Borax Category: Mineral and other nonliving resources Where Found Borax, the most widespread of the borate minerals, is found in the muds of alkaline lakes along with miner-als such as r
Trang 1the group There is only one naturally occurring
iso-tope, so the atomic weight of bismuth, 208.980, is
known very precisely The element is brittle and white
in appearance, with a pink tinge It occurs in a variety
of crystalline structures The metal has a high
resistiv-ity and melts at 271.4° Celsius with a boiling point of
1,564° Celsius Bismuth is unusual in that its volume
expands by about 3 percent when it solidifies from the
liquid The solid has a density of 9.9 grams per cubic
centimeter
Description, Distribution, and Forms
With a rarity akin to that of silver, bismuth is a
rela-tively minor component of the Earth’s crust It
pos-sesses some unique credentials: For example, all
ele-ments with an atomic number higher than bismuth
are radioactive It is one of three elements that is less
dense in the solid phase than in the liquid It is also
one of only a handful of metals that can be found in
nature in their elemental, or native, form Elemental
bismuth is not particularly toxic, an unusual property
in heavy metals However, inorganic bismuth
com-pounds are often extremely poisonous The relative
rarity of bismuth has minimized its environmental
im-pact
History
The earliest recorded use of bismuth was in the
mid-1400’s as an alloying material in casting type German
scientist Georgius Agricola stated that bismuth was a
metal in the same family of metals as tin and lead In
1753, French chemist Claude François Geoffroy
iden-tified bismuth as a chemical element, confirming
Agricola’s postulation
Obtaining Bismuth
In addition to the native state, bismuth occurs in ores
as an oxide, sulfide, and carbonate Because of the
scarcity of bismuth ores in the Earth’s crust, it is not
mined directly but is typically produced commercially
by extracting and refining it from the anode sludge
generated during the electrochemical production of
other metals Annual world production of bismuth is
on the order of 6,000 metric tons
Uses of Bismuth
Functioning as a metallurgical additive remains one
of the major uses of bismuth In particular, fusible
al-loys, which have low melting points and are
particu-larly useful in fire detection, often incorporate
bis-muth The other major use of bismuth is in the pharmaceutical industry, where it is used to treat indi-gestion and as an antisyphilitic agent
Craig B Lagrone
Web Sites Natural Resources Canada Canadian Minerals Yearbook, 2005: Bismuth http://www.nrcan-rncan.gc.ca/mms-smm/busi-indu/cmy-amc/content/2005/14.pdf U.S Geological Survey
Minerals Information: Bismuth Statistics and Information
http://minerals.usgs.gov/minerals/pubs/
commodity/bismuth/
See also: Alloys; Antimony; Belgium; Canada; China; Germany; Metals and metallurgy; Mexico; Native ele-ments
Borax
Category: Mineral and other nonliving resources
Where Found Borax, the most widespread of the borate minerals, is found in the muds of alkaline lakes along with miner-als such as rock salt, sulfates, carbonates, and other borates Large deposits are found in the western United States, South America, Turkey, and Tibet
Primary Uses Borax is essential to many industrial processes, nota-bly the manufacture of glass and enamel Other major users include the ceramics, agricultural, chemical, cleanser, and pharmaceutical industries
Technical Definition Borax (also known as sodium borate decahydrate, so-dium pyroborate, birax, soso-dium tetraborate decahy-drate, and sodium biborate) is an ore of boron with the chemical formula Na2(B4O5)(OH)4C8(H2O) Its average molecular weight is 381.4, composed of 12.06 percent sodium, 11.34 percent boron, 5.29 percent hydrogen, and 71.32 percent oxygen Borax may be colorless, white, yellowish, or gray Its hardness on the Mohs scale is 2 to 2.5 Borax occurs as prismatic
Trang 2tals or as a white powder Its specific gravity is 1.69 to
1.72 It is slightly soluble in cold water, very soluble in
hot water, and insoluble in acids It has a melting
point of 75° Celsius and a boiling point of 320°
Cel-sius When heated above 740° Celsius, it fuses to form
a “borax bead.”
