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20-407: Ivittuut is one of the few places in the world so far discovered to have naturally occurring cryolite (Na 3 AlF 6 , sodium aluminum fluoride ), an important agent in modern aluminum extraction . The area was settled by about twenty farms of Norsemen , a district called the "Middle Settlement" by modern archaeologists from its placement between the larger Western and Eastern Settlements. It

40-492: A road (which is roughly 5 km (3 mi) long). Cryolite Cryolite ( Na 3 Al F 6 , sodium hexafluoroaluminate ) is an uncommon mineral identified with the once-large deposit at Ivittuut on the west coast of Greenland , mined commercially until 1987. It is used in the reduction ("smelting") of aluminium, in pest control, and as a dye. Cryolite was first described in 1798 by Danish veterinarian and physician Peder Christian Abildgaard (1740–1801); it

60-816: A track to transport materials between departments at its Allegheny Ludlum Brackenridge Works . The Pennsylvania Salt Manufacturing Company operated its Natrona No. 1 and Natrona No. 2 bituminous coal mines at Natrona. Natrona is situated on an alluvial floodplain along the Allegheny River . The community is located within the Highlands School District . Highlands High School and Highlands Middle School are located in Natrona Heights. Air pollution levels (particularly chromium ) measured in Natrona area schools are among

80-437: A yellow color. Cryolite occurs as glassy, colorless, white-reddish to gray-black prismatic monoclinic crystals. It has a Mohs hardness of 2.5 to 3 and a specific gravity of about 2.95 to 3.0. It is translucent to transparent with a very low refractive index of about 1.34, which is very close to that of water ; thus if immersed in water, cryolite becomes essentially invisible. Natrona, Pennsylvania Natrona

100-682: Is an unincorporated community in Harrison Township, Allegheny County, Pennsylvania . It is located in western Pennsylvania within the Pittsburgh Metropolitan Statistical Area , approximately 24 miles (39 km) northeast of Downtown Pittsburgh . Natrona is situated along the Allegheny River at Lock and Dam Four , Pools Three and Four between Brackenridge , Natrona Heights , Karns , Allegheny Township , and Lower Burrell . The original village of Natrona – then known as East Tarentum –

120-432: Is the smallest and least well known of the three, and no written records of its residents survive, for which reasons it is believed to have been established last (and abandoned first) of the three. Investigations show a presence after 985 and with occupation continuing up to at least the 14th century. The town's cryolite deposit was discovered in 1799, and the veins of silver-bearing lead surrounding it were mined by

140-458: Is used as a solvent for aluminium oxide (Al 2 O 3 ) in the Hall–Héroult process , used in the refining of aluminium . It decreases the melting point of aluminium oxide from 2000–2500 °C to 900–1000 °C, and increases its conductivity thus making the extraction of aluminium more economical. Cryolite is used as an insecticide and a pesticide . It is also used to give fireworks

160-571: The Hall-Heroult process , which depends on the rare cryolite but dramatically improved the extraction of aluminum from bauxite ore, increased the deposit's importance. The Ivittuut mining operations were a major factor in the American occupation of Greenland during World War II . After World War II, the cryolite was mined by the Danish firm Kryolitselskabet Øresund, which helped fund

180-492: The 19th and 20th centuries. It was historically used as an ore of aluminium and later in the electrolytic processing of the aluminium -rich oxide ore bauxite (itself a combination of aluminium oxide minerals such as gibbsite , boehmite and diaspore ). The difficulty of separating aluminium from oxygen in the oxide ores was overcome by the use of cryolite as a flux to dissolve the oxide mineral(s). Pure cryolite itself melts at 1012 °C (1285 K ), and it can dissolve

200-705: The British engineer J.W. Tayler before the silver content was found to be too low to make the operation viable. Danish engineers began mining the cryolite itself in 1859, and in 1864 the Danish Kriolit Mine og Handels Selskabet was granted a monopoly on its extraction. These early mines simply processed the cryolite for its direct aluminum content and for sale to the Pennsylvania Salt Manufacturing Company , which used it to create caustic soda . The 1884 establishment of

