1. Trang chủ
  2. » Kỹ Thuật - Công Nghệ

Encyclopedia of Global Resources part 89 pot

10 198 0
Tài liệu đã được kiểm tra trùng lặp

Đang tải... (xem toàn văn)

THÔNG TIN TÀI LIỆU

Thông tin cơ bản

Định dạng
Số trang 10
Dung lượng 245,87 KB

Các công cụ chuyển đổi và chỉnh sửa cho tài liệu này

Nội dung

The Netherlands: Resources at a GlanceOfficial name: Kingdom of the Netherlands Government: Constitutional monarchy Capital city: Amsterdam Area: 16,041 mi2; 41,543 km2 Population 2009 e

Trang 1

The Netherlands: Resources at a Glance

Official name: Kingdom of the Netherlands Government: Constitutional monarchy Capital city: Amsterdam

Area: 16,041 mi2; 41,543 km2

Population (2009 est.): 16,715,999 Languages: Dutch and Frisian Monetary unit: euro (EUR)

Economic summary:

GDP composition by sector (2008 est.): agriculture, 1.7%; industry, 25.5%; services, 72.9%

Natural resources: natural gas, petroleum, peat, limestone, salt, sand and gravel, arable land

Land use (2005): arable land, 21.96%; permanent crops, 0.77%; other, 77.27%

Industries: agroindustries, metal and engineering products, electrical machinery and equipment, chemicals,

petroleum, construction, microelectronics, fishing

Agricultural products: grains, potatoes, sugar beets, fruits, vegetables, flowers, livestock

Exports (2008 est.): $533.2 billion

Commodities exported: machinery and equipment, chemicals, fuels, foodstuffs

Imports (2008 est.): $475.9 billion

Commodities imported: machinery and transport equipment, chemicals, fuels, foodstuffs, clothing

Labor force (2008 est.): 7.715 million

Labor force by occupation (2005 est.): agriculture, 2%; industry, 18%; services, 80%

Energy resources:

Electricity production (2007): 105.2 billion kWh

Electricity consumption (2007): 122.8 billion kWh

Electricity exports (2007): 5.48 billion kWh

Electricity imports (2007): 23.09 billion kWh

Natural gas production (2007 est.): 76.33 billion m3

Natural gas consumption (2007 est.): 46.42 billion m3

Natural gas exports (2007 est.): 55.66 billion m3

Natural gas imports (2007 est.): 25.73 billion m3

Natural gas proved reserves ( Jan 2008 est.): 1.416 trillion m3

Oil production (2007 est.): 88,950 bbl/day Oil imports (2005): 2.648 million bbl/day Oil proved reserves ( Jan 2008 est.): 100 million bbl

Source: Data from The World Factbook 2009 Washington, D.C.: Central Intelligence Agency, 2009.

Notes: Data are the most recent tracked by the CIA Values are given in U.S dollars Abbreviations: bbl/day = barrels per day;

GDP = gross domestic product; km 2 = square kilometers; kWh = kilowatt-hours; m 3 = cubic meters; mi 2 = square miles.

