Cryolite

	Email		Print
	Bookmark		Link

Cryolite

Cryolite (Na

Sodium

Sodium is an element which has the symbol Na , atomic number 11, atomic mass 23 amu , and a common oxidation number +1. Sodium is a soft, silvery white, highly reactive element and is a member of the alkali metals within "group 1" ....
₃Al

Aluminium

Aluminium or aluminum is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13....
F

Fluorine

Fluorine is the chemical element with the symbol F and atomic number 9. Fluorine forms a single bond with itself in elemental form, resulting in the diatomic F2 molecule....
₆, sodium hexafluoroaluminate

Sodium hexafluoroaluminate

Sodium hexafluoroaluminate is a chemical compound. It is a stable compound although will decompose when reacted with aluminium oxide , or sodium oxide ....
) is an uncommon mineral

Mineral

A mineral is a naturally occurring solid formed through Geology processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties....
identified with the once large deposit at Ivigtût

Ivittuut

Ivittuut, was a municipality , located on the coast of Arsuk fjord in southern Greenland. With an area of just 100 km? , it was the smallest municipality of Greenland, bordering on the former Narsaq municipality in the north, east, and south, and on the west by the Labrador Sea....
on the west coast of Greenland

Greenland

Greenland is a member country of the Kingdom of Denmark located between the Arctic Ocean and Atlantic Oceans, east of the Canadian Arctic Archipelago....
, which ran out in 1987.

It was historically used as an ore of aluminium and later in the electrolytic processing of the aluminium

Aluminium

Aluminium or aluminum is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13....
-rich oxide ore

Ore

An ore is a type of Rock that contains minerals such as gemstones and metals that can be extracted through mining and refined for use. Samples of ore in the form of exceptionally beautiful crystals, exotic layering visible when sectioned or polished or metallic presentations such as large nuggets or crystalline formations of metals suc...
bauxite

Bauxite

Bauxite is the most important aluminium ore. It consists largely of the minerals gibbsite Al3, boehmite ?-AlO, and diaspore a-AlO, together with the iron oxides goethite and hematite, the clay mineral kaolinite and small amounts of anatase TiO2....
(itself a combination of aluminium oxide

Aluminium oxide

Aluminium oxide is an amphoteric oxide of aluminium with the chemical formula 23. It is also commonly referred to as alumina or aloxite in the mining, ceramic and materials science communities....
minerals such as gibbsite

Gibbsite

Gibbsite, Al3, is one of the mineral forms of aluminium hydroxide. It is often designated as ?-Al3 . It is also sometimes called hydrargillite ....
, boehmite

Boehmite

Boehmite or B?hmite is an aluminium oxide hydroxide mineral, a component of the aluminium ore bauxite. It is dimorphous with diaspore. It crystallizes in the orthorhombic dipyramidal system and is typically massive in habit....
and diaspore

Diaspore

Diaspore is a native aluminium oxide hydroxide, a-AlO, crystallizing in the orthorhombic system and isomorphous with goethite and manganite....
). The difficulty of separating aluminium from oxygen in the oxide ores was overcome by the use of cryolite as a flux

Flux (metallurgy)

In metallurgy, a flux is a chemical cleaning agent which facilitates soldering, brazing, and welding by removing oxidation from the metals to be joined....
to dissolve the oxide mineral(s).

Discussion

Ask a question about 'Cryolite'

Start a new discussion about 'Cryolite'

Answer questions from other users

Full Discussion Forum

Encyclopedia

Cryolite (Na

Sodium

Aluminium

Aluminium or aluminum is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13....
F

Fluorine

Sodium hexafluoroaluminate

Sodium hexafluoroaluminate is a chemical compound. It is a stable compound although will decompose when reacted with aluminium oxide , or sodium oxide ....
) is an uncommon mineral

Mineral

Ivittuut

Greenland

Aluminium

Aluminium or aluminum is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13....
-rich oxide ore

Ore

Bauxite

Aluminium oxide

Gibbsite

Gibbsite, Al3, is one of the mineral forms of aluminium hydroxide. It is often designated as ?-Al3 . It is also sometimes called hydrargillite ....
, boehmite

Boehmite

Diaspore

Flux (metallurgy)

In metallurgy, a flux is a chemical cleaning agent which facilitates soldering, brazing, and welding by removing oxidation from the metals to be joined....
to dissolve the oxide mineral(s). Cryolite itself melts below 1000°C (1273 Kelvin), and it can dissolve the aluminium oxides sufficiently well to allow easy extraction of the aluminium by electrolysis. Considerable energy is still required for both heating the materials and the electrolysis, but it is much more energy-efficient than melting the oxides themselves. Now, as natural cryolite is too rare to be used for this purpose, synthetic sodium aluminium fluoride is produced from the common mineral fluorite

Fluorite

Fluorite is a mineral composed of calcium fluoride, CalciumFluorine. It is an Cubic mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon....
for this purpose.

