Lead is used in various part of life directly and indirectly. It’s biggest use in batteries specially in Lead acid battery world wide. It is also used in ammunition (bullets and shot), in pipes, cable, Lead sheet and others. The use of Lead sheet in construction and Lead cable sheathing in communications Ammunition and Metallic Lead is consumed in the manufacture of ammunition, bearing metals, and other Lead products, with subsequent Lead emissions. Lead used in the manufacture of ammunition is melted and alloyed before it is cast, sheared, extruded, swaged, or mechanically worked. Some Lead is also reacted to form Lead aside, a detonating agent. Lead is used in bearing manufacture by alloying it with copper, bronze, antimony, and tin, although Lead usage in this category is relatively small. Other Lead products include tern metal (a plating alloy), weights and ballasts, caulking Lead, plumbing supplies, roofing materials, casting metal foil, collapsible metal tubes, and sheet Lead. Lead is also used for galvanizing, annealing, and plating. In all of these cases Lead is usually melted and cast prior to mechanical forming operations.
The biggest use of Lead worldwide is for the Lead-acid battery. The commonest type of Lead-acid battery consists of a heavy duty plastic box containing Lead alloy pasted grids. The grids are made from a Lead-antimony together with minor additions of elements such as copper, arsenic, tin and selenium. These are added to confer properties such as grain refinement, fluidity and age-hardening characteristics to the grids. For the new generation of sealed, maintenance free batteries a range of Lead calcium-(tin) alloys is used. These contain up to 0.1% calcium and from zero to 0.5% tin. The tin-containing alloys are used in the positive grids to protect against corrosion. A rechargeable cell is known as a secondary cell and provides a means of storing electricity. Lead is particularly well suited for this application because of its conductivity and its resistance to corrosion. The addition of antimony or calcium gives the Lead an increased hardness to resist the mechanical stresses within the battery caused, for example, by the natural vibration of road vehicles and by the chemical reactions taking place.
The benefits of Lead sheet are considerable: it is rugged, flexible and long lasting and has considerable aesthetic appeal. Around 75% of the Lead sheet consumed by the building industry is used as flashings or weathering to prevent water penetrating at points such as the bases of chimney stacks and abutments. The remaining 25% or so of the Lead sheet is used for roofing and cladding. The use of Lead for roofing is by no means confined to traditional applications such as churches and historic buildings; architects have been won over to the attractive and long lasting properties of Lead sheet for modern buildings, both for roofing and for the vertical cladding of external walls.
By virtue of its resistance to chemical corrosion, Lead sheet also finds use for the lining of chemical treatment baths, acid Plant and storage vessels. The high density of Lead sheet and its “limpness” makes it a very effective material for reducing the transmission of noise through partitions and doors of comparatively lightweight construction. Often the Lead sheet is adhesively bonded to plywood or to other building boards for convenience of handling. A particular advantage of Lead’s high density is that only relatively thin layers are needed to suppress the transmission of sound. This makes for important space savings in the design of large modern buildings such as hotels and office blocks.
Pipe made from Lead and Lead alloys is used for its corrosion resistance and flexibility in the chemical industry and in plumbing and water distribution systems.
An electric cable consists essentially of three major components:
- Conductors to transmit power or electrical signals.
- Insulation surrounding the conductors to protect users.
a sheath and other layers surrounding the insulation to exclude moisture and protect it from corrosion and mechanical damage during the lifetime of the cable.
Due to its excellent proven corrosion resistance when in contact with a wide range of industrial and marine environments, soils and chemicals, Lead was one of the first materials to be used to provide an impervious sheath on electric cables .
Lead has the major advantage that it can be applied to the cable core in unlimited lengths by extrusion at temperatures which do not damage even the most sensitive conductors (optical fibers) or insulating materials (paper or plastics). Lead is pliable and so can withstand the several coiling, uncoiling, handling and bending operations involved during the later manufacturing stages and installation of the cable. A Lead sheath can be readily soldered (again at low temperatures) when cable lengths need to be jointed or new cables installed. With modern screw-type continuous extruders, un-jointed lengths of submarine power cables as long as 100 kilometers have been produced.
