Uses of Lead

Lead is a soft, malleable metal which is included in the group of heavy metals. It has a lustrous silver-blue appearance when freshly cut, but darkens to a dull grayish color when exposed to moist air. This occurs due to the immediate formation of an oxide film that protects the metal from further oxidation or corrosion. Lead is a dense, ductile metal with a low tensile strength. It has a face-centered cubic crystalline structure and poor electrical conductivity. Lead is highly resistant to corrosion and can be toughened by adding a small quantity of antimony, or other metals to it.

Generally, lead is the end product of a radioactive decay, hence it is harmful in nature and causes lead poisoning. The natural occurrence of lead is very rare, hence it is found in ores with zinc, copper, silver, and is later extracted from these elements. The primary lead mineral is galena (PbS) that contains 86.6% lead. Some other popular varieties of lead are anglesite (PbSO₄) and cerussite (PbCO₃).

Uses of Lead

Lead can be used as a pure metal, alloyed with other metals, or as a chemical compound. The uses of lead are as follows:

• It is a major component of the lead acid battery and is commonly used in a car battery.
• Due to its high density, weight-to-volume ratio and resistance against corrosion, lead is used for the ballast keel of sailboats and scuba diving weight belts.
• It is utilized to form glazing bars for stained glass or other multi-lit windows.
• Due to its low melting point and cost, lead is used as projectiles for fishing sinkers and firearms.
• White lead, lead sulphate and lead chromate are used as coloring elements in paints and ceramic glazes, notably in the colors red and yellow.
• It is commonly used in polyvinyl chloride (PVC) plastic, that covers electrical cords.
• Lead sheets are utilized in the construction industry for weathering, roofing and cladding, to prevent water penetration. It is also used for the lining of chemical treatment baths, acid plants and storage vessels. By the virtue of its high density, lead sheet is used for sound insulation and radiation shielding.
• Molten lead is utilized as a coolant for lead cooled fast reactors.
• It is the base metal used for organ pipes and is mixed with variable amounts of tin to control the tone of the pipe.
• Lead is used in soldering and as electrodes in the process of electrolysis.
• It is used in high voltage power cables as a sheathing material to prevent water diffusion into insulation.
• Lead, in the form of strips or tape is used in the manufacturing of tennis racquets to increase its weight.
• It is widely used in statues and sculptures and its moldings are used as decorative motifs.
• Tetra-ethyl lead is utilized as an anti-knock additive for aviation fuel in piston-driven aircrafts.
• Lead telluride, lead antimonide and lead selenide are some of the lead based semiconductors which are used in photovoltaic (solar energy) cells and infrared detectors.
• Earlier, lead was used to balance the wheels of a car, but now this application has been phased out due to environmental reasons.

Some other applications of lead, include the making of leaded bronze ornaments, toys, bullets and shot, lead weights and coffins. It is also used in medicinal ointments like soothing lotions, but has to be kept in lead containers. It is estimated that more than 1 million tons of lead is retrieved annually by recycling batteries.