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CENTRAL TANKHOUSE – SAFETY MEETING

CENTRAL TANKHOUSE – SAFETY MEETING. OUTLINE. Introduction Basics Current Density Electrical Equivalent Current Efficiency (CE) CE Calculations Factors Effecting Current Efficiency . INTRODUCTION. Tracy Westerfield Metallurgist – Hydromet Office: 865-6629

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CENTRAL TANKHOUSE – SAFETY MEETING

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  1. CENTRAL TANKHOUSE – SAFETY MEETING

  2. OUTLINE • Introduction • Basics • Current Density • Electrical Equivalent • Current Efficiency (CE) • CE Calculations • Factors Effecting Current Efficiency

  3. INTRODUCTION • Tracy Westerfield Metallurgist – Hydromet Office: 865-6629 email: twesterfield@phelpsdodge.com • Rosemary Blosser Metallurgist – Hydromet Office: 865-6451 email: rblosser@phelpsdodge.com Please feel free to contact either of us with questions concerning the EW Operations. We are here to help!!!

  4. BASICS • Each Cell in Central Tankhouse Contains: • 63 Stainless Steel Cathodes • 64 Lead Anodes • 190,000 Amps (max) • 548 Cells • Cell lines A, B, C, D & E Map of Central Tankhouse: E D Cell Line A Cell Line E C Cell Line B Cell Line Strip Machine

  5. EW CHEMISTRY: Cathode and Anode Reactions Cu + 2e- Cuo Reaction at Anode: H2O  2H+ + 1/2O2 + 2e- Fe++ Fe+++ + e- e- - + CATHODE O2 ANODE Cu++ O2 Cu++ Reaction at Cathode: Fe+++ + e- Fe++ 1/2O2 + 2H+ + 2e- H2O

  6. Current Density Calculation - Example • Cell line = 45,093 amps • Cathode per cell = 63 • Cathode area (both sides) = 21.5 ft2 • Current Density = 45,093 amps = 33.2 amps / ft2 63 x 21.5 ft2 2/3 of Cell Pulled 21 cathode 100 amps / ft2 1/3 of Cell Pulled 42 cathode 50 amps / ft2

  7. ELECTRICAL EQUIVALENT • How much electrical current does it take to plate a pound of copper? • Cu plating is a function of current and time only • 1 Faraday of electricity = 96,489 ampere-seconds • 1 ampere-second = 1 coulomb The weight of copper produced by any given current, e.g. 2.6086 lb / 1000 amp-hr. occurs in one electrolytic cell

  8. ELECTRICAL EQUIVALENT - BASICS Calculate the quantity of copper plated in one cell on the H Cell Line in 10 hours General Formula: Weight (in lbs) of Cu plated = hours x 2.6086 lb Cu x amps x # of cells 1000 amp-hr Weight of Cu = 10 hr x 2.6086 lb Cu x 45,093 amp x 1 cell 1000 amp-hr = 1,176 lb Cu/ cell

  9. ELECTRICAL EQUIVALENT Calculate the quantity of copper plated in one cell during a 7 day plate cycle lbs of Cu = 24 hour x 2.6086 lb Cu x 45,093 amp x 7 days = 19,761 lb Cu 1 day 1000 amp-hr

  10. CURRENT EFFICIENCY (CE) actual Cu deposited Current efficiency = ---------------------------------- x 100 theoretical Cu deposited Current efficiencyis the ratio of the weight of copper actually deposited by a current and the weight which theoretically should have been deposited according to Faraday's Law.

  11. CURRENT EFFICIENCY (C.E.) Actual weight of copper in cell: Pull 1: 6,200 lbs Pull 2: 6,100 lbs Pull 3: 6,000 lbs 18,300 lbs Actual weight of copper removed from cell (bundle weight in lbs) actual C.E. = -------------- x 100 theoretical = 18,300 /19,761 = 91% C.E. Value obtained in previous slides (lbs) (19,761 lbs)

  12. Deviations from Theoretical Current Efficiency • Deviations from Theoretical C.E. Can Be The Result Of: • Current Loss Caused by short circuits • Between anode and cathode • Cell to cell • By current taking any path other than through the electrolyte

  13. Short Circuits

  14. Clean Contact Need to maintain clean contacts to maximize current flow through cell.

  15. Results of no Contact No copper will be deposited on the cathode when there is no current present.

  16. DID YOU KNOW???? Feed: • Ideally, feed should be evenly introduced into the bottom of the cell through a distribution manifold • Turbulent feed distribution negatively effects copper growth Discharge: • Must maintain sufficient flow through each cell • Without sufficient flow, copper content in electrolyte will deplete

  17. DID YOU KNOW???? The Overall Reaction Occurring in the Cell: • Decreases the copper content in the electrolyte RE (38 g/L Cu)LE (34 g/L Cu) • Oxygen Liberation • Increases acid in electrolyte RE (188 g/L Acid)LE (196 g/L Acid) • Copper plates on cathode

  18. QUESTIONS?

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