Secondary lead is lead produced from recycled lead-bearing materials such as spent lead-acid batteries, cable sheathing, pipes, sheets, ammunition, and industrial scrap. Unlike primary lead sourced from ore, secondary lead is recovered through controlled recycling and refining processes.
Today, more than 60% of global lead supply originates from secondary sources, making it a cornerstone of sustainable metallurgy.
Typical Chemical Composition (Battery-Grade)
| Element | Typical Content (%) |
|---|---|
| Lead (Pb) | 99.90 – 99.99 |
| Antimony (Sb) | 0 – 0.6 (controlled) |
| Tin (Sn) | 0 – 0.3 |
| Arsenic (As) | ≤ 0.01 |
| Bismuth (Bi) | ≤ 0.005 |
| Copper (Cu) | ≤ 0.002 |
| Silver (Ag) | Trace |
Key Mechanical Properties
| Property | Typical Value |
|---|---|
| Tensile Strength | 12 – 18 MPa |
| Yield Strength | 5 – 10 MPa |
| Elongation | 35 – 55% |
| Hardness | 4 – 8 HB |
| Elastic Modulus | ~16 GPa |
| Creep Resistance | Low |
Mechanical behavior depends strongly on residual antimony, tin, and arsenic content.
Physical Properties
| Property | Value |
|---|---|
| Density | 11.30 – 11.34 g/cm³ |
| Melting Point | 327 – 330 °C |
| Thermal Conductivity | ~35 W/m·K |
| Electrical Conductivity | ~4.8 MS/m |
| Corrosion Resistance | Excellent |
| Radiation Shielding | Excellent |
Metallurgical & Strengthening Behavior
Secondary lead retains the FCC crystal structure of pure lead. It is not heat-treatable; mechanical properties are controlled through chemistry rather than thermal processing.
| Mechanism | Effect |
|---|---|
| Solid Solution (Sb, Sn) | Moderate |
| Cold Working | Minimal |
| Grain Size Control | Limited |
| Heat Treatment | Not applicable |
Key Characteristics
✔ Comparable performance to primary lead
✔ Near-infinite recyclability
✔ Lower environmental footprint
✔ Cost-effective and widely available
✔ Excellent corrosion resistance
❌ Requires strict impurity control
❌ Quality depends on recycling process
❌ Toxic – regulated handling required
Refining & Processing Properties
Secondary lead production involves scrap collection, smelting, refining, and final alloy adjustment to meet application-specific requirements.
| Process Stage | Description |
|---|---|
| Scrap Processing | Battery breaking and material separation |
| Smelting | Rotary or blast furnace reduction |
| Refining | Drossing, desilvering, de-arsenication |
| Alloying | Sb, Sn, Ca added as required |
Available Commercial Forms
Ingots (20–40 kg)
Pigs
Sheets and plates
Pipes and tubes
Battery grids
Anodes and alloyed billets
Applications of Secondary Lead
Battery Industry
Automotive, industrial, UPS, telecom, and solar batteries (≈85% of demand)
Radiation Shielding
X-ray rooms, nuclear facilities, industrial radiography
Chemical & Construction
Acid-resistant linings, roofing sheets, soundproofing, counterweights
Advantages
✔ Saves ~70% energy compared to primary lead
✔ Lower production cost and stable supply
✔ High material recovery efficiency (~95%)
✔ Matches primary lead performance when refined
Secondary vs Primary Lead
| Parameter | Secondary Lead | Primary Lead |
|---|---|---|
| Source | Recycled scrap | Ore mining |
| Cost | Lower | Higher |
| Environmental Impact | Low | High |
| Availability | High | Limited |
| Performance | Comparable | Benchmark |
Why Choose Secondary Lead?
Choose secondary lead when sustainability, cost efficiency, battery production, and controlled alloying are priorities without compromising performance.