Amsterdam

Germany

Netherlands

Belgium France

United

Kingdom

N o r t h

S e a

Trang 2

the effects on the country’s economy needed to be

considered before completely opening the market

The Netherlands was the second highest producer

of natural gas in the European Union and seventh in

the world in 2007 It was also fifth in the world in

natu-ral gas exports The country’s proven resources of

nat-ural gas are twenty-second overall (1,416,000 million

cubic meters), which is 0.8 percent of the world total

The United States ranks second worldwide in

produc-tion and first in import and consumpproduc-tion of natural

gas Russia is the largest producer and contains the

largest proven resources of natural gas in the world

At the 2009 rate of consumption, use of natural gas in

the Netherlands will surpass production by 2020 or

2025 Some gas will remain in the fields, but less

pres-sure will make extraction of the gas more difficult

Peat

Smallingerland, a region in northern Netherlands,

and its capital city, Drachten, have long histories with

the peat industry The name Drachten is believed to

be derived from darch, the Old Frisian word for peaty

soil In 1641, a businessman hired eight hundred

workers to dig peat, creating the Drachtstervaart

Ca-nal The canal spurred several other industries in the

area, including shipbuilding At that time, peat was a

main source of fuel, and the demand was more than

the Friesland area could produce Local farmers made

a deal with businessmen from Holland province to sell

peat Hundreds of people began spending their days

cutting peat, for little profit Slowly, the community

began to grow with the construction of homes,

hos-tels, businesses, and other accommodations needed

to handle the peat workers and industry

The Netherlands is third globally in peat

exporta-tion, accounting for more than $84 million in 2007 It

contains 75 percent of all the peat settlements in

northwestern Europe Peat production in the

Nether-lands started to decline near the beginning of the

twenty-first century This was partly due to the fact

that peat, like coal, is a limited resource The

Nether-lands government is working to better preserve the

peatlands In 1974, the Dutch government began its

efforts to protect, conserve, and restore peatlands

The five-step plan was to span a fifty-year time period

After cataloging all of the remaining peatlands in the

country, the government purchased them Step three

mandated stopping the drainage of the land and

re-storing its hydrology Extensive plans to manage the

reserves were developed, followed by a campaign to

educate the public about the peatlands and their importance Through this program, the Dutch gov-ernment purchased 8,000 hectares of peatland The government also opened the Veenpark, a museum de-signed to educate the public about the history of peat workers The museum includes a farmhouse, church, bakery, and other buildings that visitors can explore Another problem facing the country is subsidence

In order to have more land for farming, many peat grasslands have been drained, causing the fields to sink 1 to 2 meters farther below sea level than before The peat becomes oxidized when in contact with the air, drying, crumbling, and decaying, which causes the topsoil to sink Scientists estimate that under cur-rent conditions, the central “green heart” region of the Netherlands will continue to sink between 2 and

25 millimeters annually In order to preserve the peat and elevation above sea level, the amount of ground-water cannot be decreased

Flowers The Netherlands is the third largest exporter in the world of agricultural products, following the United States and France Agricultural exports account for

$55 billion of the Netherlands’ income each year It exports two-thirds of the fresh-cut plants, flowers, and bulbs sold throughout the world Every year, the Neth-erlands produces nine billion flower bulbs Three bil-lion of those are tulip bulbs, of which approximately two billion are exported Over one-half of the coun-try’s flower-bulb farms, 9,481 hectares, are planted with tulips Other popular bulbs include lilies, gladi-oli, narcissi, and hyacinths

The tulip arrived in Holland in 1593 with the ar-rival of botanist Charles de L’Écluse (also known as Carolus Clusius) He had taken a position at the Uni-versity of Leiden as its head botanist for the botanical garden The tulips L’Écluse brought with him were gifts from an ambassador from Constantinople whom

he had met while living in Vienna He planted his tu-lip collection behind a building at the university The flowers were popular, but L’Écluse refused to give away or sell any of the bulbs It is believed that the Dutch tulip industry started when thieves stole some

of L’Écluse’s flowers from his garden Through the seventeenth century tulips spread in the area between the North Sea and Amsterdam This region is now

known as the bollenstreek, or bulb-growing district The

town of Lisse is at the center of this district and hosts

a world-famous flower exhibition

Trang 3

Tulips were not always readily available as they are

today The years between 1634 and 1637 are known as

“the foolish tulip trade,” “the wild tulip speculation,”

and “Tulipomania.” In 1634, tulip bulbs were sold by

weight instead of per bulb Bulbs were weighed in

grain (4 to 8 centigrams), which is also used by

gold-smiths In 1636, tulips were seen as a symbol of status

and wealth Bulbs were bought at high costs, and sold

at even higher prices At the peak, some tulips sold for

the same amount as a large home along the canals in

Amsterdam Tulips also became the subject of many

paintings by famous artists In 1637, the Dutch

gov-ernment passed a law against such excessive tulip

prices That year, the tulip market crashed, an event

that has been compared to the American stock

mar-ket crash of 1929

A second bulb district developed in the North

Hol-land province during World War I In 1925, the Dutch

created the International Flower Bulb Center to assist

gardeners around the world with growing bulb

flow-ers At the end of World War II a large expansion of flower bulb cultivation occurred