Description, Distribution, and Forms
Borax is a member of a group of compounds known as
borates, minerals that contain the element boron
Bo-rax is an evaporite found in dried-up lakes and playas
(desert basins) A sedimentary deposit that forms in
arid regions, borax derives its name from b nraq, an
Arabic word meaning “white” that was used to refer to
the substance This widespread borate mineral is
found in association with other evaporites, including
rock salt, sulfates, carbonates, and other borates
Bo-rax occurs as a white powder on the soil surface or in
masses of short, prismatic crystals embedded in the
muds of alkaline lakes Borax is also present in many
mineral waters and salt lakes It commonly loses water
to form tincalconite (Na2B4O7C5H2O)
The most widespread of the borate minerals, borax
is notably found in arid regions near the sites of
Plio-cene lakes, where hot springs and volcanic activity are
believed to be the source of the boron-rich brines that
fed these lakes Upon evaporation (hence its
classifi-cation as an “evaporite”), deposits of borax and other
borates formed Buried accumulations of borax are
often found in the centers of dried-up alkaline lakes,
with outcrops of calcium and calcium-sodium boron minerals marking the periphery of the lake area
In the United States, there are large deposits of bo-rax in California, Nevada, and Oregon Almost half the world’s refined borates come from Southern Cali-fornia In California’s Mojave Desert, Searles Lake in San Bernardino County and Kramer in Kern County are two major borax deposits At Searles Lake, borax is the most abundant of the four borate-bearing miner-als found there Borax is miner-also the most abundant min-eral in the Kramer borate deposit, the largest known reserve of boron compounds in the world Other ma-jor deposits are located in Tibet, Argentina, and Tur-key In Argentina, for example, borax is mined at Salt Province (more than 4,000 meters above sea level) and at Tincalayu, Sijes, and the lakebeds at Salar Cauchari and Salar Diablillos
History Borax has been used commercially for thousands of years, with the earliest confirmed use in ceramic glazes traced to the tenth century c.e The early Chi-nese, Persians, Arabs, and Babylonians knew of the mineral and its properties It was introduced to Eu-rope by Marco Polo about 1275 c.e EuEu-rope’s earliest source for the mineral was Tibet, where tincal (crude borax) was used for making glazes and soldering gold
By the 1800’s, borax had gained widespread use in glassblowing and gold refining
Italy, Tibet, and Chile were the principal world
The mineral borax (USGS)
Trang 3pliers of borate minerals until extensive borate
depos-its were discovered in California and Nevada An 1864
report on borax crystals found in the muds of Borax
Lake in Lake County, California, was the first to
pub-lish the discovery of the mineral in the western United
States In the early 1880’s, borax was also found in
Death Valley The twenty-mule teams that hauled the
material mined from Death Valley across the
Califor-nia desert to the railroad junction at Mojave became a
widely recognized symbol for the borax industry in
the United States
Obtaining Borax
Borax may be obtained directly from dry lake beds
on which the evaporite has formed, from open-pit
borate mines, or from drilling for underground
mines At Searles Lake, borax is recovered by
frac-tional crystallization from lake brine Borax may also
be made from other borate ores, including as kernite
(Na2B4O7C4H2O), colemanite (Ca2B6O11C5H2O), and
ulexite (NaCaB5O9C8H2O), or by the reaction of boric
acid with soda Crystalline borax readily effloresces—
that is, it loses its water of crystallization to form a
white powder—particularly upon heating
Deposits of borate ores are found underground by
drilling and then blasting to remove the sandstone
that overlies the ore deposit (Eventually such sites
will turn into open-pit mining operations.) Huge
shovels remove the rubble to get at the ore, which is
then crushed and refined by mixing the crushed ore
with hot water Borates dissolve in the water, leaving
the unwanted debris in solid form; the debris-free
so-lution can then be pumped into tanks, which cool the
solution so that the borates can crystallize and then be
removed for drying, storage, and further processing
Uses of Borax
The uses of borax are based on its many functional
properties, which include metabolizing effects,
bleaching effects, buffering effects, dispersing
ef-fects, vitrifying efef-fects, inhibiting efef-fects,
flame-proof-ing effects, and neutron-absorbflame-proof-ing effects Borax has
been used for centuries in making glass and enamels,
and it has become an essential part of many other
in-dustrial processes It is used in the manufacture of
glass (notably heat-resistant and optical varieties),
porcelain enamels, ceramics, shellacs, and glazes It is
a component of agricultural chemicals such as
fertiliz-ers and herbicides It is used in the manufacture of
chemicals, soaps, starches, adhesives, cosmetics,
phar-maceuticals, insulation material, and fire retardants
In the textile industry, borax is used in fixing mor-dants on textiles, tanning leather, and spinning silk It
is effective as a mild antiseptic, a water softener, and a food preservative, although it is toxic if consumed in large doses It is added to antifreeze to inhibit corro-sion and used as a flux for soldering and welding Bo-rax is also a source of elemental boron, which is used
as a deoxidizer and alloy in nonferrous metals, a neu-tron absorber in shields for atomic reactors, and a component of motor fuel and rocket fuel
