Vanadium carbide, VC, was prepared by H.
Sefstrom definitely proved the existence of a metallic element vanadium, which had been previously detected (in 1801) in certain lead ores by A.
Chemically related to vanadium are the two elements tantalum and columbium or niobium.
Roscoelite is a mica in which the aluminium is largely replaced by vanadium (V203, 30%); it occurs as brownish-green scaly aggregates, intimately associated with gold in California, Colorado and Western Australia.
The distillate is freed from vanadium by digestion with sodium amalgam.
Within these limits are to be found most of the minerals known - gold, silver, quicksilver, copper, lead, zinc, iron, manganese, wolfram, bismuth, thorium, vanadium; mica, coal, &c. On or near the coast are coal, salt, sulphur, borax, nitrates and petroleum.
Vanadium, molybdenum and titanium may be expected soon to play an important part in the constitution of steel.
In its chemical relationships tantalum is associated with vanadium, columbium and didymium in a sub-group of the periodic classification.
Antimony, bismuth, selenium, tellurium, chromic iron ore, tin, nickel, cobalt, vanadium, titanium, molybdenum, uranium and tantalum are produced in the United States in small amounts, but such production in several cases has amounted to only slight discoveries, and in general they are of little importance in the market.
Vanadium in small quantities, 0.15 or 0.20%, is said to improve steel greatly, especially in increasing its resistance to shock and to often-repeated stress.
But the improvement may be due wholly to the considerable chromium content of these socalled vanadium steels.
The principal exports are gold, silver, copper (bars, regulus and ores), cobalt and its ores, lead and its ores, vanadium ores, manganese, coal, nitrate of soda, borate of lime, iodine, sulphur, wheat and guano.
The other metals reported in the official returns are lead, cobalt and vanadium, of which only small quantities are produced.
Important mines of gold and silver, considerable deposits of wolframite, valuable ores of molybdenum and vanadium, and quarries of onyx marble, are also worked.
Dyson has measured some eight hundred lines in the lower chromosphere and identified them with emission spectra of the following elements: hydrogen, helium, carbon with the cyanogen band, sodium, magnesium, aluminium, silicon, calcium, scandium, titanium, vanadium, chromium, manganese, iron, zinc, strontium, yttrium, zirconium, barium, lanthanum, cerium, neodymium, ytterbium, lead, europium, besides a few doubtful identifications; it is a curious fact that the agreement is with the spark spectra of these elements, where the photosphere shows exclusively or more definitely the arc lines, which are generally attributed to a lower temperature.
For vanadium steels, see Iron And Steel Manufacture.
Anodic polarization in potassium chloride solution renders molybdenum, niobium, ruthenium, tungsten, and vanadium passive (W.
Soc., 1868-1870), who showed that the supposed vanadium obtained by previous investigators was chiefly the nitride or an oxide of the element.
In small quantities, vanadium is found widely distributed, the chief sources being vanadite, mottramite, descloizite, roscoelite, dechenite and pucherite, whilst it is also found as a constituent of various clays, iron-ores and pitchblendes.
Vanadium salts may be obtained from mottramite by digesting the mineral with concentrated hydrochloric acid, the liquid being run off and the residue well washed; the acid liquid and the washings are then evaporated with ammonium chloride, when ammonium metavanadate separates.
This is recrystallized and roasted to vanadium pentoxide, which is then suspended in water into which ammonia is passed, when ammonium metavanadate is again formed and may be purified by recrystallization.
The pure metal may be obtained by reducing vanadium dichloride in hydrogen, the operation being exceedingly difficult (for details, see Roscoe's original papers).
In a somewhat impure condition it may be obtained by the reduction of vanadium pentoxide with a mixture of the rare earth metals which are obtained by reduction of the waste oxides formed in the manufacture of thoria (Weiss and Aichel, Ann., 1904, 337, p..
Gin, L'Electricien, 1903, 2 5, p. 5); and by the electrolysis of vanadium trioxide when heated in an evacuated glass tube (W.
Moissan (Comptes rendus, 1896, 122, p. 1297) obtained a vanadium containing from Io to 16% of carbon by fusing vanadic anhydride with carbon in the electric furnace.
For other methods of obtaining vanadium and its compounds, see Cowper Cowles, Engin.
Vanadium is a light-coloured metal of specific gravity 5.5.
Vanadium may be detected by converting it into the pentoxide, which on passing sulphuretted hydrogen through its acid solution becomes reduced to the dioxide, the solution at the same time becoming lavender blue in colour; or if zinc be used as a reducing agent, the solution becomes at first green and ultimately blue.
Many salts of oxy-acids of vanadium are known, but of the more common oxy-acids, metavanadic acid, HV03, and pyrovanadic acid, H 4 V 2 0 7, alone appear to have been isolated.
Of the salts of these acids, those of the orthoand pyro-acids are the least stable, the orthovanadates being obtained on fusion of vanadium pentoxide with an alkaline carbonate.
Ammonium metavanadate is obtained when the hydrated vanadium pentoxide is dissolved in excess of ammonia and the solution concentrated.
Vanadium dichloride, VC12, is a green crystalline solid obtained when the tetrachloride is reduced with hydrogen at a dull red heat.
The trichloride, VC1 31 is a deliquescent solid formed when the tetrachloride is heated in a retort as long as chlorine is given off (Roscoe), or by heating vanadium trisulphide in a current of chlorine and fractionally distilling the resulting product at 150° C. in a current of carbon dioxide (Halberstadt, Ber., 1882, 15, p. 1619).
The tetrachloride, VC14, is formed by the direct union of vanadium and chlorine or by the action of sulphur chloride on vanadium pentoxide (Matignon, Comptes rendus, 1904, 138, p. 631).
Moissan (Coniptes rendus, 1896, 122, p. 1297) by heating vanadium pentoxide and carbon for a few minutes in the electric furnace.
Chromic acid converts it into quinone, while chlorates, in the presence of certain metallic salts (especially of vanadium), give aniline black.