Limestone Limestone quarries are found throughout the world Several of the largest are found in the Netherlands and Belgium, spanning more than 100 kilometers Mount Saint Peter, near St Pietersberg in the Nether-lands, is covered with massive limestone quarries The Netherlands also has several underground limestone caves The city of Valkenburg is famous for its caves, which have been used for centuries The walls contain ancient charcoal drawings and other art-work The caverns were used during World War II as a shelter for refugees Public tours are given of a por-tion of the more than 70 kilometers of caves and pas-sageways beneath Valkenburg In the Limburg region

of Holland and Belgium, there are more than three hundred room and pillar limestone mines, some as large as 85 hectares In the Maastricht region,

exten-A windmill in Zaanse Schans Wind power has been utilized in the Netherlands for centuries (©exten-Alexshalamov/Dreamstime.com)

Trang 4

sive mining of limestone has resulted in both local

and large-scale collapses These collapses have caused

faulting, surface subsidence, and the formation of

sinkholes

The quarry near the village of Winterswijk is a

source of Mesozoic limestone from the Muschelkalk

period Students, scientists, and the general public

search the quarry for fossils on weekends and over the

summer They search for fossils of ancient reptiles

that date back 240 million years Fossils of imprints of

claws of the Rhynchosauroides peabodyi are common in

the quarry No bone fossils of the coastal reptile have

been found, only claw prints and skin These trace

fos-sils can be helpful to scientists, telling them the

ani-mal’s weight and speed In 2006, the Dutch Geologic

Society found a trace sequence in the Winterswijk

quarry that was more than 10 meters long Scientists

search for trace fossils by splitting the limestone into very thin sheets, about 0.5 centimeter in thickness Fossilized fish scales and bones, seashells, and reptile bones have also been found in the quarry

Salt The collection of peat in the eighth and ninth centu-ries caused the land to sink and fill with salt water By the eleventh century, this peat was heavily concen-trated with salt, so it was used for salt making instead

of fuel It was only possible to collect this peat during low tide The peat was dried and then burned The ashes were taken to salt sheds, where they were placed

in large drums full of salt water, which was used to increase the amount of salt collected The water was then evaporated away During medieval times, eel-grass was also used in salt making in the northwestern

The Erasmus Bridge links the southern and northern parts of Rotterdam, one of the busiest ports in the world (©Bob Bouwman/

Dreamstime.com)