Borax also plays an important role in chemical analysis Borax fused by heating is used in the “bead test,” a form of chemical analysis used in the identifi-cation of certain metals Powdered borax is heated in
a platinum-wire loop over a flame until the mineral fuses to form a clear glassy bead The borax bead is then dipped into a small quantity of the metallic oxide
to be identified Upon reheating over the flame, the bead reacts chemically with the metallic oxide to form
a metal borate, which gives the bead a characteristic color that helps identify the metal For example, co-balt compounds yield a deep blue bead, and manga-nese compounds produce a violet one
Perhaps the most familiar use of borax is as a cleansing agent Borax combined with hot water will create hydrogen peroxide; it lowers the acidity of water, which facilitates the bleaching action of other cleansers Borax also acts as both a disinfectant and a pesticide by blocking the biochemistry of both macro-and microorganisms, such as bacteria, fungi, fleas, roaches, ants, and other pests These same properties, however, mean that people must avoid overexposure
to borax lest it prove toxic to the kidneys and other or-gans (a typical symptom is red and peeling skin) Finally, borates such as borax enhance the power of other cleansing chemicals by bonding with other compounds in such a way that it maintains the even dispersal of these cleansing agents in solution, thereby maximizing their surface area and hence their effectiveness
Karen N Kähler
Further Reading Chatterjee, Kaulir Kisor “Borax and Related
Min-erals.” In Uses of Industrial Minerals, Rocks, and Fresh-water New York: Nova Science, 2009.
Garrett, Donald E “Borax.” In Borates: Handbook of Deposits, Processing, Properties, and Use San Diego,
Calif.: Academic Press, 1998
Trang 4Grew, E S., and L M Anovitz, eds Boron: Mineralogy,
Petrology, and Geochemistry Washington, D.C.:
Min-eralogical Society of America, 1996
Spears, John Randolph Illustrated Sketches of Death
Val-ley and Other Borax Deserts of the Pacific Coast Edited
by Douglas Steeples Chicago: Rand McNally, 1892
Reprint Baltimore: Johns Hopkins University
Press, 2001
Travis, N J., and E J Cocks The Tincal Trail: A History
of Borax London: Harrap, 1984.
U.S Borax and Chemical Corporation The Story of
Bo-rax 2d ed Los Angeles: Author, 1979.
Web Sites
U.S Geological Survey
Boron: Statistics and Information
http://minerals.usgs.gov/minerals/pubs/
commodity/boron/index.html#myb
U.S Geological Survey
Death Valley Geology Field Trip: All About Death
Valley Borax
http://geomaps.wr.usgs.gov/parks/deva/
fthar4.html#basics
U.S Geological Survey
Death Valley Geology Field Trip: Harmony Borax
Works
http://geomaps.wr.usgs.gov/parks/deva/
fthar1.html
See also: Boron; Ceramics; Evaporites; Fertilizers;
Glass; Sedimentary processes, rocks, and mineral
de-posits
Boron
Category: Mineral and other nonliving resources
Where Found
Boron is not abundant There are about 9 parts per
million of boron in the Earth’s crust, which makes
bo-ron the thirty-eighth element in abundance
Com-mercially valuable deposits are rare, but the deposits
in California and Turkey are very large
Primary Uses
The main uses of boron are in heat-resistant glasses,
glass wool, fiberglass, and porcelain enamels It is also
used in detergents, soaps, cleaners and cosmetics, and synthetic herbicides and fertilizers
Technical Definition Boron (abbreviated B), atomic number 5, belongs to Group III of the periodic table of the elements and re-sembles silicon in many of its chemical properties It has two naturally occurring isotopes: boron 10 (19.8 percent) and boron 11 (80.2 percent) Boron exists in several allotropic forms The crystalline forms are a dark red color, and the powdered forms are black The most stable form has a melting point of 2,180° Celsius, a boiling point of 3,650° Celsius, and a density
of 2.35 grams per cubic centimeter
Description, Distribution, and Forms Boron is found primarily in dried lake beds in Califor-nia and Turkey Isolated deposits also occur in China and numerous South American countries The major deposits of borate minerals occur in areas of former volcanic activity and in association with the waters of former hot springs Searles Lake in southeastern Cali-fornia has layers that are 1.6 percent and 2.0 percent borax Boron is found naturally only as borate miner-als such as ulexite [B5O6(OH)6]C5H2O and borax
Na2[B4O5(OH)4]C8H2O or as borosilicates Boron is more concentrated in plants than in animal tissue The use of borax laundry detergents, the burning
of coal, and mining have filled the atmosphere and ir-rigation waters in some areas with boron compounds Although there have been some reports of damage to grazing animals, boron is not considered a danger un-less it is in the form of a pesticide, an herbicide, or fi-berglass, which is carcinogenic
Boron is an essential element only for higher plants The amount needed by those plants and the amount that is toxic are only a few parts per million apart, so toxicity effects can easily occur Boron is not known to be necessary to animal life, and it is quickly excreted in urine In high concentrations toxicity ef-fects can occur, especially in the brain, before all the boron is excreted
History Borax was used in ancient times to make glazes and hard glass and was traded by the Babylonians four thousand years ago However it was not isolated in pure enough form to be characterized as an element until 1808 The isolation was achieved by Joseph-Louis Gay-Lussac and Joseph-Louis-Jacques Thénard and
Trang 5dependently by Sir Humphry Davy.
