WikiPortallus: Zinc.html

Zinc (pronounced /ˈzɪŋk/, from German: Zink) is a metallic chemical element with the symbol Zn and atomic number 30. Although zinc was used in the copper-zinc alloy brass since Roman times, and the metal was produced in large scale in India around 1200 AD, the pure metal was unknown to Europe until the end of the 16th century. Industrial-scale production in Europe had not started until the late 18th century. Corrosion-resistant zinc plating of steel is the major application for zinc. Other applications are in batteries and alloys, such as brass. Sphalerite, a zinc sulfide, is the most important zinc ore. Zinc production includes roasting, leaching and, at the end, pyrometallurgic winning or electrowinning.

Characteristics

Zinc, also referred to in nonscientific contexts as spelter,¹ is a moderately reactive bluish-grey metal that tarnishes in moist air. It can also burn in air with a bright bluish-green flame, giving off fumes of zinc oxide. It reacts with acids, alkalis and other non-metals.² If not completely pure, zinc reacts with dilute acids to release hydrogen. The one common oxidation state of zinc is +2³

From 100 °C to 210 °C (212 °F to 410 °F) zinc metal is malleable and can be easily beaten into various shapes. Above 210 °C (410 °F), the metal becomes brittle and can be pulverized by beating.⁴ Zinc is nonmagnetic.

Isotopes

Naturally occurring zinc is composed of 5 stable isotopes: ⁶⁴Zn, ⁶⁶Zn, ⁶⁷Zn, ⁶⁸Zn, and ⁷⁰Zn. Although it slowly decays, ⁶⁴Zn is considered stable because its half-life is over 2.3×10¹⁸ years. The most abundant isotope is ⁶⁴Zn at 48.6%, and the least abundant is ⁷⁰Zn at .6%. 25 radioisotopes have been characterised, ranging in atomic mass from 54 to 83. The most stable of these are ⁶⁵Zn with a half-life of 244.26 days and ⁷²Zn with a half-life of 46.5 hours. The least stable of those whose half-lives have been measured are ⁵⁵Zn and ⁵⁶Zn with half-lives of 20 ms and 36 ms, respectively. Zinc also has at least 9 meta states ranging in atomic mass from 61 to 78. ⁶¹Zn has three excitation states, the highest of which has a half-life of 130 ms.⁵

Zinc has been proposed as a salting material for nuclear weapons (cobalt is another, better-known salting material). A jacket of isotopically enriched ⁶⁴Zn, irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope ⁶⁵Zn with a half-life of 244 days and produce approximately 2.27 MeV of gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several days. Such a weapon is not known to have ever been built, tested, or used.⁶

Occurrence

Zinc is the 23rd most abundant element in the Earth's crust. The most heavily mined ore, sphalerite, tends to contain roughly 10% iron as well as 40–50% zinc. Other minerals from which zinc is extracted include smithsonite (zinc carbonate), hemimorphite (zinc silicate), and franklinite (a zinc spinel).

At the current rate of consumption, the earth has been estimated to have 46 years supply of zinc remaining.⁷ Based on data gathered by the United States Geological Survey and the University of Augsburg, the available supply has also been estimated to last for 20 to 30 years.⁸

Compounds

History

Antiquity

The name of the metal zinc is unusual and, while vague in origin, was probably first used by Paracelsus, a Swiss-born German chemist, who referred to the metal as "zincum" in the 16th century.⁹ The word supposedly meant "tooth-like, pointed or jagged part" and, as metallic zinc crystals are needle-like, the derivation appears plausible.

The zinc mines of Zawar, near Udaipur, India, were active around 400 BC, and there are references to medicinal uses of zinc in the Charaka Samhita, which is believed to have been written as early as 300 BC.¹⁰ The Rasaratna Samuccaya, written in approximatley 800 AD, explains the existence of two types of ores containing zinc metal, one of which is ideal for metal extraction while the other is used for medicinal purposes.¹⁰ Because of the low boiling point and high chemical reactivity of this metal, the true nature of it may not have been fully understood in ancient times.

