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100-477: The Golden Grove mine is a copper , lead , silver , zinc and gold mine located 52 km south-southeast of Yalgoo, Western Australia . It is operated by 29Metals Limited after a 2021 divestment by EMR Capital. The mine was originally owned by Australian Consolidated Minerals Pty Ltd before passing into the ownership of Normandy Poseidon Ltd in November 1991. Normandy, now renamed Normandy Mining Ltd,

200-579: A Gilman reagent . These can undergo substitution with alkyl halides to form coupling products ; as such, they are important in the field of organic synthesis . Copper(I) acetylide is highly shock-sensitive but is an intermediate in reactions such as the Cadiot–Chodkiewicz coupling and the Sonogashira coupling . Conjugate addition to enones and carbocupration of alkynes can also be achieved with organocopper compounds. Copper(I) forms

300-696: A covalent character and are relatively weak. This observation explains the low hardness and high ductility of single crystals of copper. At the macroscopic scale, introduction of extended defects to the crystal lattice , such as grain boundaries, hinders flow of the material under applied stress, thereby increasing its hardness. For this reason, copper is usually supplied in a fine-grained polycrystalline form, which has greater strength than monocrystalline forms. The softness of copper partly explains its high electrical conductivity ( 59.6 × 10   S /m ) and high thermal conductivity, second highest (second only to silver) among pure metals at room temperature. This

400-643: A nickel ) consists of 75% copper and 25% nickel in homogeneous composition. Prior to the introduction of cupronickel, which was widely adopted by countries in the latter half of the 20th century, alloys of copper and silver were also used, with the United States using an alloy of 90% silver and 10% copper until 1965, when circulating silver was removed from all coins with the exception of the half dollar—these were debased to an alloy of 40% silver and 60% copper between 1965 and 1970. The alloy of 90% copper and 10% nickel, remarkable for its resistance to corrosion,

500-407: A pinkish-orange color . Copper is used as a conductor of heat and electricity, as a building material , and as a constituent of various metal alloys , such as sterling silver used in jewelry , cupronickel used to make marine hardware and coins , and constantan used in strain gauges and thermocouples for temperature measurement. Copper is one of the few metals that can occur in nature in

600-425: A spin of 3 ⁄ 2 . The other isotopes are radioactive , with the most stable being Cu with a half-life of 61.83 hours. Seven metastable isomers have been characterized; Cu is the longest-lived with a half-life of 3.8 minutes. Isotopes with a mass number above 64 decay by β , whereas those with a mass number below 64 decay by β . Cu , which has

700-499: A base of nickel above those required to cause a transition from internal to external modes of oxidation, and by selecting solutes (silicon and magnesium) that preferentially oxidize to form a diffusion-barrier, and hence oxidation-inhibiting films. Type N thermocouples are suitable alternative to type K for low-oxygen conditions where type K is prone to green rot. They are suitable for use in vacuum, inert atmospheres, oxidizing atmospheres, or dry reducing atmospheres. They do not tolerate

800-399: A blast furnace. A potential source of copper is polymetallic nodules, which have an estimated concentration 1.3%. Like aluminium , copper is recyclable without any loss of quality, both from raw state and from manufactured products. In volume, copper is the third most recycled metal after iron and aluminium. An estimated 80% of all copper ever mined is still in use today. According to

900-464: A blue crystalline penta hydrate , the most familiar copper compound in the laboratory. It is used in a fungicide called the Bordeaux mixture . Polyols , compounds containing more than one alcohol functional group , generally interact with cupric salts. For example, copper salts are used to test for reducing sugars . Specifically, using Benedict's reagent and Fehling's solution the presence of

1000-513: A device that packages the reference junction block (with T ref thermometer), voltmeter, and equation solver. The Seebeck effect refers to the development of an electromotive force across two points of an electrically conducting material when there is a temperature difference between those two points. Under open-circuit conditions where there is no internal current flow, the gradient of voltage ( ∇ V {\displaystyle \scriptstyle {\boldsymbol {\nabla }}V} )

1100-709: A directly usable metallic form ( native metals ). This led to very early human use in several regions, from c.  8000 BC . Thousands of years later, it was the first metal to be smelted from sulfide ores, c.  5000 BC ; the first metal to be cast into a shape in a mold, c.  4000 BC ; and the first metal to be purposely alloyed with another metal, tin , to create bronze , c.  3500 BC . Commonly encountered compounds are copper(II) salts, which often impart blue or green colors to such minerals as azurite , malachite , and turquoise , and have been used widely and historically as pigments. Copper used in buildings, usually for roofing, oxidizes to form

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1200-457: A green patina of compounds called verdigris . Copper is sometimes used in decorative art , both in its elemental metal form and in compounds as pigments. Copper compounds are used as bacteriostatic agents , fungicides , and wood preservatives . Copper is essential to all living organisms as a trace dietary mineral because it is a key constituent of the respiratory enzyme complex cytochrome c oxidase . In molluscs and crustaceans , copper

