MEPS 531MEPS 531INDUSTRIAL INDUSTRIAL PROCESSESPROCESSES

COPPERCOPPER

INTRODUCTION/ INTRODUCTION/ HISTORYHISTORY

CopperCopper is a is a chemical elementchemical element in the in the periodic tableperiodic table that has the symbol that has the symbol CuCu ( (LatinLatin: : cuprumcuprum) and ) and atomic numberatomic number 29. It is a 29. It is a ductileductile metalmetal with excellent with excellent electrical conductivityelectrical conductivity, and finds extensive , and finds extensive use as an electrical conductor, heat use as an electrical conductor, heat conductor, as a building material, and as a conductor, as a building material, and as a component of various component of various alloysalloys. .

Copper is an essential nutrient to all high Copper is an essential nutrient to all high plants and animals. In animals, including plants and animals. In animals, including humans, it is found primarily in the humans, it is found primarily in the bloodstreambloodstream, as a co-factor in various , as a co-factor in various enzymesenzymes, and in copper-based , and in copper-based pigmentspigments. In . In sufficient amounts, copper can be poisonous sufficient amounts, copper can be poisonous and even fatal to organisms.and even fatal to organisms.

Copper has played a significant part in the Copper has played a significant part in the history of mankind, which has used the history of mankind, which has used the easily accessible uncompounded metal for easily accessible uncompounded metal for nearly 10,000 years. Civilizations in places nearly 10,000 years. Civilizations in places like like IraqIraq, , ChinaChina, , EgyptEgypt, , GreeceGreece and the and the SumerianSumerian cities all have early evidence of cities all have early evidence of using copper. During the Roman Empire, using copper. During the Roman Empire, copper was principally mined on copper was principally mined on CyprusCyprus, , hence the origin of the name of the metal hence the origin of the name of the metal as Cyprium, "metal of Cyprus", later as Cyprium, "metal of Cyprus", later shortened to Cuprum. A number of shortened to Cuprum. A number of countries, such as countries, such as ChileChile and the and the United StatesUnited States, still have sizeable reserves , still have sizeable reserves of the metal which are extracted through of the metal which are extracted through large open pit mines.large open pit mines.

Nevertheless, the price of copper rose rapidly, Nevertheless, the price of copper rose rapidly, increasing 500% from a 60-year low in 1999, increasing 500% from a 60-year low in 1999, largely due to increased demand. This metal largely due to increased demand. This metal has come into the limelight on account of high has come into the limelight on account of high volatility in prices. According to volatility in prices. According to New ScientistNew Scientist (May 26, 2007) the earth has an estimated 61 (May 26, 2007) the earth has an estimated 61 years supply of copper left.years supply of copper left.

Copper is a reddish-colored Copper is a reddish-colored metalmetal, with a high , with a high electricalelectrical and thermal conductivity ( and thermal conductivity (silversilver is is the only pure metal to have a higher electrical the only pure metal to have a higher electrical conductivity at room temperature). In conductivity at room temperature). In oxidationoxidation copper is mildly copper is mildly basicbasic. Copper has its . Copper has its characteristic color because it reflects red and characteristic color because it reflects red and orange light and absorbs other frequencies in orange light and absorbs other frequencies in the visible spectrum, due to its the visible spectrum, due to its band structureband structure. . This can be contrasted with the optical This can be contrasted with the optical properties of properties of silversilver, , goldgold and and aluminiumaluminium. .

Copper occupies the same family of the periodic Copper occupies the same family of the periodic table as silver and gold, since they each have table as silver and gold, since they each have one s-orbital electron on top of a filled one s-orbital electron on top of a filled electron shellelectron shell. This similarity in electron . This similarity in electron structure makes them similar in many structure makes them similar in many characteristics. All have very high thermal and characteristics. All have very high thermal and electrical conductivity, and all are malleable electrical conductivity, and all are malleable metals.metals.

In its liquified state, a pure copper surface In its liquified state, a pure copper surface without ambient light appears somewhat without ambient light appears somewhat greenish, another characteristic shared with greenish, another characteristic shared with gold. Silver does not have this property, so it is gold. Silver does not have this property, so it is not a complementary color for the orange not a complementary color for the orange incandescence color. When liquid copper is in incandescence color. When liquid copper is in bright ambient light, it retains some of its bright ambient light, it retains some of its pinkish luster.pinkish luster.

Due to its high surface tension, the liquid Due to its high surface tension, the liquid metal does not wet surfaces but instead metal does not wet surfaces but instead forms spherical droplets when poured on a forms spherical droplets when poured on a surface.surface.

Copper is insoluble in water (H2O) as well as Copper is insoluble in water (H2O) as well as in in isopropanolisopropanol..

There are two stable There are two stable isotopesisotopes, 63Cu and 65Cu, , 63Cu and 65Cu, along with a couple dozen along with a couple dozen radioisotopesradioisotopes. The . The vast majority of radioisotopes have half lives vast majority of radioisotopes have half lives on the order of minutes or less; the longest on the order of minutes or less; the longest lived, 67Cu, has a half life of 61.8 hours.lived, 67Cu, has a half life of 61.8 hours.

Numerous Numerous copper alloyscopper alloys exist, many with exist, many with important historical and contemporary uses. important historical and contemporary uses. Speculum metalSpeculum metal and and bronzebronze are alloys of are alloys of copper and copper and tintin..

BrassBrass is an alloy of copper and is an alloy of copper and zinczinc. . MonelMonel metal, also called metal, also called cupronickelcupronickel, is an alloy of , is an alloy of copper and copper and nickelnickel. While the metal "bronze" . While the metal "bronze" usually refers to copper-tin alloys, it also is a usually refers to copper-tin alloys, it also is a generic term for any alloy of copper, such as generic term for any alloy of copper, such as aluminiumaluminium bronze bronze, silicon bronze, and , silicon bronze, and manganese bronze.manganese bronze.

Copper is germicidal, via the Copper is germicidal, via the oligodynamicoligodynamic effect effect. For example, brass doorknobs disinfect . For example, brass doorknobs disinfect themselves of many bacteria within eight themselves of many bacteria within eight hours. This effect is useful in many hours. This effect is useful in many applications. applications.

The purity of copper is expressed as 4N for The purity of copper is expressed as 4N for 99.99% pure or 7N for 99.99999% pure. The 99.99% pure or 7N for 99.99999% pure. The numeral gives the number of nines after the numeral gives the number of nines after the decimal point when expressed as a decimal decimal point when expressed as a decimal (eg 4N means 0.9999, or 99.99%).(eg 4N means 0.9999, or 99.99%).

Copper, as Copper, as native coppernative copper, is one of the few , is one of the few metals to naturally occur as an metals to naturally occur as an uncompounded mineral. Copper was known uncompounded mineral. Copper was known to some of the oldest civilizations on record, to some of the oldest civilizations on record, and has a history of use that is at least 10,000 and has a history of use that is at least 10,000 years old. A copper pendant was found in years old. A copper pendant was found in what is now northern what is now northern IraqIraq that dates to 8700 that dates to 8700 BCE. By 5000 BCE, there are signs of copper BCE. By 5000 BCE, there are signs of copper smeltingsmelting, the refining of copper from simple , the refining of copper from simple copper compounds such as copper compounds such as malachitemalachite or or azuriteazurite. Among archaeological sites in . Among archaeological sites in Anatolia, Anatolia, ÇatalÇatal HöyükHöyük (~6000 BCE) features (~6000 BCE) features native copper artifacts and smelted lead native copper artifacts and smelted lead beads, but no smelted copper. But beads, but no smelted copper. But Can Can HasanHasan (~5000 BCE) had access to smelted copper; (~5000 BCE) had access to smelted copper; this site has yielded the oldest known cast this site has yielded the oldest known cast copper artifact, a copper copper artifact, a copper macemace head. head.

Copper smelting appears to have been Copper smelting appears to have been developed independently in several parts of developed independently in several parts of the world. In addition to its development in the world. In addition to its development in Anatolia by 5000 BCE, it was developed in Anatolia by 5000 BCE, it was developed in China before 2800 BCE, in the Andes around China before 2800 BCE, in the Andes around 2000 BCE, in Central America around 600 2000 BCE, in Central America around 600 AD, and in West Africa around 900 AD. AD, and in West Africa around 900 AD. Copper is found extensively in the Copper is found extensively in the Indus Valley CivilizationIndus Valley Civilization by the 3rd by the 3rd millennium BC. In Europe, millennium BC. In Europe, ÖtziÖtzi the Iceman the Iceman, , a well-preserved male dated to a well-preserved male dated to 3200 BC3200 BC, , was found with a copper-tipped axe whose was found with a copper-tipped axe whose metal was 99.7% pure. High levels of metal was 99.7% pure. High levels of arsenicarsenic in his hair suggest he was involved in his hair suggest he was involved in copper smelting.in copper smelting.