The manufacture of brass was known to the Romans by about 30 BC, using a technique in which calamine and copper were heated together in a crucible. The zinc oxides in calamine were reduced, and the free zinc metal was trapped by the copper, forming an alloy. The resulting calamine brass was then either cast or hammered into shape.

Smelting and extraction of impure forms of zinc were accomplished around 1200 AD in India.⁹ The Chinese did not learn of the technique until the 17th century AD.⁹ In the West, impure zinc was known since antiquity to exist in the remnants in melting ovens, but it was usually discarded, as it was thought to be worthless. Strabo mentions it as pseudo-argyros—"mock silver". The Berne zinc tablet is a votive plaque dating to Roman Gaul, probably made from such zinc remnants.

Pure zinc

In 1597, German metallurgist Andreas Libavius received a quantity of zinc metal in its pure form, which was unknown in the West before then. Libavius referred to it as Indian lead and Malabar lead. It was regularly imported to Europe from the Orient in the 17th and early 18th centuries,⁹ but was at times very expensive.

The isolation of metallic zinc in the West may have been achieved independently by several people:

In 1758, William's brother, John, developed a new process for calcining zinc sulfide into an oxide for use in the retort process. Prior to this only calamine could be used to produce zinc. This process was then used into the 20th century. In 1798, Johann Ruberg built the first horizontal retort smelter in Upper Silesia. This was much more fuel efficient and less labor intensive than the vertical retort process. Jean-Jacques Daniel Dony built a different kind of horizontal zinc smelter in Belgium, which processes more.⁹

Production

Zinc is the fourth most common metal in use, trailing only iron, aluminium, and copper with an annual production of 11.38 megatonnes.^{citation needed} The world's largest zinc producer is Nyrstar, a merger of the Australian Zinifex and the Belgian Umicore.¹⁵ About 70% of the world's zinc originates from Mining, while the remaining 30% comes from recycling, secondary zinc.¹⁶

Zinc metal is produced using extractive metallurgy. Worldwide, 95% of the zinc is mined from sulfidic ore deposits, in which sphalerite ZnS is nearly always mixed with the sulfides of copper, lead and iron. After grinding the ore froth flotation, which selectively separates minerals from gangue by taking advantage of differences in their hydrophobicity, is used to get a ore concentrate. A final concentration of zinc in the range of 40–60% is reached by this process. Roasting converts zinc sulfide to zinc oxide.¹⁷

The sulfur dioxide is used for the production of sulfuric acid, which is necessary for the leaching process. If deposits of zinc carbonate, zinc silicate or zinc spinel, like the Skorpion Deposit in Namibia are used for zinc production the roasting can be omitted.¹⁸ For further processing two basic methods are used pyrometallurgy or electrowinning. The first is the older process in which the zinc oxide is reduced by carbon or carbon monoxide at high temperatures of 950 °C (1,740 °F) into the metal which is distilled of as zinc vapour. The zinc vapour is collected in a condenser.¹⁷

For the second process the zinc is leached from the ore concentrate by sulfuric acid. The following electrolysis makes it necessary to precipitate the also leached sulfates of other metals, like iron, nickel and copper. After this step electrolysis is used to produce the zinc metal.¹⁷

Commercially pure zinc is known as Special High Grade, often abbreviated SHG, and is 99.995% pure.¹⁹

Environmental Impacts

The production of zinc which is often combined with the production of lead results in environmental problems, because the production for sulfidic ores produces large amounts of sulfur dioxide and cadmium vapor and the smelter slag and other residues contain significant amounts of heavy metals. The Belgian towns of La Calamine and Plombières are good examples for the environmental impacts of the industrial mining and smeltering of 1,100,000 tonnes of metallic zinc and 130,000 tonnes of lead between 1806 and 1882.²⁰ The dumps of the mining operations leach significant amounts of zinc and cadmium and the sediments of the Gaul river contain significant amounts of heavy metals.²⁰