1300-505: A half-life of 12.7 hours, decays both ways. Cu and Cu have significant applications. Cu is used in Cu Cu-PTSM as a radioactive tracer for positron emission tomography . Copper is produced in massive stars and is present in the Earth's crust in a proportion of about 50 parts per million (ppm). In nature, copper occurs in

1400-687: A layer of brown-black copper oxide which, unlike the rust that forms on iron in moist air, protects the underlying metal from further corrosion ( passivation ). A green layer of verdigris (copper carbonate) can often be seen on old copper structures, such as the roofing of many older buildings and the Statue of Liberty . Copper tarnishes when exposed to some sulfur compounds, with which it reacts to form various copper sulfides . There are 29 isotopes of copper. Cu and Cu are stable, with Cu comprising approximately 69% of naturally occurring copper; both have

1500-461: A much higher thermal conductivity than the alloys generally used in thermocouple constructions, and so it is necessary to exercise extra care with thermally anchoring type-T thermocouples. A similar composition is found in the obsolete Type U in the German specification DIN 43712:1985-01. Types B, R, and S thermocouples use platinum or a platinum/ rhodium alloy for each conductor. These are among

1600-442: A multi-wire cable for carrying many thermocouple circuits. With expensive noble metal thermocouples, the extension wires may even be made of a completely different, cheaper material that mimics the standard type over a reduced temperature range. Thermocouples are often used at high temperatures and in reactive furnace atmospheres. In this case, the practical lifetime is limited by thermocouple aging. The thermoelectric coefficients of

1700-532: A natural color other than gray or silver. Pure copper is orange-red and acquires a reddish tarnish when exposed to air. This is due to the low plasma frequency of the metal, which lies in the red part of the visible spectrum, causing it to absorb the higher-frequency green and blue colors. As with other metals, if copper is put in contact with another metal in the presence of an electrolyte , galvanic corrosion will occur. Copper does not react with water, but it does slowly react with atmospheric oxygen to form

1800-529: A precise E ( T ) {\displaystyle \scriptstyle E(T)} curve, independent of any other details. In reality, thermocouples are affected by issues such as alloy manufacturing uncertainties, aging effects, and circuit design mistakes/misunderstandings. A common error in thermocouple construction is related to cold junction compensation. If an error is made on the estimation of T r e f {\displaystyle T_{\mathrm {ref} }} , an error will appear in

1900-407: A red-brown precipitate with copper(II) salts. Compounds that contain a carbon-copper bond are known as organocopper compounds. They are very reactive towards oxygen to form copper(I) oxide and have many uses in chemistry . They are synthesized by treating copper(I) compounds with Grignard reagents , terminal alkynes or organolithium reagents ; in particular, the last reaction described produces

2000-542: A relatively flat voltage curve near room temperature, meaning that a large uncertainty in a room-temperature T r e f {\displaystyle T_{\mathrm {ref} }} translates to only a small error in T s e n s e {\displaystyle T_{\mathrm {sense} }} . Junctions should be made in a reliable manner, but there are many possible approaches to accomplish this. For low temperatures, junctions can be brazed or soldered; however, it may be difficult to find

2100-451: A rich variety of compounds, usually with oxidation states +1 and +2, which are often called cuprous and cupric , respectively. Copper compounds promote or catalyse numerous chemical and biological processes. As with other elements, the simplest compounds of copper are binary compounds, i.e. those containing only two elements, the principal examples being oxides, sulfides, and halides . Both cuprous and cupric oxides are known. Among

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2200-431: A sacrificial titanium wire) can be added. Alternatively, additional oxygen can be introduced into the thermowell. Another option is using a different thermocouple type for the low-oxygen atmospheres where green rot can occur; a type N thermocouple is a suitable alternative. Type M (82%Ni/18% Mo –99.2%Ni/0.8% Co , by weight) are used in vacuum furnaces for the same reasons as with type C (described below). Upper temperature

2300-419: A single thermocouple junction. Power generation using multiple thermocouples, as in a thermopile , is common. The standard configuration of a thermocouple is shown in the figure. The dissimilar conductors contact at the measuring (aka hot) junction and at the reference (aka cold) junction. The thermocouple is connected to the electrical system at its reference junction. The figure shows the measuring junction on

2400-404: A suitable flux and this may not be suitable at the sensing junction due to the solder's low melting point. Reference and extension junctions are therefore usually made with screw terminal blocks . For high temperatures, the most common approach is the spot weld or crimp using a durable material. One common myth regarding thermocouples is that junctions must be made cleanly without involving

2500-448: A thermocouple wire type is often described by its chemical composition, the actual aim is to produce a pair of wires that follow a standardized E ( T ) {\displaystyle \scriptstyle E(T)} curve. Impurities affect each batch of metal differently, producing variable Seebeck coefficients. To match the standard behaviour, thermocouple wire manufacturers will deliberately mix in additional impurities to "dope"

