Lead: properties, grades and applications / Articles

Lead (Pb) is a heavy, soft and ductile bluish-silvery metal, one of the oldest metals known to mankind. Despite its historical antiquity, lead retains strategic importance for modern industry. Its unique ability to absorb radiation, high density, chemical resistance and exceptional electrochemical properties in combination with sulfuric acid make it indispensable in the production of lead-acid batteries, radiation shielding, cable sheathing and chemical engineering.

Chemical Nature and Physicochemical Properties

Lead is a transition metal with atomic number 82 and atomic mass 207.2 g/mol. The density of lead is 11.34 g/cm³, making it one of the heaviest non-radioactive metals. Its melting point is relatively low — 327.4 °C, and its boiling point is about 1740 °C.

Lead has high ductility and malleability; it is easily rolled into thin sheets and drawn into wire. It is very soft (Brinell hardness about 4–5 kgf/mm²), which allows it to be easily machined and shaped. On the lead surface in moist air, a thin and dense protective film (oxide, carbonate) forms, which protects the metal from further oxidation, ensuring high corrosion resistance in atmospheric conditions.

Lead is resistant to hydrochloric and sulfuric acids (due to the formation of insoluble films) but dissolves in nitric and acetic acids. It also actively reacts with alkalis. In the electrochemical series, lead stands before hydrogen, which allows it to be used as an anode in lead-acid batteries. Lead is a good absorber of gamma and X-rays due to its high density and high atomic number.

Classification, Grades and Standards

Requirements for primary lead in ingots, blocks and pigs in Russia and CIS countries are established by GOST 3778-98 "Lead. Specifications" (with the current amendment). The standard applies to lead intended for national needs and export and regulates chemical composition, delivery form and marking.

Depending on the lead content and impurities (bismuth, copper, antimony, tin, arsenic, iron, zinc, etc.), the following main grades are established:

C0 (special purity lead, 99.992% Pb) — the purest metal with minimal impurity content. Used for critical electrical products, optics and special chemical processes.
C1 (99.97% Pb) — a high-quality grade used for cable sheathing, sheets, anodes and lead plates.
C2 (99.94% Pb) — used for solders, battery parts, babbitts and other technical needs.
C3 (99.90% Pb) — used for less critical applications, including certain types of batteries, sheathing and alloys.

Grades with additives (e.g., antimonial alloys for battery grids) and ultra-pure grades (C0000, C000) for special purposes are also produced. Lead is supplied in the form of pigs weighing 19–25 kg, large blocks, ingots, as well as rolled products (sheets, plates, rods, wire).

Production Technology and Refining

The main raw material for lead production is sulphide polymetallic ores containing galena (PbS). The technological chain includes ore mining and beneficiation by flotation to obtain lead concentrate.

Two main industrial methods are then used:

Pyrometallurgical method — roasting the concentrate to convert sulphide to oxide, then reduction smelting in blast or reverberatory furnaces to produce crude lead (Pb content 96–98%). Crude lead is subjected to refining to remove impurities (copper, antimony, tin, arsenic, bismuth). Refining may include pyrometallurgical (oxidative, antimonial, alkaline) and electrolytic stages.
Hydrometallurgical (electrolytic) method — leaching lead from the concentrate followed by electrolysis. This method allows high-purity lead to be obtained and reduces sulphur dioxide emissions but currently lags behind pyrometallurgy in production scale.

A significant share of the world's lead is produced from secondary raw materials (spent lead-acid batteries) through remelting and refining. Lead recycling is an economically efficient and environmentally important industry, as lead is a 100% recyclable material.

Applications

Lead-acid batteries. This is the absolutely dominant area of lead consumption — it accounts for about 80–85% of global demand. Lead is used for the manufacture of current collectors (grids), plates, terminals and connectors in batteries for cars, uninterruptible power supplies, solar and wind energy systems, and backup power for hospitals and communication centres.

Radiation shielding. Due to its high density and atomic number, lead is an effective material for shielding X-ray and gamma radiation. It is used in medical X-ray rooms, laboratories, nuclear energy, and in computer and television screens (as part of glass).

Cable industry. Lead has excellent ductility and corrosion resistance, making it an ideal material for sheathing power and telecommunication cables, especially submarine ones, where protection from moisture and aggressive environments is required.

Chemical industry. Lead is used for lining vessels, pipes and apparatus operating with aggressive chemical media (sulfuric, hydrochloric acids) due to its chemical resistance.

Sound and vibration insulation. The density and softness of lead make it an effective absorber of sound and vibration. Thin lead sheets are laminated onto building materials for sound insulation, and are also used for vibration isolation of buildings and equipment.

Other applications. Lead is used in the production of solders (with tin), babbitts (anti-friction alloys), shot and ammunition, weights and ballast (yacht keels, sinkers), crystal and glass, and for noise protection in construction and industry.

Safety and Storage

Lead and its inorganic compounds belong to hazard class 1 (extremely hazardous substances) according to GOST 12.1.007. The maximum allowable concentration (MAC) of lead in the working area air is 0.05 mg/m³ (time-weighted average). Lead is a polytropic poison affecting the haematopoietic and nervous systems, liver, kidneys and bone tissue. The toxic dose for humans is about 1 mg, and the lethal dose is 10 g.

When working with lead and its compounds, personal protective equipment (respirators, safety goggles, gloves, protective clothing) must be used, effective ventilation of premises must be ensured, and strict personal hygiene rules must be observed (no eating at the workplace, thorough hand washing). Lead and its compounds can enter the body through the respiratory tract, gastrointestinal tract and skin.

Lead is non-flammable. Storage of lead in pigs and blocks is carried out in dry, closed warehouses or on areas with hard surfacing, protected from moisture and contamination. Lead rolled products are stored under conditions that prevent mechanical damage and contact with acids.

Market and Trends

The global lead market demonstrates steady dynamics. Global refined lead consumption is estimated at about 13.2–13.4 million tonnes per year and is projected to grow at a moderate pace (about 1–2% per year) in the medium term. The key demand driver remains the production of lead-acid batteries, including for vehicles with internal combustion engines, hybrids and backup power systems.

The largest producers and consumers of lead are China, the USA, European countries, India and Australia. An important trend is the development of lead recycling from spent batteries, which reduces the burden on primary mining and contributes to the sustainable development of the industry. Tightening environmental requirements stimulate the introduction of cleaner hydrometallurgical technologies and the modernisation of refining capacities.

Conclusion

Lead remains a fundamental industrial metal, ensuring the operation of battery systems, radiation safety, reliability of cable networks and chemical resistance of equipment. Understanding the grade composition according to GOST 3778-98, refining technologies and safety requirements is the basis for competent material selection and the organisation of efficient supplies.