Section III., 1915 [81] Trans. R.S.C. 



The Preparation of Metallic Vanadium. 

 By R. Edson and D. McIntosh, F. R.S.C. 



(Read May Meeting, 1915). 



The element vanadium, although known in the combined state 

 since 1801, is extremely difficult to isolate. Roscoe obtained the pure 

 metal in 1867, and proved that the material thought by Berzelius 

 to be metal, was actually the nitride. In the last few years, due 

 to its importance as a constituent of various alloys, large amounts of 

 impure vanadium have been made. In the electric furnace, reduction 

 of the pentoxide gives an alloy high in carbon; made by the Gold- 

 chmidt process, the regulus contains appreciable quantities of alu- 

 minium and the dioxide; better results are obtained by substituting 

 "mischmetall" — a mixture of the rare earth metals — for aluminium; 

 but even here the metal is impure. Electro-chemical methods, 

 although attempted, yield but indifferent results. 



Roscoe reduced the dichloride of vanadium to the metal by heating 

 in a stream of hydrogen. This process, while it appears simple, 

 presents many difficulties. Vanadium at a red heat combines with 

 oxygen or nitrogen with the greatest ease; hence the utmost precau- 

 tion must be taken to exclude all air and moisture, while the dichloride 

 is unstable and difficult to obtain in any quantity. Moreover, the 

 process is a long one, requiring 80 hours to produce a gram of metal. 

 Vanadium prepared in this way is a crystalline powder with a silver- 

 white lustre. 



De Lodyguine, in U.S. patents 575,002 and 575,668, has shown 

 that tungsten, chromium, etc., may be deposited from a volatile 

 salt on a "fillet" of platinum or carbon heated by the electric current. 

 Dr. F. M. G. Johnson and one of us have investigated this method, 

 and have found it most satisfactory for the preparation of the metals 

 mentioned by de Lodyguine, and for boron. Metallic boron — so 

 carefully investigated by Dr. Weintraub — can easily be deposited on a 

 platinum or tungsten wire, and its distinctive property, the change in 

 electrical resistance with temperature, easily demonstrated. We 

 have applied this method to the preparation of vanadium. 



The first problem was the preparation of a salt of vanadium 

 which would be fairly volatile and could be easily made in quantity. 

 The compound finally found most satisfactory was vanadyl trichloride, 

 VOCI3. This salt is readily prepared by heating a mixture of the 