2600-570: A third metal, to avoid unwanted added EMFs. This may result from another common misunderstanding that the voltage is generated at the junction. In fact, the junctions should in principle have uniform internal temperature; therefore, no voltage is generated at the junction. The voltage is generated in the thermal gradient, along the wire. A thermocouple produces small signals, often microvolts in magnitude. Precise measurements of this signal require an amplifier with low input offset voltage and with care taken to avoid thermal EMFs from self-heating within

2700-424: A variety of minerals, including native copper , copper sulfides such as chalcopyrite , bornite , digenite , covellite , and chalcocite , copper sulfosalts such as tetrahedite-tennantite , and enargite , copper carbonates such as azurite and malachite , and as copper(I) or copper(II) oxides such as cuprite and tenorite , respectively. The largest mass of elemental copper discovered weighed 420 tonnes and

2800-436: A variety of weak complexes with alkenes and carbon monoxide , especially in the presence of amine ligands. Copper(III) is most often found in oxides. A simple example is potassium cuprate , KCuO 2 , a blue-black solid. The most extensively studied copper(III) compounds are the cuprate superconductors . Yttrium barium copper oxide (YBa 2 Cu 3 O 7 ) consists of both Cu(II) and Cu(III) centres. Like oxide, fluoride

2900-479: Is 0 to 2315 °C, which can be extended to 2760 °C in inert atmosphere and to 3000 °C for brief measurements. Pure tungsten at high temperatures undergoes recrystallization and becomes brittle. Therefore, types C and D are preferred over type G in some applications. In presence of water vapor at high temperature, tungsten reacts to form tungsten(VI) oxide , which volatilizes away, and hydrogen. Hydrogen then reacts with tungsten oxide, after which water

3000-583: Is a constituent of the blood pigment hemocyanin , replaced by the iron-complexed hemoglobin in fish and other vertebrates . In humans, copper is found mainly in the liver, muscle, and bone. The adult body contains between 1.4 and 2.1 mg of copper per kilogram of body weight. In the Roman era , copper was mined principally on Cyprus , the origin of the name of the metal, from aes cyprium (metal of Cyprus), later corrupted to cuprum (Latin). Coper ( Old English ) and copper were derived from this,

3100-405: Is a highly basic anion and is known to stabilize metal ions in high oxidation states. Both copper(III) and even copper(IV) fluorides are known, K 3 CuF 6 and Cs 2 CuF 6 , respectively. Some copper proteins form oxo complexes , which, in extensively studied synthetic analog systems, feature copper(III). With tetrapeptides , purple-colored copper(III) complexes are stabilized by

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3200-401: Is because the resistivity to electron transport in metals at room temperature originates primarily from scattering of electrons on thermal vibrations of the lattice, which are relatively weak in a soft metal. The maximum possible current density of copper in open air is approximately 3.1 × 10  A/m , above which it begins to heat excessively. Copper is one of a few metallic elements with

3300-427: Is calculated, then the function E ( T ) {\displaystyle \scriptstyle E(T)} is searched for a matching value. The argument where this match occurs is the value of T s e n s e {\displaystyle \scriptstyle T_{\mathrm {sense} }} : Thermocouples ideally should be very simple measurement devices, with each type being characterized by

3400-586: Is directly proportional to the gradient in temperature ( ∇ T {\displaystyle \scriptstyle {\boldsymbol {\nabla }}T} ): where S ( T ) {\displaystyle S(T)} is a temperature-dependent material property known as the Seebeck coefficient . The standard measurement configuration shown in the figure shows four temperature regions and thus four voltage contributions: The first and fourth contributions cancel out exactly, because these regions involve

3500-508: Is limited to 1400 °C. It is less commonly used than other types. Type N ( Nicrosil – Nisil ) thermocouples are suitable for use between −270 °C and +1300 °C, owing to its stability and oxidation resistance. Sensitivity is about 39 μV/°C at 900 °C, slightly lower compared to type K. Designed at the Defence Science and Technology Organisation (DSTO) of Australia, by Noel A. Burley, type-N thermocouples overcome

3600-533: Is melted in a furnace and then reduced and cast into billets and ingots ; lower-purity scrap is refined by electroplating in a bath of sulfuric acid . The environmental cost of copper mining was estimated at 3.7 kg CO2eq per kg of copper in 2019. Codelco, a major producer in Chile, reported that in 2020 the company emitted 2.8t CO2eq per ton (2.8 kg CO2eq per kg) of fine copper. Greenhouse gas emissions primarily arise from electricity consumed by

3700-428: Is non-magnetic). Hydrogen in the atmosphere is the usual cause of green rot. At high temperatures, it can diffuse through solid metals or an intact metal thermowell. Even a sheath of magnesium oxide insulating the thermocouple will not keep the hydrogen out. Green rot does not occur in atmospheres sufficiently rich in oxygen, or oxygen-free. A sealed thermowell can be filled with inert gas, or an oxygen scavenger (e.g.

