On the aluminothermic reduction of calcium vanadate
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the same as described in our e a r l i e r publication,a Several preliminary tests were conducted to a s c e r tain the g e n e r a l conduct of the aluminothermic process for vanadium preparation. It was not possible to accomplish the reaction by initiating the calcium. vanadate and aluminum c h a r g e at room temperature. The charge when preheated t o 673 to 773 K and subsequently reacted briskly t o completion and produced metal well separated from the s l a g . For s i m i l a r r e sults with the c h a r g e at room temperature a need a r o s e for incorporating either KCIO3 or V205 t o s e r v e as a t h e r m a l booster. This procedure, as a matter of convenience, was preferred over the other mode involving preheating p r i o r t o ignition. Finally the r e duction process was studied in the presence of a thermal booster for which V205 s e e m e d preferable t o the other reagent, KC1Oa, which is somewhat costlier. Apart from cost considerations, VaO5 use also meant an additional vanadium source in the Thermit charge. This contribution was taken into account in the reported results on vanadium yields. The amount of aluminum to be used in the reduction was calculated on the b a s i s of the requirement for calcium vanadate as well as for V~Os. Results of reductions performed on 0.I kg s c a l e of 2 CaO.VzO5 and of 4;~ CaO.VaO5 when varying the quantity of V205 and u s i n g essentially the stoichiom e t r i c amount of aluminum are shown in Fig. i. In the case of 2 CaO-VaO5 (Fig. I, Curve A) a vanadium yield of over 90 pct was achieved by 20 wt pct of V205. In the case of 4 CaO.VaO5 (Fig. I, Curve B) on the other hand, a vanadium yield of about 78 pct was obtained by 35 wt pct of V205. In both c a s e s little additional benefit was derived from further increasing the amount of VaO5. F i g u r e 2 presents the results on
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OMPRAKASH K. MEHRA and CHIRANJIB K. GUPTA are with the Extractive Metallurgy Section, Metallurgy Division, BhabhaAtomic Research Centre, Trombay, Bombay 400085, India. Manuscript submitted March 14, 1977. METALLURGICAL TRANSACTIONS B
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PENTOXIDE IN CHARGE, % OF CALCIUM VANADATE.
Fig. 1--Effect of vanadium pentoxide quantity on vanadium yield in aluminothermic reduction of (a) 2CaO .V20s, and (b) 4CaO • V205. VOLUME 8B, DECEMBER 1977-683
Table I. Results o f Aluminothermic Reduction o f Calcium Vanadate Intermediates for the Production o f Ferrovanadium
Charge Composition Wt,Kg
2CaO" 4CaO. V2Os V2Os 0.1 0.1 -
Fig. 2--Effect of aluminum quantity and aluminum content of vanadium button produced in aluminothermic reduction of (a) 2CaO .V205 and (b) 4CaO .V205.
the influence of percentage of stoichiometric aluminum on vanadium yie:d from the two vanadium compounds in presence of the requisite amounts of Vz05 established as above. Results indicated a common trend in that as the aluminum content increased the yield inc r e a s e d reaching an upper l i m i t with
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