Cryolite occurs as glassy, colorless, white-reddish to grey-black prismatic monoclinic crystals. It has a Mohs hardness of 2.5 to 3 and a specific gravity

Specific gravity

Specific gravity is defined as the ratio of the density of a given solid or liquid substance to the density of water at a specific temperature and pressure, typically at 4?C and , making it a dimensionless quantity ....
of about 2.95 to 3.0. It is translucent to transparent with very low refractive indices

Refractive index

The refractive index of a medium is a measure for how much the speed of light is reduced inside the medium. For example, typical soda-lime glass has a refractive index of 1.5, which means that in glass, light travels at times the speed of light in a vacuum....
of a=1.3385–1.339, b=1.3389–1.339, g=1.3396–1.34. These RI values are very close to that of water

Water

Water is a common chemical substance that is essential for the survival of all known forms of life. In typical usage, water refers only to its liquid form or States of matter, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam....
, and thus if it is immersed in water, cryolite becomes essentially invisible.

Cryolite has also been reported at Pikes Peak

Pikes Peak

Pikes Peak is a mountain in the Front Range of the Rocky Mountains, west of Colorado Springs, Colorado, in El Paso County, Colorado. It is named for Zebulon Pike, an explorer who led an expedition to the southern Colorado area in 1806....
, Colorado

Colorado

The State of Colorado is a U.S. state located in the Mountain States of the United States of America. Colorado may also be considered to be a part of the Western United States and Southwestern United States regions of the United States....
; Mont Saint-Hilaire

Mont Saint-Hilaire

Mont Saint-Hilaire , is an isolated hill, high, in the Mont?r?gie region of southern Quebec. It is about thirty kilometers east of Montreal, and immediately east of the Richelieu river....
, Quebec

Quebec

Quebec , in French language, Qu?bec , is a Provinces and territories of Canada in the Central Canada and Eastern Canada regions of Canada....
; and at Miass

Miass

Miass is a city in Chelyabinsk Oblast, Russia, situated 96 km from Chelyabinsk, on the eastern slope of the southern Ural Mountains, on the bank of the Miass River....
, Russia

Russia

Russia , or the Russian Federation , is a list of countries spanning more than one continent country extending over much of northern Eurasia....
. It is also known in small quantities in Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is a country in South America. It is the List of countries and outlying territories by total area country by geographical area, occupying nearly half of South America, the List of countries by population country, and the fourth most populous democracy in the world....
, the Czech Republic

Czech Republic

The Czech Republic , is a landlocked country in Central Europe. The country borders Poland to the northeast, Germany to the west, Austria to the south and Slovakia to the east....
, Namibia

Namibia

Namibia, officially the Republic of Namibia, is a country in southern Africa on the Atlantic Ocean coast. It shares borders with Angola and Zambia to the north, Botswana to the east, and South Africa to the south....
, Norway

Norway

Norway , officially the Kingdom of Norway, is a constitutional monarchy in Northern Europe that occupies the western portion of the Scandinavian Peninsula....
, Ukraine

Ukraine

Ukraine is a country in Eastern Europe. It is bordered by Russia to the east; Belarus to the north; Poland, Slovakia, and Hungary to the west; Romania and Moldova to the southwest; and the Black Sea and Sea of Azov to the south....
, and several American states.

Cryolite was first described in 1799 from a deposit of it in Ivigtut and Arksukfiord, West Greenland. The name is derived from the Greek language

Greek language

Greek is an Indo-European languages native to the southern Balkan peninsula, the language of the Greek people. It forms an independent branch within Indo-European....
words cryò = chill, and lithòs = stone.

Cryolite has also been used as a pesticide.

Cryolite

Footnotes