Zinc
Introduction
Zinc is a chemical element with the symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a silver-grey hue. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral.
Properties and Characteristics
Zinc is a transition metal that occurs in the center of the periodic table. The periodic table is a chart that shows how chemical elements are related to each other. Zinc is also known as a "heavy metal" and has a density about five times the density of water. This metal is not considered toxic and is an essential nutrient in the human body.
Zinc has a hexagonal crystal structure and is a fair conductor of electricity. It exhibits a variety of unique physical properties, including high ductility, high thermal conductivity, and high resistance to corrosion. Zinc is also highly recyclable and is often reused in various applications.
History
The element zinc was discovered in India in 1746 by the German chemist Andreas Marggraf. However, zinc ores were commonly used to make brass many centuries prior to the discovery of the element. The use of zinc ores in brass was mentioned in Greek, Roman, and Sanskrit texts.
The name "zinc" is derived from the German word "Zinke," which means "pointed." This is likely a reference to the sharp, pointed crystals formed after zinc is smelted.
Production and Refinement
Zinc is the fourth most commonly used metal, following iron, aluminum, and copper. Its primary use is in galvanizing, which is the process of applying a protective zinc coating to iron or steel to prevent rusting.
The most common method of zinc production is the process of roasting and sintering, followed by reduction and refining. The zinc ores are crushed and ground to a fine powder before being roasted in a furnace to produce zinc oxide. The zinc oxide is then reduced by carbon to zinc metal.
Applications
Zinc is used in a wide variety of applications. The most common use is in the galvanization of steel and iron products, which accounts for about 50% of its use. Zinc is also used extensively in the battery industry, in the form of zinc-carbon and alkaline batteries. Other applications include the production of alloys such as brass, bronze, and nickel silver, and in the manufacture of die-casting alloys.
Zinc is also used in the pharmaceutical industry, where it is an essential component in the production of certain medications. It is also used in the production of paint, rubber, cosmetics, plastics, inks, soap, batteries, textiles, and electrical equipment.
Biological Role
Zinc is an essential trace element, necessary for the growth and development of all organisms. It is required for the function of over 300 enzymes and involved in many important processes in the body. Zinc deficiency can lead to a variety of health problems, including growth retardation, low blood pressure, retardation of sexual maturation, loss of appetite, and impaired immune function.
Environmental Impact
While zinc is an essential element for life, excessive levels of zinc can be harmful to the environment. Zinc pollution is primarily caused by the industrial production of zinc and by the burning of coal and waste. When released into the environment, zinc can become a danger to plants, animals, and humans.