Trang 5

regions of Holland Salt was an important

preserva-tive for fish, bacon, other meats, and butter at the time

In some ways, the Netherlands owes its

indepen-dence to salt During its revolution against Spain, it

blockaded the Iberian saltworks, effectively

bankrupt-ing Spain The Netherlands began minbankrupt-ing and

pro-ducing salt in 1918 Halite, or rock salt, deposits exist

throughout the world, left behind after the

evapora-tion of ancient lakes Halite can be mined the same

way as other rocks, or it can be dissolved with water

underground The saltwater solution is then brought

to the surface, where the salt can be removed This

method is more cost-effective The salt is then

puri-fied, removing the magnesium, calcium, and any other

unwanted elements Most of the world’s salt is

pro-duced for food storage or consumption; more than

8 percent is used in other industries Salt is used in

the production of pulp and paper, the dyeing of

fab-rics, and soapmaking The Netherlands ranks among

the top dozen nations in overall salt production,

accru-ing more than $780 million from exportaccru-ing salt in

2007 China and the United States top the list,

ac-counting for more than one-third of the world’s

pro-duction in 2008

Arable Land

The term “arable land” is defined as land that can be

used to grow crops Land is deemed nonarable if it is

too rocky, too cold or hot, too dry, too mountainous,

too rainy or snowy, or too polluted An average of

more than 200,000 square kilometers of arable land

is lost each year It is possible however, to turn

non-arable land (sometimes referred to as wasteland) into

arable land The process depends on why the land is

nonarable Some of the processes are planting trees

indeserts to create shade, digging irrigation ditches,

using fertilizers, creating hills to shelter areas from

high winds, and constructing greenhouses for areas

with harsh climates or little sunlight These processes

are often huge undertakings that cost large amounts

of money

In 2005, the Netherlands was ranked forty-seventh

in the world by percentage of arable land used for

ag-riculture (21.96 percent) Bangladesh was first with

more than 55 percent Much of the Netherlands has

been reclaimed from the North Sea by draining water

and building dikes and levees Less than 5 percent of

Dutch citizens work in agricultural jobs The Dutch

work hard to maintain the quality of their arable

farm-land

Other Resources The Netherlands ranks fifty-second in oil production

in the world In 2007, it produced 88,950 barrels of oil per day The Shell gasoline company, officially the Royal Dutch Shell plc, was created in 1907 after Dutch and British gas companies merged Jean Baptiste Au-gust Kessler and Henri W A Deterding founded the Royal Dutch Petroleum Company in 1890

The Netherlands produces an annual average of 5,000 metric tons of industrial sand and gravel In

2007, the country was fourteenth worldwide in ex-ports of stone, sand, and gravel, amounting to almost

$100 million

The Netherlands also produces and exports a large number of vegetables It exports one-quarter of the world’s tomatoes and one-third of all peppers and cu-cumbers During the 1990’s, Dutch tomato farmers were struggling to sell their produce German con-sumers stopped buying the tomatoes, claiming that they lacked flavor and tasted industrially mass-pro-duced European shoppers had begun choosing to-matoes imported from the Mediterranean instead, along with French cheese, cucumbers from Greece, and Danish bacon, instead of those produced in the Netherlands One drawback to Holland tomatoes is that they are grown in large greenhouses, instead of outdoors

Jennifer L Campbell

Further Reading

Bedford, Neal The Netherlands 3d ed Oakland, Calif.:

Lonely Planet, 2007

Blom, J C H., and Emiel Lamberts History of the Low Countries New ed New York: Berghahn Books,

2006

Cech, Thomas V Principles of Water Resources: History, Development, Management, and Policy 2d ed New

York: John Wiley & Sons, 2005

Ciriacono, Salvatore Building on Water: Venice, Hol-land, and the Construction of the European Landscape

in Modern Times New York: Berghahn Books, 2006 Dash, Mike Tulipomania: The Story of the World’s Most Coveted Flower and the Extraordinar y Passions It Aroused London: Phoenix, 2003.

De Vries, Jan, and A M van der Woude The First Mod-ern Economy: Success, Failure, and Perseverance of the Dutch Economy, 1500-1815 Cambridge, England:

Cambridge University Press, 1997

Grattan, Thomas Colley Holland: The History of the Netherlands New York: Cosimo Classics, 2007.

Trang 6

Wesseler, Justus, Hans-Peter Weikard, and Robert

Weaver, eds Risk and Uncertainty in Environmental

and Natural Resource Economics Northampton,

Mass.: Edward Elgar, 2004

Whited, Tamara Northern Europe: An Environmental

History Santa Barbara, Calif.: ABC-CLIO, 2005.

See also: Agricultural products; Agriculture

indus-try; Limestone; Oil and natural gas distribution; Peat;

Salt

Nickel

Category: Mineral and other nonliving resources

Where Found

Sudbury, Ontario, Canada, has the largest exploited

nickel ore deposit in the world Other major ore

de-posits 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,

mag-nets, coinage, and tableware In 2008, the apparent

consumption of primary nickel in the United States

was about 127,000 metric tons, while world

produc-tion 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

ta-ble—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

meteor-ites 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 mi-crograms 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 sili-cates, which often also contain copper The largest commercially exploited nickel ore deposit is in Sud-bury, Ontario, Canada The ore there is a complex sul-fide 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 Sud-bury Major ore deposits also occur in the western Si-berian 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 im-ported 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 ma-jor 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 ab-sorbing 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 accumu-late nickel

Four types of nickel-containing enzymes have been identified: urease, hydrogenase, methyl coenzyme M methylreductase (MCR), and carbon monoxide de-hydrogenase (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

Trang 7

methano-genic bacteria that flourish in the bodies of termites.

