In the field of non-ferrous metal refining, electrolytic copper purification technology continues to
dominate the production of high-purity copper by virtue of its irreplaceable purification effect. This
article will analyze the core process logic of this technology, reveal its key role in modern industry,
and provide industry practitioners with a practical value of the reference framework.
The underlying technical logic of electrolytic purification process
Electrolytic purification is a deep extension of pyrometallurgical smelting, and the essence of its technology
lies in the use of differences in electrochemical activity of metals to achieve directional purification. The anode
plate with 98%-99% copper content and pure copper cathode are immersed in electrolyte, and selective
reaction occurs under the action of direct current:
Anodic reaction: Cu (crude copper) → Cu²⁺ + 2e-
Impurity metals (Fe, Ni, As, etc.) are preferentially dissolved to form ions.
Cathodic reaction: Cu²⁺ + 2e- → Cu (purity 99.99%+)
Metal ions with low standard reduction potentials (e.g. Ag⁺, Au³⁺) cannot be deposited
This process realizes a leap in copper quality through a triple purification mechanism:
Potential difference screening: precious metals are retained in the anodic sludge due to high reduction potentials
Concentration gradient control: The copper ion concentration gradient in the electrolyte is maintained at 2.5-3.5 mol/L.
Dynamic equilibrium system: anode dissolution rate and cathode deposition rate are precisely matched.
Five core control modules for industrialized production
1. Raw material pretreatment system
Preparation of anode plate: fire-casting of crude copper into 680×860×35mm standard plate.
Surface treatment: high-pressure water jet (15MPa) to remove oxidized skin.
Overhang calibration: 110±2mm spacing control to ensure uniform electric field.
2. Electrolyte intelligent regulation system
Dynamic maintenance program:
Temperature control: 55±2°C (titanium tube heat exchanger)
Circulation flow rate: 18-25L/min-tank (magnetic pump)
Purification cycle: 15% electrolyte replacement per 100 tons of copper output
3. Optimization model of electric energy parameters
Current density: 220-280A/m² (Dk value)
Tank voltage: 0.25-0.35V (including contact loss)
Co-polar distance: 95-105mm (titanium busbar structure)
Current efficiency: ≥96% (loss source monitoring system)
4. Impurity control technology route
Anode sludge treatment: precious metal recovery rate Au>99%, Ag>98
Electrolyte purification:
Arsenic and antimony removal: crystallization precipitation method (cooling down to 10℃)
Nickel accumulation control: extraction process (activated at <15g/L)
Suspended matter treatment: Bag filter (precision 5μm)
5. Cathode copper quality assurance
Surface quality: ASTM B115 Grade 1 Standard
Physical specifications: Beginning pole piece thickness 0.6-0.8mm
Chemical purity: Cu≥99.994% (GD-MS test)
Process innovation and energy efficiency breakthrough
1. Application of bipolar membrane technology
New three-chamber electrolyzer design realized:
Automatic acidity balance (H+ migration rate control)
Current efficiency upgraded to 98.5%
Steam consumption is reduced by 30%.
2. Intelligent control system
Online concentration analyzer (XRF technology)
Pole distance automatic adjustment device (±0.5mm accuracy)
Digital twin model (predicts deposition defects)
3. Wastewater Resourcing Program
Acidic wastewater preparation of copper sulfate crystals (92% recovery)
Rinse water closed loop recycling system (40% water saving)
Heavy metal ion trapping technology (effluent Cu²⁺<0.5ppm)
Industrial application value mapping
1. Electronic grade copper foil production
Thickness control: 6-70μm (CV value <3%)
Tensile strength: ≥350MPa
Surface roughness: Rz≤3μm (lithium copper foil standard)
2. High-end wire manufacturing
Conductivity: ≥101% IACS
Oxygen content: <5ppm
Application areas: superconducting magnets / chip bonding wire
3. Special alloy base material
Copper ingot purity: 6N grade (99.9999%)
Grain size: ASTM grade 8 or above
Application Scenario: Aerospace high temperature resistant parts
Environmental protection and safety specifications
Acid mist treatment system: three-stage counter-current scrubbing (emission concentration <5mg/m³)
Heavy metal prevention and control: emergency interceptor pool capacity ≥ 1.5 times the maximum tank liquid volume
Power monitoring: harmonic distortion rate <5% (with dynamic reactive power compensation)
Operation protection: perfluorine mask + titanium alloy protection toolkit
Technology Outlook
With the explosive growth of new energy and semiconductor industries, electrolytic purification technology
is evolving into three dimensions:
Ultra-purification: breakthrough in 6N grade copper mass production technology (total impurities <1ppm)
Intelligent: digital electrolysis workshop (unit energy consumption reduced to 2200kWh/t)
Decarbonization: green power coupling technology (carbon footprint reduced by 40%)
It is recommended that producers focus on it:
New additive molecular design (directional regulation of crystal growth)
Hydrodynamic optimization of electrolyzer structure
Precious metal synergistic extraction technology research and development
Mastering the core process control points and establishing a dynamic process database will become the
key to winning the competition in the high-purity copper market. In the next five years, the speed of
technology iteration in this field is expected to increase by 300%, and it is imperative to lay out an
innovative technology system in advance.