The physical behavior of a gas jet injected horizontally into liquid metal
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i n j e c t i o n of gas j e t s into m e l t s for the p u r p o s e of m e t a l e x t r a c t i o n o r r e f i n i n g has b e e n p r a c t i c e d i n the m e t a l l u r g i c a l i n d u s t r y for o v e r a c e n t u r y . S u b m e r g e d gas i n j e c t i o n was f i r s t u t i l i z e d c o m m e r c i a l l y in the p r o d u c t i o n of s t e e l as e a r l y as 1860 when the b o t t o m - b l o w n B e s s e m e r p r o c e s s b e c a m e o p e r a t i o n a l in Sheffield. L a t e r at the t u r n of the c e n t u r y s u b m e r g e d gas j e t s found a new a p p l i c a t i o n in the p r o d u c t i o n of b l i s t e r copper f r o m m a t t e i n the P e i r c e S m i t h c o n v e r t e r . O t h e r p r o c e s s e s r e l y i n g on gas i n j e c t i o n have followed, e s p e c i a l l y i n the l a s t decade, and include the g a s e o u s deoxidation of copper, 1-4 the N o r a n d a continuous copper s m e l t i n g p r o c e s s , S the new b o t t o m - b l o w n oxygen s t e e l m a k i n g p r o c e s s e s (OBM and LWS), 6-8 new p r o c e s s e s for s t a i n l e s s s t e e l p r o d u c t i o n (AOD and CLU), 9-11 ladle d e g a s s i n g of s t e e l 12 a n d ladle d e s u l p h u r i s a t i o n of pig i r o n . ~3 The p o p u l a r i t y of s u b m e r g e d gas j e t s as a m e a n s of c o n t a c t i n g a r e a c t i v e gas with a m e l t is easy to u n d e r s t a n d . The j e t s a r e t u r b u l e n t and p r o v i d e effic i e n t m i x i n g of both the gas and liquid p h a s e s so that m a s s t r a n s f e r rates are rapid. Moreover, because the gas e n t e r s the liquid at a high flow r a t e and b r e a k s up into a s w a r m of b u b b l e s , the a r e a of contact b e t w e e n the gas and liquid is l a r g e . Both effects c o m b i n e to p r o d u c e a highly efficient r e a c t i o n s y s t e m . Although s u b m e r g e d gas j e t s a r e p l a y i n g a n i n creasingly important role in metallurgical p r o c e s s ing v e r y little is known about t h e i r b e h a v i o r i n d i f f e r ent m e l t s . Q u e s t i o n s of how a s u b m e r g e d j e t b r e a k s up, the bubble s i z e and d i s t r i b u t i o n i n a jet, the r a t e s G. N. ORYALL and J. K. BRIMACOMBEare former Graduate Student and Associate Professor, respectively, Department of Metallurgy, University of British Columbia, Vancouver, Canada V6T lW5. Manuscript submitted October 6, 1975. METALLURGICALTRANSACTIONSB
of heat and m a s s t r a n s f e r b e t w e e n a jet and a m e l t , and the i n f l u e n c e of p r o c e s s v a r i a b l e s on j e t b e h a v i o r r e m a i n u n a n s w e r e d . T h i s p a u c i t y of i n f o r m a t i o n m a k e s it i m p o s s i b l e to r e l i a b l y p r e d i c t r e a c t i o n r a t e s b e t w e e n a s u b m e r g e d jet and a m e l t or the shape and p o s i t i o n of a jet i n a bath. H e n c e gas u t i l i z a t i o n eff i c i e n c i e s cannot be p r e d i c t e d for a p r o c e s s u n d e r d i f
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