Applications

Metal and alloys

The most important application of zinc is coating of iron or steel as protection against corrosion. Although zinc is more reactive than iron or steel it forms a protective oxide and carbonate (Zn₅(OH)₆(CO₃)₂) layer which protects the material underneath. The zinc is applied electrochemically by galvanize or as liquid zinc by hot-dip galvanizing or spraying. The galvanization zinc layer is thinner when applied by hot-dipping, but hot dipping induces a thermal stress in the material, because the molten zinc has a temperature of 460 °C. In 2006 in the United States 56% or 773,000 tonnes of the zinc metal was used for this purpose,²² while worldwide 47% was used for this purpose.²³ Similar corrosion resistance can be achieved by plating with tin or cadmium.

Alloys of primarily zinc with small amounts of copper, aluminium, and magnesium are useful in die casting as well as spin casting, especially in the automotive, electrical, and hardware industries. These alloys are marketed under the name Zamak. An example of this is zinc aluminium. The low boiling point together with the low viscosity of the alloy makes the production of small and intricate shapes possible. The low working temperature leads to rapid cooling of the casted products and therefore fast assembly is possible.²³²⁴²⁵ Similar alloys with the addition of a small amount of lead can be cold-rolled into sheets. An alloy of 96% zinc and 4% aluminium is used to make stamping dies for low production run applications where ferrous metal dies would be too expensive.²⁶ Zinc for building facades, roofs or other applications where zinc is used as sheet metal and methods like deep drawing, roll forming or bending used zinc alloys with titanium and copper are used. Unalloyed zinc is too brittle for these kind of manufacturing processes.²⁷

An important alloy of zinc is brass, in which copper is alloyed with anywhere from 9% to 45% zinc, depending upon the type of brass, along with much smaller amounts of lead and tin. Other widely used alloys contain zinc, including nickel silver, typewriter metal, soft and aluminum solder, and commercial bronze.²⁵ Zinc is also used in contemporary pipe organs as a substitute for the traditional lead/tin alloy in pipes.²⁸ Alloys of 85–88% zinc, 4–10% copper, and 2–8% aluminium find limited use in certain types of machine bearings. Zinc is the primary metal used in making American one cent coins since 1982.²⁹ The zinc core is coated with a thin layer of copper to give the impression of a copper coin. In 1994, 33,200 tons of zinc were used to produce 13.6 billion pennies.³⁰

Electrochemistry

With a electrochemical potential of -0.7628 volt, zinc make a good material for anode materials. Zinc is used as part of batteries. The most widespread such use is as the anode in alkaline batteries and the similar zinc-carbon batteries, in which (for both types) the oxidation of the zinc is the reaction at the anode.³¹³²

Other

Zinc oxide is perhaps the best known and most widely used zinc compound, as it makes a good base for white pigments in paint. It also finds industrial use in the rubber industry, and is sold as opaque sunscreen. A variety of other zinc compounds find use industrially, such as zinc chloride (in deodorants), zinc pyrithione (anti-dandruff shampoos), zinc sulfide (in luminescent paints), and zinc methyl or zinc diethyl in the organic laboratory. Roughly one quarter of all zinc output is consumed in the form of zinc compounds.

Biological role

Zinc is an essential trace element, necessary for sustaining all life. It is a key factor in prostate gland function and reproductive organ growth. It is estimated that 3,000 of the hundreds of thousands of proteins in the human body contain zinc prosthetic groups, one type of which is the so-called zinc finger, and most of zinc is contained in muscles and bones. In addition, there are over a dozen types of cells in the human body that secrete zinc ions, and the roles of these secreted zinc signals in medicine and health are now being actively studied. Zinc ions are now considered to be neurotransmitters^{citation needed}. Cells in the salivary gland, prostate, immune system and intestine use zinc signaling.⁴⁸