Boron was isolated from boric acid
through a heated reaction with
po-tassium The first pure (95 to 98
per-cent) boron was isolated by Henri
Moissan in 1892
Obtaining Boron
The four main methods of isolating
boron are reduction by metals at high
temperature, electrolytic reduction
of fused borates or
tetrafluoro-borates, reduction by hydrogen of
volatile compounds, and thermal
de-composition of hydrides or halides
About 3.8 million metric tons are
produced annually Boron will form
compounds with almost every
ele-ment except the noble gases and a
few of the heavier metals It is said to
have the most diverse chemistry next
to carbon and is characterized as a
metalloid by some properties and as a
nonmetal by others This rich
chem-istry leads to a wide range of uses
Uses of Boron
One of the most common uses of
bo-ron is in the production of
borosili-cate glass (Pyrex glass) Borosiliborosili-cate glass does not
ex-pand or contract as much as regular glass, so it does
not break with temperature changes as easily as
regu-lar glass Pyrex cooking vessels and most laboratory
glassware are made of borosilicate glass Boron
im-proves the tempering of steel better than other
alloy-ing elements Boron carbide is one of the hardest
sub-stances known and is used in both abrasive and
abrasion-resistant applications as well as in nuclear
shielding Lighter elements are better shields for
neu-trons than are heavy elements such as lead Boron-10
neutron capture therapy is one of the few ways to treat
a nonoperable brain tumor The boron-10 isotope
collects in the tumor When a neutron hits the boron,
a reaction produces radiation to kill the cancer cells
Borate is used in the production of glass fiber
ther-mal insulation, the principal insulating material used
in construction Another glass application is as a thin,
glassy coating fused onto ceramics and metals
Exam-ples include wall and floor tiles, tableware, bone china,
porcelain, washing machines, pots, and architectural
paneling Boron is also used in algicides, fertilizers, herbicides, insecticides, and water treatments Sodium polyborate can be used to control fleas, and boric acid has been used in the control of cockroaches Fire re-tardants include zinc borate, ammonium pentaborate, and boric oxide These are used in chipboard, cellu-lose insulation, and cotton mattresses Boron com-pounds are also used in metallurgical processes such
as fluxes and shielding slags and in electroplating baths Borax is a water-softening agent, while boron
is used as a bleaching agent Perborates in water form hydrogen peroxide to act as a bleach Boron is also used in cosmetics, pharmaceutical and hygienic products, pH adjusters, emulsifiers, stabilizers, and buffers
C Alton Hassell
Further Reading
Adriano, Domy C “Boron.” In Trace Elements in Terres-trial Environments: Biogeochemistry, Bioavailability, and Risks of Metals 2d ed New York: Springer, 2001.
Glass 34%
Fire retardants 3% Soaps & detergents 3%
Textile-grade glass fibers 13%
Undistributed 34.5%
Other 12.5%
Source:
Historical Statistics for Mineral and Material Commodities in the United States
Note:
U.S Geological Survey, 2005, boron statistics, in T D Kelly and G R Matos, comps.,
, U.S Geological Survey Data Series 140 Available online at http://pubs.usgs.gov/ds/2005/140/.
“Undistributed” reflects trade, stocks changes, and data not reported by end use “Other” includes agriculture, enamels, frits, glazes, metallurgy, and nuclear applications.
U.S End Uses of Boron
Trang 6Greenwood, N N., and A Earnshaw “Boron.” In
Chemistry of the Elements 2d ed Boston:
Butter-worth-Heinemann, 1997
Grew, E S., and L M Anovitz, eds Boron: Mineralogy,
Petrology, and Geochemistry Washington, D.C.:
Min-eralogical Society of America, 1996
Housecroft, Catherine E Cluster Molecules of the P-Block
Elements New York: Oxford University Press, 1994.
