JuCaTec JUMBO ELECTRODE TECHNOLOGY FOR COPPER ELECTROWINNING

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Lawrence Stokes
6 years ago
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1 JUMBO ELECTRODE TECHNOLOGY FOR COPPER ELECTROWINNING N. Anastasijevic 1, J.-P.Nepper 2 and Michael H. Barker 3 Outokumpu Technology GmbH, Ludwig-Erhard-Strasse 21, D Oberursel, Germany. 1 Vice President. R & D, Telephone Nikola.Anastasijevic@Outokumpu.com 2 Senior Product Manager Copper, Telephone Jean-Paul.Nepper@Outokumpu.com 3 Senior Research Metallurgist - Electrochemistry Outokumpu Research Oy, Kuparitie 10, FIN Pori, Finland. Michael.Barker@Outokumpu.com

2 METAL ELECTROWINNING Major Processes Zinc Copper Production* t/y 7,900,000 2,800,000 * approx. figures

3 The cathode size currently used in copper electrowinning is driven more by history and product marketing than by technological reasons. Taken from the copper refinery process at the time when SX-EW was introduced (acceptance). EW and copper refinery share the same development in terms of cell design, size and cathode design (permanent cathode), handling, stripping etc..

4 Increase of cathode size not yet implemented in copper electrowinning ( ) Increase in cell and cathode size has been used successfully to reduce production costs of Zn electrowinning (Cathode/bar contact has been a bottleneck for enlargement of Zinc cathode) Immersed area, single cathode (m²). Cathodes per Cell Zinc Copper

5 Is the Jumbo size cathode feasible for Copper electrowinning? If yes, does it work? Next Step?

6 FEASIBILITY / BASE CASE: t/y copper EW tankhouse in Chile Lead anodes and stainless steel cathodes. Same electrolyte composition (40 to 37 g/l Copper and 180 to 185 g/l free acid). Same assumptions for both plants: average crane velocity, current density (300 A/m²) and 95% availability. Use of biggest possible commercially available cell 84 cathodes for state-of-the-art technology and 114 cathodes/cell for JuCaTec (biggest Jumbo cell used in Zinc electrolysis). Stripping machine capacities: 450 cathodes/hr for the state-of-the-art technology and 350 for JuCaTec size cathodes/h (conservative approach).

7 FEASIBILITY / BASE CASE (continuation): 4m² vs. 2m² immersed cathode area comparison. Investment costs included equipment (stripping machine(s), storage racks, crane(s)), cell area, power supply, electrolyte piping, cell ventilation systems, engineering, transport to the site and packaging. Operating costs included power consumption, labour and others e.g. chemicals and consumables. Impact of plant size considered range: 100,000 to 500,000 t/y electrowon copper

8 FEASIBILITY / RESULTS: Savings potential with JuCaTec : - lower investment costs, up to 20% savings - lower operating costs (up to 10%). Reasons: - more compact tankhouse (smaller tankhouse footprint) - shorter crane distances, - less handling (means less labour), - reduced number of stripping machines and cranes.

9 VERIFICATION: Single Electrode Test with artificial electrolyte (done) Industrial size Prototype cell test (pending)

10 Single Cathode Test Conditions: Electrode sizes: Anode-to-anode centre spacing Electrolyte at inlet: C.D. 500 x 2105mm cathode (JuCaTec) 500 x 1105mm cathode (state-of-the-art height) 100 mm 40g/l Cu + 150g/l free 40 C 300 A/m² Manual stripping

11 8 8a K K K A A A A A a Electrically both cells connected in series. 3

12 easy stripping, copper was removed as a single rigid panel

13 During the run monitoring of: Cell voltage, T INLET / C & T OUTLET / C Electrolyte analysis Sampled manually from overflow of CuO enrichment tank Cathode analysis Cathode ID, map & numbering Photos of whole cathode After stripping, masses & length of 4 parts measured Samples punched (2cm Ø discs) Micrographs Cathode Chemical analysis

14 MAIN RESULTS OF THE SINGLE ELECTRODE VERIFICATION TEST Tests with a single jumbo cathode and artificial electrolyte successfully performed: - Current Efficiencies > 90% - Same Cathode Microstructure and impurity level, e.g. same cathode quality as with normal sized EW cathodes - Practically same cell voltage

15 Next step: Test of a Prototype industrial size cell In-plant Verification (SX-EW)

Sinergies in Electrowinning and Electrorefining

Sinergies in Electrowinning and Electrorefining QUALIFICATIONS JUne 22, 2009 1 Background and Experience More than 30 years experience with special dedication to non-ferrous hydrometallurgy and electrometallurgy,