Vanadium sponge

The vanadium alloy is purified and consoHdated by one of two procedures, as shown in the flow diagram of the entire aluminothermic reduction process presented in Figure 1. In one procedure, the brittle alloy is cmshed and heated in a vacuum at 1790°C to sublime most of the aluminum, oxygen, and other impurities. The aluminum faciHtates removal of the oxygen, which is the feature that makes this process superior to the calcium process. Further purification and consoHdation of the metal is accompHshed by electron-beam melting of pressed compacts of the vanadium sponge. 

Fig. 6.18. Melting and sublimation of slag from vanadium sponge production (Foley, E., Ward, M. and Hock, A. L. Ref. 34).

An interesting oxidative decarboxylation process was reported for a /(-hydroxy acid. Reaction of 2-ethyl-2-(l -hydroxycyclobutyl)butanoic acid with vanadium(III) chloride in the presence of 1 equivalent of l,8-bis(dimethylamino)naphthalcne (Proton Sponge) gave 3-cyclobutylidene-pentane (20).181... 

Salts, sawdust, scrap metals, shales, silicates, soda ash, sodium chloride, sodium compounds, sodium cyanide, sponge iron, steel turnings, stone wool, sugar, sulfur Teas, tin, titanium sponge, turnings Urea, urea formaldehyde Vanadium, vermiculite, vitamins Waxes, welding powder, wood dust, wood shavings Yeast (dry)... 

On the other hand, absorption onto a solid surface may be employed and solids employed for this purpose include activated carbon, charcoal, and iron sponge. Finally, acid gases may be chemically converted by reactants such as ferric oxide, zinc oxide, calcium oxide, and vanadium pentoxide. Some of these processes remove both carbon dioxide and hydrogen sulfide, whereas others selectively remove hydrogen sulfide (Speight, 2007). 

A titanium sponge production process was originally developed by KrolP - 27.28, 29 using titanium tetrachloride and magnesium. The technique has since been applied to zirconium, 30,31,32 33 vanadium, and... 

The overall recovery efficiency, from vanadium trichloride to metal sponge, is 96 to 98 per cent. Typical vanadium and impurity contents are as follows ... 

The route shown in Fig. 9.12 is one which has been operated commercially in the U.K. on a fairly small scale, quite successfully. As in the case of niobium, it is convenient to use the crude ferro alloy as feed to the chlorination stage. The chloride purification stages lead to pure vanadium trichloride, which is reduced with magnesium in a manner similar to that employed for titanium, zirconium or hafnium. Some of the complexities, applicable in the latter processes owing to the volatile nature of the chlorides, are absent with vanadium. The vanadium metal sponge has some properties in common with the other metal sponges. 

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