Vanadium ferro

Vanadin-blelerz, n., -bleispat, m. vanadinite. -chlond, n. = Vanadiumchlorid. -eisen, n. ferro vanadium. 

Preparation. Commercially it is prepared mainly as ferro-vanadium alloy. It can be obtained by aluminothermic reduction of the oxide. Pure V may be obtained through the de Boer-Van Arkel process by iodide thermal decomposition (vanadium iodide is decomposed on an electrical heated W wire). 

Ferro-alloys Master alloys containing a significant amount of bon and a few elements more or less soluble in molten bon which improve properties of bon and steels. As additives they give bon and steel better characteristics (increased tensile sbength, wear resistance, corrosion resistance, etc.). For master alloy production carbothermic processes are used for large-scale ferro-sihcon, ferro-chromium, ferro-tungsten, ferro-manganese, ferro-nickel and metallothermic processes (mainly alumino and sihco-thermic) for ferro-titanium, ferro-vanadium, ferro-molybdenum, ferro-boron. 

Iron. Industrial hygiene chemists have analyzed iron as the o-phenanthrollne or thiocyanate complexes (6,13). In the AAS analysis at 248.3 nm with air-acetylene atomization, nickel and silica are interferences. If iron in ferro-vanadium must be analyzed, a more oxidative solution than the ntiric acid wet ashing of P CAM 173 is required. Nitric acid-hydrofluoric acid will solubilize refractories containing iron. 

By reduction of the trioxide with carbon.2 (5) By the thermite reduction process.3 A product which was 99 per cent pure has been obtained by this method or by reduction with vanadium carbide. (6) By electrolysis of a solution of the trioxide in fused calcium vanadate.4 The anode is made of carbon and the cathode is prepared by pulverizing ferro-vanadium and pressing the powder into a cone-shaped form. The current density used is 4.5 amperes per square inch of anode surface. 

Vanadium is not used commercially in the pure state. More than 90 per cent of it is marketed as ferro-vanadium and used in the manufacture of steels ferro-vanadium contains from 30 to 40 per cent of vanadium. The metal enhances the toughness, tensile... 

Within the United States milling capacity is estimated at 19 million pounds of vanadium. A new producer has announced plans to enter the business in 1976, bringing domestic production capacity to 21.1 million pounds. These figures are well in excess of the 1973 estimated demand of 12.5 million pounds for the United States and Canada, and the production is adequate to satisfy the projected demand of 16.1 million pounds in 1980. In addition to basic vanadium oxide producers, a major domestic converter of ferro-vanadium is now producing millions of pounds of vanadium per year for sale in the United States from imported, duty free, steel slags. 

The above considerations will be illustrated by the simultaneous determination of manganese and chromium in steel and other ferro-alloys. The absorption spectra of 0.001 M permanganate and dichromate ions in 1M sulphuric acid, determined with a spectrophotometer and against 1M sulphuric acid in the reference cell, are shown in Fig. 17.20. For permanganate, the absorption maximum is at 545 nm, and a small correction must be applied for dichromate absorption. Similarly the peak dichromate absorption is at 440 nm, at which permanganate only absorbs weakly. Absorbances for these two ions, individually and in mixtures, obey Beer s Law provided the concentration of sulphuric acid is at least 0.5M. Iron(III), nickel, cobalt, and vanadium absorb at 425 nm and 545 nm, and should be absent or corrections must be made. 

Stable oxides, such as those of chromium, vanadium and titanium cannot be reduced to the metal by carbon and the production of these metals, which have melting points above 2000 K, would lead to a refractory solid containing carbon. The co-reduction of the oxides with iron oxide leads to the formation of lower melting products, the ferro-alloys, and this process is successfully used in industrial production. Since these metals form such stable oxides and carbides, the process based on carbon reduction in a blast furnace would appear to be unsatisfactory, unless a product saturated with carbon is acceptable. This could not be decarburized by oxygen blowing without significant re-oxidation of the refractory metal. 

On a commercial scale uranous oxide is prepared by fusing at red heat a mixture of 35 parts of common salt and 20 parts of sodium uranate with 1 part of powdered charcoal, the heating being continued until the escape of gas ceases. After cooling, the mass is lixiviated with water, and the residue of uranous oxide is washed by decantation. By washing with 5 per cent, hydrochloric acid, any iron, aluminium, or vanadium compounds may be removed, and a commercial product of purity equivalent to 97 per cent. U3O3 is obtained. If the uranous oxide is required for the production of ferro-uranium, the complete removal of iron is not necessary. 

A silver (or copper) catalyst suitable for the oxidation of methanol may also be prepared by heating silver or copper cyanide or a mixture of these in the presence of air to the point where puffing occurs. By incorporating a fervo- or ferri-cyanide, e.g., bismuth ferro-cyanide, bismuth ferri-cyanide, calcium cerium ferro-cyanide, cerium cobalt ferro-cyanide, vanadium or molybdenum ferro-cyanide with the starting material, an activated product may be obtained. The silver or copper cyanides are prepared by precipitating a soluble cyanide with silver nitrate or cupric chloride respectively.30... 

As in the case of vanadium, it is convenient to use the ferro alloy as the raw material for a chlorination process, since it is readily available for use in the steel industry. A typical analysis of ferroniobium is 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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