On the aluminothermic reduction of calcium vanadate
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the s a m e as d e s c r i b e d in o u r e a r l i e r p u b l i c a t i o n . 8 S e v e r a l p r e l i m i n a r y t e s t s w e r e c o n d u c t e d to a s c e r tain the g e n e r a l c o n d u c t of the a l u m i n o t h e r m i c p r o c e s s f o r v a n a d i u m p r e p a r a t i o n . It was not p o s s i b l e to a c c o m p l i s h the r e a c t i o n by i n i t i a t i n g the c a l c i u m v a n a d a t e and a l u m i n u m c h a r g e at r o o m t e m p e r a t u r e . The c h a r g e when p r e h e a t e d to 673 to 773 K and s u b s e q u en t l y r e a c t e d b r i s k l y to c o m p l e t i o n and p r o d u c e d m e t a l well s e p a r a t e d f r o m the s l a g . F o r s i m i l a r r e s u i t s with the c h a r g e at r o o m t e m p e r a t u r e a n e e d a r o s e f o r i n c o r p o r a t i n g e i t h e r KC103 o r VzO5 to s e r v e as a t h e r m a l b o o s t e r . T h i s p r o c e d u r e , as a m a t t e r of c o n v e n i e n c e , was p r e f e r r e d o v e r the o t h e r m o d e i n v o l v i n g p r e h e a t i n g p r i o r to i g n i t i o n . F i n a l l y the r e d u ct i o n p r o c e s s was s t u d i e d in the p r e s e n c e of a t h e r m a l b o o s t e r f o r which V205 s e e m e d p r e f e r a b l e to the o t h e r r e a g e n t , KC1Oa, w h i ch i s s o m e w h a t c o s t l i e r . A p a r t f r o m c o s t c o n s i d e r a t i o n s , V2Os u s e a l s o m e a n t an a d d i t i o n a l v a n a d i u m s o u r c e in the T h e r m i t c h a r g e . T h i s c o n t r i b u t i o n was t ak en into a c c o u n t in the r e p o r t e d r e s u l t s on v a n a d i u m y i e l d s . Th e a m o u n t of a l u m i n u m to be u s e d in the r e d u c t i o n w as c a l c u l a t e d on the b a s i s of the r e q u i r e m e n t f o r c a l c i u m v a n a d a t e as well as f o r V205. R e s u l t s of r e d u c t i o n s p e r f o r m e d on 0.1 kg s c a l e of 2 CaO-VaO5 and of 4;~ CaO-V205 when v a r y i n g t he quantity of V205 and u s i n g e s s e n t i a l l y the s t o i c h i o m e t r i c a m o u n t of a l u m i n u m a r e shown in F i g . 1. In the c a s e of 2 CaO-V20~ ( F i g . 1, C u r v e A) a v a n a d i u m y i e l d of o v e r 90 p c t w as a c h i e v e d by 20 wt p c t of V205. In the c a s e of 4 CaO.VzOs ( F i g . 1, C u r v e B) on the o t h e r hand, a v a n a d i u m y i e l d of about 78 p ct was o b t a i n e d by 35 wt p ct of V205. In both c a s e s l i t t l e a d d i t i o n a l b e n e f i t was d e r i v e d f r o m f u r t h e r i n c r e a s i n g the a m o u n t of V205. F i g u r e 2 p r e s e n t s the r e s u l t s on
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OMPRAKASH K. MEHRA and CHIRANJIB K. GUPTA are with the Extractive Metallurgy Section, Metallurgy Division, Bhabha Atomic Research Centre, Trombay, Bombay 400085, India. Manuscript submitted March 14, 1977. METALLURGICAL TRANSACTIONS B
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