There are copper and There are copper and bronzebronze artifacts from artifacts from SumerianSumerian cities that date to 3000 BC, and cities that date to 3000 BC, and EgyptianEgyptian artifacts of copper and copper- artifacts of copper and copper-tintin alloys nearly as old. In one pyramid, a alloys nearly as old. In one pyramid, a copper plumbing system was found that is copper plumbing system was found that is 5000 years old. The Egyptians found that 5000 years old. The Egyptians found that adding a small amount of tin made the adding a small amount of tin made the metal easier to cast, so bronze alloys metal easier to cast, so bronze alloys were found in Egypt almost as soon as were found in Egypt almost as soon as copper was found. In the Americas copper was found. In the Americas production in the production in the Old Copper ComplexOld Copper Complex, , located in present day Michigan and located in present day Michigan and Wisconsin, was dated back to between Wisconsin, was dated back to between 6000 to 3000 BC.6000 to 3000 BC.

The use of The use of bronzebronze became so pervasive in a became so pervasive in a certain era of civilization that it has been certain era of civilization that it has been named the named the Bronze AgeBronze Age. The transitional . The transitional period in certain regions between the period in certain regions between the preceding preceding NeolithicNeolithic period and the Bronze period and the Bronze Age is termed the Age is termed the ChalcolithicChalcolithic ("copper- ("copper-stone"), with some high-purity copper tools stone"), with some high-purity copper tools being used alongside stone tools. being used alongside stone tools. BrassBrass was known to the Greeks, but only became was known to the Greeks, but only became a significant supplement to bronze during a significant supplement to bronze during the Roman empire. In Greek the metal was the Roman empire. In Greek the metal was known by the name known by the name chalkoschalkos. Copper was a . Copper was a very important resource for the Romans, very important resource for the Romans, Greeks and other ancient peoples. Greeks and other ancient peoples.

In Roman times, it became known as In Roman times, it became known as aes aes CypriumCyprium ( (aesaes being the generic Latin term being the generic Latin term for copper alloys such as for copper alloys such as bronzebronze and other and other metals, and metals, and CypriumCyprium because so much of it because so much of it was mined in was mined in CyprusCyprus). From this, the phrase ). From this, the phrase was simplified to was simplified to cuprumcuprum and then and then eventually Anglicized into the English eventually Anglicized into the English coppercopper. Copper was associated with the . Copper was associated with the goddess goddess AphroditeAphrodite//VenusVenus in mythology and in mythology and alchemyalchemy, owing to its lustrous beauty, its , owing to its lustrous beauty, its ancient use in producing mirrors, and its ancient use in producing mirrors, and its association with association with CyprusCyprus, which was sacred , which was sacred to the goddess. In to the goddess. In alchemyalchemy the symbol for the symbol for copper was also the symbol for the planet copper was also the symbol for the planet VenusVenus..

Mining for copper in the Philippines dates Mining for copper in the Philippines dates back to the 14th century when crudely back to the 14th century when crudely smelted copper was traded by the Chinese. smelted copper was traded by the Chinese. Significant production did not start until Significant production did not start until 1842 when the San Remegio Copper Mines, 1842 when the San Remegio Copper Mines, Inc. opened the Carawisan Mine in Antique. Inc. opened the Carawisan Mine in Antique. This was followed by Mankayan Mine in This was followed by Mankayan Mine in Benguet that was operated by the Benguet that was operated by the Contrabro-Filipino Co. from 1864 to 1874.Contrabro-Filipino Co. from 1864 to 1874.

The American took little interest in the metal The American took little interest in the metal up until 1936 when the Mankayan Mine up until 1936 when the Mankayan Mine was reopened. Soon in 1939, the Hixbar was reopened. Soon in 1939, the Hixbar Mine in Rapu-Rapu Island, Albay was put Mine in Rapu-Rapu Island, Albay was put into production. These two mines into production. These two mines accounted for all the copper produced in accounted for all the copper produced in the Philippines before World War II.the Philippines before World War II.

The years after the war saw a rapidly The years after the war saw a rapidly emerging interest in copper and other base emerging interest in copper and other base metals, almost at the expense of gold, metals, almost at the expense of gold, which was plagued with depressed prices which was plagued with depressed prices and mine rehabilitation problems. For its and mine rehabilitation problems. For its high-grade copper ore, the Lepanto high-grade copper ore, the Lepanto Consolidated Mining Company reopened Consolidated Mining Company reopened Mankayan Mine in 1948. New technologies Mankayan Mine in 1948. New technologies were introduced for the economic were introduced for the economic extraction of large low-grade porphyry extraction of large low-grade porphyry copper deposits. Thus, Atlas Mine in Cebu copper deposits. Thus, Atlas Mine in Cebu started production in 1955, followed by the started production in 1955, followed by the Sipalay Mine in Negros in 1957, and Sto. Sipalay Mine in Negros in 1957, and Sto. Tomas II Mine in Benguet in 1958.Tomas II Mine in Benguet in 1958.

By the 1960s, a full-blown copper boom By the 1960s, a full-blown copper boom dominated the mining industry. The boom dominated the mining industry. The boom was accompanied by extensive exploration was accompanied by extensive exploration activities, which led to the discovery and activities, which led to the discovery and opening of new porphyry copper mines such opening of new porphyry copper mines such as Sto. Nino Mine in 1971 and Boneng-Lobo as Sto. Nino Mine in 1971 and Boneng-Lobo Mine in 1974. By 1974, 18 copper producing Mine in 1974. By 1974, 18 copper producing mines were in operation.mines were in operation.The latter part of the 1970?s saw some of the The latter part of the 1970?s saw some of the newly opened copper mines struggling newly opened copper mines struggling against high inflationary trends, high cost of against high inflationary trends, high cost of money, and marginal ores. Ino-Capayang and money, and marginal ores. Ino-Capayang and the nearby Mogpog Mine of Consolidated the nearby Mogpog Mine of Consolidated Mines Inc. in Marinduque were thus forced to Mines Inc. in Marinduque were thus forced to stop operation in 1978 and 1981. This was stop operation in 1978 and 1981. This was followed suit by the closure of Boneng-Lobo followed suit by the closure of Boneng-Lobo and Sto. Ni?o Mines in Benguet.and Sto. Ni?o Mines in Benguet.

Despite these indications of trouble, however, Despite these indications of trouble, however, several new mines managed to start several new mines managed to start operation. Basay Mine in Negros, Dizon Mine operation. Basay Mine in Negros, Dizon Mine in Zambales, Sabena and North Davao Mines in Zambales, Sabena and North Davao Mines in Davao del Norte, and Hercules Mine in in Davao del Norte, and Hercules Mine in Ilocos Norte opened between 1979 and 1981. Ilocos Norte opened between 1979 and 1981. During the early 1980?s the Philippines had During the early 1980?s the Philippines had 20 primary and secondary copper producers. 20 primary and secondary copper producers. However, due to the sluggish economic and However, due to the sluggish economic and political condition in the country, coupled political condition in the country, coupled with the outdated mining laws and with the outdated mining laws and regulations, most companies were forced to regulations, most companies were forced to either scale down or shutdown its mining either scale down or shutdown its mining operations. At the turn of the decade only operations. At the turn of the decade only seven (7) copper mining companies operated seven (7) copper mining companies operated in the Philippines. Finally in 1999 only three in the Philippines. Finally in 1999 only three (3) were left in operation. (3) were left in operation.

USES AND USES AND ECONOMICSECONOMICS

Copper is Copper is malleablemalleable and and ductileductile, a good , a good conductor of heatconductor of heat and, when very pure, a and, when very pure, a good good conductor of electricityconductor of electricity..

It is used extensively, in products such as:It is used extensively, in products such as: PipingPiping, including, but not limited to, , including, but not limited to,

domestic domestic waterwater supply supply Electronics:Electronics:

Copper wireCopper wire. . ElectromagnetsElectromagnets. . Printed circuit boardsPrinted circuit boards. . Electrical machinesElectrical machines, especially , especially

electromagnetic motors, generators and electromagnetic motors, generators and transformers.transformers.

Electrical Electrical relaysrelays, electrical , electrical busbarsbusbars and electrical and electrical switchesswitches. .

Vacuum tubesVacuum tubes, , cathode ray tubescathode ray tubes, and , and the the magnetronsmagnetrons in in microwave ovensmicrowave ovens..

Wave guidesWave guides for microwave radiation. for microwave radiation. Integrated circuitsIntegrated circuits, increasingly , increasingly

replacing replacing aluminiumaluminium because of its because of its superior electrical conductivity. superior electrical conductivity.

As a material in the manufacture of As a material in the manufacture of computer computer heat sinksheat sinks, as a result of its , as a result of its superior heat dissipation capacity to superior heat dissipation capacity to aluminiumaluminium. .

Structural Engineering:Structural Engineering: Copper has been used as water-proof Copper has been used as water-proof

roofingroofing material since ancient times, material since ancient times, giving many old buildings their giving many old buildings their greenish roofs and domes. greenish roofs and domes.