In humans, zinc is a cofactor for over 100 enzymes, notably certain metalloenzymes. It is absorbed 15 to 40 percent in the intestines, with higher absorption when zinc status is low. Once absorbed, it may be held in metallothionein reserves within the intestines or the liver. Zinc is also recycled through the pancreas, which secretes zinc-containing enzymes into the intestines at mealtimes in a process called enteropancreatic circulation. Zinc is transported through the blood by albumin and transferrin. Since transferrin also transports iron, excessive iron reduces zinc absorption, and vice-versa. A similar situation exists with zinc and copper.⁴⁹ As of 2005 an effective measure of zinc status in humans "remained elusive", although a method involving reverse transcription polymerase chain reaction showed promise.⁵⁰ Plasma zinc concentrations are insensitive indicators of zinc status since a narrow homeostatic range is maintained in the body.⁵¹^:447

Zinc is an activator of certain enzymes, such as carbonic anhydrase. Carbonic anhydrase is important in the transport of carbon dioxide in vertebrate blood. It is also required in plants for leaf formation, the synthesis of indole acetic acid (auxin) and anaerobic respiration (alcoholic fermentation).⁵²

Zinc is a good lewis acid, making it a useful catalytic agent in hydroxylation and other enzymatic reactions. Also zinc has a flexible coordination geometry, allowing enzymes using zinc to rapidly shift conformations and perform biological reactions.⁵³

Sources

Zinc is found in oysters, and to a far lesser degree in most animal proteins, beans, nuts, almonds, whole grains, pumpkin seeds, sunflower seeds and blackcurrant.⁵⁴ A turkey's neck and beef's chuck or shank also contain significant amounts of zinc. Phytates, which are found in whole grain breads, cereals, legumes and other products, have been known to decrease zinc absorption. Clinical studies have found that zinc, combined with antioxidants, may delay progression of age-related macular degeneration.⁵⁵ Soil conservation analyzes the vegetative uptake of naturally occurring zinc in many soil types. The US recommended dietary allowance of zinc from puberty on is 11 milligrams for males and 8 milligrams for females, with higher amounts recommended during pregnancy and lactation.

Other sources include fortified food and dietary supplements, which come in various forms. A 1998 review concluded that zinc oxide, one of the most common supplements in the United States, and zinc carbonate are nearly insoluble and poorly absorbed, and cited studies which found low plasma zinc concentrations after zinc oxide and zinc carbonate consumption relative to the plasma concentrations seen after consumption of zinc acetate and sulfate salts.⁵⁶ For fortification, however, a 2003 review recommended zinc oxide in cereals as cheap, stable, and as easily absorbed as more expensive forms.⁵⁷ A 2005 study found that various compounds of zinc, including oxide and sulfate, did not show statistically significant differences in absorption when added as fortificants to maize tortillas.⁵⁸

Deficiency

Zinc deficiency occurs where insufficient zinc is available for metabolic needs. It is usually nutritional, but can also be associated with malabsorption, acrodermatitis enteropathica, chronic liver disease, chronic renal disease, sickle cell disease, diabetes, malignancy, and other chronic illnesses.

Zinc has been identified as one of ten major factors contributing to disease in developing nations. In Southeast Asia and sub-Saharan Africa, zinc intake is inadequate for one-third of the population and stunted growth affects 40% of children. Although the case for food fortification or dietary supplementation seems strong, it has been relatively neglected; the World Health Organization only advocates zinc supplementation for severe malnutrition and diarrhea. Evidence suggests that zinc supplements prevent disease and reduce mortality, especially among children with low-birth weight or stunted growth. However, zinc supplements should not be administered alone, since many in the developing world have several deficiencies, and zinc interacts with other micronutrients.⁵⁹

Immune system

Zinc salts are effective against pathogens in direct application. Gastroenteritis is strongly attenuated by ingestion of zinc, and this effect could be due to direct antimicrobial action of the zinc ions in the GI tract, or to the absorption of the zinc and re-release from immune cells (all granulocytes secrete zinc), or both.⁶⁰⁶¹