220-760: The United States became involved with protecting the world's largest cryolite mine in Ivittuut, Greenland from falling into Nazi Germany's control. Besides Ivittuut , on the west coast of Greenland where cryolite was once found in commercial quantities, small deposits of cryolite have also been reported in some areas of Spain , at the foot of Pikes Peak in Colorado , Francon Quarry near Montreal in Quebec , Canada and also in Miask, Russia . Molten cryolite

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240-450: The aluminium oxides sufficiently well to allow easy extraction of the aluminium by electrolysis . Substantial energy is still needed for both heating the materials and the electrolysis, but it is much more energy-efficient than melting the oxides themselves. As natural cryolite is now too rare to be used for this purpose, synthetic sodium aluminium fluoride is produced from the common mineral fluorite . In 1940 before entering World War II,

260-477: The crude mineral to its works in Natrona, where the mineral was pulverized, sifted, heated, reacted with calcium carbonate and leached to produce pure carbonate of soda ( sodium carbonate ) and aluminate of soda ( sodium aluminate ). The Pennsylvania Canal once passed through Natrona and nearby communities in the early- to mid-19th century. The Pennsylvania Railroad had a train station in Natrona at Vine and Federal streets; its rail line began running through

280-463: The establishment of Grønlandsfly , today's Air Greenland . Cryolite was eventually synthesized, reducing the importance of the mine. The mine ran empty, but production was proceeded using earlier 'waste rock'. The mine was finally shut down in 1987. The community was abandoned soon after. In 1924, it was a stopping place for the first aerial circumnavigation , during which new engines were installed in two American biplane aircraft. Ivittuut holds

300-558: The record for Greenland's highest recorded temperature of 30.1 °C (86.2 °F), recorded on 23 June 1915. The lowest recorded temperature was −28.9 °C (−20.0 °F) in February. Ivittuut has a tundra climate ( ET ) bordering on a subarctic climate (Dfc), with July having an average of 49.6 °F (9.8 °C). Summertime temperatures are cool with chilly nights, and wintertime temperatures are very cold with frigid nights. Ivittuut and Kangilinnguit are connected by

320-711: The town in the mid-19th century. Later, the Pennsylvania Railroad merged with rival New York Central Railroad in 1968 to form the Penn Central Transportation Company . The Interstate Commerce Commission required that the ailing New York, New Haven and Hartford Railroad be added in 1969. The Consolidated Rail Corporation replaced the Penn Central Transportation Company and operated freight service through Natrona from 1976 until 1999 when it

340-500: The worst in the United States. The film Knightriders ( 1981 ) by George A. Romero starring Ed Harris used scenes shot on Garfield Street in Natrona (1980) for the movie. Most of the film was shot in nearby Fawn Township . Also, the film Striking Distance ( 1993 ) starring Bruce Willis and Sarah Jessica Parker uses a sequence where boats jump over the dam at Natrona; the Tarentum Bridge can be seen just above

360-399: Was built as a company town by the Pennsylvania Salt Manufacturing Company in the 1850s. It received its name from " natron ", a naturally occurring mineral composed primarily of sodium carbonate and sodium bicarbonate. The company began with two salt wells in 1850, and continued operations until 1959. By 1876, the company, which owned the cryolite deposits of Greenland, brought

380-676: Was divided between two companies. The Norfolk Southern Railway then operated trains through the town. Amtrak has detoured passenger service through Natrona on occasion; its nearest station is Penn Station in Downtown Pittsburgh . The West Penn Railways provided electric street car service to Natrona from 1906 until 1937. Local factories, beginning with the Pennsylvania Salt Manufacturing Company's Natrona Works, also operated trains through Natrona. As of 2011, Allegheny Technologies used

400-664: Was obtained from a deposit of it in Ivigtut (old spelling) and nearby Arsuk Fjord, Southwest Greenland. The name is derived from the Greek language words κρύος (cryos) = frost, and λίθος (lithos) = stone. The Pennsylvania Salt Manufacturing Company used large amounts of cryolite to make caustic soda and fluorine compounds, including hydrofluoric acid at its Natrona, Pennsylvania , works, and at its integrated chemical plant in Cornwells Heights, Pennsylvania , during

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