StatuaryStatuary: The : The Statue of LibertyStatue of Liberty, for , for example, contains 179,220 pounds example, contains 179,220 pounds (81.3 (81.3 tonnestonnes) of copper. ) of copper.

Alloyed with Alloyed with nickelnickel, e.g. , e.g. cupronickelcupronickel and and MonelMonel, used as corrosive , used as corrosive resistant materials in resistant materials in shipbuildingshipbuilding. .

WattWatt's 's steam enginesteam engine..

Household Products:Household Products: Copper Copper plumbingplumbing fittings and fittings and

compression tubes. compression tubes. Doorknobs and other fixtures in houses. Doorknobs and other fixtures in houses. RoofingRoofing, guttering, and rainspouts on , guttering, and rainspouts on

buildings. buildings. In In cookwarecookware, such as , such as frying pansfrying pans. . Most Most flatwareflatware ( (knivesknives, , forksforks, , spoonsspoons) )

contains some copper (contains some copper (nickel silvernickel silver). ). Sterling silverSterling silver, if it is to be used in , if it is to be used in

dinnerware, must contain a few percent dinnerware, must contain a few percent copper. copper.

Copper water heating cylinders.Copper water heating cylinders.

Coinage:Coinage: As a component of As a component of coinscoins, often as cupronickel , often as cupronickel

alloy. alloy. Coins in the following countries all contain Coins in the following countries all contain

copper: European Union (Euro), United States, copper: European Union (Euro), United States, United Kingdom (sterling) and Australia. United Kingdom (sterling) and Australia.

Ironically, Ironically, U.S. NickelsU.S. Nickels are 75.0% copper by are 75.0% copper by weight and only 25.0% weight and only 25.0% nickelnickel..

Biomedical applications:Biomedical applications: As a As a biostaticbiostatic surface in hospitals, and to line surface in hospitals, and to line

parts of parts of shipsships to protect against to protect against barnaclesbarnacles and and musselsmussels, originally used pure, but superseded , originally used pure, but superseded by by MuntzMuntz Metal Metal. . BacteriaBacteria will not grow on a will not grow on a copper surface because it is biostatic. Copper copper surface because it is biostatic. Copper doorknobsdoorknobs are used by are used by hospitalshospitals to reduce the to reduce the transfer of disease, and transfer of disease, and Legionnaires' diseaseLegionnaires' disease is is suppressed by copper tubing in suppressed by copper tubing in air-conditioningair-conditioning systems.systems.

Copper(IICopper(II) sulfate) sulfate is used as a is used as a fungicidefungicide and as algae control in domestic lakes and as algae control in domestic lakes and ponds. It is used in gardening and ponds. It is used in gardening powders and sprays to kill powders and sprays to kill mildewmildew. .

Copper-62-PTSMCopper-62-PTSM, a complex containing , a complex containing radioactive radioactive copper-62copper-62, is used as a , is used as a Positron emission tomographyPositron emission tomography radiotracer for heart blood flow radiotracer for heart blood flow measurements. measurements.

Copper-64Copper-64 can be used as a can be used as a Positron emission tomographyPositron emission tomography radiotracer for radiotracer for medical imagingmedical imaging. When . When complexed with a chelate it can be used complexed with a chelate it can be used to treat cancer through to treat cancer through radiation therapyradiation therapy..

Chemical applications:Chemical applications: Compounds, such as Compounds, such as Fehling'sFehling's solution solution, ,

have applications in chemistry. have applications in chemistry. As a component in As a component in ceramic glazesceramic glazes, and to , and to

color color glassglass. . Others:Others:

Musical instrumentsMusical instruments, especially , especially brass instrumentsbrass instruments and and cymbalscymbals. .

Class D Fire ExtinguisherClass D Fire Extinguisher, used in powder , used in powder form to extinguish lithium fires by form to extinguish lithium fires by covering the burning metal and covering the burning metal and performing similar to a heat sink. performing similar to a heat sink.

Textile fibers to create Textile fibers to create antimicrobialantimicrobial protective fabrics.protective fabrics.

PRODUCTION PRODUCTION STATISTICSSTATISTICS

America is noted to have the richest mineable America is noted to have the richest mineable copper deposit in the world recorded at 7.68 copper deposit in the world recorded at 7.68 million metric tons (MT), which is more than million metric tons (MT), which is more than 62% of the total mine production for 1999. 62% of the total mine production for 1999. Leading producers like Chile and U.S.A at Leading producers like Chile and U.S.A at 4.38 million MT and 1.59 million MT, 4.38 million MT and 1.59 million MT, respectively were also noted in the same respectively were also noted in the same region. Combined mine production of Europe, region. Combined mine production of Europe, Asia, Africa and Oceana accounts for about Asia, Africa and Oceana accounts for about 48% for the same year which is minimal 48% for the same year which is minimal compared to that of Americas annual compared to that of Americas annual contribution. Mine production has been contribution. Mine production has been growing annually at an average growth rate growing annually at an average growth rate of 3.3% for the past ten (10) years from 1990 of 3.3% for the past ten (10) years from 1990 to 1999. The highest annual growth was noted to 1999. The highest annual growth was noted in 1996 at 9.1% or 11.1 million MT.in 1996 at 9.1% or 11.1 million MT.

This was followed by 1998 at 6.9% This was followed by 1998 at 6.9% growth, or 12.3 million MT. The growth, or 12.3 million MT. The highest mine production was recorded highest mine production was recorded in 1999 at 12.36 million MT. in 1999 at 12.36 million MT.

In terms of world production of refined copper In terms of world production of refined copper by region, America ranks the highest at 4.0 by region, America ranks the highest at 4.0 million metric tons or 44.9% of the world total million metric tons or 44.9% of the world total for 1999. Chile and U.S.A are the top for 1999. Chile and U.S.A are the top producers from the same region, contributing producers from the same region, contributing 2.7 million metric tons and 2.1 million metrics 2.7 million metric tons and 2.1 million metrics tons, respectively. Likewise, top producers tons, respectively. Likewise, top producers from Asia, such as Japan and China, posted as from Asia, such as Japan and China, posted as much as 1.3 million metric tons and 1.0 much as 1.3 million metric tons and 1.0 million metric tons, respectively.million metric tons, respectively.

Production of refined copper grew at an annual Production of refined copper grew at an annual average growth rate of 2.9% from 1990 to average growth rate of 2.9% from 1990 to 1999. The highest growth periods were noted 1999. The highest growth periods were noted in 1996 at 7.8% and in 1997 at 6.7%. The in 1996 at 7.8% and in 1997 at 6.7%. The highest refined copper production was highest refined copper production was recorded in 1999 at 14.3 million metric tons recorded in 1999 at 14.3 million metric tons (MT). (MT).

Consumption of refined copper grew at an Consumption of refined copper grew at an annual average growth rate of 2.8% from annual average growth rate of 2.8% from 1990 to 1999. The highest annual growth 1990 to 1999. The highest annual growth was noted in 1996 at 6.4% and lowest in was noted in 1996 at 6.4% and lowest in 1991 at a negative annual growth of 0.9%. 1991 at a negative annual growth of 0.9%. The major consumer of refined copper in The major consumer of refined copper in 1999 was noted in Asia at 5.2 million metric 1999 was noted in Asia at 5.2 million metric tons, or 37.4% of the world consumption. tons, or 37.4% of the world consumption. This was followed by America at 4.2 million This was followed by America at 4.2 million metric tons, or 30.5% and Europe at 30.1%, metric tons, or 30.5% and Europe at 30.1%, or at 4.1 million metric tons. The top four or at 4.1 million metric tons. The top four (4) countries comprising the leading (4) countries comprising the leading consumers of refined copper in 1999 were consumers of refined copper in 1999 were U.S.A. at 3.0 million metric tons, China and U.S.A. at 3.0 million metric tons, China and Japan both at 1.3 million metric tons, and Japan both at 1.3 million metric tons, and Federal Republic of Germany at 1.2 million Federal Republic of Germany at 1.2 million metric tons.metric tons.

World copper prices for the past ten (10) years from World copper prices for the past ten (10) years from 1990 to 1999 were basically at a declining trend. 1990 to 1999 were basically at a declining trend. This was reversed in 1995 when world price This was reversed in 1995 when world price posted a 24.6% increase from 111.0 5c/lb in 1994 posted a 24.6% increase from 111.0 5c/lb in 1994 to 138.33 c/lb in 1995. The highest decline in to 138.33 c/lb in 1995. The highest decline in world copper price was noted between 1997 and world copper price was noted between 1997 and 1998, from 103.22 c/lb to 74.97 c/lb or a negative 1998, from 103.22 c/lb to 74.97 c/lb or a negative growth of 27.4%. This negative trend was due to growth of 27.4%. This negative trend was due to the economic recession that hounded most the economic recession that hounded most economies throughout the nineties. The prolonged economies throughout the nineties. The prolonged depressed state has played havoc to the supply and depressed state has played havoc to the supply and demand pattern. The gap in supply and demand demand pattern. The gap in supply and demand occurred during the period since there was an occurred during the period since there was an increase in mineral production as major markets increase in mineral production as major markets were contracting. Mining firms all over the world were contracting. Mining firms all over the world started adopting new technologies that increased started adopting new technologies that increased capacity utilization rates resulting to the surplus.capacity utilization rates resulting to the surplus.