In clinical trials, both zinc gluconate and zinc gluconate glycine (the formulation used in lozenges) have been shown to shorten the duration of symptoms of the common cold.⁶² The amount of glycine can vary from two to twenty moles per mole of zinc gluconate. One review of the research found that out of nine controlled experiments using zinc lozenges, the results were positive in four studies, and no better than placebo in five.⁶³ This review also suggested that the research is characterized by methodological problems, including differences in the dosage amount used, and the use of self-report data. The evidence suggests that zinc supplements may be most effective if they are taken at the first sign of cold symptoms.

Precautions

Toxicity

Even though zinc is a very essential requirement for a healthy body, excess zinc can be harmful. Excessive absorption of zinc can also suppress copper and iron absorption. The free zinc ion in solution is highly toxic to plants, invertebrates, and even vertebrate fish. The Free Ion Activity Model (FIAM) is well-established in the literature, and shows that just micromolar amounts of the free ion kills some organisms. A recent example showed 6 micromolar killing 93% of all Daphnia in water.⁶⁴

The free zinc ion is also a powerful Lewis acid up to the point of being corrosive. Stomach acid contains hydrochloric acid, in which metallic zinc dissolves readily to give corrosive zinc chloride. Swallowing a post-1982 American one cent piece (97.5% zinc) can cause damage to the stomach lining due to the high solubility of the zinc ion in the acidic stomach.⁶⁵

There is evidence of induced copper deficiency at low intakes of 100–300 mg Zn/d. The USDA RDA is 15 mg Zn/d. Even lower levels, closer to the RDA, may interfere with the utilization of copper and iron or to adversely affect cholesterol.⁶⁶

There is also a condition called the zinc shakes or "zinc chills" that can be induced by the inhalation of freshly formed zinc oxide formed during the welding of galvanized materials.

Poisoning

In 1983, the United States Mint began minting pennies coated in copper but made primarily of zinc. With the new zinc pennies, there is the potential for zinc toxicosis, which can be fatal. One reported case of chronic ingestion of 425 pennies (over 1 kg of zinc) resulted in death due to gastrointestinal bacterial and fungal sepsis, while another patient, who ingested 12 grams of zinc, only showed lethargy and ataxia (gross lack of coordination of muscle movements).⁶⁷ Several other cases are reported of humans suffering zinc intoxication by the ingestion of zinc coins.⁶⁸⁶⁹

Pennies and other small coins are sometimes ingested by dogs, resulting in the need for medical treatment to remove the foreign body. The zinc content of some coins can also cause zinc toxicity, which is commonly fatal in dogs, where it causes a severe hemolytic anemia, also liver or kidney damage; vomiting and diarrhoea are possible symptoms.⁷⁰⁷¹⁷² Zinc is highly toxic in parrots and poisoning can often be fatal.⁷³

