Nickel (Ni)
Nickel (Ni) is a lustrous, corrosion-resistant metal with the atomic number 28, known for its malleability and ductility. It plays a crucial role in various industries, particularly in the production of stainless steel, where it typically comprises about 8% of the alloy, and in other applications like plating, batteries, and catalysts. Major global suppliers of nickel include Russia, Canada, Indonesia, Australia, and New Caledonia, with Sudbury, Ontario, housing the largest known deposit of nickel ore. The metal is primarily extracted from sulfide ores, particularly pentlandite, and is also found in smaller amounts in meteorites and marine nodules.
While nickel is essential for certain biological processes in plants and animals, it can be toxic at high levels, leading to health issues such as dermatitis and respiratory problems for those exposed in mining or industrial settings. The compound nickel carbonyl is notable for its unique properties, allowing the extraction of pure nickel. Historically, the element was first identified in Sweden in the 18th century, and its applications have expanded over time to include a variety of alloys and specialized uses, such as in rechargeable batteries for electronics and hybrid vehicles. As demand for nickel continues to grow, especially in sustainable technologies like wind power, its strategic importance remains significant in global markets.
Nickel (Ni)
Where Found
Sudbury, Ontario, Canada, has the largest exploited nickel ore deposit in the world. Other major ore deposits include those in Norway, New Caledonia, Cuba, northwestern Siberia, and the Kola Peninsula.
Primary Uses
Nickel is widely used in stainless steel and other alloys as well as in plating, catalytic processes, and batteries. Stainless steel is commonly about 8 percent nickel. Nickel alloys are also used in marine hardware, magnets, coinage, and tableware. In 2008, the apparent consumption of primary nickel in the United States was about 127,000 metric tons, while world production was about 1.6 million metric tons.
Technical Definition
Nickel (symbol Ni) is a shiny metal with a density of 8.9 grams per cubic centimeter (slightly greater than that of iron). Nickel melts at 1,455° Celsius and boils at 2,920° Celsius. Along with iron and cobalt, it constitutes the iron group triad in the periodic table—traditionally Group VIII, now Group 10. Nickel (atomic number 28) has five stable isotopes and an atomic weight of 58.71. It is malleable and ductile, and it resists corrosion in air.
Description, Distribution, and Forms
Nickel occurs in detectable amounts in the Earth’s crust, the atmosphere, and the seas. Earth’s core is thought to contain nickel and iron, and some meteorites do. The average crustal concentration is about 100 micrograms per gram, which ranks twenty-second among the elements. Rural air may contain as much as 10 nanograms per cubic meter, and urban air ten times as much. Average nickel content in seawater is 0.1-0.6 microgram per liter, and there are about 4 micrograms per liter in groundwater.
Elemental nickel occurs in meteorites, marine nodules, and the metallic core of the Earth. Ores of nickel include oxides, sulfides, arsenides, and silicates, which often also contain copper. The largest commercially exploited nickel ore deposit is in Sudbury, Ontario, Canada. The ore there is a complex sulfide called pentlandite, which contains in addition to nickel a number of other metals, including iron and platinum group elements. Approximately 30 percent of the world’s known reserves of nickel are in Sudbury. Major ore deposits also occur in the western Siberian arctic and the Kola Peninsula in Russia. silicate ores such as garnierite (a nickel-magnesium silicate) are mined in Australia, Cuba, Indonesia, and New Caledonia. The major producers of nickel are Russia, Canada, Indonesia, Australia, and New Caldonia. In 1998, the United States stopped producing primary nickel. From 1999 to 2007, the United States imported an average of 150,000 metric tons a year. A large body of ore has been discovered in Labrador, making it likely that Canada will continue to be a major producer for many years.
Elemental nickel moves through the environment via water-soluble compounds such as nickel chloride or sulfate, through particulate matter, and possibly through the formation of volatile tetracarbonyl nickel. In the biosphere, nickel is found to a greater extent in plants than in animals. Many plants are harmed by absorbing nickel from the soil, but some 150 species have been found to hyperaccumulate, resulting in nickel contents up to 25 percent of dry weight. Mosses and sponges are among the organisms that accumulate nickel.
Four types of nickel-containing enzymes have been identified: urease, hydrogenase, methyl coenzyme M methylreductase (MCR), and carbon monoxide dehydrogenase (also called acetyl coenzyme A synthase). Urease, which catalyzes the breakdown of urea into ammonia, is found in plants, bacteria, algae, lichens, fungi, and certain invertebrates. Urease from the jack bean (Canavalia ensiformis) was the first enzyme to be obtained in crystalline form (by James Batcheller Sumner in 1926) but was not known to contain nickel until 1975. The other nickel enzymes are found mainly in bacteria. For example, MCR occurs in methanogenic bacteria that flourish in the bodies of termites. These insects release enormous amounts of methane (a greenhouse gas) as a result of the bacteria. Bacterial carbon monoxide dehydrogenase catalyzes the conversion of carbon monoxide to carbon dioxide and is responsible for removing about 100 metric tons per year of carbon monoxide from the atmosphere.
