Method for the electrolytic recovery of metal employing improved electrolyte convection

Abstract

An electrodeposition method in which high quality metal such as copper is produced on a non-retentive cathode blank at a high current density. A predetermined close cathode-anode spacing and a gas bubble tube for continuously agitating the electrolyte across the face of the cathode enable effective use of high current densities to electrowin or electrorefine a metal such as copper. Method includes maintaining anodes apart from cathodes at a predetermined close distance, optimally less than one inch face to face. Bubble tubes are positioned between cathode-anode pairs and are supported by bubble tube support members. For electrowinning, anode is provided with a non-conductive extension on its base and non-conductive convection baffles at opposite edges of its faces. Baffles and extension prevent electrodeposition on unwanted areas of cathode. Baffles, close spacing, and bubble tubes cause desired convection of electrolyte throughout cell. In an electrorefining cell, convection baffles are positioned on vertical support members within the tank.

We claim: 
     
       1. A method of performing electrodeposition at a high ratio of current density to metal ion concentration in a cell which includes anodes, cathodes and an electrolyte with an attendant production of high quality metal which can be easily stripped from the cathodes comprising the following steps: a. positioning non-conductive convection edge baffles adjacent to opposite edges of the anode faces so as to extend toward the cathode faces;   b. positioning non-conductive anode bottom extensions beneath the anodes;   c. providing cathodes that are wider than the anodes so that the edges of the cathodes extend outwardly from the convection edge baffles;   d. submerging the cathodes so that the submerged length of the cathodes are equal to or greater than the submerged length of the anodes and the anode bottom extensions;   e. positioning bubble tubes having orifices between the non-conductive anode extensions and the cathode faces;   f. spacing opposed anode and cathode faces apart from each other at a distance of about 11/4 inches or less; and,   g. electrodepositing metal on the cathodes while generating a sheet of gas bubbles from the bubble tubes through the electrolyte between opposed anode-cathode faces to produce agitation of the electrolyte over the cathode faces as metal is being deposited thereon and maintaining said convection edge baffles during electrodeposition to form enclosures between cathode and anode faces to minimize lateral spreading and contraction of the sheet of bubbles and prevent deposition of metal at the edges of the cathodes extending beyond the baffles, and maintaining said anode bottom extension during electrodeposition to prevent deposition of metal at the bottom of the cathode faces.   
     
     
       2. The method as set forth in claim 1 wherein the sheet of air bubbles is saturated with water vapor and generated through a perforated bubble tube. 
     
     
       3. The method as set forth in claim 2 wherein clamps are positioned on cathode suspension bars to reduce resistance of the current connection. 
     
     
       4. The method as set forth in claim 1 wherein clamps are positioned on anode suspension bars to reduce electrical resistance of the current connection. 
     
     
       5. The method as set forth in claim 1 wherein the convection edge baffles are attached to the walls of the cell. 
     
     
       6. The method as set forth in claim 1 wherein the convection edge baffles are positioned on vertical support members on the walls of the cell. 
     
     
       7. A method of electrowinning a metal at a high ratio of current density to metal ion concentration in a cell which includes insoluble anodes, cathodes and an electrolyte with an attendant production of high quality metal which can be easily stripped from the cathodes comprising the following steps: a. attaching non-conductive convection edge baffles to opposite edges of the anode faces so as to extend toward the cathode faces;   b. attaching non-conductive anode bottom extensions the anodes;   c. providing cathodes that are wider than the anodes so that the edges of the cathodes extend outwardly from the convection edge baffles;   d. submerging the cathodes so that the submerged length of the cathodes are equal to or greater than the submerged length of the anodes and the anode bottom extensions;   e. positioning bubble tubes having orifices between the non-conductive anode extensions and the cathode faces;   f. spacing opposed anode and cathode faces apart from each other at a distance of about 11/4 inches or less; and,   g. electrodepositing metal on the cathodes while generating a sheet of gas bubbles from the bubble tubes through the electrolyte between opposed anode-cathode faces to produce agitation of the electrolyte over the cathode faces as metal is being deposited thereon and maintaining said convection edge baffles during electrodeposition to form enclosures between cathode and anode faces to minimize lateral spreading and contraction of the sheet of bubbles and prevent deposition of metal at the edges of the cathodes extending beyond the baffles, and maintaining said anode bottom extension during electrodeposition to prevent deposition of metal at the bottom of the cathode faces.   
     
     
       8. The method as set forth in claim 7 wherein the electrodepositing is performed at a current density between the range of 40-300 ASF. 
     
     
       9. The method as set forth in claim 8 wherein step (f) opposed anode and cathode faces are spaced apart a distance of less than 1 inch from each other. 
     
