Chapter 3 - Applications of Lead

Examples of lead use have been known for thousands of years. The Romans used lead on a large-scale for plumbing, tank lining and domestic articles such as cooking pots and tableware, and also in glasses and glazes on pottery. Lead use has continued to grow and, in recent times, has risen from 4 million tonnes per annum in the 1960s to 6 million tonnes in the 1990s, due primarily to an increase in demand for lead-acid batteries. Present uses of lead and lead compounds are:

LEAD METAL

Lead-acid storage batteries
The major use worldwide, primarily as a starter battery in motor vehicles, but also as traction batteries for zero-emission electric vehicles and to provide emergency backup power supply, mostly for computer and telecommunication systems. Good rates of recycling are already achieved for starter batteries, though they could be improved upon in some countries; very high recycling rates are achieved for traction and backup batteries. Alternatives are under development for some applications, though at present these could not replace lead at comparable cost, or for technical reasons.

Constructional uses: pipe and sheet
Lead piping is now a minor application, as it is no longer used for domestic water supplies because of concerns that lead slowly dissolves in soft water and may pose a risk to health, and because of improvements in alternative materials. However, much lead piping remains in place. New lead pipes are used in the chemical industry.

Lead sheet is widely used on roofs for flashings and weatherproofings, and is often used for complete roofs on both historic and modern buildings.

Cable sheathing
Lead sheaths are used to protect underwater and some underground power cables. This is now a minor application of lead.

Radiation screening
Lead is the most effective of the commonly available materials for screening from X-rays and some other types of radiation. It is widely used in hospitals as part of X-ray equipment, and also in nuclear power stations.

Miscellaneous products
Lead is widely used in shot and other munitions. Some alternatives are available, and are used in situations where lead poses a particular risk to wildlife, especially to birds, as a result of ingestion. Lead is also used extensively in weighting applications.

Lead alloys
Lead-tin solder is widely used, particularly by the electronics industry. Very minor applications are in bearings and ornamental ware (pewter) - though alternative materials are now generally used. Small additions of lead are made to some steels, brasses and bronzes to improve machinability.

COMPOUNDS OF LEAD

Batteries
This is a major use of lead oxide. Lead dioxide is pasted on to the battery grids, and is the active material in the electrochemical reaction.

Pigments and other paint additives
Lead compounds were widely used until a few decades ago. They have been replaced in certain applications following concerns about potential impacts to human health. Leaded paints are still used in specialised outdoor applications as coatings for commercial vehicles and other industrial applications because of excellent rust-proofing properties. Lead dryers are still used in alkyd-based air-drying paints as very efficient and cost effective through-dryers.

Glasses and glazes
Lead additions improve the appearance and cutting properties of crystal glass. Small additions are also made to optical and electrical glass. The major application of leaded glass is in television screens and computer monitors, to protect viewers from the harmful X-rays generated by these appliances. Lead-containing glazes are used for some pottery, tiles and tableware.

Functional ceramics
Lead titanates/zirconates are used in the electronics industry in various functions.

Additions to PVC
Small additions of organic lead compounds to some grades of PVC improve durability and heat resistance, both in manufacture and in service. This is a significant market for lead compounds.

Leaded petrol
Lead compounds were universally added to petrol to improve its efficiency at low cost. This has been the major source of lead emissions to the environment. It is now being phased out almost universally because of concerns about health impacts.