Copper Hydrometallurgy Process: Demystifying the Core Technology of Permanent Stainless Steel Cathodes

2025-04-01

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In the field of copper hydrometallurgy, the efficiency of electrolysis 

and electro-refining processes directly affects the capacity and cost 

of metal purification. As technology advances, traditional electrolytic 

starting plates are gradually being replaced by permanent stainless 

steel cathodes. This innovative material, with its long life, high corrosion 

resistance and stability, has become a key equipment for modern 

metallurgical industry to reduce costs and increase efficiency. In this 

paper, we will analyze its core technology composition and industry 

application value.

Why permanent stainless steel cathode has become 

the industry's new favorite?

In the traditional electrolysis process, the frequent replacement of soluble anode 

and starting plate leads to high production cost and long downtime. The 

permanent stainless steel cathode combines the three core components of 

stainless steel plate, conductive rods and side strips through modular structural 

design, realizing an ultra-long service cycle of more than 10 years. The 

advantages are as follows:

Reduced downtime maintenance: no need to replace cathode plate 

periodically, and the production efficiency is increased by more than 20%;

Reduced metal loss: more thorough copper stripping on cathode surface, 

and the metal recovery rate is over 99.5%;

Adaptation to harsh environments: resistant to high temperatures (80℃+), 

high acid (H2SO4 concentration of 150g/L+), and mechanical shocks.

Core component technology analysis

1. Stainless steel plate: metallurgical grade anti-corrosion barrier

Precision processing technology: 3mm ± 0.2mm thick stainless steel 

substrate is used, cold rolled and polished, with the roughness controlled 

at 0.16-0.60Ra (ASTM standard), to ensure the electrolytic copper is 

uniformly deposited and easy to be peeled off;

Strengthened deformation-resistant design: Yield strength is enhanced 

through heat treatment process, and the bending stiffness is up to the 

industry's highest standard, with no warping in long-term use. Enhanced

 anti-deformation design: heat treatment process to enhance the yield 

strength, bending stiffness to the industry's highest standard, long-term use 

without warping;

passivation film protection: chromium oxide passivation layer to resist 

electrolyte corrosion, service life of more than 10 years.

2. Conductivity bar: high performance composite conductor

steel-copper composite structure: the outer layer of stainless steel coated with 

high-purity copper core, extruded and rolled molding, straightness error ≤ 1mm / m, 

to avoid uneven distribution of the current;

directional conductive design: only a single end of the exposed copper conductor, 

the rest of the fully enclosed corrosion-resistant, conductive efficiency up to 

270A / m ² when the pressure drop ≤ 12.5mV;

antipolarization treatment: inhibit the deposition of copper ions in electrolysis to 

reduce the risk of short-circuit. Antipolarization treatment: inhibit copper ion 

deposition during the electrolysis process, reduce the risk of short circuit.

3. Edge strip: weatherproof insulation shield

Polymer material innovation: polypropylene (PP) modified formula, temperature 

range -20℃ to 120℃, anti-acid corrosion, anti-aging performance through 2000 

hours of accelerated aging test;

Flexible structure design: can withstand the mechanical stress caused by the 

electrolyzer thermal expansion and contraction, sealing performance increased by 50%;

Modular installation: Snap-in connector design, 2-minute quick replacement, 

maintenance costs reduced by 70%. Modular installation: snap-in interface 

design, quick replacement in 2 minutes, maintenance cost reduced by 70%.

Application Scenarios and Economic Benefits

In copper electrowinning and refining process, the permanent stainless steel 

cathode can be adapted to a variety of electrolysis systems:

High-acid and high-copper electrolyte: suitable for heap leaching-extraction-

electrowinning (SX-EW) process, with a current efficiency up to 94%;

High-immurity system: tolerate arsenic, antimony and other impurity ions, with 

a cathode copper purity up to 99.99% or more;

Large-scale continuous production: the cathode loading capacity of a single tank 

is increased by 30%, and the energy consumption of tons of copper is reduced by 

15%. Large-scale continuous production: single-slot cathode loading capacity 

increased by 30%, copper energy consumption decreased by 15%.

According to industry statistics, after adopting this technology, the average 

annual cost savings of enterprises include:

material cost: 90% reduction of cathode plate procurement expenditure;

labor cost: 80% reduction of maintenance man-hours;

energy cost: 300kWh/ton of copper reduction in DC power consumption.

Technology Trends and Industry Outlook

With the popularization of the green metallurgy concept, the low-carbon attributes

 of permanent stainless steel cathode in the whole life cycle are further highlighted. 

Future technology iterations include:

intelligent monitoring: integrated current sensor real-time detection of cathode status;

lightweight design: titanium alloy composite plate to reduce the dead weight of the equipment;

recycling cycle: stainless steel substrate recycling rate of more than 95%.

Conclusion

permanent stainless steel cathode is a revolutionary breakthrough to promote the 

industry to efficient and sustainable direction of transformation. Its technological

maturity and large-scale application experience have made it the preferred solution

for global copper smelters. With the continuous upgrading of material science and

manufacturing processes, this technology will unleash even greater economic and

environmental value.