Copper reserve was estimated at 4.79 million metric tons Copper reserve was estimated at 4.79 million metric tons in 1996. The biggest deposit was found in Cordillera in 1996. The biggest deposit was found in Cordillera Autonomous Region that is estimated at 1.83 million Autonomous Region that is estimated at 1.83 million metric tons followed by Region 7 at 1.15 million metric metric tons followed by Region 7 at 1.15 million metric tons. tons.

Production of copper decreased from 698.17 Production of copper decreased from 698.17 dry metric tons (DMT) in 1990 to 151.22 dry dry metric tons (DMT) in 1990 to 151.22 dry metric tons (DMT) in 1999. The years 1992 metric tons (DMT) in 1999. The years 1992 and 1993 posted an increase in volume from and 1993 posted an increase in volume from 491.75 dry metric tons (DMT) to 526.22 dry 491.75 dry metric tons (DMT) to 526.22 dry metric tons (DMT), or at a rate of 8.0%, due to metric tons (DMT), or at a rate of 8.0%, due to the increase in production of Marcopper the increase in production of Marcopper Mining Corporation?s San Antonio Project and Mining Corporation?s San Antonio Project and Maricalum Mining Corporation. Maricalum Mining Corporation. As of 1999, there were three (3) remaining As of 1999, there were three (3) remaining primary producers, namely: Philex Mining primary producers, namely: Philex Mining Corp., Maricalum Mining Corp. and Manila Corp., Maricalum Mining Corp. and Manila Mining Corp. Of the three (3) producers, Mining Corp. Of the three (3) producers, Philex Mining Corp. ? Padcal Project located Philex Mining Corp. ? Padcal Project located at Benguet, contributed 64.44% to the total at Benguet, contributed 64.44% to the total copper production amounting to 1,382.62 copper production amounting to 1,382.62 million pesos or 82.294 dry metric tons million pesos or 82.294 dry metric tons (DMT).(DMT).

The price of Philippine copper (metal) had been The price of Philippine copper (metal) had been fluctuating between a low of P44,793/DMT in 1993 to fluctuating between a low of P44,793/DMT in 1993 to a high of P66,803/DMT in 1995. In terms of year-to-a high of P66,803/DMT in 1995. In terms of year-to-year growth, the highest was recorded between 1994 year growth, the highest was recorded between 1994 to1995 at an increase of 27.99%. Likewise, a negative to1995 at an increase of 27.99%. Likewise, a negative growth of 14.27% was noted between 1995 to 1996. growth of 14.27% was noted between 1995 to 1996.

RAW MATERIALRAW MATERIAL

Any mineral from which copper is extracted, Any mineral from which copper is extracted, including native copper, Cu; chalcocite, including native copper, Cu; chalcocite, Cu2S; chalcopyrite, CuFeS2; bornite, Cu2S; chalcopyrite, CuFeS2; bornite, Cu5FeS4; azurite, Cu3(CO3)2(OH)2; Cu5FeS4; azurite, Cu3(CO3)2(OH)2; malachite, Cu2CO3(OH)2; and chrysocolla, malachite, Cu2CO3(OH)2; and chrysocolla, CuSiO3.2H2O. Native copper and the copper CuSiO3.2H2O. Native copper and the copper sulphides are usually found in veins sulphides are usually found in veins associated with igneous intrusions. associated with igneous intrusions. Chrysocolla and the carbonates are products Chrysocolla and the carbonates are products of the weathering of copper-bearing rocks. of the weathering of copper-bearing rocks. Copper was one of the first metals to be Copper was one of the first metals to be worked, because it occurred in native form worked, because it occurred in native form and needed little refining. Today the main and needed little refining. Today the main producers are the USA, Russia, Kazakhstan, producers are the USA, Russia, Kazakhstan, Georgia, Uzbekistan, Armenia, Zambia, Chile, Georgia, Uzbekistan, Armenia, Zambia, Chile, Peru, Canada, and the Democratic Republic Peru, Canada, and the Democratic Republic of Congo (formerly Zaire).of Congo (formerly Zaire).

Copper oresCopper ores may refer to: may refer to: BorniteBornite ChalcociteChalcocite CupriteCuprite TennantiteTennantite TetrahedriteTetrahedrite MalachiteMalachite

BorniteBornite is a is a sulfide mineralsulfide mineral with chemical composition with chemical composition Cu5FeS4 that crystallizes in the Cu5FeS4 that crystallizes in the orthorhombicorthorhombic system. It has a brown to copper-red color on fresh system. It has a brown to copper-red color on fresh surfaces that tarnishes to an iridescent purple. Its surfaces that tarnishes to an iridescent purple. Its purple to bronze iridescence gives it the nickname purple to bronze iridescence gives it the nickname peacock copperpeacock copper or or peacock orepeacock ore..

Bornite is an important copper ore mineral Bornite is an important copper ore mineral and occurs widely in and occurs widely in porphyry copperporphyry copper deposits along with the more common deposits along with the more common chalcopyritechalcopyrite. Chalcopyrite and bornite are . Chalcopyrite and bornite are both typically replaced by both typically replaced by chalcocitechalcocite and and covellitecovellite in the in the supergenesupergene enrichment zone enrichment zone of copper deposits. Bornite is also found as of copper deposits. Bornite is also found as disseminations in disseminations in maficmafic igneous rocksigneous rocks, in , in contact metamorphiccontact metamorphic skarnskarn deposits, in deposits, in pegmatitespegmatites and in and in sedimentarysedimentary cupriferous cupriferous shalesshales. It is important for its . It is important for its coppercopper content content of about 63 percent by mass and is found in of about 63 percent by mass and is found in ArizonaArizona, , Butte, MontanaButte, Montana, and , and MexicoMexico..

It has been reported since 1725, but in 1845 It has been reported since 1725, but in 1845 it was named for it was named for AustrianAustrian mineralogistmineralogist IgnazIgnaz EdlerEdler von Born von Born (1742–1791). (1742–1791).

ChalcociteChalcocite, copper(I) sulfide (Cu2S), is an important , copper(I) sulfide (Cu2S), is an important coppercopper oreore mineral. It is opaque, being colored dark- mineral. It is opaque, being colored dark-gray to black with a metallic gray to black with a metallic lusterluster. It has a hardness . It has a hardness of 2½ - 3. It is a of 2½ - 3. It is a sulfidesulfide with an with an orthorhombicorthorhombic crystal crystal system. system.

Chalcocite is sometimes found as a primary Chalcocite is sometimes found as a primary veinvein mineral in mineral in hydrothermalhydrothermal veins. However, most veins. However, most chalcocite occurs in the chalcocite occurs in the supergenesupergene enriched enriched environment below the oxidation zone of copper environment below the oxidation zone of copper deposits as a result of the leaching of copper from deposits as a result of the leaching of copper from the oxidized minerals. It is also often found in the oxidized minerals. It is also often found in sedimentary rockssedimentary rocks..

It has been mined for centuries and is one of the most It has been mined for centuries and is one of the most profitable copper ores. The reasons for this is its profitable copper ores. The reasons for this is its high copper content (67% atomic ratio and nearly high copper content (67% atomic ratio and nearly 80% by weight) and the ease at which copper can be 80% by weight) and the ease at which copper can be separated from separated from sulfursulfur. Still, it is not considered a . Still, it is not considered a primary source of copper ore due to its scarcity. primary source of copper ore due to its scarcity. Fine crystals of chalcocite are quite uncommon and Fine crystals of chalcocite are quite uncommon and are much sought after. The now depleted mines at are much sought after. The now depleted mines at CornwallCornwall, , Great BritainGreat Britain and and Bristol, ConnecticutBristol, Connecticut have produced the most famous clusters of have produced the most famous clusters of wonderfully formed chalcocite crystals. wonderfully formed chalcocite crystals.

Since chalcocite is a secondary mineral that Since chalcocite is a secondary mineral that forms from the alteration of other minerals, it forms from the alteration of other minerals, it has been known to form has been known to form pseudomorphspseudomorphs of of many different minerals. A pseudomorph is a many different minerals. A pseudomorph is a mineral that has replaced another mineral mineral that has replaced another mineral atom by atom, but it leaves the original atom by atom, but it leaves the original mineral's crystal shape intact. Chalcocite has mineral's crystal shape intact. Chalcocite has been known to form pseudomorphs of the been known to form pseudomorphs of the minerals minerals bornitebornite, , covellitecovellite, , chalcopyritechalcopyrite, , pyritepyrite, , enargiteenargite, millerite, , millerite, galenagalena and and sphaleritesphalerite..