Kogel, Jessica Elzea, et al., eds “Boron and Borates.”
In Industrial Minerals and Rocks: Commodities,
Mar-kets, and Uses 7th ed Littleton, Colo.: Society for
Mining, Metallurgy, and Exploration, 2006
Krebs, Robert E The History and Use of Our Earth’s
Chemical Elements: A Reference Guide Illustrations by
Rae Déjur 2d ed Westport, Conn.: Greenwood
Press, 2006
Massey, A G “Group 13: Boron, Aluminum, Gallium,
Indium, and Thallium.” In Main Group Chemistry.
2d ed New York: Wiley, 2000
Smallwood, C Boron Geneva, Switzerland: World
Health Organization, 1998
Weeks, Mary Elvira Discovery of the Elements: Collected
Reprints of a Series of Articles Published in the “Journal
of Chemical Education.” Kila, Mont.: Kessinger, 2003.
Web Site
U.S Geological Survey
Boron: Statistics and Information
http://minerals.usgs.gov/minerals/pubs/
commodity/boron/index.html#myb
See also: Borax; China; Fiberglass; Glass; Herbicides;
Pesticides and pest control; Turkey
Botany
Category: Scientific disciplines
Any topic dealing with plants, from the level of their
cellular biology to the level of their economic
produc-tion, is considered part of the field of botany.
Definition
Botany is an old branch of science that began with
early humankind’s interest in the plants around them
In modern society, plant science extends beyond that
interest to cutting-edge biotechnology
Overview The origins of botany, beginning around 5000 b.c.e., are rooted in human attempts to improve their lot by raising better food crops This practical effort devel-oped into intellectual curiosity about plants in gen-eral, and the science of botany was born Some of the earliest botanical records are included with the writ-ings of Greek philosophers, who were often physi-cians and who used plant materials as curative agents
In the second century b.c.e., Aristotle had a botanical garden and an associated library
As more details became known about plants and their function, particularly after the discovery of the microscope, the growing body of knowledge became too great for general understanding, so a number of subdisciplines arose Plant anatomy is concerned chiefly with the internal structure of plants Plant physiology delves into the living functions of plants Plant taxonomy has as its interest the discovery and systematic classification of plants Plant geography deals with the global distribution of plants Plant ecol-ogy studies the interactions between plants and their surroundings Plant morphology studies the form and structure of plants Plant genetics attempts to un-derstand and work with the way that plant traits are in-herited Plant cytology, often called cell biology, is the science of cell structure and function Economic any, which traces its interest back to the origins of bot-any, studies those plants that play important economic roles (these include major crops such as wheat, rice, corn, and cotton) Ethnobotany is a rapidly developing subarea in which scientists communicate with indige-nous peoples to explore the knowledge that exists as a part of their folk medicine Several new drugs and the promise of others have developed from this search
At the forefront of modern botany is the field of ge-netic engineering, including the cloning of organ-isms New or better crops have long been developed
by the technique of cross-breeding, but genetic engi-neering offers a much more direct course Using its techniques scientists can introduce a gene carrying a desirable trait directly from one organism to another
In this way scientists hope to protect crops from frost damage, to inhibit the growth of weeds, to provide in-sect repulsion as a part of the plant’s own system, and
to increase the yield of food and fiber crops
The role that plants play in the energy system of the Earth (and may someday play in space stations or other closed systems) is also a major area of study Plants, through photosynthesis, convert sunlight into
Trang 7other useful forms of energy upon which humans
have become dependent During the same process
carbon dioxide is removed from the air, and oxygen is
delivered Optimization of this process and
discover-ing new applications for it are goals for botanists
Kenneth H Brown
See also: Agricultural products; Agriculture
indus-try; Biotechnology; Farmland; Grasslands; Green
Rev-olution; Horticulture; Plant domestication and
breeding; Plants as a medical resource; Rain forests
Brass
Category: Products from resources
Brass, a metal alloy, has numerous practical
applica-tions because of its ease of fabrication, corrosion
resis-tance, and attractive appearance It is used in
hard-ware items, electrical fixtures, inexpensive jewelry, and
metal decorations.
