Methods and apparatus for cathode plate production

Abstract

The present invention relates to electrolytic recovery of metal, and in particular methods and apparatus for producing cathode plates suitable for such electrolytic recovery. A first aspect of the invention provides a method of providing an electrically conductive coating on a cathode plate comprising inverting and submerging an upper portion of the cathode plate in an electrolytic bath adjacent at least one anode and applying a current to electroplate the upper portion of the cathode plate wherein each anode includes: i) a first base portion adapted to be positioned adjacent to a hanger bar of said cathode plate; ii) a second extended portion connected to and extending from the base portion and adapted to be positioned adjacent a blade of the cathode plate wherein the profile of each anode is shaped such that in use, a consistent thickness of coating is electroplated over said hanger bar and cathode blade. A second aspect of the invention provides an anode for use in an electroplating and upper portion of a cathode plate having a hanger bar and cathode blade, said anode comprising: i)a first exposed base portion being longer than said hanger bar and having a constant cross sectional profile over its length; ii) a second exposed portion connected to and extending from said first base portion and being shorter in length than the width of the cathode blade. A third aspect of the invention provides a process for refurbishing a cathode plate comprising following a process of removal of an electrically conductive coating on the hanger bar and cathode plate, applying a current density to the cathode plate in a deplating bath at a level sufficient to etch the exposed metal below the solution line of the deplating bath, but insufficient to preferentially attack any weld connection between the hanger bar and the cathode blade.

1 - 7 . (canceled) 
     
     
         8 . An anode for use in an electroplating and an upper portion of a cathode plate having a hanger bar and cathode blade, said anode comprising:
 i). a first exposed base portion being longer than said hanger bar and having a constant cross sectional profile over its length;   ii) a second exposed portion connected to and extending from said base portion and being shorter in length than the width of the cathode blade.   
     
     
         9 . An anode as claimed in  claim 8  wherein, in use, the second portion extends in a plane from the first base portion parallel to the plane of the cathode blade. 
     
     
         10 . An anode as claimed in  claim 8  wherein, in use, the ends of the second exposed portion terminate short of the side edges of the cathode blade. 
     
     
         11 . An anode as claimed in  claim 8  wherein, in use, the ends of the first base portion extend past the free ends of the hanger bar. 
     
     
         12 . An anode as claimed in  claim 8  wherein the anode is of constant cross-section throughout its length, one or more shrouds being positioned on the anode to at least partially cover the anode, and thereby selectively alter the exposed area of the first and/or second portions of the anode along its length. 
     
     
         13 . An anode as claimed in  claim 8  wherein the cross-sectional profile of the second exposed portion is altered along its length such that the quantity of second portion of the anode adjacent to areas on the cathode blade or hanger bar where electrically conductive coating is desired is greater than areas where little or no coating is desired. 
     
     
         14 . An anode as claimed in  claim 8  wherein the first base portion extends 10 to 40 mm passed the free ends of the hanger bar. 
     
     
         15 . An anode as claimed in  claims 8  wherein the second portion terminates 10 to 40 mm short of the side edges of the cathode blade. 
     
     
         16 . An anode as claimed in  claim 8  further comprising acid mist and/or bubble suppression media over the anode to reduce the quantity of mist liberated from the electroplating cell and/or decreasing the quantity of air bubbles reaching the cathode plate. 
     
     
         17 . A process for refurbishing a cathode plate comprising following a process of removal of an electrically conductive coating on the hanger bar and cathode plate, applying a current density to the cathode plate in a deplating bath at a level sufficient to etch the exposed metal below the solution line of the deplating bath, but insufficient to preferentially attack any weld connection between the hanger bar and the cathode blade. 
     
     
         18 . A process as claimed in  claim 17  wherein the electrically conductive coating on a hanger bar and/or cathode plate is at least partially removed by electrolytic deplating, and the etching is accomplished by application of a current to the cathode plate in the electrolytic bath. 
     
     
         19 . A process as claimed in  claim 17  further comprising following etching of the exposed material, an electrically conductive coating is applied to the cathode plate according to the method as claimed in claim  1 . 
     
     
         20 - 22 . (canceled)