Preparation and properties of high-purity vanadium and V-15Cr-5Ti
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V A N A D I U M has b e e n p r o d u c e d by the a l u m i n o t h e r m i c r e d u c t i o n of v a n a d i u m pentoxide with a product f r o m 80 to 95.4 pct p u r i t y , and by c a l c i u m r e d u c t i o n y i e l d ing a m a t e r i a l up to 99.8 pct purity with a h a r d n e s s of about 130 Dph. V a n a d i u m of 99.5 pct p u r i t y was also p r o d u c e d by the m a g n e s i u m r e d u c t i o n of v a n a d i u m t r i c h l o r i d e . 1'2 M a t e r i a l of h i g h e r p u r i t y has b e e n p r e p a r e d by s e v e r a l i n v e s t i g a t o r s u s i n g the iodide r e f i n ing p r o c e s s on a l a b o r a t o r y s c a l e , s-5 R e c e n t l y it has b e e n found that v a n a d i u m a l l o y s a r e p r o m i s i n g c a n d i d a t e s for use in liquid m e t a l cooled fast b r e e d e r r e a c t o r s , e- lz T h i s development has s p u r r e d an i n t e n s i v e s e a r c h for new p r o c e s s e s to p r e p a r e v a n a d i u m . The p r o c e s s should be r e a d i l y s c a l e d up and the p r o d u c t should be of high p u r i t y . Sullivan has developed the e l e c t r o l y t i c r e f i n i n g p r o c e s s to produce v a n a d i u m up to 99.99 pct p u r i t y . 13'~4 C a r l s o n et al., have d e m o n s t r a t e d a p r o c e s s for p r o d u c i n g 99.9 pct p u r i t y v a n a d i u m which e x h i b i t s exc e l l e n t ductility. The p r o c e s s i n c l u d e s a l u m i n o t h e r m i c r e d u c t i o n of v a n a d i u m pentoxide followed by a dea l u m i n i z i n g s i n t e r i n g t r e a t m e n t at 1700 ~ to 1800~ in v a c u u m , with s u b s e q u e n t p u r i f i c a t i o n by e l e c t r o n b e a m m e l t i n g . ~s,,e The p r e s e n t p r o c e s s i s a f u r t h e r d e v e l o p m e n t of the C a r l s o n p r o c e s s . The m e t a l is produced by a l u m i n o t h e r m i c r e d u c t i o n of v a n a d i u m pentoxide followed by e l e c t r o n b e a m m e l t i n g without an i n t e r m e d i a t e v a c u u m s i n t e r i n g step. Due to its e c o n o m y of i n i t i a l cost a s well as production c o s t , the p r o c e s s is m o r e a t t r a c t i v e to the m e t a l s i n d u s t r y .
a l u m i n u m powder, was ignited by e l e c t r i c a l r e s i s t a n c e heating. The r e d u c t i o n p r o c e e d e d to c o m p l e t i o n exot h e r m i c a l l y a c c o r d i n g to the following r e a c t i o n at 2000oc.17 1 0 A l + 3V2Os = 6 V + 5A1203 AH = - 3 1 8 , 0 0 0 cal per mole of V205 The r e d u c t i o n v e s s e l was cooled by a s t r e a m of water while the r e a c t i o n was in p r o c e s s . In some r u n s the AI-V2Os r a t i o was n e a r s t o i c h i o m e t r i c at 49.4 p a r t s of A1 to 100 p a r t s of V2Os. In other r u n s l a r g e a m o u n t s of e x c e s s a l u m i n u m were used in o r d e r to produce low-oxygen t h e r m i t e s and v a n a d i u m ingots as will be d i s c u s s e d l a t e r in the following s e c t i o n s .
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