Zinc
Zinc carries the symbol Zn and holds atomic number 30 on the periodic table. It sits as the first element in group 12, also known as IIB. This metal appears slightly brittle at room temperature until surface oxidation is removed. Once cleaned, it displays a shiny blue whitish appearance. Scientists measure its abundance in Earth's crust at roughly 70 grams per ton. That concentration equals 70 parts per million or 0.007 percent of total mass. Five stable isotopes exist naturally within zinc samples. The most abundant form is Zn-64, which makes up nearly half of all natural zinc. Other isotopes include Zn-66, Zn-67, Zn-68, and Zn-70 with varying abundances. Some radioisotopes have been characterized for study purposes. One specific isotope has a half-life of 243.66 days while another lasts only 46.5 hours. Zinc shares chemical similarities with magnesium due to their similar ion sizes. Both elements exhibit a single normal oxidation state of plus two.
Brass alloys containing copper and zinc were used as early as the third millennium BC. These early mixtures appeared across the Aegean area and regions now including Iraq and Georgia. Romans knew how to manufacture brass by about 30 BC using calamine ore. They heated powdered calamine mixed with charcoal and copper inside a crucible. The oldest known pure zinc comes from Zawar in Rajasthan dating back to the 9th century AD. A distillation process created virtually pure metal there during that era. Alchemists burned this zinc metal in air to produce what they called philosopher's wool or white snow. This substance was actually zinc oxide. Andreas Sigismund Marggraf isolated pure metallic zinc in Germany in 1746. He heated a mixture of calamine and charcoal in a closed vessel without any copper present. William Champion patented a vertical retort-style smelter in Great Britain in 1738. His technique resembled methods used at the ancient mines near Udaipur. John Lane carried out experiments to smelt zinc prior to his bankruptcy in 1726. P.M. de Respour reported extracting metallic zinc from zinc oxide in 1668. The name likely originated from Paracelsus who referred to it as zinken meaning tooth-like or pointed.
China produced four million tonnes of zinc in recent years according to mineral commodity summaries. Peru followed with approximately 1.4 million tonnes while Australia contributed around 1.1 million tonnes. India generated 860,000 tonnes and the United States made 750,000 tonnes. About 70 percent of global zinc originates from mining operations worldwide. The remaining 30 percent comes from recycling secondary zinc sources. Commercially pure zinc is known as Special High Grade or SHG. This grade contains 99.995 percent purity levels. Sphalerite remains the most heavily mined zinc-containing ore available today. It contains between 60 and 62 percent zinc by mass. Mines are scattered throughout China, Australia, and Peru among other locations. The ore undergoes froth flotation to separate minerals from gangue material. Roasting converts zinc sulfide concentrate into zinc oxide using oxygen. Pyrometallurgy reduces zinc oxide with carbon at temperatures reaching 950 degrees Celsius. Electrowinning leaches zinc from ore concentrates using sulfuric acid before electrolysis. Nyrstar stands as the world's largest zinc producer through a merger of Australian OZ Minerals and Belgian Umicore. Total identified resources across the globe total between 1.9 and 2.8 billion tonnes.
Nearly two billion people in developing nations suffer from zinc deficiency according to health surveys. Children face increased infection risks and diarrhea contributing to approximately 800,000 deaths annually. Zinc serves as the second most abundant trace metal in humans after iron. It appears in all enzyme classes making it unique among metals. Over 300 enzymes require zinc for proper function within living organisms. Carbonic anhydrase converts carbon dioxide into bicarbonate inside vertebrate blood rapidly. Without this enzyme conversion would occur about one million times slower at normal pH levels. Carboxypeptidase cleaves peptide linkages during protein digestion processes. Roughly two grams of zinc distribute throughout the human body. Most resides in brain muscle bones kidney and liver tissues. Highest concentrations appear in prostate glands and parts of the eye. Semen contains particularly rich amounts supporting reproductive organ growth. Zinc homeostasis controls absorption primarily through intestinal mechanisms. ZIP4 and TRPM7 transporters facilitate essential uptake for postnatal survival. Dysregulation can induce neurotoxicity through mitochondrial oxidative stress pathways. About ten percent of human proteins bind zinc directly according to a 2015 review.
Galvanization accounted for fifty-five percent or 893,000 tons of US zinc usage in 2009. This process coats iron or steel with anti-corrosion layers effectively. Brass alloys combine copper with anywhere from three to forty-five percent zinc depending on type. These mixtures prove more ductile and stronger than pure copper alone. They offer superior corrosion resistance suitable for musical instruments and water valves. Die casting uses alloys containing small amounts of aluminum magnesium and copper. Zamak markets these specific formulations under that brand name globally. Pennies minted since 1982 contain primarily zinc cores coated thinly with copper. In 1994 fifteen billion pennies required significant quantities of zinc metal production. Zinc oxide serves as a white pigment widely used in paints today. It protects rubber polymers and plastics from ultraviolet radiation damage. Zinc sulfide appears in luminescent pigments found on clock hands and television screens. Zinc chloride often gets added to lumber as fire retardant material. Organic chemistry utilizes dimethylzinc and diethylzinc reagents extensively. These compounds perform nucleophilic addition reactions on electrophiles like aldehydes. Zinc dithiocarbamate complexes function as agricultural fungicides including Zineb and Metiram.
Refinement of sulfidic zinc ores produces large volumes of sulfur dioxide gas annually. Smelter slag contains significant quantities of metals alongside cadmium vapor emissions. About 1.1 million tonnes of metallic zinc were mined between 1806 and 1882 in Belgian towns. Sediments of the Geul River contain non-trivial amounts of leaked metals today. Emissions peaked at 3.4 million tonnes per year during the 1980s before declining slightly. Concentrations reaching twenty parts per million occur in rivers flowing through industrial areas. Levels exceeding five hundred ppm interfere with plant absorption of essential iron and manganese. Swallowing post-1982 American pennies can cause stomach lining damage due to high solubility. People taking one hundred to three hundred milligrams daily may suffer induced copper deficiency. Inhalation of zinc fumes while brazing induces a condition called zinc shakes or chills. The FDA ordered removal of zinc-based intranasal cold products from store shelves in June 2009. Loss of smell resulting from these products can be life-threatening for consumers. Excess zinc particularly impairs copper absorption because metallothionein absorbs both metals simultaneously. Six micromolar free ion concentrations killed ninety-three percent of all Daphnia in water samples.
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Common questions
What is the atomic number and symbol of zinc?
Zinc holds atomic number 30 on the periodic table and carries the symbol Zn. It sits as the first element in group 12 also known as IIB.
When was pure metallic zinc first isolated by scientists?
Andreas Sigismund Marggraf isolated pure metallic zinc in Germany in 1746. He heated a mixture of calamine and charcoal in a closed vessel without any copper present.
Which countries produce the most zinc today?
China produced four million tonnes of zinc in recent years while Peru followed with approximately 1.4 million tonnes. Australia contributed around 1.1 million tonnes to global production totals.
How does zinc deficiency affect human health and mortality rates?
Nearly two billion people in developing nations suffer from zinc deficiency according to health surveys. Children face increased infection risks and diarrhea contributing to approximately 800,000 deaths annually.
Why did the FDA remove zinc-based intranasal cold products in June 2009?
The FDA ordered removal of zinc-based intranasal cold products from store shelves in June 2009 due to loss of smell resulting from these products. This condition can be life-threatening for consumers who lose their sense of smell.