These insects release enormous amounts of

meth-ane (a greenhouse gas) as a result of the bacteria

Bacterial carbon monoxide dehydrogenase catalyzes

the conversion of carbon monoxide to carbon

diox-ide and is responsible for removing about 100 metric tons per year of carbon monoxide from the atmo-sphere

There is evidence from animal studies that nickel may be an essential trace element in rats and pigs,

20,100 211,000 92,600 88,400 276,000 38,000 20,000 6,530 28,600

Metric Tons of Nickel Content

5,000,000 4,000,000

3,000,000 2,000,000

1,000,000 Zimbabwe

Russia Philippines

New Caledonia

Indonesia

Greece

South Africa

Venezuela

Other countries

180,000 36,000

4,500,000

250,000 85,000 74,900 77,000 47,000

Dominican Republic

China Canada

Brazil Botswana

Australia

Colombia

Cuba

Nickel: World Mine Production, 2008

Trang 8

which fail to show normal weight gain if nickel is

rigor-ously excluded from the diet Similarly, many plants

suffer a distortion of their nitrogen metabolism if

de-prived 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

concen-trated 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,

sea-food, and cereals all contain traces of nickel

Individ-uals who suffer myocardial infarction, stroke, or

ex-tensive thermal burns of the skin exhibit elevated

levels of nickel in the blood Skin contact with nickel

or nickel compounds can produce dermatitis; the

im-mune 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

can-cer in miners who breathed dust containing nickel

sulfide Nickel-containing dust and smoke badly

pol-luted the area around Sudbury, at one time, causing

widespread blighting of all types of

vegetation

History

The European history of nickel

be-gan with Saxon miners who

encoun-tered an ore of nickel they thought

contained copper and derisively

named kupfernickel, or “devil’s

cop-per.” In 1751, Axel Fredrik

Cron-stedt 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

ob-tained 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

mo-tivation for nickel production was

the desire to produce nickel-silver

al-loy from local resources instead of

importing it from China The nickel

reserves in New Caledonia were noted by Jules Gar-nier, who helped establish a French nickel indus-try and later served as a consultant in Ontario, Can-ada, after the Sudbury nickel deposits started to be exploited in 1888 The founder of the nickel indus-try 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 devel-oped 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

Source:Data from the U.S Geological Survey,Mineral Commodity Summaries, 2009 U.S Government Printing Office, 2009.

Transportation 30%

Chemicals 15%

Electical equipment 10%

Construction 9%

Fabricated metal products 8%

Appliances 8%

Petroleum industry 7%

Machinery 6%

Other 7%

U.S End Uses of Nickel

Trang 9

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,

cop-per, and zinc) is used for coinage, jewelry, and

table-ware 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,

cord-less telephones, and flashlights are often nickel

cad-mium 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)

bat-teries 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

reac-tions of hydrogen gas with various substrates Thus

nickel catalysts are used in the hydrogenation of

vege-table 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

radioac-tivity; several more thousand tons of nickel were

ex-pected 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,

construc-tion, food processing, and transportation China was

the world’s largest consumer of the metal

John R Phillips

Further Reading

Adriano, Domy C “Nickel.” In Trace Elements in Terres-trial Environments: Biogeochemistry, Bioavailability, and Risks of Metals 2d ed New York: Springer, 2001.

Greenwood, N N., and A Earnshaw “Nickel,

Palla-dium, and Platinum.” In Chemistry of the Elements 2d

ed Boston: Butterworth-Heinemann, 1997

Hausinger, Robert P Biochemistry of Nickel New York:

Plenum Press, 1993

Howard-White, F B Nickel: An Historical Review

To-ronto: Longmans Canada, 1963

Lippard, Stephen J., and Jeremy M Berg Principles of Bioinorganic Chemistry Mill Valley, Calif.: University

Science Books, 1994

Sigel, Astrid, Helmut Sigel, and Roland K O Sigel,

eds Nickel and Its Surprising Impact in Nature.