Definition
Brass is a copper-based alloy consisting mainly of
cop-per and zinc It can also be mixed with lead, tin,
nickel, aluminum, iron, manganese, arsenic,
anti-mony, and phosphorus
Overview
The first brass was probably made accidentally by
melting copper ore that contained a small amount of
zinc The earliest known brass object was made by the
Romans about 20 b.c.e By the eleventh century, brass
was made on a large scale throughout Western
Eu-rope, and brass coins, kettles, and ornaments were
manufactured In the United States, the brass
indus-try developed mainly in Connecticut; at first it was
de-voted primarily to making buttons
The color and composition of brass vary with the
amount of copper, which ranges from 55 percent to
95 percent When the alloy contains about 70 percent
copper, it has a golden-yellow color (such brass is
called yellow brass or cartridge brass) When it
con-tains 80 percent or more copper, it has a reddish
cop-per color (red brass) When zinc is added, brass
be-comes stronger and tougher The ductility (ability to
be stretched) improves with increasing amounts of
zinc up to about 30 percent The best combination of
strength and ductility occurs in yellow brass
Lead is added to improve machinability (ease of cutting) Tin and nickel are often added to increase the alloy’s resistance to corrosion and wear Nickel may be added to obtain a silvery-white color that makes the alloy a more suitable base for silver plating Aluminum is useful in improving the corrosion resis-tance of brass in turbulent or fast-moving water The strength of brass is also improved with the addition of iron, manganese, nickel, and aluminum
The first step in making brass is to melt copper in
an electric furnace Solid pieces of zinc are then added to the melted copper, and the zinc melts rap-idly After the copper and zinc have been melted and thoroughly mixed, the brass is ready for pouring It is typically made into blocklike forms (ingots) or small bars (billets), making it easy to work with the brass or
to store it When it is time to make a particular piece, the bars are placed in a furnace, and after they have been reheated to the proper temperature for work-ing, the brass can be rolled and formed into the de-sired shape A milling machine removes surface im-perfections, and the brass is then cold rolled Brass is used in making automobile components, ship propellers, refrigeration and air-conditioning equipment (condenser tubes), decorative elements (architectural trim), plumbing hardware, camera parts, valves, screws, buttons, keys, watch and clock parts, and coins Some brasses, mainly containing tin and manganese, are called bronzes, which are used to make statues, bells, vases, cups, and a variety of orna-ments
Alvin K Benson
See also: Alloys; Bronze; Copper; Metals and metal-lurgy; Tin; Zinc
Brazil
Categories: Countries; government and resources
Brazil’s metallic mineral resources, especially iron and aluminum, underpin a strong industrial sector and are high-value exports Brazil is the second most impor-tant producer of iron ore in the world after China and
is a significant gold-producing nation It ranks tenth
as a diamond producer and has the second largest crude oil reserves in South America after Venezuela.
Trang 8Brazil’s forest industry contributes about 4 percent to
the nation’s gross domestic product (GDP) and
ac-counts for 7 percent of its exports, providing
employ-ment for two million people Brazil is in the top five
among world nations in relation to area of land used
for agriculture and ranks in the top three as an
ex-porter of agricultural produce.
The Country
Brazil is the fifth largest country in the world, with an
area of 8.5 million square kilometers It is the largest
and most geographically diverse country in South
America, occupying most of the northeast of the
con-tinent, and has a coastline of about 7,490 kilometers
along the Atlantic Ocean The country has a tropical
or semitropical climate, with diverse natural
vegeta-tion dominated by tropical rain forests, dry forests,
and savannas Brazil is generally low lying, with
eleva-tions between 200 and 800 meters Higher elevaeleva-tions,
of about 1,200 meters, are limited to the south Brazil
has a drainage system dominated by the Amazon
River, which originates in the Andes Mountains and
has created an extensive lowland floodplain area in
the northern part of the country
Brazil’s economy is growing rapidly It is the largest
in South America and the eighth largest in the world
Its resource base has not been fully ascertained, but
key resources so far exploited include iron ore, in the
states of Minas Gerais (in the south-central region)
and Pará (in the north); oil, mostly in offshore fields;
timber, from extensive natural forests and
planta-tions; and precious stones in various locations
Agri-culture is most important in the south, where most of
Brazil’s commercial crops are produced and where
most cattle ranches are located In the northeast
and in the Amazon basin, agriculture tends to be
