Cathode copper (electrolytic copper) refers to copper products obtained through electrolytic refining, with copper content ≥99.95% (GB/T 467-2010 standard). It is the primary form of industrial pure copper.

I. Core Physical Properties

1. Electrical Conductivity:

• Resistivity: 1.673×10⁻⁸ Ω·m (20°C)

• Conductivity: 101% IACS (International Annealed Copper Standard)

2. Mechanical Properties:

• Tensile Strength: 210-250 MPa

• Elongation: ≥45%

3. Impurity Control Requirements:

• Oxygen Content: ≤10 ppm

• Sulfur Content: ≤15 ppm

• Arsenic + Antimony + Bismuth: ≤0.0015%

II. Production Process Flow

1. Electrolytic Refining:

• Cu²⁺: 45±5 g/L

• H₂SO₄: 180±20 g/L

• Temperature: 50±2°C

• Anode Plate Composition: 99.0% Cu, ≤0.03% impurities

• Electrolyte Composition:

• Current Density: 300-330 A/m²

Additives Dosage:

Additive	Function	Dosage
Gelatin	Inhibit nodules	0.3-0.5 g/t
Thiourea	Improve surface finish	5-10 ppm
Cl⁻	Enhance deposit density	15-25 mg/L

2. Post-Treatment Processes:

• Periodic Current Reversal: Frequency 2-3 times/hour to prevent edge nodules

• Vacuum Annealing: 450°C × 4 hours to relieve internal stress

• Acid Pickling: Nitric-sulfuric acid mixture (3:1 v/v) to remove oxides

III. Grade Classification and Performance Differences

IV. Advances in High-Purity Copper Production

1. 5N Copper (99.999%):

• Process: Electrolytic refining + zone refining

• Impurity Control: Fe<0.5ppm, Ni<0.3ppm

• Cost: 8-10× conventional cathode copper

2. Oxygen-Free Copper (OFHC):

• Oxygen Content: ≤1 ppm

• Thermal Conductivity: 398 W/(m·K)

• Energy Consumption: +35-40%

V. Quality Control Points

1. Surface Defects:

• Nodule height ≤0.3 mm

• Surface pit depth ≤0.1 mm

2. Internal Defect Detection:

• Ultrasonic testing: Inclusion detection (sensitivity Φ0.2mm)

• Metallographic inspection: Grain size ≥0.015 mm

3. Factory Inspection Items:

• Chemical composition (ICP-MS)

• Conductivity (eddy current method)

• Mechanical properties (GB/T 228.1)

Production Economic Data

This document strictly adheres to current industrial standards (GB/T, ASTM) and actual smelter operating parameters. Suitable for production specifications or procurement standards.