Electrowinning

High Current at Low Voltage

Electrowinning is the electrochemical recovery of metals from leach solutions. The process passes high DC current through an electrolyte between inert anodes and cathode blanks, depositing pure metal onto the cathodes. Copper electrowinning typically operates at 200–400 A/m² cathode current density and just 2–3V per cell. With tankhouses containing hundreds of cells wired in series, total circuit voltages remain low (typically 3–6V DC) but current demands are enormous — 10,000A to 60,000A or more for a single rectifier circuit. The power supply must deliver massive, stable DC current with minimal voltage drop across busbars and connections.

Current Efficiency and Energy Cost

In electrowinning, current efficiency — the percentage of electrical energy that actually deposits metal rather than generating heat or side reactions — directly determines the cost per tonne of recovered metal. Copper electrowinning typically achieves 85–92% current efficiency under optimal conditions. Every percentage point of efficiency loss translates to increased energy consumption per tonne (typically 1,800–2,200 kWh/t for copper). The rectifier’s output quality, particularly ripple content and regulation accuracy, is a major determinant of current efficiency. Clean, stable DC maximises faradaic efficiency and minimises parasitic reactions.

Scalability and Industrial Integration

Mining and refining operations require rectifier systems that scale with production capacity and integrate into plant-wide control networks. Parallelable IGBT rectifier cabinets allow operators to add capacity incrementally as throughput grows. Industrial communication protocols — Profinet, PROFIBUS, Modbus TCP, and OPC-UA — enable the rectifier to report real-time current, voltage, power consumption, and fault status to SCADA systems. Water cooling is essential at high current levels, providing reliable thermal management in harsh tankhouse environments with ambient temperatures of 40–65°C and corrosive acid mist.