There is evidence from animal studies that nickel may be an essential trace element in rats and pigs, which fail to show normal weight gain if nickel is rigorously excluded from the diet. Similarly, many plants suffer a distortion of their nitrogen metabolism if deprived of nickel. On the other hand, toxic and even carcinogenic effects can result from particular types and levels of nickel exposure. In rats the LD50 (lethal dose for 50 percent of the test subjects) for orally administered nickel (II) acetate is 350 milligrams per kilogram.
The average 70-kilogram human being carries a burden of 0.5 milligram of nickel, which is concentrated in the hair and nails. Dietary intake is 100-200 micrograms per day, with elimination largely through the urine and perspiration. Oils and fats, meat, seafood, and cereals all contain traces of nickel. Individuals who suffer myocardial infarction, stroke, or extensive thermal burns of the skin exhibit elevated levels of nickel in the blood. Skin contact with nickel or nickel compounds can produce dermatitis; the immune system becomes involved, and once sensitized, a person reacts to very small exposures. There is also a long and melancholy history of lung lesions and cancer in miners who breathed dust containing nickel sulfide. Nickel-containing dust and smoke badly polluted the area around Sudbury, at one time, causing widespread blighting of all types of vegetation.
History
The European history of nickel began with Saxon miners who encountered an ore of nickel they thought contained copper and derisively named kupfernickel, or “devil’s copper.” In 1751, Axel Fredrik Cronstedt investigated a sample of ore from a mine in Hälsingland, Sweden and concluded that it contained a new element, which he obtained in impure form. In 1754, he named the element. Torbern Olaf Bergman obtained a sample of the pure metal in 1775. The first nickel smelter began operating in Sweden in 1838 and was followed by others in Norway and elsewhere in Europe. One early motivation for nickel production was the desire to produce nickel-silver alloy from local resources instead of importing it from China. The nickel reserves in New Caledonia were noted by Jules Garnier, who helped establish a French nickel industry and later served as a consultant in Ontario, Canada, after the Sudbury nickel deposits started to be exploited in 1888. The founder of the nickel industry in the United States was Joseph Wharton, whose smelter in Camden, New Jersey, at one time in the nineteenth century produced one-sixth of the world’s nickel.
In Britain the nickel carbonyl process was developed in the late nineteenth century by Ludwig Mond and soon became commercially important.
Obtaining Nickel
Only nickel—not copper or the other metals in nickel ores—reacts with carbon monoxide, yielding volatile tetracarbonyl nickel. This substance, after separation by distillation, yields pure nickel upon heating to 180° Celsius.
Uses of Nickel
Nickel finds its most important uses in stainless steel and other alloys, in plating, and in catalysts. Valued for its resistance to rusting, stainless steel exists in a multitude of types and compositions, but it is most typically 18 percent chromium, 8 percent nickel, and the rest iron. Nickel-copper alloys such as Monel (68 percent nickel) possess corrosion resistance toward chlorine compounds and salt and are used in marine hardware. Nichrome (60 percent nickel, 40 percent chromium) is used for heating elements in resistance heaters, while nickel silver (composed of nickel, copper, and zinc) is used for coinage, jewelry, and tableware. Powerful permanent magnets make use of a steel alloy called alnico (aluminum, nickel, cobalt). Nickel plating is important for protecting steel from corrosion and for steel’s appearance. Rechargeable batteries for portable equipment such as radios, cordless telephones, and flashlights are often nickel cadmium cells, while nickel hydride cells have been used in computers and electric vehicles. Thomas Edison developed a battery using hydrated nickel oxide as an electrode coating, and in the late twentieth century, a nickel chloride-sodium battery was developed. One growing use is in nickel-metal hydride (NiMH) batteries for hybrid vehicles, despite competition from lithium-ion batteries. Nickel-based batteries have also experienced higher demand with the growth of the wind-power industry.
Nickel in finely divided form accelerates the reactions of hydrogen gas with various substrates. Thus nickel catalysts are used in the hydrogenation of vegetable oils and in “methanation”—the conversion of carbon monoxide to hydrocarbons. Nickel carbonyl derivatives and cyclooctadiene-nickel complexes are homogeneous catalysts for oligomerization of dienes and acetylenes. Small amounts of nickel oxide are used to impart a green color to glass.
Because nickel alloys are vital in aircraft engines and armor plate, nickel was considered a strategic resource and was stockpiled by the U.S. government. In 1999, however, the U.S. government sold off the nickel in the National Defense Stockpile. As of 2009, the U.S. Department of Energy continued to hold several thousand tons of nickel ingot and scrap, some of which was contaminated with low levels of radioactivity; several more thousand tons of nickel were expected to be recovered from decomissioned defense sites.
World production of nickel in 2008 continued at a fairly high level, despite a global economic downturn, and was used mainly in steel production, construction, food processing, and transportation. China was the world’s largest consumer of the metal.
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