Notes

^ "Spelter". American Heritage Dictionary of the English Language. Houghton Mifflin (2000). Retrieved on 2008-11-29.
^ Holleman, Arnold F.; Wiberg, Egon; Wiberg, Nils; (1985). "Zink" (in German). Lehrbuch der Anorganischen Chemie (91–100 ed.). Walter de Gruyter. pp. 1034–1041. ISBN 3-11-007511-3.
^ Gmelin, Leopold; List, K. (1853). "Zink" (in German). Handbuch der anorganischen Chemie. 3. Karl Winter. pp. 1–49. http://books.google.de/books?id=99APAAAAQAAJ.
^ Scoffern, John (1861). The Useful Metals and Their Alloys. Houlston and Wright. http://books.google.de/books?id=SSkKAAAAIAAJ.
^ Audi, Georges (2003). "The NUBASE Evaluation of Nuclear and Decay Properties". Nuclear Physics A (Atomic Mass Data Center) 729: 3–128. doi:10.1016/j.nuclphysa.2003.11.001.
^ Win, David Tin; Masum, Al (2003). "Weapons of Mass Destruction" (PDF). AU Journal of Technology (Assumption University) 6 (4): 199–219. http://www.journal.au.edu/au_techno/2003/apr2003/aujt6-4_article07.pdf.
^ Cohen, David (2007). "Earth audit". New Scientist 194 (2605): 8. http://search.ebscohost.com/login.aspx?direct=true&db=aph&AN=27199200&site=ehost-live.
^ "Augsberg University Calculate When Our Materials Run Out". IDTechEx (2007-06-04). Retrieved on 2008-12-09.
^ ^a ^b ^c ^d ^e ^f ^g ^h Habashi, Fathi. "Discovering the 8th Metal" (PDF). International Zinc Association (IZA). Retrieved on 2008-12-13..
^ ^a ^b ^c Craddock, P. T.; Gurjar L. K.; Hegde K. T. M. (1983). "Zinc production in medieval India". World Archaeology 15 (2): 211–21. http://www.jstor.org/pss/124653.
^ Metals Reference and Encyclopedia (Atlas Publishing Co, 1968).
^ R. O. Roberts, 'Dr John Lane and the foundation of the non-ferrous metal industry in the Swansea valley' Gower 4 (1951), 19–24; F. V. Emery, 'Further light on Dr John Lane' Gower 20 (1969), 8–13; R. O. Roberts, 'Further note on Dr John Lane' Gower 22 (1972), 23-5.
^ Rhys Jenkins, 'The Zinc Industry in England: the early years up to 1850' Transactions of the Newcomen Society 25 (1945–7), 41–52.
^ Jasinski, Stephen M. "Mineral Commodity Summaries 2007: Zinc". United States Geological Survey. Retrieved on 2008-11-25.
^ "Zinifex and Umicore to create largest zinc producer". Retrieved on 24 November 2008.
^ "Zinc Recycling". International Zinc Association. Retrieved on 2008-11-28.
^ ^a ^b ^c Porter, Frank C. (1991). Zinc Handbook. CRC Press. ISBN 9780824783402. http://books.google.com/books?&id=laACw9i0D_wC.
^ Borg, Gregor; Kärner, Katrin; Buxton, Mike; Armstrong, Richard; van der Merwe, Schalk W. (2003). "Geology of the Skorpion Supergene Zinc Deposit, Southern Namibia". Economic Geology 98 (4): 749–771. doi:10.2113/98.4.749.
^ (PDF)Special High Grade Zinc (SHG) 99.995%, Nyrstar, 2008, http://nyrstar.com/nyrstar/en/products/zinccongalvanising/techdownloads/shg_budel.pdf, retrieved on 1 December 2008
^ ^a ^b Kucha, H.; Martens, A.; Ottenburgs, R.; De Vos, W.; Viaene, W. (1996). "Primary minerals of Zn-Pb mining and metallurgical dumps and their environmental behavior at Plombières, Belgium". Environmental Geology 27 (1).
^ "Jewish Museum Berlin: The Façadede". Retrieved on 2008-11-29.
^ Tolcin, Amy C.. "Mineral Yearbook 2006: Zinc" (PDF). United States Geological Survey.
^ ^a ^b You must specify title = and url = when using {{cite web}}.Panagapko, Doug (2006). "". Natural Resources Canada. Retrieved on 2008-12-12.
^ Apelian, D.; Paliwal, M.; Herrschaft, D. C. (1981). "Casting with Zinc Alloys". Journal of Metals 33: 12–19.
