Alloy and anode for use in the electrowinning of metals
A lead calcium tin alloy to which cobalt has been added is described. The alloy is useful in the formation of anodes to be used in electrowinning cells. Electrowinning cells containing the cobalt alloys are particularly suited for electrowinning metals, such as copper, from sulfuric acid electrolytes. The cobalt-containing anodes improve the efficiency of oxygen evolution at the anode during electrowinning and reduce corrosion of the anode.
1. A lead tin alloy containing greater than 0% of a member selected from the group consisting of calcium, barium and strontium and also containing between 0.005 and 0.300% cobalt and up to 0.035% aluminum.
2. The alloy of claim 1 containing 0.03 to 0.10% calcium, 0.5 to 2.5% tin and 0.005 to 0.300% cobalt.
3. The alloy of claim 2 containing up to 0.08% calcium, up to 2.2% tin and up to 0.1% cobalt.
4. The alloy of claim 2 containing at least 0.05% calcium, at least 1.0% tin and at least 0.01% cobalt.
5. The alloy of claim 4 containing no more than 0.04% cobalt.
6. The alloy of claim 2 which additionally comprises up to 0.1% silver.
7. The alloy of claim 6 which additionally comprises 0.001 to 0.035% aluminum.
8. The alloy of claim 1 containing 0.05 to 0.08% calcium, 1.0 to 2.2% tin and 0.01 to 0.100% cobalt.
9. The alloy of claim 8 containing 0.002 to 0.08% silver.
10. An electrowinning anode comprising a lead tin alloy containing greater than 0% of a member selected from the group consisting of calcium, barium and strontium and also containing between 0.005 and 0.300% cobalt.
11. An electrowinning anode comprising the alloy of claim 10 containing 0.03 to 0.10% calcium, 0.5 to 2.5% tin and 0.005 to 0.300% cobalt.
12. An electrowinning anode comprising the alloy of claim 10 containing 0.05 to 0.08% calcium, 1.0 to 2.2% tin and 0.01 to 0.100% cobalt.
13. An electrowinning anode comprising the alloy of claim 10 which additionally comprises up to 0.1% silver.
14. In a cell for electrowinning metals containing an anode, a cathode and an electrolyte, the improvement comprising the anode of claim 10 .
15. In a method of electrowinning a metal in an electrowinning cell, the improvement comprising electrowinning the metal using the anode of claim 10 .
16. The method of claim 15 , wherein the electrowinning is conducted in a sulfuric acid electrolyte.
17. The method of claim 15 , wherein the metal being electrowon is selected from the group consisting of copper, nickel and manganese.