Electrolytic Metal Recovery
Electrowinning is the final purification step in many hydrometallurgical circuits: dissolved metal ions are driven onto a cathode by electrical current, producing high-purity metal plate. In a typical copper tankhouse, hundreds of cells are arranged in series, each containing dozens of alternating anodes and cathodes immersed in hot acidified copper sulfate solution. Over 5–7 days, copper deposits to a thickness of about 1 cm, and the cathodes are harvested, washed, and sold as LME Grade A copper (99.99% Cu).
Faraday's Law in Practice
Michael Faraday's 1834 law of electrolysis remains the governing equation: the mass deposited equals the charge passed times the electrochemical equivalent. But real cells never achieve 100% current efficiency — parasitic reactions like hydrogen evolution and Fe³⁺ reduction consume charge without depositing metal. Current efficiency typically ranges from 85–95% for copper and 88–92% for zinc. This simulation uses Faraday's law with adjustable efficiency to predict real production rates and energy costs.
Voltage Components
The cell voltage is the sum of the thermodynamic decomposition potential (~0.9 V for Cu from CuSO₄), anodic overpotential (oxygen evolution on lead alloy, ~0.5 V), cathodic overpotential (~0.05 V for Cu deposition), and ohmic drop across the electrolyte (~0.3–0.5 V depending on electrode spacing and acid concentration). Each component offers optimization opportunities: better anodes, closer spacing, hotter electrolyte, and higher acid concentration all reduce voltage and save energy.
Scale and Economics
A single large copper tankhouse produces 200,000–400,000 tonnes of cathode per year, consuming 1.8–2.2 kWh/kg. At industrial electricity prices, energy represents 15–25% of operating costs. Zinc electrowinning is even more energy-intensive at 3.0–3.5 kWh/kg due to higher cell voltages. This simulator lets you explore the interplay between current density, voltage, efficiency, and economics that drives every tankhouse design decision.