subsistent and may involve shifting cultivation
Metals
Brazil’s iron ore accounts for about 5 percent of its
to-tal exports, with approximately half going to China,
Japan, and Germany Reserves of iron ore are
esti-mated at almost 20 billion metric tons, about 7
per-cent of the world total, ranking Brazil sixth in the
world However, in terms of iron content the reserves
are the best in the world Iron ore accounts for almost
58 percent of the value of Brazil’s mineral production
There are thirty-seven companies extracting iron and
fifty-nine mines, all of which are open cast The
Brazil-ian mining company Vale S.A (formerly Companhia
Vale do Rio Doce) produces more than 60 percent of the iron ore in Brazil and about 15 percent of world iron ore, making it the world’s largest producer of iron ore It is also the world’s second largest producer
of nickel and is involved in the mining of bauxite, manganese, copper, kaolin, and potash
Approximately 70 percent of Brazil’s iron reserves are in the state of Minas Gerais and 25 percent are in Pará The ores occur as hematite (ferric oxide), and,
in 2007, more than 300 million metric tons were pro-duced The Carajás Mine in Pará is the world’s largest iron-ore mine Owned by Vale S.A., it is an open-cast mine with reserves of 1.4 billion metric tons, plus de-posits of manganese, copper, tin, cobalt, and alumi-num In general, the Carajás District is exceptionally rich in minerals and has iron-ore reserves estimated at
16 billion metric tons Other base metals produced in substantial quantities include manganese and alumi-num, of which Brazil accounts for 25 percent and 12.4 percent, respectively, of world production
Gold, tantalum, and niobium are also produced in Brazil The late 1980’s were the period of peak gold production for Brazil Reserves comprise almost 2 percent of the world total and are found mainly in Minas Gerais and Pará In 2006, Brazil produced 40 metric tons; the chief mining company was Anglogold Ashanti Mineração Ltda., which contributed about 7.7 metric tons Most was used by the jewelry industry About 32 metric tons were exported; Japan was the major recipient
Tantalum and niobium are relatively rare metals, but Brazil is a major source of both Tantalum is extracted from tantalite and colombite mined from one site, Pitinga/Mineração Taboca, in the state of Amazonas It is used for the manufacture of electro-lytic capacitors Brazil provides roughly 20 percent of the world total, making it the second largest producer behind Australia This mine also produces tin, ura-nium, and niobium The latter is used in forensic sci-ence and to make alloys with iron to improve the strength of piping, among other uses It is found in four states, of which Minas Gerais contains 73 percent
of the reserves, and is extracted from pyrochlore (bium oxide) Brazil produces most of the world’s nio-bium, which amounted to about 57,000 metric tons in 2008
Fossil Fuels Brazil has substantial reserves of coal, oil, and natural gas Brazil’s energy production is as follows: 38
Trang 9138 • Brazil Global Resources
Brazil: Resources at a Glance
Official name: Federative Republic of Brazil Government: Federal republic
Capital city: Brasília Area: 3,287,851 mi2; 8,514,877 km2
Population (2009 est.): 198,739,269 Language: Portuguese
Monetary unit: real (BRL)
Economic summary:
GDP composition by sector (2008 est.): agriculture, 6.7%; industry, 28%; services, 65.3%
Natural resources: bauxite, gold, iron ore, manganese, nickel, niobium, phosphates, platinum, tin, tantalum,
uranium, petroleum, hydropower, timber, precious and semiprecious stones, graphite
Land use (2005): arable land, 6.93%; permanent crops, 0.89%; other, 92.18%
Industries: textiles, shoes, chemicals, cement, lumber, iron ore, tin, steel, aircraft, motor vehicles and parts, other
machinery and equipment
Agricultural products: coffee, soybeans, wheat, rice, corn, sugarcane, cocoa, citrus, beef
Exports (2008 est.): $197.9 billion
Commodities exported: transport equipment, iron ore, soybeans, footwear, coffee, automobiles
Imports (2008 est.): $173.1 billion
Commodities imported: machinery, electrical and transport equipment, chemical products, oil, automotive parts,
electronics
Labor force (2008 est.): 93.65 million
Labor force by occupation (2003 est.): agriculture, 20%; industry, 14%; services, 66%
Energy resources:
Electricity production (2007 est.): 437.3 billion kWh
Electricity consumption (2007 est.): 402.2 billion kWh
Electricity exports (2007 est.): 2.034 billion kWh
Electricity imports (2007 est.): 40.47 billion kWh (supplied by Paraguay)
Natural gas production (2007 est.): 9.8 billion m3
Natural gas consumption (2007 est.): 19.8 billion m3
Natural gas exports (2007 est.): 0 m3
Natural gas imports (2007 est.): 10 billion m3
Natural gas proved reserves ( Jan 2008 est.): 347.7 billion m3
Oil production (2007 est.): 2.277 million bbl/day Oil imports (2005): 648,800 bbl/day
Oil proved reserves ( Jan 2008 est.): 12.35 billion 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.
