Electrolysis

Kaplan G. L.
Assistant Examiner:
Solomon I, W.
Attorney, Agent or Firm:
Nisbett, Robert S.
Claims:
We claim

1. A process for efficient electrolysis of an aqueous pregnant liquor electrolyte containing copper producing high purity copper, said process comprising circulating said electrolyte in an external loop electrolyte system from an electrowinning tank which contains the electrolyteand electrodes, at least one electrode being a cathode and at least one electrode being an anode, with the electrodes being immersed in said electrolyte and connected with a means for supplying electrical current so that electrical potential can be impressed between said anode and cathode electrodes through said electrolyte; said tank having parallel side walls substantially perpendicular to saidelectrodes; circulating said electrolyte through a distributor means in said electrowinning tank uniformly and upwardly between said electrodes overflowing along the entire length of said side walls; maintaining the temperature of said electrolyte above about 70°F with a temperature control means in said external loop; adjusting in said external loop the residual concentration of SO2 iron, and acidto maintain a concentration of SO2 of at least about 0.01 gram per liter of electrolyte as it enters the tank, of iron of at least 1.0 g/l of electrolyte as it enters the tank, and of acid of at least 5 g/l of electrolyte as it enters the tank; impressing an electrical voltage of at least 0.4 volts between said anode and cathode electrodes through said electrolyte forming sulfuric acid at theanode and depositing high purity copper at the cathode; and recovering a coherent high purity copper product.

2. A process of claim 1 wherein said electrolyte is circulated at a rate sufficient to prevent chemical polarization in the vicinity of said anode and cathode electrodes in said electrowinning tank.

3. A process of claim 1 wherein the carbon material of said anode electrode is selectedfrom carbon black, coke or graphite and the metal of said anode electrode is selected from platinum, silver, gold, lead, mercury, tin, iron, chromium, zinc, aluminum, magnesium, antimony, silicon, titanium, and combination thereof.

4. A process of claim 1 for producing a copper product wherein the electrolyte system has an electrowinning tank of rectangular horizontal cross-section wherein theelectrodes are substantially rectangular plates suspended in a vertical plane with supporting means at the upper edge of said electrodes which supports the electrodes from vertical tank side-walls which are substantially perpendicular to said electrodes; wherein electrolyte is circulated upwardly into said tank through a distributor means with jets located beneath said electrodes so that theupward electrolyte flow rate is substantially uniform along the side-walls of said tank and the electrolyte leaves said tank near the upper edge of said side-wall at a rate which is substantially uniform along the length of said tank and the electrolyte velocity at said jet is in the range of about 400-800 feet per second.

5. A process of claim 1 for efficient electrolysis by which coherent copperof high purity can be produced with high efficiency and high current density from an aqueous pregnant liquor electrolyte containing copper, said process comprising circulating said electrolyte through an external loop electrolyte system from an electrowinning tank which contains the electrolyte and electrodes, at least one electrode being a cathode and at least one electrode being an anode, withthe electrodes being immersed in said electrolyte and connected with a means for supplying electrical current so that electrical potential can be impressed between said anode and cathode electrodes through said electrolyte; said electrolytic system having a temperature control means, an SO2 injection means and an electrolyte circulation means; said electrolyte being derived from an aqueous acid...