The term chalcocite comes from the alteration The term chalcocite comes from the alteration of the obsolete name of the obsolete name chalcosinechalcosine, from the , from the GreekGreek khalkoskhalkos, meaning copper. It is also , meaning copper. It is also known as redruthite, vitreous copper and known as redruthite, vitreous copper and copper-glance.copper-glance.

CupriteCuprite is a is a mineralmineral composed of composed of copper(Icopper(I) oxide) oxide Cu2O, and is a minor Cu2O, and is a minor oreore of copper. of copper.

Its dark crystals with red internal reflections are in the Its dark crystals with red internal reflections are in the isometricisometric system hexoctahedral class, appearing as system hexoctahedral class, appearing as cubic, octahedral, or dodecahedral forms, or in cubic, octahedral, or dodecahedral forms, or in combinations. Penetration combinations. Penetration twinstwins frequently occur. In frequently occur. In spite of its nice color it is rarely used for spite of its nice color it is rarely used for jewelryjewelry because of its low because of its low MohsMohs hardness hardness of 3.5 to 4. It has a of 3.5 to 4. It has a relatively high relatively high specific gravityspecific gravity of 6.1, imperfect of 6.1, imperfect cleavage and a brittle to conchoidal fracture. The cleavage and a brittle to conchoidal fracture. The luster is sub-metallic to brilliant adamantine. The luster is sub-metallic to brilliant adamantine. The "chalcotrichite" variety typically shows greatly "chalcotrichite" variety typically shows greatly elongated capillary or needle like crystals forms.elongated capillary or needle like crystals forms.

It is a secondary mineral which forms in the oxidized It is a secondary mineral which forms in the oxidized zone of copper sulfide deposits. It frequently occurs zone of copper sulfide deposits. It frequently occurs in association with in association with native coppernative copper, , azuriteazurite, , chrysocollachrysocolla, , malachitemalachite, , tenoritetenorite and a variety of and a variety of iron oxideiron oxide minerals. It is known as minerals. It is known as ruby copperruby copper due due to its distinctive red color.to its distinctive red color.

Cuprite was first described in 1845 and the name Cuprite was first described in 1845 and the name derives from the derives from the LatinLatin cuprumcuprum for its copper for its copper content.content.

TennantiteTennantite is a is a coppercopper arsenicarsenic sulfosaltsulfosalt mineralmineral. Its chemical formula is . Its chemical formula is Cu12As4S13. It is found in Cu12As4S13. It is found in hydrothermalhydrothermal veins and contact veins and contact metamorphicmetamorphic deposits. It deposits. It is grey-black, steel-gray, iron-gray or black is grey-black, steel-gray, iron-gray or black in color. A closely related mineral, in color. A closely related mineral, tetrahedritetetrahedrite (Cu12Sb4S13) has (Cu12Sb4S13) has antimonyantimony substituting for arsenic and the two form a substituting for arsenic and the two form a solid solution series. The two have very solid solution series. The two have very similar properties and is often difficult to similar properties and is often difficult to distinguish between tennantite and distinguish between tennantite and tetrahedrite. tetrahedrite. IronIron, , zinczinc, and , and silversilver substitute substitute up to about 15% for the copper site.up to about 15% for the copper site.

The mineral was named after the English The mineral was named after the English chemist chemist Smithson TennantSmithson Tennant (1761-1815). (1761-1815).

is a copper antimony is a copper antimony sulfosaltsulfosalt mineral with mineral with formula: . It is the antimony endmember of formula: . It is the antimony endmember of the continuous the continuous solid solutionsolid solution series with series with arsenic bearing arsenic bearing tennantitetennantite. Pure endmembers . Pure endmembers of the series are seldom if ever seen in of the series are seldom if ever seen in nature. Of the two, the antimony rich phase is nature. Of the two, the antimony rich phase is more common. Other elements also substitute more common. Other elements also substitute in the structure, most notably iron and zinc in the structure, most notably iron and zinc along with less common silver, mercury and along with less common silver, mercury and lead. Bismuth also substitutes for the lead. Bismuth also substitutes for the antimony site and antimony site and bismuthian tetrahedritebismuthian tetrahedrite or or anniviteannivite is a recognized variety. The releated, is a recognized variety. The releated, silver dominant, mineral species silver dominant, mineral species freibergitefreibergite, , although rare, is notable in that it can contain although rare, is notable in that it can contain up to 18% silver.up to 18% silver.

Tetrahedrite gets its name from the Tetrahedrite gets its name from the distinctive distinctive tetrahedrontetrahedron shaped shaped cubiccubic crystals. The mineral usually occurs in crystals. The mineral usually occurs in massive form, it is a steel grey to black massive form, it is a steel grey to black metallic mineral with metallic mineral with MohsMohs hardness hardness of of 3.5 to 4 and 3.5 to 4 and specific gravityspecific gravity of 4.6 to 5.2. of 4.6 to 5.2.

It occurs in low to moderate temperature It occurs in low to moderate temperature hydrothermalhydrothermal veins and in some veins and in some contact metamorphiccontact metamorphic deposits. It is a deposits. It is a minor minor oreore of copper and associated of copper and associated metals. It was first described in 1845 for metals. It was first described in 1845 for occurrences in Freiberg, occurrences in Freiberg, SaxonySaxony, , GermanyGermany..

MalachiteMalachite is a is a carbonate mineralcarbonate mineral, , copper(IIcopper(II) carbonate) carbonate hydroxidehydroxide Cu2CO3(OH)2. It Cu2CO3(OH)2. It crystallizes in the crystallizes in the monoclinicmonoclinic crystal system, and crystal system, and most often forms most often forms botryoidalbotryoidal, fibrous, or , fibrous, or stalagmiticstalagmitic masses. Individual crystals are rare, but do occur masses. Individual crystals are rare, but do occur as slender to acicular prisms. as slender to acicular prisms. PseudomorphsPseudomorphs after after more tabular or blocky azurite crystals also occur. more tabular or blocky azurite crystals also occur. Malachite often results from weathering of Malachite often results from weathering of coppercopper oresores and is often found together with and is often found together with azuriteazurite (Cu3(CO3)2(OH)2), (Cu3(CO3)2(OH)2), goethitegoethite, and , and calcitecalcite. Except . Except for the vibrant green colour, the properties of for the vibrant green colour, the properties of malachite are very similar to those of azurite and malachite are very similar to those of azurite and aggregates of the two minerals together are aggregates of the two minerals together are frequently found, although malachite is more frequently found, although malachite is more common than azurite. Typically associated with common than azurite. Typically associated with copper deposits associated with copper deposits associated with limestoneslimestones, the , the source of the carbonate.source of the carbonate.

The stone's name derives (via The stone's name derives (via LatinLatin and and FrenchFrench) from ) from GreekGreek molochitismolochitis, ", "mallowmallow--green stone", from green stone", from molochēmolochē, variant of , variant of malachēmalachē, "mallow". Malachite was used as a , "mallow". Malachite was used as a mineral pigment in green paints from mineral pigment in green paints from antiquity until about antiquity until about 18001800. The pigment is . The pigment is moderately lightfast, very sensitive to moderately lightfast, very sensitive to acidsacids and varying in colour. The natural form was and varying in colour. The natural form was being replaced by its synthetic form, being replaced by its synthetic form, verditerverditer amongst other synthetic greens. It is also amongst other synthetic greens. It is also used for decorative purposes, such as in the used for decorative purposes, such as in the Malachite Room in the Malachite Room in the HermitageHermitage which which features a huge features a huge malachite vasemalachite vase. "The . "The TazzaTazza", ", one of the largest pieces of malachite in one of the largest pieces of malachite in North America and a gift from North America and a gift from Tsar Nicholas IITsar Nicholas II, stands as the focal point in , stands as the focal point in the center of the room of the center of the room of Linda Hall LibraryLinda Hall Library..

Large quantities of malachite have been Large quantities of malachite have been mined in the mined in the UralsUrals. It is found in the . It is found in the Democratic Republic of CongoDemocratic Republic of Congo; ; TsumebTsumeb, , NamibiaNamibia; Ural mountains, ; Ural mountains, RussiaRussia; ; MexicoMexico; ; Broken Hill, New South WalesBroken Hill, New South Wales; ; EnglandEngland; ; LyonLyon; and in the Southwestern ; and in the Southwestern United StatesUnited States especially in especially in ArizonaArizona at at BisbeeBisbee and and MorenciMorenci..

In In IsraelIsrael, malachite is extensively mined at , malachite is extensively mined at TimnaTimna, often called , often called King Solomon's MinesKing Solomon's Mines. . Archeological evidence indicates that the Archeological evidence indicates that the mineral has been mined and smelted at the mineral has been mined and smelted at the site for over 3,000 years. Most of Timna's site for over 3,000 years. Most of Timna's current production is also smelted, but the current production is also smelted, but the finest pieces are worked into silver jewelry.finest pieces are worked into silver jewelry.

