Vanadium pentoxide charge

Vanadium pentoxide, vanadium(V) oxide, V2O5, is the most important compound in this oxidation state. It is a coloured solid (colour due to charge transfer, p. 60), the colour varying somewhat (red -> brown) with the state of subdivision it is formed when vanadium (or some of its compounds) is completely oxidised, and also by heating ammonium vanadate)V) ... 

In practice, the production of vanadium by aluminothermic reduction is also governed by some other considerations. The reduction has to be carried out under an inert atmosphere (helium or argon) to avoid nitrogen pick-up from the air by vanadium metal. The composition of the oxide-aluminum charge has to be so chosen that the thermit (metal obtained by aluminothermic reduction) contains between 11 and 19% aluminum. This is necessary for the subsequent refining step in the vanadium metal production flowsheet. Pure vanadium pentoxide and pure aluminum are used as the starting materials, and the reduction is conducted in a closed steel bomb as shown in Figure 4.17 (C). 

The preparation of ferrovanadium by this route is carried out batchwise in refractory-lined open reactors, with vanadium pentoxide, aluminum powder, iron scrap and lime or fluorspar constituting the charge. The reactions once initiated, proceed briskly to completion. The reaction heat is sufficient to melt the ferrovanadium and the alumina-lime/fluor-spar slag, which readily separate due to density difference. The aluminothermic ferroalloy product contains practically no carbon. 

Spectroelectrochemical analysis of charge-insertion nanostructured materials already offers important insight into these systems. These methods were recently exploited to characterize the electrochemical processes of nanostructured manganese oxide ambi-gel and xerogel films. " 6-229 Spectroelectrochemical measurements were used to corroborate electronic state changes with the observed electrochemical response for the insertion of small cations (Li+, Mg2+) and the unexpected insertion of a bulky organic cation (tetrabutylammonium). Vanadium pentoxide exhibits two distinct electrochromic features that can be assigned to the transition at either sto-... 

Vanadium pentoxide sols can be employed to bring about coagulation of positively charged colloids for example, ferric hydroxide and aluminium hydroxide. The amount necessary for the coagulation of a given quantity of the positive colloid is very small in comparison with the required quantities of arsenic trisulphide, antimony trisulphide, and other negative colloids. It appears, therefore, that the colloidal... 

A ubiquitous characteristic of vanadium chemistry is the fact that vanadium and many of its complexes readily enter into redox reactions. Adjustment of pH, concentration, and even temperature have often been employed in order to extend or maintain system integrity of a specific oxidation state. On the other hand, deliberate attempts to use redox properties, particularly in catalytic reactions, have been highly successful. Vanadium redox has also been successfully utilized in development of a redox battery. This battery employs the V(V)/V(IV) and V(III)AT(II) redox couples in 2.5 M sulfuric acid as the positive and negative half-cell electrolytes, respectively. Scheme 12.2 gives a representation of the battery. The vanadium components in both redox cells are prepared from vanadium pentoxide. There are two charge-discharge reactions occurring in the vanadium redox cells, as indicated in Equation 12.1 and Equation 12.2. The thermodynamics of the redox reactions involved have been extensively studied [8],... 

Fig. 26. Perspective view of the (010)-surface of the vanadium pentoxide with different mutual arrangements of neighboring pyramidal [VOs] units (Panel a). Panels b and c correspond to neutral, stoichiometric surface cluster including two layers of the (010) surface pyramids (126 atoms) in Panel b, which illustrates the SINDO AIM net-charge distribution, the bipyramidal subsystems I and II are shown (see Table 1) Panel c represents the AIM FF distribution diagram...

Colloidal vanadium pentoxide is negatively charged and according to Biltz can be made by treating ammonium vanadate Avith HCl. The precipitate is washed until it goes into solution and then it is dialyzed. The hydrosol is colored yellow. Concentrated solutions coagulate easily. 

Sulfuric acid is produced by burning sulfur and H S to SO with air. Then more air is added and reacted in a catalyst bed of vanadium pentoxide to produce SO. The SO, is mixed with water to make sulfuric acid. The reaction is exothermic and takes place in the vapor phase. Sulfuric acid is, by weight, one of the main chemicals produced in the world. I spent 1974 to 1976 in charge of a sulfuric acid regeneration plant in Texas City. In 1975, I had 34 shutdowns and start-ups. I ve kept a piece of lead wire, part of that awful plant, in my desk drawer. When things seem bad, that memento reminds me that it could be a lot worse. 

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