3800-402: Is non-magnetic. Wide range is −270 °C to +740 °C and narrow range is −110 °C to +140 °C. Type J ( iron – constantan ) has a more restricted range (−40 °C to +1200 °C) than type K but higher sensitivity of about 50 μV/°C. The Curie point of the iron (770 °C) causes a smooth change in the characteristic, which determines the upper-temperature limit. Note,

3900-458: Is not sufficient to just measure V {\displaystyle \scriptstyle V} . The temperature at the reference junctions T r e f {\displaystyle \scriptstyle T_{\mathrm {ref} }} must also be known. Two strategies are often used here: In both cases the value V + E ( T r e f ) {\displaystyle \scriptstyle V+E(T_{\mathrm {ref} })}

4000-465: Is not suitable for direct insertion into metallic protecting tubes. Long term high temperature exposure causes grain growth which can lead to mechanical failure and a negative calibration drift caused by Rhodium diffusion to pure platinum leg as well as from Rhodium volatilization. This type has the same uses as type S, but is not interchangeable with it. Type S (90%Pt/10%Rh–Pt, by weight) thermocouples, similar to type R, are used up to 1600 °C. Before

4100-444: Is one of the most important constituents of silver and karat gold solders used in the jewelry industry, modifying the color, hardness and melting point of the resulting alloys. Some lead-free solders consist of tin alloyed with a small proportion of copper and other metals. The alloy of copper and nickel , called cupronickel , is used in low-denomination coins, often for the outer cladding. The US five-cent coin (currently called

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4200-411: Is pulled partly out of a furnace—as the sensor is pulled back, aged sections may see exposure to increased temperature gradients from hot to cold as the aged section now passes through the cooler refractory area, contributing significant error to the measurement. Likewise, an aged thermocouple that is pushed deeper into the furnace might sometimes provide a more accurate reading if being pushed further into

4300-437: Is recovered from mine tailings and heaps. A variety of methods are used including leaching with sulfuric acid, ammonia, ferric chloride. Biological methods are also used. A significant source of copper is from recycling. Recycling is facilitated because copper is usually deployed in its metallic state. In 2001, a typical automobile contained 20–30 kg of copper. Recycling usually begins with some melting process using

4400-411: Is used for various objects exposed to seawater, though it is vulnerable to the sulfides sometimes found in polluted harbors and estuaries. Alloys of copper with aluminium (about 7%) have a golden color and are used in decorations. Shakudō is a Japanese decorative alloy of copper containing a low percentage of gold, typically 4–10%, that can be patinated to a dark blue or black color. Copper forms

4500-491: The Australian Securities Exchange -listed 29Metals Limited as the new owner of the mine. Production figures for the mine: Copper Copper is a chemical element ; it has symbol Cu (from Latin cuprum ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity . A freshly exposed surface of pure copper has

4600-686: The British Geological Survey , in 2005, Chile was the top producer of copper with at least one-third of the world share followed by the United States, Indonesia and Peru. Copper can also be recovered through the in-situ leach process. Several sites in the state of Arizona are considered prime candidates for this method. The amount of copper in use is increasing and the quantity available is barely sufficient to allow all countries to reach developed world levels of usage. An alternative source of copper for collection currently being researched are polymetallic nodules , which are located at

4700-607: The Great Lakes may have also been mining copper during this time, making it one of the oldest known examples of copper extraction in the world. There is evidence from prehistoric lead pollution from lakes in Michigan that people in the region began mining copper c.  6000 BC . Evidence suggests that utilitarian copper objects fell increasingly out of use in the Old Copper Complex of North America during

4800-553: The International Resource Panel 's Metal Stocks in Society report , the global per capita stock of copper in use in society is 35–55 kg. Much of this is in more-developed countries (140–300 kg per capita) rather than less-developed countries (30–40 kg per capita). The process of recycling copper is roughly the same as is used to extract copper but requires fewer steps. High-purity scrap copper

4900-726: The Neolithic period and the Bronze Age was formerly termed the Chalcolithic period (copper-stone), when copper tools were used with stone tools. The term has gradually fallen out of favor because in some parts of the world, the Chalcolithic and Neolithic are coterminous at both ends. Brass, an alloy of copper and zinc, is of much more recent origin. It was known to the Greeks, but became a significant supplement to bronze during

5000-461: The Seebeck coefficients of the conductors attached to the positive and negative terminals of the voltmeter, respectively (chromel and alumel in the figure). The thermocouple's behaviour is captured by a characteristic function E ( T ) {\displaystyle \scriptstyle E(T)} , which needs only to be consulted at two arguments: In terms of the Seebeck coefficients,

5100-525: The Vinča culture date to 4500 BC. Sumerian and Egyptian artifacts of copper and bronze alloys date to 3000 BC. Egyptian Blue , or cuprorivaite (calcium copper silicate) is a synthetic pigment that contains copper and started being used in ancient Egypt around 3250 BC. The manufacturing process of Egyptian blue was known to the Romans, but by the fourth century AD the pigment fell out of use and