PROCESS PROCESS DIAGRAMDIAGRAM

The process of extracting copper from The process of extracting copper from copper ore varies according to the type copper ore varies according to the type of ore and the desired purity of the final of ore and the desired purity of the final product. Each process consists of several product. Each process consists of several steps in which unwanted materials are steps in which unwanted materials are physically or chemically removed, and physically or chemically removed, and the concentration of copper is the concentration of copper is progressively increased. Some of these progressively increased. Some of these steps are conducted at the mine site steps are conducted at the mine site itself, while others may be conducted at itself, while others may be conducted at separate facilities.separate facilities.

Here are the steps used to process the Here are the steps used to process the sulfide ores commonly found in the sulfide ores commonly found in the western United States.western United States.

MiningMining 1 Most sulfide ores are taken from huge 1 Most sulfide ores are taken from huge

open-pit mines by drilling and blasting with open-pit mines by drilling and blasting with explosives. In this type of mining, the explosives. In this type of mining, the material located above the ore, called the material located above the ore, called the overburden, is first removed to expose the overburden, is first removed to expose the buried ore deposit. This produces an open buried ore deposit. This produces an open pit that may grow to be a mile or more pit that may grow to be a mile or more across. A road to allow access for equipment across. A road to allow access for equipment spirals down the interior slopes of the pit. spirals down the interior slopes of the pit.

2 The exposed ore is scooped up by large 2 The exposed ore is scooped up by large power shovels capable of loading 500-900 power shovels capable of loading 500-900 cubic feet (15-25 cubic meters) in a single cubic feet (15-25 cubic meters) in a single bite. The ore is loaded into giant dump bite. The ore is loaded into giant dump trucks, called haul trucks, and is trucks, called haul trucks, and is transported up and out of the pit.transported up and out of the pit.

ConcentratingConcentrating The copper ore usually contains a large The copper ore usually contains a large

amount of dirt, clay, and a variety of non-amount of dirt, clay, and a variety of non-copper bearing minerals. The first step is copper bearing minerals. The first step is to remove some of this waste material. to remove some of this waste material. This process is called concentrating and is This process is called concentrating and is usually done by the flotation method.usually done by the flotation method.

3 The ore is crushed in a series of cone 3 The ore is crushed in a series of cone crushers. A cone crusher consists of an crushers. A cone crusher consists of an interior grinding cone that rotates on an interior grinding cone that rotates on an eccentric vertical axis inside a fixed outer eccentric vertical axis inside a fixed outer cone. As the ore is fed into the top of the cone. As the ore is fed into the top of the crusher, it is squeezed between the two crusher, it is squeezed between the two cones and broken into smaller pieces.cones and broken into smaller pieces.

4 The crushed ore is then ground even 4 The crushed ore is then ground even smaller by a series of mills. First, it is mixed smaller by a series of mills. First, it is mixed with water and placed in a rod mill, which with water and placed in a rod mill, which consists of a large cylindrical container filled consists of a large cylindrical container filled with numerous short lengths of steel rod. As with numerous short lengths of steel rod. As the cylinder rotates on its horizontal axis, the cylinder rotates on its horizontal axis, the steel rods tumble and break up the ore the steel rods tumble and break up the ore into pieces about 0.13 in (3 mm) in into pieces about 0.13 in (3 mm) in diameter. The mixture of ore and water is diameter. The mixture of ore and water is further broken up in two ball mills, which further broken up in two ball mills, which are like a rod mill except steel balls are used are like a rod mill except steel balls are used instead of rods. The slurry of finely ground instead of rods. The slurry of finely ground ore that emerges from the final ball mill ore that emerges from the final ball mill contains particles about 0.01 in (0.25 mm) in contains particles about 0.01 in (0.25 mm) in diameter.diameter.

5 The slurry is mixed with various 5 The slurry is mixed with various chemical reagents, which coat the chemical reagents, which coat the copper particles. A liquid, called a copper particles. A liquid, called a frother, is also added. Pine oil or long-frother, is also added. Pine oil or long-chain alcohol are often used as frothers. chain alcohol are often used as frothers. This mixture is pumped into rectangular This mixture is pumped into rectangular tanks, called flotation cells, where air is tanks, called flotation cells, where air is injected into the slurry through the injected into the slurry through the bottom of the tanks. The chemical bottom of the tanks. The chemical reagents make the copper particles reagents make the copper particles cling to the bubbles as they rise to the cling to the bubbles as they rise to the surface. The frother forms a thick layer surface. The frother forms a thick layer of bubbles, which overflows the tanks of bubbles, which overflows the tanks and is collected in troughs.and is collected in troughs.

The bubbles are allowed to condense and the The bubbles are allowed to condense and the water is drained off. The resulting mixture, called water is drained off. The resulting mixture, called a copper concentrate, contains about 25-35% a copper concentrate, contains about 25-35% copper along with various sulfides of copper and copper along with various sulfides of copper and iron, plus smaller concentrations of gold, silver, iron, plus smaller concentrations of gold, silver, and other materials. The remaining materials in and other materials. The remaining materials in the tank are called the gangue or tailings. They the tank are called the gangue or tailings. They are pumped into settling ponds and allowed to are pumped into settling ponds and allowed to dry. dry.

SmeltingSmelting Once the waste materials have been physically Once the waste materials have been physically

removed from the ore, the remaining copper removed from the ore, the remaining copper concentrate must undergo several chemical concentrate must undergo several chemical reactions to remove the iron and sulfur. This reactions to remove the iron and sulfur. This process is called smelting and traditionally process is called smelting and traditionally involves two furnaces as described below. Some involves two furnaces as described below. Some modern plants utilize a single furnace, which modern plants utilize a single furnace, which combines both operations.combines both operations.

6 The copper concentrate is fed into a furnace 6 The copper concentrate is fed into a furnace along with a silica material, called a flux. Most along with a silica material, called a flux. Most copper smelters utilize oxygen-enriched flash copper smelters utilize oxygen-enriched flash furnaces in which preheated, oxygen-enriched furnaces in which preheated, oxygen-enriched air is forced into the furnace to combust with air is forced into the furnace to combust with fuel oil. The copper concentrate and flux melt, fuel oil. The copper concentrate and flux melt, and collect in the bottom of the furnace. Much and collect in the bottom of the furnace. Much of the iron in the concentrate chemically of the iron in the concentrate chemically combines with the flux to form a slag, which is combines with the flux to form a slag, which is skimmed off the surface of the molten material. skimmed off the surface of the molten material. Much of the sulfur in the concentrate combines Much of the sulfur in the concentrate combines with the oxygen to form sulfur dioxide, which is with the oxygen to form sulfur dioxide, which is exhausted from the furnace as a gas and is exhausted from the furnace as a gas and is further treated in an acid plant to produce further treated in an acid plant to produce sulfuric acid. The remaining molten material in sulfuric acid. The remaining molten material in the bottom of the furnace is called the matte.the bottom of the furnace is called the matte.

It is a mixture of copper sulfides and iron sulfides It is a mixture of copper sulfides and iron sulfides and contains about 60% copper by weight.and contains about 60% copper by weight.

7 The molten matte is drawn from the furnace 7 The molten matte is drawn from the furnace and poured into a second furnace called a and poured into a second furnace called a converter. Additional silica flux is added and converter. Additional silica flux is added and oxygen is blown through the molten material. oxygen is blown through the molten material. The chemical reactions in the converter are The chemical reactions in the converter are similar to those in the flash furnace. The silica similar to those in the flash furnace. The silica flux reacts with the remaining iron to form a flux reacts with the remaining iron to form a slag, and the oxygen reacts with the remaining slag, and the oxygen reacts with the remaining sulfur to form sulfur dioxide. The slag may be sulfur to form sulfur dioxide. The slag may be fed back into the flash furnace to act as a flux, fed back into the flash furnace to act as a flux, and the sulfur dioxide is processed through the and the sulfur dioxide is processed through the acid plant. After the slag is removed, a final acid plant. After the slag is removed, a final injection of oxygen removes all but a trace of injection of oxygen removes all but a trace of sulfur. The resulting molten material is called sulfur. The resulting molten material is called the blister and contains about 99% copper by the blister and contains about 99% copper by weight.weight.

RefiningRefining Even though copper blister is 99% pure copper, it Even though copper blister is 99% pure copper, it

still contains high enough levels of sulfur, oxygen, still contains high enough levels of sulfur, oxygen, and other impurities to hamper further refining. To and other impurities to hamper further refining. To remove or adjust the levels of these materials, the remove or adjust the levels of these materials, the blister copper is first fire refined before it is sent to blister copper is first fire refined before it is sent to the final electrorefining process.the final electrorefining process.