Brasília
Brazil
Colombia
Argentina
Bolivia
Peru
Paraguay
Uruguay
Venezuela
A t l a n t i c
O c e a n
P a c i f i c
O c e a n
Trang 10cent from oil, 9.6 percent from natural gas, 6
per-cent from coal, and the remainder comprising
hydro-electric power, ethanol from sugarcane, and nuclear
power Globally, its coal reserves are not extensive (930
million metric tons compared to 271,000 million
met-ric tons produced by the United States) More than 50
percent of Brazil’s coal comes from the state of Rio
Grande do Sul, while 46 percent comes from Santa
Catarina and 1.3 percent comes from Paraná, Brazil’s
southernmost states This coal is used within Brazil
In relation to global oil reserves and production,
Brazil is ranked sixteenth and fourteenth,
respec-tively, and has about 1 percent of estimated global
re-serves In 2006, production was about 90 million
met-ric tons, an annual increase of more than 5 percent
that was mainly due to raised output from offshore
oil fields, notably the Campos and Santos basins
lo-cated off the southeast coast of the state of Rio de
Ja-neiro These fields contain the vast majority of Brazil’s
proven reserves Such increases have made Brazil
al-most self sufficient in oil, though light crude is still
im-ported because of refinery capacity The state-owned
company Petrobras controls about 95 percent of crude
oil production, which amounts to about 2.277 million
barrels per day Brazil ranks fortieth for natural gas
re-serves and thirty-third for production It produced
about 9.8 billion cubic meters in 2007, mostly from
offshore fields, all of which is consumed within Brazil
Other Energy Resources
Most of Brazil’s remaining energy needs are met by
hydroelectric power and ethanol, a biofuel made from
sugarcane Brazil is the third largest producer of
hydropower in the world Approximately 27 percent
of its potential could be exploited economically
Al-though just less than half has been realized, it
pro-vides about 84 percent of Brazil’s electricity Much of
this has been made possible by the vast Itaipu Dam
constructed in the late 1980’s, which Brazil shares
with neighboring Paraguay Other large-scale schemes
include the Tucurui Dam on the Tocantins River in
Pará and Boa Esperança on the Parnaíba River near
the city of Guadalupe Another dam, the Belo Monte,
is proposed on the Xingu River, also in the state of
Pará However, this project is controversial because of
the adverse environmental and social impacts
associ-ated with such large-scale projects Many small-scale
dams also contribute to Brazil’s hydropower capacity
Although Brazil is not the only nation to develop
biofuels, it is unique insofar as ethanol became
avail-able as a fuel in the 1920’s Ethanol rose to promi-nence in the mid-1970’s, when world oil crises prompted the Brazilian government to decree that all automobiles had to operate on a fuel that contained
at least 10 percent ethanol Brazil is a leading pro-ducer of ethanol and user of ethanol as a fuel; it has been described as having the world’s first sustainable biofuel economy In 2006, Brazil was responsible for
33 percent of the global production of ethanol and for 42 percent of the ethanol used as fuel Ethanol is produced by the fermentation of sugarcane, one of Brazil’s major crops, which was introduced by Europe-ans in the sixteenth century In 2007, Brazil produced
514 million metric tons of sugarcane from 6.7 million hectares, mostly in the central/southern region Be-tween 40 and 50 percent is used for ethanol fuel and the rest for sugar, which is a major export The sucrose content is the raw material for ethanol, which is pro-duced at more than 370 processing plants, mostly in Brazil’s southern and coastal states Brazil has auto-mobiles that can run on any combination of petro-leum/ethanol-based fuels, though environmental im-plications remain because sugarcane plantations rely
on irrigation, mechanization, and other techniques that affect the environment
Agricultural Resources Brazil is a world leader in the export of agricultural products, and the agricultural sector contributes more than 5 percent to the nation’s gross domestic product (GDP) Of Brazil’s total land area (almost 8.5 million square kilometers), about 2.6 million square kilome-ters are used for crop production Apart from sugar-cane, soybeans, maize, rice, coffee, wheat, and cotton are significant economic crops Beef production is also important in Brazil; the country has extensive cat-tle ranches in the hinterland of São Paulo According
to statistics compiled by the Food and Agriculture Or-ganization, soybeans and maize are grown on 20.6 and 13.8 million hectares, respectively, crops that pro-duce about 58 and 50 million metric tons, respec-tively Soybean cultivation has increased significantly but is no longer dominant in São Paulo’s hinterland, having expanded into central western and northeast-ern regions (where its and sugarcane’s spread occurs
at the expense of savanna and forest ecosystems) This expansion is partly associated with increased demand for biofuels Brazil is the world’s biggest exporter of soybeans, sending 25 million metric tons to markets
in Asia and Europe