Method for the electrolytic refining of copper

Claim 2

The copper electro-refining process of claim 2, wherein said cathode metal is titanium, wherein the time period during the forward flow of current ranges from about 15 to 55 seconds at a current density of about 25 to 45 amps/sq.ft., wherein the time period during the reverse flow current is about one-eighteenth to one-twenty second of the time period employed in the forward flow of current, and wherein the current density of the reverse flow of current is 25 to 45 percent less than the current density corresponding to the forward flow of current.

Claim 3

A copper electro-refining process for producing heavy deposits of high purity copper on a cathode at improved production rates which comprises, selecting a metal cathode material which is self-passivating in an electrolytic copper solution, said cathode metal being characterized by a negative free energy of formation of the oxide of at least about 90,000 calories per gram atom of oxygen, providing a plating system comprising at least one tank containing a plurality of said cathodes immersed in said copper sulfate electrolyte alternately spaced between copper anodes to be refined, said copper electrolyte containing 20 to 50 grams/liter of copper in the form of copper sulfate and 100 to 240 grams/liter of sulfuric acid making up substantially the balance of said solution, continuously circulating said electrolyte through said tank by means of a circulating system, continuously subjecting said system to a period forward and reverse flow of current from said anodes to said cathodes and from said cathodes to said anodes, respectively, said forward flow of current being carried out for a time ranging from about 10 seconds to 100 seconds, at a current density of about 20 to 65 amps/sq.ft., said reverse flow of current being carried out for a time ranging from about one-fifteenth to one-fiftieth of the time employed in the forward flow of current, the reverse flow of current being maintained at a current density level of 15 to 65 percent less than the current density corresponding to the forward flow of current, and maintaining said periodic application of the current to said system until a heavy deposit of high purity copper is obtained on said cathodes.

Claim 4

The copper electro-refining process of claim 4, wherein the cathode metal is selected from the group consisting of titanium, zirconium and stainless steel, wherein the time period during the forward flow of current ranges from about 15 to 55 seconds at a current density of about 25 to 45 amps/sq.ft., wherein the time period during the reverse flow current is about one-eighteenth to one-twenty second of the time period employed in the forward flow of current, and wherein the current density of the reverse flow of current is 25 to 45 percent less than the current density corresponding to the forward flow of current.