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5200-548: The 9th or 10th century AD. Carbon dating has established mining at Alderley Edge in Cheshire , UK, at 2280 to 1890 BC. Ötzi the Iceman , a male dated from 3300 to 3200 BC, was found with an axe with a copper head 99.7% pure; high levels of arsenic in his hair suggest an involvement in copper smelting. Experience with copper has assisted the development of other metals; in particular, copper smelting likely led to

5300-517: The Bronze Age and a shift towards an increased production of ornamental copper objects occurred. Natural bronze, a type of copper made from ores rich in silicon, arsenic, and (rarely) tin, came into general use in the Balkans around 5500 BC. Alloying copper with tin to make bronze was first practiced about 4000 years after the discovery of copper smelting, and about 2000 years after "natural bronze" had come into general use. Bronze artifacts from

5400-616: The European/German Type L is a variant of the type J, with a different specification for the EMF output (reference DIN 43712:1985-01 ). The positive wire is made of hard iron, while the negative wire consists of softer copper - nickel . Due to its iron content, the J-type is slightly heavier and the positive wire is magnetic. It is highly vulnerable to corrosion in reducing atmospheres, which can lead to significant degradation of

5500-550: The Gossan Hill underground mine and the Scuddles underground mine, which both produce zinc, copper, lead, silver and gold. The Gossan Hill deposit was discovered in 1971, and the Scuddles deposit was discovered in 1979. In 2008, the mine's revenue was A$ 266.2 million and had a segment operating result of A$ 72.1 million. In June 2009, OZ Minerals announced that a trunnion bearing failure on its mill at Golden Grove had put

5600-541: The Middle East; a copper pendant was found in northern Iraq that dates to 8700 BC. Evidence suggests that gold and meteoric iron (but not smelted iron) were the only metals used by humans before copper. The history of copper metallurgy is thought to follow this sequence: first, cold working of native copper, then annealing , smelting , and, finally, lost-wax casting . In southeastern Anatolia , all four of these techniques appear more or less simultaneously at

5700-774: The Roman Empire. Thermocouple Commercial thermocouples are inexpensive, interchangeable, are supplied with standard connectors , and can measure a wide range of temperatures. In contrast to most other methods of temperature measurement, thermocouples are self-powered and require no external form of excitation. The main limitation with thermocouples is accuracy; system errors of less than one degree Celsius (°C) can be difficult to achieve. Thermocouples are widely used in science and industry. Applications include temperature measurement for kilns , gas turbine exhaust, diesel engines , and other industrial processes. Thermocouples are also used in homes, offices and businesses as

5800-521: The affected areas is highly acidic, with a pH range of 2.1–4.9, and shows elevated electrical conductivity levels between 280 and 1561 mS/cm. These changes in water chemistry make the environment inhospitable for fish, essentially rendering the water uninhabitable for aquatic life. Numerous copper alloys have been formulated, many with important uses. Brass is an alloy of copper and zinc . Bronze usually refers to copper- tin alloys, but can refer to any alloy of copper such as aluminium bronze . Copper

5900-475: The aged section of the thermocouple circuit is exposed to a temperature gradient, the measured voltage will differ, resulting in error. Aged thermocouples are only partly modified; for example, being unaffected in the parts outside the furnace. For this reason, aged thermocouples cannot be taken out of their installed location and recalibrated in a bath or test furnace to determine error. This also explains why error can sometimes be observed when an aged thermocouple

6000-446: The alloy, compensating for uncontrolled variations in source material. As a result, there are standard and specialized grades of thermocouple wire, depending on the level of precision demanded in the thermocouple behaviour. Precision grades may only be available in matched pairs, where one wire is modified to compensate for deficiencies in the other wire. A special case of thermocouple wire is known as "extension grade", designed to carry

6100-541: The atmosphere; 150 mg/kg in soil; 30 mg/kg in vegetation; 2 μg/L in freshwater and 0.5 μg/L in seawater. Most copper is mined or extracted as copper sulfides from large open pit mines in porphyry copper deposits that contain 0.4 to 1.0% copper. Sites include Chuquicamata , in Chile, Bingham Canyon Mine , in Utah, United States, and El Chino Mine , in New Mexico, United States. According to

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6200-766: The beginning of the Neolithic c.  7500 BC . Copper smelting was independently invented in different places. The earliest evidence of lost-wax casting copper comes from an amulet found in Mehrgarh , Pakistan, and is dated to 4000 BC. Investment casting was invented in 4500–4000 BC in Southeast Asia Smelting was probably discovered in China before 2800 BC, in Central America around 600 AD, and in West Africa about

6300-419: The characteristic function is defined by The constant of integration in this indefinite integral has no significance, but is conventionally chosen such that E ( 0 ∘ C ) = 0 {\displaystyle \scriptstyle E(0\,{}^{\circ }{\rm {C}})=0} . Thermocouple manufacturers and metrology standards organizations such as NIST provide tables of