^ ^a ^b CRC contributors (2007–2008). "Zinc". in Lide, David R.. CRC Handbook of Chemistry and Physics. 4. New York: CRC Press. pp. 42. 978-0-8493-0488-0.
^ Samans, Carl Hubert (1949). Engineering Metals and Their Alloys. Macmillan Co..
^ Porter, Frank (1994). "Wrought Zinc". Corrosion Resistance of Zinc and Zinc Alloys. CRC Press,. ISBN 9780824792138. http://books.google.de/books?id=C-pAiedmqp8C.
^ Bush, Douglas Earl; Kassel, Richard (2006). The Organ: An Encyclopedia. Routledge. pp. 679. ISBN 9780415941747. http://books.google.com/books?id=cgDJaeFFUPoC.
^ "Coin Specifications". United States Mint. Retrieved on 2008-10-08.
^ Jasinski, Stephen M.. "Mineral Yearbook 1994: Zinc" (PDF). United States Geological Survey. Retrieved on 2008-11-13.
^ Besenhard, Jürgen O.. "Handbook of Battery Materials" (PDF). Retrieved on 2008-10-08.
^ Wiaux, J. -P.; Waefler, J. -P. (1995). "Recycling zinc batteries: an economical challenge in consumer waste management". Journal of Power Sources 57 (1–2): 61–65. doi:10.1016/0378-7753(95)02242-2.
^ Culter, T.. "A design guide for rechargeable zinc-air battery technology". Southcon/96. Conference Record. doi:10.1109/SOUTHC.1996.535134.
^ Whartman, Jonathan. "Zinc Air Battery-Battery Hybrid for Powering Electric Scooters and Electric Buses" (PDF). The 15th International Electric Vehicle Symposium. Retrieved on 2008-10-08.
^ Cooper, J. F.. "A refuelable zinc/air battery for fleet electric vehicle propulsion". Society of Automotive Engineers future transportation technology conference and exposition. Retrieved on 2008-10-08.
^ Bounoughaz, M.; Salhi, E.; Benzine, K.; Ghali E.; Dalard F.. "A comparative study of the electrochemical behaviour of Algerian zinc and a zinc from a commercial sacrificial anode". Journal of Materials Science 38 (6): 1139–1145. doi:10.1023/A:1022824813564.
^ Blew, Joseph Oscar (1953). Wood preservatives. Madison, Wis.. http://hdl.handle.net/1957/816.
^ E. Frankland (1849). "Notiz über eine neue Reihe organischer Körper, welche Metalle, Phosphor u. s. w. enthalten". Liebig's Annalen der Chemie und Pharmacie 71 (2): 213–216. doi:10.1002/jlac.18490710206.
^ Ananda S., Prasad; Fitzgerald, James T.; Bao, Bin; Beck, Frances W.J.; Chandrasekar, Pranatharthi H. (2000). "Duration of Symptoms and Plasma Cytokine Levels in Patients with the Common Cold Treated with Zinc Acetate: A Randomized, Double-Blind, Placebo-Controlled Trial". Annals of Internal Medicine 133 (4): 245–252. http://www.annals.org/cgi/reprint/133/4/245.pdf.
^ Roldán, S.; Winkel, E. G.; Herrera, D.; Sanz, M.; Van Winkelhoff, A. J. (2003). The effects of a new mouthrinse containing chlorhexidine, cetylpyridinium chloride and zinc lactate on the microflora of oral halitosis patients: a dual-centre, double-blind placebo-controlled study. 30. pp. 427–434. doi:10.1034/j.1600-051X.2003.20004.x.
^ Marks, R.; Pearse, A. D.; Walker, A. P.. "The effects of a shampoo containing zinc pyrithione on the control of dandruff". British Journal of Dermatology 112 (4): 415–422. doi:10.1111/j.1365-2133.1985.tb02314.x.
^ Konstantinou, I. K.; Albanis, T. A. (2004). "Worldwide occurrence and effects of antifouling paint booster biocides in the aquatic environment: a review". Environment International volume = 30 (2): 235–248. doi:10.1016/S0160-4120(03)00176-4.
^ Ullmann's Agrochemicals. Wiley-Vch (COR). 2007. pp. 592. ISBN 3527316043.
^ Technical Information, Zinc Counters, 2008, http://www.zinccounters.co.uk/html/tech/tech.htm, retrieved on 29 November 2008
^ Boudreaux, Kevin A.. "

Zinc.html

Contents