     
       10. The method as set forth in claim 9 wherein copper is electrodeposited on the cathode. 
     
     
       11. The method as set forth in claim 8 wherein a non-retentive cathode is provided. 
     
     
       12. The method as set forth in claim 11 wherein copper is electrodeposited on the cathode. 
     
     
       13. The method as set forth in claim 8 wherein copper is electrodeposited on the cathode. .Iadd. 14. A method of performing electrodeposition at a high ratio of current density to metal ion concentration in a cell which includes anodes, cathodes and an electrolyte with an attendant production of high quality metal which can be easily stripped from the cathodes comprising the following steps: a. positioning non-conductive convection edge baffles adjacent to opposite edges of the anode faces so as to extend toward the cathode faces;   b. positioning non-conductive anode bottom extensions beneath the anodes;   c. providing cathodes that are wider than the anodes so that the edges of the cathodes extend outwardly from the convection edge baffles;   d. submerging the cathodes so that the submerged length of the cathodes is sufficiently greater than the submerged length of the anodes so that metal does not deposit at the bottom of the cathode faces;   e. positioning bubble tubes having orifices between the non-conductive anode extensions and the cathode faces;   f. spacing opposed anode and cathode faces apart from each other at a distance of about 11/4 inches or less; and,   g. electrodepositing metal on the cathodes while generating a sheet of gas bubbles from the bubble tubes through the electrolyte between opposed anode-cathode faces to produce agitation of the electrolyte over the cathode faces as metal is being deposited thereon and maintaining said convection edge baffles during electrodeposition to form enclosures between cathode and anode faces to minimize lateral spreading and contraction of the sheet of bubbles and prevent deposition of metal at the edges of the cathodes extending beyond the baffles, and maintaining said anode bottom extension during electrodeposition to prevent deposition of metal at the bottom of the cathode faces. .Iaddend. .Iadd. 15. The method as set forth in claim 14 wherein the sheet of air bubbles is saturated with water vapor and generated through a perforated bubble tube. .Iaddend..Iadd. 16. The method as set forth in claim 15 wherein clamps are positioned on cathode suspension bars to reduce resistance of the current connection. .Iaddend..Iadd. 17. The method as set forth in claim 14 wherein clamps are positioned on anode suspension bars to reduce electrical resistance of the current connection. .Iaddend..Iadd. 18. The method as set forth in claim 14 wherein the convection edge baffles are attached to the walls of the cells. .Iaddend..Iadd. 19. The method as set forth in claim 14 wherein the convection edge baffles are positioned on vertical support members on the walls of the cells. .Iaddend. .Iadd. 20. A method of electrowinning a metal at a high ratio of current density to metal ion concentration in a cell which includes insoluble anodes, cathodes and an electrolyte with an attendant production of high quality metal which can be easily stripped from the cathodes comprising the following steps:   a. attaching non-conductive convection edge baffles to opposite edges of the anode faces so as to extend toward the cathode faces;   b. attaching non-conductive anode bottom extensions beneath the anodes;   c. providing cathodes that are wider than the anodes so that the edges of the cathodes extend outwardly from the convection edge baffles;   d. submerging the cathodes so that the submerged length of the cathodes is sufficiently greater than the submerged length of the anodes so that metal does not deposit at the bottom of the cathode faces;   e. positioning bubble tubes having orifices between the non-conductive anode extensions and the cathode faces;   f. spacing opposed anode and cathode faces apart from each other at a distance of about 11/4 inches or less; and,   g. electrodepositing metal on the cathodes while generating a sheet of gas bubbles from the bubble tubes through the electrolyte between opposed anode-cathode faces to produce agitation of the electrolyte over the cathode faces as metal is being deposited thereon and maintaining said convection edge baffles during electrodeposition to form enclosures between cathode and anode faces to minimize lateral spreading and contraction of the sheet of bubbles and prevent deposition of metal at the edges of the cathodes extending beyond the baffles, and maintaining said anode bottom extension during electrodeposition to prevent deposition of metal at the bottom of the cathode faces. .Iaddend. .Iadd. 21. The method as set forth in claim 20 wherein the electrodepositing is performed at a current density between the range of 40-300 ASF. .Iaddend..Iadd. 22. The method as set forth in claim 21 wherein step (f) opposed anode and cathode faces are spaced apart a distance of less than 1 inch from each other. .Iaddend..Iadd. 23. The method as set forth in claim 22 wherein copper is electrodeposited on the cathode. .Iaddend..Iadd. 24. The method as set forth in claim 21 wherein a non-retentive cathode is provided. .Iaddend..Iadd. 25. The method as set forth in claim 24 wherein copper is electrodeposited on the cathode. .Iaddend..Iadd. 26. The method as set forth in claim 21 wherein copper is electrodeposited on the cathode. .Iaddend.