8 The blister copper is heated in a refining furnace, 8 The blister copper is heated in a refining furnace, which is similar to a converter described above. Air which is similar to a converter described above. Air is blown into the molten blister to oxidize some is blown into the molten blister to oxidize some impurities. A sodium carbonate flux may be added impurities. A sodium carbonate flux may be added to remove traces of arsenic and antimony. A sample to remove traces of arsenic and antimony. A sample of the molten material is drawn and an experienced of the molten material is drawn and an experienced operator determines when the impurities have operator determines when the impurities have reached an acceptable level. The molten copper, reached an acceptable level. The molten copper, which is about 99.5% pure, is then poured into which is about 99.5% pure, is then poured into molds to form large electrical anodes, which act as molds to form large electrical anodes, which act as the positive terminals for the electrorefining the positive terminals for the electrorefining process.process.

9 Each copper anode is placed in an individual tank, or 9 Each copper anode is placed in an individual tank, or cell, made of polymer-concrete. There may be as cell, made of polymer-concrete. There may be as many as 1,250 tanks in operation at one time. A many as 1,250 tanks in operation at one time. A sheet of copper is placed on the opposite end of the sheet of copper is placed on the opposite end of the tank to act as the cathode, or negative terminal. The tank to act as the cathode, or negative terminal. The tanks are filled with an acidic copper sulfate tanks are filled with an acidic copper sulfate solution, which acts as an electrical conductor solution, which acts as an electrical conductor between the anode and cathode. When an electrical between the anode and cathode. When an electrical current is passed through each tank, the copper is current is passed through each tank, the copper is stripped off the anode and is deposited on the stripped off the anode and is deposited on the cathode. Most of the remaining impurities fall out of cathode. Most of the remaining impurities fall out of the copper sulfate solution and form a slime at the the copper sulfate solution and form a slime at the bottom of the tank. After about 9-15 days, the bottom of the tank. After about 9-15 days, the current is turned off and the cathodes are removed. current is turned off and the cathodes are removed. The cathodes now weigh about 300 lb (136 kg) and The cathodes now weigh about 300 lb (136 kg) and are 99.95-99.99% pure copper. are 99.95-99.99% pure copper.

10 The slime that collects at the bottom of the tank 10 The slime that collects at the bottom of the tank contains gold, silver, selenium, and tellurium. It is contains gold, silver, selenium, and tellurium. It is collected and processed to recover these precious collected and processed to recover these precious metals.metals.

CastingCasting

11 After refining, the copper cathodes are melted 11 After refining, the copper cathodes are melted and cast into ingots, cakes, billets, or rods and cast into ingots, cakes, billets, or rods depending on the final application. Ingots are depending on the final application. Ingots are rectangular or trapezoidal bricks, which are rectangular or trapezoidal bricks, which are remelted along with other metals to make brass remelted along with other metals to make brass and bronze products. Cakes are rectangular slabs and bronze products. Cakes are rectangular slabs about 8 in (20 cm) thick and up to 28 ft (8.5 m) about 8 in (20 cm) thick and up to 28 ft (8.5 m) long. They are rolled to make copper plate, strip, long. They are rolled to make copper plate, strip, sheet, and foil products. Billets are cylindrical logs sheet, and foil products. Billets are cylindrical logs about 8 in (20 cm) in diameter and several feet about 8 in (20 cm) in diameter and several feet (meters) long. They are extruded or drawn to make (meters) long. They are extruded or drawn to make copper tubing and pipe. Rods have a round cross-copper tubing and pipe. Rods have a round cross-section about 0.5 in (1.3 cm) in diameter. They are section about 0.5 in (1.3 cm) in diameter. They are usually cast into very long lengths, which are usually cast into very long lengths, which are coiled. This coiled material is then drawn down coiled. This coiled material is then drawn down further to make copper wire.further to make copper wire.

Leaching phase:Leaching phase:  A leach pad or heap is sprinkled   A leach pad or heap is sprinkled with an aqueous acidic solution.  In this schematic with an aqueous acidic solution.  In this schematic it is described as the acidified liquor spray.  This it is described as the acidified liquor spray.  This comes from the raffinate of the extraction comes from the raffinate of the extraction stage(s).  The liquid passes through the heap, stage(s).  The liquid passes through the heap, dissolving minerals along the way.  It is typically dissolving minerals along the way.  It is typically collected in a pond, which is affectionately called collected in a pond, which is affectionately called the pregnant leach solution or PLS.the pregnant leach solution or PLS.

In-situ leachingIn-situ leaching In-situ leachingIn-situ leaching is also called "solution mining." is also called "solution mining."

The process initially involves drilling of holes into The process initially involves drilling of holes into the ore deposit. Explosives or hydraulic fracturing the ore deposit. Explosives or hydraulic fracturing are used to create open pathways within the are used to create open pathways within the deposit for solution to penetrate into. Leaching deposit for solution to penetrate into. Leaching solution is pumped into the deposit where it solution is pumped into the deposit where it makes contact with the ore. The solution is then makes contact with the ore. The solution is then collected and processed. The collected and processed. The Beverley uranium depositBeverley uranium deposit is an example of in-situ is an example of in-situ leaching.leaching.

Heap leachingHeap leaching In heap leaching processes, crushed (and In heap leaching processes, crushed (and

sometimes agglomerated) ore is piled in a heap sometimes agglomerated) ore is piled in a heap which is lined with an impervious layer. Leach which is lined with an impervious layer. Leach solution is sprayed over the top of the heap, and solution is sprayed over the top of the heap, and allowed to percolate downward through the heap. allowed to percolate downward through the heap. The heap design usually incorporates collection The heap design usually incorporates collection sumps which allow the "pregnant" leach solution sumps which allow the "pregnant" leach solution (i.e. solution with dissolved valuable metals) to be (i.e. solution with dissolved valuable metals) to be pumped for further processing.pumped for further processing.

Dump leachingDump leaching Dump leaching combines characteristics of heap Dump leaching combines characteristics of heap

leaching and in-situ leaching. In a dump leach, an leaching and in-situ leaching. In a dump leach, an impervious layer may or may not be used impervious layer may or may not be used depending on the dump location. Ore is dumped depending on the dump location. Ore is dumped to allow processing similar to heap leaching, but to allow processing similar to heap leaching, but the physical characteristics of the location allow the physical characteristics of the location allow for a valley or pit to act as the sump.for a valley or pit to act as the sump.

Vat leachingVat leaching Vat leaching involves contacting material, Vat leaching involves contacting material,

which has usually undergone size reduction which has usually undergone size reduction and classification, with leach solution in and classification, with leach solution in large tanks or vats. Often the vats are large tanks or vats. Often the vats are equipped with agitators to keep the solids in equipped with agitators to keep the solids in suspension in the vats and improve the solid suspension in the vats and improve the solid to liquid contact. After vat leaching, the to liquid contact. After vat leaching, the leached solids and pregnant solution are leached solids and pregnant solution are usually separated prior to further processing.usually separated prior to further processing.

Other leaching techniquesOther leaching techniques In some cases, special leaching processes are In some cases, special leaching processes are

required due to refractory nature of the required due to refractory nature of the material. These techniques include pressure material. These techniques include pressure or autoclave leaching and concentrate or autoclave leaching and concentrate leaching.leaching.

After leaching, the leach liquor must After leaching, the leach liquor must normally undergo concentration of the normally undergo concentration of the metal ions that are to be recovered. metal ions that are to be recovered. Additionally, some undesirable metals may Additionally, some undesirable metals may have also been taken into solution during have also been taken into solution during the leach process. The solution is often the leach process. The solution is often purified to eliminate the undesirable purified to eliminate the undesirable components. The processes employed for components. The processes employed for solution concentration and purification solution concentration and purification include:include:

Precipitation Precipitation Cementation Cementation Solvent Extraction Solvent Extraction Ion Exchange Ion Exchange

Solvent extractionSolvent extraction A mixture of an A mixture of an extractantextractant in a in a diluentdiluent is used is used

to extract a metal from one phase to another. to extract a metal from one phase to another. In solvent extraction this mixture is often In solvent extraction this mixture is often referred to as the "organic" because the main referred to as the "organic" because the main constituent (diluent) is some type of oil.constituent (diluent) is some type of oil.

The PLS (pregnant leach solution) is mixed to The PLS (pregnant leach solution) is mixed to emulsification with the stripped organic and emulsification with the stripped organic and allowed to separate. The metal will be allowed to separate. The metal will be exchanged from the PLS to the organic. The exchanged from the PLS to the organic. The resulting streams will be a loaded organic resulting streams will be a loaded organic and a and a raffinateraffinate. When dealing with . When dealing with electrowinning, the loaded organic is then electrowinning, the loaded organic is then mixed to emulsification with a lean electrolyte mixed to emulsification with a lean electrolyte and allowed to separate. The metal will be and allowed to separate. The metal will be exchanged from the organic to the exchanged from the organic to the electrolyte.electrolyte.

