together by welding. 
     
     
         17 . The method according to  claim 15 , wherein in step a), the structural support member comprises a pin longitudinally extending from a pin head, step b) of the method then comprising:
 passing the pin through a central orifice of the bi-metal tube.   
     
     
         18 . The method according to  claim 17 , wherein the pin head is configured to radially extend beyond an external surface of the lower section of the bi-metal tube, step b) of the method then comprising:
 connecting the pin head to a bottom end of the bi-metal tube formed by the second metal.   
     
     
         19 . The method according to  claim 18 , wherein the pin assembly further comprises a metallic form comprising a conductive metal or an alloy thereof, the metallic form comprising a stem longitudinally extending from a bottom end of a cup, step b) of the method then further comprising:
 wrapping the cup around the pin head to form an interlocking connection between the metallic form and the pin once the pin is inserted into the tube; and   step c) then comprises:
 inserting the stem of the metallic form in an orifice of the electrode body for operatively connecting the pin assembly to the electrode body; 
 wherein the cup and the stem of the metallic form are optionally formed as one part. 
   
     
     
         20 . The method according to  claim 19 , wherein the cup has a circular lateral section with a cup diameter superior than a diameter of the pin head, step b) comprising:
 assembling the metallic form over the pin head so that the cup extends over of the lower section of the bimetal tube in order to form a radial gap all around the pin head, and   permanently connecting the metallic form to the bimetal tube by a metal forming or forging operation of the radial gap; or   
       wherein the cup has an elliptic-like lateral section defining a major axis and a minor axis, the major axis being larger than a diameter of the pin head, step b) comprising:
 assembling the metallic form over the pin head so that the cup extends over of the lower section of the bimetal tube in order to form two opposites gaps between the pin head and the cup along the major axis. 
 
     
     
         21 . The method according to  claim 15 , wherein step c) of electrically connecting the pin assembly to the electrode body comprises:
 installing and aligning in fixture the pin assembly into an orifice of the electrode body;   pouring a first copper shot into the orifice of the electrode body;   optionally, compacting the first copper shot;   pouring castable material into the orifice over the first copper shot; and   allowing castable material to cure.   
     
     
         22 . The method according to  claim 21 , further comprising pouring a second copper shot above the first copper shot, wherein the second copper shot comprises copper particles smaller in size than copper particles of the first copper shot. 
     
     
         23 . The method according to  claim 15 , wherein the electrode is an anode, wherein the anode is optionally an inert anode or oxygen evolving anode.