6400-476: The chemical inertness of the thermocouple material and whether it is magnetic or not. Standard thermocouple types are listed below with the positive electrode (assuming T sense > T ref {\displaystyle T_{\text{sense}}>T_{\text{ref}}} ) first, followed by the negative electrode. Type E ( chromel – constantan ) has a high output (68 μV/°C), which makes it well suited to cryogenic use. Additionally, it

6500-531: The company, especially when sourced from fossil fuels, and from engines required for copper extraction and refinement. Companies that mine land often mismanage waste, rendering the area sterile for life. Additionally, nearby rivers and forests are also negatively impacted. The Philippines is an example of a region where land is overexploited by mining companies. Copper mining waste in Valea Şesei, Romania, has significantly altered nearby water properties. The water in

6600-425: The constituent metals, nickel , is magnetic; a characteristic of thermocouples made with magnetic material is that they undergo a deviation in output when the material reaches its Curie point , which occurs for type K thermocouples at around 185 °C. They operate very well in oxidizing atmospheres. If, however, a mostly reducing atmosphere (such as hydrogen with a small amount of oxygen) comes into contact with

6700-522: The deprotonated amide ligands. Complexes of copper(III) are also found as intermediates in reactions of organocopper compounds, for example in the Kharasch–Sosnovsky reaction . A timeline of copper illustrates how this metal has advanced human civilization for the past 11,000 years. Copper occurs naturally as native metallic copper and was known to some of the oldest civilizations on record. The history of copper use dates to 9000 BC in

6800-461: The depths of the Pacific Ocean approximately 3000–6500 meters below sea level. These nodules contain other valuable metals such as cobalt and nickel . Copper has been in use for at least 10,000 years, but more than 95% of all copper ever mined and smelted has been extracted since 1900. As with many natural resources, the total amount of copper on Earth is vast, with around 10 tons in

6900-563: The discovery of iron smelting . Production in the Old Copper Complex in Michigan and Wisconsin is dated between 6500 and 3000 BC. A copper spearpoint found in Wisconsin has been dated to 6500 BC. Copper usage by the indigenous peoples of the Old Copper Complex from the Great Lakes region of North America has been radiometrically dated to as far back as 7500 BC. Indigenous peoples of North America around

7000-545: The fastest water exchange rate (speed of water ligands attaching and detaching) for any transition metal aquo complex . Adding aqueous sodium hydroxide causes the precipitation of light blue solid copper(II) hydroxide . A simplified equation is: Aqueous ammonia results in the same precipitate. Upon adding excess ammonia, the precipitate dissolves, forming tetraamminecopper(II) : Many other oxyanions form complexes; these include copper(II) acetate , copper(II) nitrate , and copper(II) carbonate . Copper(II) sulfate forms

7100-419: The function E ( T ) {\displaystyle \scriptstyle E(T)} that have been measured and interpolated over a range of temperatures, for particular thermocouple types (see External links section for access to these tables). To obtain the desired measurement of T s e n s e {\displaystyle \scriptstyle T_{\mathrm {sense} }} , it

7200-566: The furnace causes the temperature gradient to occur only in a fresh section. Certain combinations of alloys have become popular as industry standards. Selection of the combination is driven by cost, availability, convenience, melting point, chemical properties, stability, and output. Different types are best suited for different applications. They are usually selected on the basis of the temperature range and sensitivity needed. Thermocouples with low sensitivities (B, R, and S types) have correspondingly lower resolutions. Other selection criteria include

7300-759: The introduction of the International Temperature Scale of 1990 (ITS-90), precision type-S thermocouples were used as the practical standard thermometers for the range of 630 °C to 1064 °C, based on an interpolation between the freezing points of antimony , silver , and gold . Starting with ITS-90, platinum resistance thermometers have taken over this range as standard thermometers. These thermocouples are well-suited for measuring extremely high temperatures. Typical uses are hydrogen and inert atmospheres, as well as vacuum furnaces . They are not used in oxidizing environments at high temperatures because of embrittlement . A typical range

7400-511: The later spelling first used around 1530. Copper, silver , and gold are in group 11 of the periodic table; these three metals have one s-orbital electron on top of a filled d- electron shell and are characterized by high ductility , and electrical and thermal conductivity. The filled d-shells in these elements contribute little to interatomic interactions, which are dominated by the s-electrons through metallic bonds . Unlike metals with incomplete d-shells, metallic bonds in copper are lacking

7500-465: The left, the reference junction in the middle and represents the rest of the electrical system as a voltage meter on the right. The temperature T sense is obtained via a characteristic function E ( T ) for the type of thermocouple which requires inputs: measured voltage V and reference junction temperature T ref . The solution to the equation E ( T sense ) = V + E ( T ref ) yields T sense . Sometimes these details are hidden inside