Hoboken, N.J.: Wiley, 2007

Silva, J J R Fraústo da, and R J P Williams “Nickel

and Cobalt: Remnants of Life?” In The Biological Chemistry of the Elements: The Inorganic Chemistry of Life 2d ed New York: Oxford University Press,

2001

Web Sites Natural Resources Canada Canadian Minerals Yearbook, Mineral and Metal Commodity Reviews

http://www.nrcan-rncan.gc.ca/mms-smm/busi-indu/cmy-amc/com-eng.htm

U.S Geological Survey Nickel: Statistics and Information http://minerals.usgs.gov/minerals/pubs/

commodity/nickel See also: Alloys; Canada; Cobalt; Indonesia; Iron; Magnetic materials; Mining safety and health issues; Russia; Steel; Strategic resources

Niobium

Category: Mineral and other nonliving resources

Where Found Niobium is most often found as niobium pentoxide in the mineral niobite (also called columbite or tanta-lite), which in the United States is found in Colorado, Connecticut, Maine, North Carolina, South Dakota,

Trang 10

and Virginia This mineral is also found

in Australia, Brazil, Canada, Madagascar,

South Africa, the Democratic Republic of

the Congo, Nigeria, Norway, and Russia

Primary Uses

Niobium is used to toughen and harden

steel It is also used to make low- and

high-temperature superconductors In its

Min-eral Commodity Summaries (January, 2009),

the U.S Geological Survey reported that

approximately 78 percent of U.S end use

of niobium is in manufacturing of steels,

with the remaining 22 percent devoted to

production of superalloys

Technical Definition

Niobium (symbol Nb), or columbium

(symbol Cb), has an atomic number of 41, an atomic

weight of 92.9064, and sixteen isotopes It is a hard,

lustrous metal, gray or silver-white in color, malleable

(capable of being bent or flattened), and ductile

(ca-pable of being stretched) It has a melting point of

2,468° Celsius, a boiling point of 4,742° Celsius, and a

specific gravity of 8.4

Description, Distribution, and Forms

Niobium is named for Niobe, the mythical daughter

of the Greek god Tantalus The designation niobium

was officially adopted by the International Union of

Pure and Applied Chemistry in 1949 However, an

al-ternative name, columbium, is still used by many

met-allurgists in the United States and, to a lesser degree,

England

History

Niobium was discovered by the English chemist

Charles Hatchett in 1801, and it was first prepared in

1864 when Christian Wilhelm Blomstrand of Sweden

isolated it from niobium chloride by reduction in a

stream of hydrogen Niobium is easily welded and

re-sists tarnish It exhibits a variable valency of +2, +3, +5,

and possibly +4 At high temperatures, it reacts with

oxygen, carbon, nitrogen, sulfur, chlorine, fluorine,

bromine, iodine, and other nonmetals

Obtaining Niobium

Niobite forms in pegmatite (exceptionally

coarse-grained igneous rocks typically made of granite),

of-ten with tin and tungsof-ten minerals Ores of niobium

are also sometimes found in placer deposits Niobium

is rarely found without a similar element called tanta-lum Eighty-five percent of all niobium reserves are lo-cated in Brazil The element niobium is extracted from niobite by reducing the complex alkali fluoride with sodium, or the oxide with calcium, aluminum, or hydrogen

Uses of Niobium Because niobium has excellent gas-absorbing qualities and a high melting point, it is used in the manufacture

of vacuum tubes Niobium is used as an alloying agent

in carbon and alloy steels In the preparation of stain-less steel, it is used to prevent corrosion at high tem-peratures and to permit fabrication without added heat treatment Niobium adds strength, toughness, and ductility to chrome steel Niobium alloys are used

in jet and rocket engines In the form of a carbide, ni-obium is used in making cutting tools Combined with selenium and hydrogen, it forms a low-temperature superconductor (a material that can conduct electric-ity without any resistance), which is used in the con-struction of superconducting magnets Applications include monorail trains, where the tracks are made of superconductor material and the trains are magne-tized and glide along without any resistance It is also combined with other elements to form high-tempera-ture superconductors Since niobium allows neutrons

to pass through it without interference, it is used in nuclear reactors, particularly in the walls of experi-mental fusion reactors

Alvin K Benson

A columbite sample from South Dakota Columbite is another name for niobite, from which niobium is derived (USGS)

Ngày đăng: 04/07/2014, 01:20

TỪ KHÓA LIÊN QUAN