![]() Some are completely eroded away and may be recycled by natural processes into the earth. These deposits may eventually be exposed at the surface following weathering and erosion. ![]() Other fluids may escape to the surface through fractures into shallow seas and under suitable conditions, lead-zinc-silver deposits may form.įor thousands of millions of years, deposits have been forming in these manners. Examples of this last type of deposit are forming today under the oceans off Papua New Guinea, Canada and elsewhere in the world. Some fluids may reach the ocean floor in areas of underwater volcanic activity to form volcanogenic deposits. Where limestones occur, the fluids may flow through cavities to form rich but patchy deposits. These fluids may flow along sub-surface fractures where sphalerite and other minerals may precipitate to make vein deposits. In some cases, these secondary minerals are also zinc ores.ĭeposits containing zinc form from hot, aqueous (or hydrothermal) fluids generated within the earth. Smithsonite (ZnCO3, 52%), willemite (Zn2SiO4, 59%) and hemimorphite (Zn4Si2O7(OH)2 H2O, 54%) may occur in the near-surface weathered or oxidised zone of an orebody. The main zinc mineral is sphalerite ((Zn,Fe)S), which contains up to 67% zinc by mass. The Romans also used calamine for healing wounds.Pure zinc was probably first produced in India and China in the 13th or 14th century.Commercial production of zinc did not start in Europe until the middle of the 18th century and until 1860 in the United States. They did not actually realise that zinc was a metal. The Romans and Chinese smelted zinc ores such as calamine (zinc carbonate) with copper to produce brass, used for coins, containers, armour and jewellery. Zinc (Zn) was used in Rome and China more than 2000 years ago as a component of brass which is a zinc-copper alloy. Zinc dust is very flammable when dry so it is used in fireworks. In luminous dials on watches, TV screens and fluorescent lights.Īs a dissolving agent, to help prevent plastics from cracking, in surgical dressings, glues, and to preserve and fire-proof timber. Zinc oxide is a unique and very useful material, used in the manufacture of rubber tyres, skin products (such as zinc cream, anti-dandruff shampoos, antiseptic ointments and calamine lotion for healing skin disorders), paints, floor coverings, plastics (to help prevent them cracking) and ceramic glazes. Fruits, nuts, meat, oysters and other shellfish are good sources of zinc. Humans and other animals need to ingest zinc for proper growth and healing of wounds to occur. Zinc is also used in the very common zinc-carbon battery, and zinc-bromide and zinc-nickel power cells are amongst the newest types of batteries. When alloyed with other metals, zinc becomes a good electrical conductor. Brass is also used to make decorative pieces, from light fittings to taps, and instruments for astronomy, surveying, navigation and other scientific purposes. Many musical instruments are made from brass. Its low melting point enables it to be diecast (cast into different shapes in steel moulds) to make all sorts of items (some requiring fine detail) from carburettors to door handles, staples to zips, even MatchboxÔ cars.īrass (70% copper, 30% zinc) is particularly rust-resistant and so is used to make the hulls of sailing boats and other marine hardware. Zinc mixed with small amounts of aluminium produces a very strong alloy. Products include steel beams, roofs, poles, wires, nails, household appliances and car bodies. ![]() The steel is dipped in molten zinc, often also with aluminium. About two-thirds of all the zinc used in Australia today is to protect steel from rusting, by coating it using a process called galvanising (named after the Italian chemist, Luigi Galvani, who invented the process).
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