7600-419: The level of <1% Cu. Concentration of the ore is required, which begins with comminution followed by froth flotation . The remaining concentrate is the smelted, which can be described with two simplified equations: Cuprous oxide reacts with cuprous sulfide to convert to blister copper upon heating This roasting gives matte copper, roughly 50% Cu by weight, which is purified by electrolysis. Depending on

7700-567: The mill out of service for almost a month, shortly before the approval of the sale of the mine, but operations resumed in July 2009. It was purchased by EMR Capital, a specialist resources private equity manager, who purchased the mine from MMG in February 2017. Minerals and Metals Group was formed after its parent company China Minmetals bought the mine from OZ Minerals in June 2009. Golden Grove

7800-472: The modern world. The price of copper is volatile . After a peak in 2022 the price unexpectedly fell. The global market for copper is one of the most commodified and financialized of the commodity markets , and has been so for decades. The great majority of copper ores are sulfides. Common ores are the sulfides chalcopyrite (CuFeS 2 ), bornite (Cu 5 FeS 4 ) and, to a lesser extent, covellite (CuS) and chalcocite (Cu 2 S). These ores occur at

7900-588: The most stable thermocouples, but have lower sensitivity than other types, approximately 10 μV/°C. Type B, R, and S thermocouples are usually used only for high-temperature measurements due to their high cost and low sensitivity. For type R and S thermocouples, HTX platinum wire can be used in place of the pure platinum leg to strengthen the thermocouple and prevent failures from grain growth that can occur in high temperature and harsh conditions. Type B (70%Pt/30%Rh–94%Pt/6%Rh, by weight) thermocouples are suited for use at up to 1800 °C. Type-B thermocouples produce

8000-516: The numerous copper sulfides , important examples include copper(I) sulfide ( Cu 2 S ) and copper monosulfide ( CuS ). Cuprous halides with fluorine , chlorine , bromine , and iodine are known, as are cupric halides with fluorine , chlorine , and bromine . Attempts to prepare copper(II) iodide yield only copper(I) iodide and iodine. Copper forms coordination complexes with ligands . In aqueous solution, copper(II) exists as [Cu(H 2 O) 6 ] . This complex exhibits

8100-428: The ore, sometimes other metals are obtained during the electrolysis including platinum and gold. Aside from sulfides, another family of ores are oxides. Approximately 15% of the world's copper supply derives from these oxides. The beneficiation process for oxides involves extraction with sulfuric acid solutions followed by electrolysis. In parallel with the above method for "concentrated" sulfide and oxide ores, copper

8200-415: The presence of sulfur. Type T ( copper – constantan ) thermocouples are suited for measurements in the −200 to 350 °C range. Often used as a differential measurement, since only copper wire touches the probes. Since both conductors are non-magnetic, there is no Curie point and thus no abrupt change in characteristics. Type-T thermocouples have a sensitivity of about 43 μV/°C. Note that copper has

8300-433: The sale as it was within sensitive military area and the sale went only ahead after Prominent Hill was excluded. EMR Capital purchased the mine in 2017 for US$ 210 million after MMG had been looking for a buyer since 2016. EMR Capital had been founded by Owen Hegarty , who had led Oxiana when it acquired Golden Grove from Newmont in 2005. In June 2021, EMR Capital divested itself of Golden Grove and other assets, launching

8400-679: The same output at 0 °C and 42 °C, limiting their use below about 50 °C. The emf function has a minimum around 21 °C (for 21.020262 °C emf=-2.584972 μV), meaning that cold-junction compensation is easily performed, since the compensation voltage is essentially a constant for a reference at typical room temperatures. Type R (87%Pt/13%Rh–Pt, by weight) thermocouples are used 0 to 1600 °C. Type R Thermocouples are quite stable and capable of long operating life when used in clean, favorable conditions. When used above 1100 °C ( 2000 °F), these thermocouples must be protected from exposure to metallic and non-metallic vapors. Type R

8500-537: The same temperature change and an identical material. As a result, T m e t e r {\displaystyle \scriptstyle T_{\mathrm {meter} }} does not influence the measured voltage. The second and third contributions do not cancel, as they involve different materials. The measured voltage turns out to be where S + {\displaystyle \scriptstyle S_{+}} and S − {\displaystyle \scriptstyle S_{-}} are

8600-750: The secret to its manufacturing process became lost. The Romans said the blue pigment was made from copper, silica, lime and natron and was known to them as caeruleum . The Bronze Age began in Southeastern Europe around 3700–3300 BC, in Northwestern Europe about 2500 BC. It ended with the beginning of the Iron Age, 2000–1000 BC in the Near East, and 600 BC in Northern Europe. The transition between

8700-438: The sugar is signaled by a color change from blue Cu(II) to reddish copper(I) oxide. Schweizer's reagent and related complexes with ethylenediamine and other amines dissolve cellulose . Amino acids such as cystine form very stable chelate complexes with copper(II) including in the form of metal-organic biohybrids (MOBs). Many wet-chemical tests for copper ions exist, one involving potassium ferricyanide , which gives

