Did You Know?Lead was used extensively in construction in the past. In fact, according to the HUD, more than 60% of buildings constructed before 1978, and almost 90% of buildings constructed before 1940, contain lead.
Lead is a soft, malleable metal 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.
A dense, ductile metal with low tensile strength, lead has a face-centered cubic crystalline structure, and poor electrical conductivity. It is highly resistant to corrosion and can be toughened by adding a small quantity of antimony, or other metals, to it. Natural occurrence of lead is very rare; it is found in ores with zinc, copper, and silver, and is later extracted from these elements. The most important mineral that lead is extracted from is Galena (PbS), which contains 86.6% lead. Cerussite (PbCO3), or lead carbonate, is another important ore of lead, as is Anglesite (PbSO4), a lead sulfate mineral that occurs after oxidation of the primary lead sulfide ore, Galena.
Lead was one of the earliest metals discovered by humans. Due to its corrosion-resistive property, the Romans used it to make water pipes and for lining baths. Later, it was used to cover ship hulls. Around 4,000 years ago, the Chinese started using lead to forge coins. Moreover, lead was used for roofing and construction purposes because of its high fire and water-resistive properties. In ancient times, lead was also widely used in sculptures and decorative objects.
With the passage of time, the uses for lead have grown to a wider aspect. Lead, in one form or the other, is present all round us. The various uses of lead have been discussed below.
Apart from the above, there are also other miscellaneous uses of lead. Some of the other beneficial uses for lead have been listed below.
- Lead is also used for the lining of chemical treatment baths, acid plants and storage vessels.
- It is utilized to form glazing bars for stained glass or other multi-lit windows.
- 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, in the form of strips or tape, is used in the manufacturing of tennis rackets to increase their weight.
- Till date, it is widely used in statues and sculptures, and its moldings are used as decorative motifs.
- Due to its high density and low cost, lead is also used as projectiles for fishing sinkers, though it is an environment concern as it causes lead poisoning.
- Earlier, lead was used to balance the wheels of a car, but has now been phased out due to environmental concerns of lead poisoning.
Lead poisoning is quite common in people who consume water stored in lead containers or use water pipes made of lead. Leaded gasoline has been banned in most countries due to the adverse effects it has on health. The manufacture of paints containing lead have also been banned in many countries, because of the harmful health effects they generate. Thus, along with versatility, lead can be quite harmful to mankind if not used in a proper manner.