Cryolite Sentence Examples
A few other minerals may be noticed, and some have been worked to a small extent - graphite is abundant, particularly near Upernivik; cryolite is found almost exclusively at Ivigtut; copper has been observed at several places, but only in nodules and laminae of limited extent; and coal of poor quality is found in the districts about Disco Bay and Umanak Fjord.
The trade of Greenland has on the whole much decreased in modern times, and trading and missions cost the Danish state a comparatively large sum (about £i i,000 every year), although this is partly covered by the income from the royalty of the cryolite mines at Ivigtut.
Various minerals are employed in the manufacture of alum, the most important being alunite or alum-stone, alum schist, bauxite and cryolite.
Semi-opacity and opacity are usually produced by the addition to the glass-mixtures of materials which will remain in suspension in the glass, such as oxide of tin, oxide of arsenic, phosphate of lime, cryolite or a mixture of felspar and fluorspar.
Cryolite, a fluoride of aluminium and sodium, is extensively mined in Greenland and elsewhere for industrial purposes.
Cryolite (A1F 3.5NaF) is a double fluoride of aluminium and sodium, which is scarcely known except on the west coast of Greenland.
Rose also carried out experiments on the decomposition of cryolite, and expressed an opinion that it was the best of all compounds for reduction; but, finding the yield of metal to be low, receiving a report of the difficulties experienced in mining the ore, and fearing to cripple his new industry by basing it upon the employment of a mineral of such uncertain supply, Deville decided to keep to his chlorides.
Cryolite is not a safe body to electrolyse, because the minimum voltage needed to break up the aluminium fluoride is 4.0, whereas the sodium fluoride requires only 4.7 volts; if, therefore, the current rises in tension, the alkali is reduced, and the final product consists of an alloy with sodium.
Molten cryolite dissolves roughly 30% of its weight of pure alumina, so that when ready for treatment the solution contains about the same proportion of what may be termed "available" aluminium as does the fused double chloride of aluminium and sodium.
For the production of the final aluminium, ioo parts of the chloride and 45 parts of cryolite to serve as a flux were powdered together and mixed with 35 parts of sodium cut into small pieces.
AdvertisementTissier, formerly his assistants, who had devised an improved sodium furnace and had acquired a thorough knowledge of their leader's experiments, also left, and erected a factory at Amfreville, near Rouen, to work the cryolite process.
It consisted simply in reducing cryolite with metallic sodium exactly as in Deville's chloride method, and it was claimed to possess various mythical advantages over its rival.
Gerhard at Battersea, who also employed cryolite, made his own sodium, and was able to sell the product at 3s.
In 1888 the Alliance Aluminium Co., organized to work certain patents for winning the metal from cryolite by means of sodium, erected plant in London, Hebburn and Wallsend, and by 1889 were selling the metal at 11s.
Kleiner propounded a cryolite method which was worked for a time by the Aluminium Syndicate at Tyldesley near Manchester, but was abandoned in 1890.
AdvertisementMinet took out patents for electrolysing a mixture of sodium chloride with aluminium fluoride, or with natural or artificial cryolite.
The cell is filled up with cryolite, and the current is turned on till this is melted; then the pure powdered alumina is fed in continuously as long as the operation proceeds.
As a part of the voltage is consumed in the latter duty, only the residue can be converted into chemical work, and as the theoretical voltage of the aluminium fluoride in the cryolite is 4.0, provided the bath is kept properly supplied with alumina, the fluorides are not attacked.
The latter therefore appears the better material, and was originally preferred by Hall; cryolite, however, dissolves more alumina, and has been finally adopted by both inventors.
There is a reaction between the aluminum oxide and the cryolite to produce a range of complex ions involving aluminum, oxygen and/or fluorine.
AdvertisementIt follows, therefore, except for mechanical losses, that one charge of cryolite lasts indefinitely, that the sodium and other impurities in it are not liable to contaminate the product, and that only the alumina itself need be carefully purified.
It forms a series of double fluorides, the most important of which is cryolite; this mineral has been applied to the commercial preparation of the metal (see above).
When cryolite is used for the preparation of alum, it is mixed with calcium carbonate and heated.