8800-612: The temperature measurement. For the simplest measurements, thermocouple wires are connected to copper far away from the hot or cold point whose temperature is measured; this reference junction is then assumed to be at room temperature, but that temperature can vary. Because of the nonlinearity in the thermocouple voltage curve, the errors in T r e f {\displaystyle T_{\mathrm {ref} }} and T s e n s e {\displaystyle T_{\mathrm {sense} }} are generally unequal values. Some thermocouples, such as Type B, have

8900-483: The temperature sensors in thermostats , and also as flame sensors in safety devices for gas-powered appliances. In 1821, the German physicist Thomas Johann Seebeck discovered that a magnetic needle held near a circuit made up of two dissimilar metals got deflected when one of the dissimilar metal junctions was heated. At the time, Seebeck referred to this consequence as thermo-magnetism. The magnetic field he observed

9000-464: The thermocouple's performance. Type K ( chromel – alumel ) is the most common general-purpose thermocouple with a sensitivity of approximately 41 μV/°C. It is inexpensive, and a wide variety of probes are available in its −200 °C to +1350 °C (−330 °F to +2460 °F) range. Type K was specified at a time when metallurgy was less advanced than it is today, and consequently characteristics may vary considerably between samples. One of

9100-473: The thermoelectric circuit over a longer distance. Extension wires follow the stated E ( T ) {\displaystyle \scriptstyle E(T)} curve but for various reasons they are not designed to be used in extreme environments and so they cannot be used at the sensing junction in some applications. For example, an extension wire may be in a different form, such as highly flexible with stranded construction and plastic insulation, or be part of

9200-485: The three principal characteristic types and causes of thermoelectric instability in the standard base-metal thermoelement materials: The Nicrosil and Nisil thermocouple alloys show greatly enhanced thermoelectric stability relative to the other standard base-metal thermocouple alloys because their compositions substantially reduce the thermoelectric instabilities described above. This is achieved primarily by increasing component solute concentrations (chromium and silicon) in

9300-399: The top kilometer of Earth's crust, which is about 5 million years' worth at the current rate of extraction. However, only a tiny fraction of these reserves is economically viable with present-day prices and technologies. Estimates of copper reserves available for mining vary from 25 to 60 years, depending on core assumptions such as the growth rate. Recycling is a major source of copper in

9400-440: The voltmeter itself. If the thermocouple wire has a high resistance for some reason (poor contact at junctions, or very thin wires used for fast thermal response), the measuring instrument should have high input impedance to prevent an offset in the measured voltage. A useful feature in thermocouple instrumentation will simultaneously measure resistance and detect faulty connections in the wiring or at thermocouple junctions. While

9500-497: The wires in a thermocouple that is used to measure very high temperatures may change with time, and the measurement voltage accordingly drops. The simple relationship between the temperature difference of the junctions and the measurement voltage is only correct if each wire is homogeneous (uniform in composition). As thermocouples age in a process, their conductors can lose homogeneity due to chemical and metallurgical changes caused by extreme or prolonged exposure to high temperatures. If

9600-413: The wires, the chromium in the chromel alloy oxidizes. This reduces the emf output, and the thermocouple reads low. This phenomenon is known as green rot , due to the color of the affected alloy. Although not always distinctively green, the chromel wire will develop a mottled silvery skin and become magnetic. An easy way to check for this problem is to see whether the two wires are magnetic (normally, chromel

9700-445: Was acquired by Newmont Australia Ltd in February 2002. Newmont passed on the mine to Oxiana Limited in June 2005 for A$ 265 million and Oxiana merged with Zinifex to form OZ Minerals in mid-2008. OZ Minerals had to sell Golden Grove in June 2009 to China Minmetals, like almost all its other mines, when the company was hit by severe financial difficulties. Golden Grove currently consists of two operations that are 3 km apart,

9800-527: Was found in 1857 on the Keweenaw Peninsula in Michigan, US. Native copper is a polycrystal , with the largest single crystal ever described measuring 4.4 × 3.2 × 3.2 cm . Copper is the 26th most abundant element in Earth's crust , representing 50 ppm compared with 75 ppm for zinc , and 14 ppm for lead . Typical background concentrations of copper do not exceed 1 ng/m in

9900-482: Was later shown to be due to thermo-electric current. In practical use, the voltage generated at a single junction of two different types of wire is what is of interest as this can be used to measure temperature at very high and low temperatures. The magnitude of the voltage depends on the types of wire being used. Generally, the voltage is in the microvolt range and care must be taken to obtain a usable measurement. Although very little current flows, power can be generated by

10000-716: Was part of a deal in which the Sepon, Century, Rosebery and Avebury Mines, the Dugald River, High Lake, and Izok Lake Projects, as well as some exploration assets were sold for US$ 1.354 billion by OZ Minerals to China Minmetals. The deal, initially including the Prominent Hill Mine , was blocked by the Australian Government , citing national security concerns. Wayne Swan , Treasurer of Australia , stated that Prominent Hill could not be included in

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