Lead cames have long been a feature of stained glass windows in churches and cathedrals. They consist of H-shaped sections of Lead which hold together the individual pieces of glass. They are now being used more widely in modern homes both in the traditional way and in the form of self-adhesive strips stuck on to a larger piece of glass to simulate an integral came. The use of Lead in this manner is attractive and lends a traditional air to a home.
This composite material is manufactured by cold rolling Lead sheet on to sheet steel which has been pretreated with a thin tin-Lead alloy coating (terne plate). This forms a strong metallurgical bond between the Lead and the steel and provides a material that combines the physical and chemical properties of Lead with the mechanical properties of steel. Although primarily aimed at the sound insulation market, Lead clad steel has also found use in radiation shielding and in the cladding of buildings.
Lead powder incorporated into a plasticizer is added to plastics to form sheets of Lead loaded plastic. This material is used to make radiation protective clothing and aprons for the medical, scientific and nuclear industries. It also has sound insulating properties. Lead powder is also used as the basis for some corrosion resistant paints.
By far the biggest use of Lead-antimony alloys is in batteries. Lead-antimony alloys with antimony contents of between 1 and 12% are used widely in the chemical industry for pumps and valves on chemical Plant and in radiation shielding both for lining the walls of X-ray rooms and for bricks to house radioactive sources in the nuclear industry.
Lead for Radiation Shielding
Lead and its alloys in metallic form and Lead compounds are used in various forms of radiation shielding. Their high densities meet the primary requirement of a shielding material and in certain shielding applications Lead’s high atomic number is also important. The ease with which Lead can be worked is of added value. The shielding of containers for radioactive materials is usually metallic Lead. Radioactive materials in laboratories and hospitals are usually handled by remote control from a position of safety behind a wall of Lead bricks and X ray machines are normally installed in rooms lined with sheet Lead. Lead compounds are a constituent of the glass used in shielding partitions to permit safe viewing and Lead powder is incorporated into plastic and rubber sheeting as a material for protective clothing.
Lead in Glass
Decorative Lead crystal glass is one of the most attractive forms in which Lead is used. Normally added in the form of Lead oxide at 24-36%, it adds luster, density and brilliance to the glass. The glass is further enhanced by its ability to have decorative patterns cut on it and has the characteristic ring associated with Lead crystal. There is now a substantial market for a cheaper form of Lead ‘semi-crystal’ containing in the region of 14-24% Lead oxide and glasses are usually molded with the decorative pattern rather than hand-cut later.
Lead is also used in optical glasses (e.g.: telescopes, binoculars), ophthalmic glass (e.g. spectacles), electrical glass (e.g.: lamp tubing) and radiation protection glasses (e.g.: for windows for radiation remote handling boxes, TV tubes)
Lead for Ceramics
Lead is used in a wide range of glaze formulations for items such as tableware (earthenware and china), wall and floor tiles, porcelain and some sanitary ware. The Lead compounds used are largely litharge, red Lead and Lead silicates. The advantageous properties offered by Lead compounds are lower melting points and wider softening ranges, low surface tension, good electrical properties and a hard wearing and impervious finish. Considerable research effort has been put into developing glazes with very low Lead release. Lead compounds are also used in the formulation of enamels used on metals and glasses.
The use of white Lead (basic Lead carbonate) in decorative paints has been phased out but still has the reputation of making paint with good external weathering characteristics,
Red Lead is the traditional pigment for rust-inhibiting priming paints applied direct to iron and steel. Calcium plumbate based paints are particularly effective on galvanized steel avoiding the need for etch primers.
Lead chromate (yellow) and Lead molybdate (red orange) are still used in plastics and to a lesser extent paints. Lead chromate is used extensively as the yellow pigment in road markings.
Lead wool is made by scratching fine strands from the surface of a Lead disc. It is used for the caulking of joints in large pipes e.g. gas mains and in some specialist batteries.