The resulting streams will be a stripped The resulting streams will be a stripped organic and a rich electrolyte. The organic organic and a rich electrolyte. The organic stream is recycled through the solvent stream is recycled through the solvent extraction process while the aqueous extraction process while the aqueous streams cycle through leaching and streams cycle through leaching and electrowinning processes respectively.electrowinning processes respectively.

Ion exchangeIon exchange ChelatingChelating agents, natural zeolite, activated agents, natural zeolite, activated

carbon, resins, and liquid organics carbon, resins, and liquid organics impregnated with chelating agents are all impregnated with chelating agents are all used to exchange cations or anions with used to exchange cations or anions with the solution. Selectivity and recovery are a the solution. Selectivity and recovery are a function of the reagents used and the function of the reagents used and the contaminants present.contaminants present.

Metal recovery is the final step in a Metal recovery is the final step in a hydrometallurgical process. Metals suitable for hydrometallurgical process. Metals suitable for sale as raw materials are often directly sale as raw materials are often directly produced in the metal recovery step. produced in the metal recovery step. Sometimes, however, further refining is Sometimes, however, further refining is required if ultra-high purity metals are to be required if ultra-high purity metals are to be produced. The primary types of metal recovery produced. The primary types of metal recovery processes are electrolysis, gaseous reduction, processes are electrolysis, gaseous reduction, and precipitation.and precipitation.

ElectrolysisElectrolysis Electrowinning and electrorefining respectively Electrowinning and electrorefining respectively

involve the recovery and purification of metals involve the recovery and purification of metals using electrodeposition of metals at the using electrodeposition of metals at the cathode, and either metal dissolution or a cathode, and either metal dissolution or a competing oxidation reaction at the anode.competing oxidation reaction at the anode.

PrecipitationPrecipitation Precipitation in hydrometallurgy involves Precipitation in hydrometallurgy involves

the chemical precipitation of either the chemical precipitation of either metals and their compounds or of the metals and their compounds or of the contaminants from aqueous solutions. contaminants from aqueous solutions. Precipitation will proceed when, through Precipitation will proceed when, through reagent addition, evaporation, pH reagent addition, evaporation, pH change or temperature manipulation, change or temperature manipulation, any given species exceeds its limit of any given species exceeds its limit of solubility. In order to improve efficiency solubility. In order to improve efficiency in downstream processes, seeding to in downstream processes, seeding to initiate crystallization is often used.initiate crystallization is often used.

Extraction phase:  Extraction phase:  Through gravity or Through gravity or from the suction of the pumper mixer in from the suction of the pumper mixer in the Extract Stage, PLS is mixed in a the Extract Stage, PLS is mixed in a pump-box (mixer, pumper stage) with an pump-box (mixer, pumper stage) with an organic solution often referred to as the organic solution often referred to as the barren organic (here called Regenerated barren organic (here called Regenerated Extractant coming from the Strip Stage) Extractant coming from the Strip Stage) to form a liquid-liquid dispersion.  Mass to form a liquid-liquid dispersion.  Mass transfer occurs and ideally only the transfer occurs and ideally only the desired mineral transfers selectively desired mineral transfers selectively from the aqueous phase to the organic from the aqueous phase to the organic phase.  In this schematic, the mineral is phase.  In this schematic, the mineral is copper.copper.

In most SX plants, there is usually a pump-box In most SX plants, there is usually a pump-box followed by one or more auxiliary mixing followed by one or more auxiliary mixing tanks.  Their purpose is to maintain the tanks.  Their purpose is to maintain the dispersion and give more residence time for dispersion and give more residence time for the extraction to take place.  Then the the extraction to take place.  Then the dispersion is sent to a settler, where the two dispersion is sent to a settler, where the two phases disengage.  The lighter fluid (organic) phases disengage.  The lighter fluid (organic) is removed from the top, while the heavier is removed from the top, while the heavier fluid (aqueous phase) is removed from the fluid (aqueous phase) is removed from the bottom of the end of the settler.  The aqueous bottom of the end of the settler.  The aqueous is now called raffinate and is returned to the is now called raffinate and is returned to the heap or leach pad.  It contains lots of heap or leach pad.  It contains lots of dissolved minerals, but very little of the dissolved minerals, but very little of the desired mineral.  The aqueous cycle is desired mineral.  The aqueous cycle is complete.  The organic (labeled above as complete.  The organic (labeled above as Copper Loaded Extractant), now heavy with Copper Loaded Extractant), now heavy with the desired mineral, is pumped into the Strip the desired mineral, is pumped into the Strip Stage.Stage.

Stripping phase: Stripping phase:  The loaded organic extractant is The loaded organic extractant is mixed with the aqueous lean electrolyte (hear strip mixed with the aqueous lean electrolyte (hear strip solution) to form another liquid-liquid dispersion.  solution) to form another liquid-liquid dispersion.  Due to a shift in pH, the desired mineral transfers Due to a shift in pH, the desired mineral transfers back from the organic phase to the aqueous phase.  back from the organic phase to the aqueous phase.  Once again, it is not unusual to find one pump-box Once again, it is not unusual to find one pump-box followed by one or more auxiliary mixing tanks to followed by one or more auxiliary mixing tanks to achieve the desired residence time and mass achieve the desired residence time and mass transfer efficiency.  The dispersion is again sent to a transfer efficiency.  The dispersion is again sent to a settler so that the two liquid phases can be settler so that the two liquid phases can be separated again.  A portion of the aqueous phase, separated again.  A portion of the aqueous phase, called here the Concentrated Copper Electrolyte, is called here the Concentrated Copper Electrolyte, is pumped to the Electrowinning house, while the rest pumped to the Electrowinning house, while the rest is recycled back to the Strip Stage Pure copper is recycled back to the Strip Stage Pure copper (desired purity is called five-nines = 99.999%) is (desired purity is called five-nines = 99.999%) is deposited on plates, pulling the copper out of deposited on plates, pulling the copper out of solution.  This solution is called the lean electrolyte, solution.  This solution is called the lean electrolyte, or here as the strip solution, and returns to the or here as the strip solution, and returns to the Stripper.  This completes this aqueous loop.  The Stripper.  This completes this aqueous loop.  The barren organic (here called regenerated extractant) barren organic (here called regenerated extractant) returns to the Extractor to complete the organic returns to the Extractor to complete the organic loop.loop.

This method almost doubles the throughput of This method almost doubles the throughput of copper, because E1P (or E3(P)) replaces the copper, because E1P (or E3(P)) replaces the former S2 allowing essentially twice the former S2 allowing essentially twice the copper to be processed.  Although the single copper to be processed.  Although the single stage E1P will not have the same transfer stage E1P will not have the same transfer efficiency as the dual stage E1-E2, the copper efficiency as the dual stage E1-E2, the copper remaining in the raffinate goes back to the pad remaining in the raffinate goes back to the pad and will eventually come back to the plant to and will eventually come back to the plant to be processed another day. be processed another day. 

Regardless of the SX circuit layout, each stage is Regardless of the SX circuit layout, each stage is treated in the same way with CFD.  The only treated in the same way with CFD.  The only difference is the density (and other properties) difference is the density (and other properties) and flow rates through each stage.  E1 and S1 and flow rates through each stage.  E1 and S1 are often not only pumped by the pumper-are often not only pumped by the pumper-mixer, but are also externally fed by gravity or mixer, but are also externally fed by gravity or through additional pumps from the PLS or TOC through additional pumps from the PLS or TOC (total organic container = inventory storage).(total organic container = inventory storage).

POLLUTION AND POLLUTION AND ABATEMENTABATEMENT

Byproducts/WasteByproducts/Waste

The recovery of sulfuric acid from the The recovery of sulfuric acid from the copper smelting process not only copper smelting process not only provides a profitable byproduct, but provides a profitable byproduct, but also significantly reduces the air also significantly reduces the air pollution caused by the furnace pollution caused by the furnace exhaust. Gold, silver, and other exhaust. Gold, silver, and other precious metals are also important precious metals are also important byproducts.byproducts.

Waste products include the overburden from Waste products include the overburden from the mining operation, the tailings from the the mining operation, the tailings from the concentrating operation, and the slag from concentrating operation, and the slag from the smelting operation. This waste may the smelting operation. This waste may contain significant concentrations of arsenic, contain significant concentrations of arsenic, lead, and other chemicals, which pose a lead, and other chemicals, which pose a potential health hazard to the surrounding potential health hazard to the surrounding area. In the United States, the Environmental area. In the United States, the Environmental Protection Agency (EPA) regulates the Protection Agency (EPA) regulates the storage of such wastes and the remediation storage of such wastes and the remediation of the area once mining and processing of the area once mining and processing operations have ceased. The sheer volume of operations have ceased. The sheer volume of the material involved—in some cases, billions the material involved—in some cases, billions of tons of waste—makes this a formidable of tons of waste—makes this a formidable task, but it also presents some potentially task, but it also presents some potentially profitable opportunities to recover the profitable opportunities to recover the useable materials contained in this waste.useable materials contained in this waste.