Introduction: Industrial Value of Electrolytic Copper Refining
As the ultimate link in the production of refined copper, the electrolysis process directly determines
the purity and economic value of copper. Globally, more than 25 million tons of copper cathode are
produced through electrolysis each year, accounting for more than 85% of the total amount of refined
copper. With the explosive growth of new energy industry's demand for 6N grade high purity copper
(99.9999% purity), the precision and green innovation of electrolysis technology is triggering a deep
change in the industry. This article will systematically analyze the core process of electrolytic copper
refining, technical bottlenecks and cutting-edge development direction.
Four core processes of copper electrolysis
1. Anode plate preparation: precise control of purity and physical specifications
Raw material requirements: the purity of crude copper should be over 99.3%, and the
content of arsenic, bismuth and other harmful elements should be <0.003%.
Casting process:
Vertical mold casting: the thickness error of anode plate is controlled at ±3mm to avoid short
circuit in electrolysis process.
Double-sided milling: surface roughness Ra≤6.3μm, improve the uniformity of electrolytic deposition.
Industry pain point: the pass rate of traditional casting anode plate is only 92%, but intelligent continuous
casting technology can increase it to 98.5%.
2. Electrolyte system: composition management and dynamic balance
Key parameters Traditional process Optimization
Sulfuric acid concentration (g/L) 160-180 180-200 (improve conductivity)
Copper ion concentration (g/L) 40-45 45-50 (reduce pole spacing)
Temperature control (℃) 55-60 62-65 (accelerate ion migration)
Additive type Bone glue + thiourea Composite organic inhibitor (enhance cathode flatness)
Technical Innovation:
Online ion chromatograph monitors the concentration of nickel, iron and other impurities in real time and
automatically triggers the purification program
Arsenic adsorption resin system reduces the arsenic content of electrolyte from 200mg/L to less than 5mg/L.
3. Electrolyzer operation: the game of current efficiency and energy consumption
Pole spacing optimization: the pole plate spacing is reduced from 95mm to 80mm, reducing DC power
consumption by 8%-12% per ton of copper.
Current density control:
Conventional density: 280-320A/m² (for 99.99% copper cathode)
High Density Mode: 380-420A/m² (35% increase in productivity, but requires matching pulse power supply)
Intelligent management:
Tank voltage monitoring system real-time warning of short-circuit and disconnection faults
Robot automatic stripping of copper cathode, residual pole rate from 15% to 8%
4. Post-treatment of cathode copper: progression from stripping to high purification
Washing process: three-stage counter-current spray system to remove electrolyte residue on the surface,
chlorine ion content <1ppm
Vacuum melting and casting: melting under 10-³Pa pressure, oxygen content is controlled within 3ppm.
Electrolytic refining: secondary electrolysis to prepare 5N grade high purity copper, silver, selenium
and other impurities <0.5ppm.
Technology attack: crack the four industry pain points
1. Crack the way of impurity interference
Separation of nickel and cobalt: selective adsorption of nickel ions in electrolyte by chelating resin, recovery rate >95%.
Bismuth pollution control: Sodium thiosulfate precipitation method to reduce bismuth concentration from 50mg/L to 0.1mg/L.
2. Energy efficiency improvement program
Pulse current technology: Through 0.1-1Hz frequency pulse, the current efficiency is increased from 94% to 97%.
Waste heat recovery system: preheat the new liquid by utilizing electrolysis tank heat dissipation, reducing steam consumption by 25%.
3. Key technology of environmental protection treatment
Acid mist capture: double-layer PVDF membrane capture efficiency of 99%, workshop sulfuric acid mist concentration <1mg/m³.
Wastewater recycling: membrane separation + electrodialysis combination process, water reuse rate increased from 70% to 95%.
4. Efficient recovery of precious metals
Anode sludge treatment:
Extraction of gold and silver by pressurized leaching, with recovery rates of 99.2% and 98.5% respectively.
The comprehensive recovery rate of selenium, tellurium and other rare metals exceeds 90%.
Frontier trend: Intelligent and ultra-purification revolution
1. Digital twin system landing
Real-time acquisition of temperature, flow rate, ion concentration and other parameters through 500+ sensors
AI model dynamically optimizes the current density and additives, and the cathode qualification rate is increased to 99.8%.
2. Breakthrough in the preparation of 6N grade high purity copper
Three-dimensional pulse electrolysis technology: Atomic level deposition control in a special PP diaphragm tank.
Ultra-clean environment control: 99.9999% copper purity under Class 10 clean room conditions.
3. Green chemical additives research and development
Bio-based inhibitors: non-toxic grain refiner developed from plant extracts
Self-repairing electrolytic membrane material: can automatically repair microporous defects during operation to extend service life.
4. Direct electrolytic refining of copper scrap
Development of direct electrolysis process for waste cables and motor stators with copper content >99%, with energy
consumption reduced by 40%.
Conclusion: technology iteration drives industrial upgrading
Copper electrolysis refining is shifting from “scale-driven” to “quality + green” double-engine mode. With the popularization
of new electrode materials and intelligent control systems, the DC power consumption of electrolysis is expected to drop
from 2200kWh/t to below 1800kWh/t in the next five years. In the new energy and high-end electronics industry demand
pull, 6N grade high purity copper, low oxygen copper and other specialty products market share will exceed 30%.
Enterprises need to focus on the digital transformation of processes and rare and precious metals recovery technology
layout, build a new advantage of the circular economy.