Mass transfer between a horizontal, submerged gas jet and a liquid
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MANYi m p o r t a n t
m e t a l l u r g i c a l p r o c e s s e s including c o p p e r and n i c k e l m a t t e c o n v e r t i n g , the g a s e o u s d e o x i d a t i o n of c o p p e r , x and the n e w e r continuous c o p p e r s m e l t i n g 2- and b o t t o m blown oxygen s t e e l m a k i n g 3 p r o c e s s e s r e l y on the high i n t r i n s i c m a s s t r a n s f e r r a t e b e t w e e n a s u b m e r g e d g a s j e t and a m e l t . In the t y p i c a l c o p p e r d e o x i d a t i o n p r o c e s s c a r r i e d out in a r o t a r y anode f u r n a c e , g a s e o u s h y d r o c a r b o n s such a s p r o p a n e o r n a t u r a l g a s a r e i n j e c t e d through n e a r - h o r i z o n t a l t u y e r e s into the m o l t e n c o p p e r c o n t a i n i n g up to about 1 p c t oxygen. The h y d r o c a r b o n s r e a c t with d i s s o l v e d oxygen to f o r m w a t e r v a p o r , c a r b o n d i o x i d e and o t h e r p r o d u c t s . Any u n r e a c t e d h y d r o c a r b o n s r e p r e s e n t a l o s s in p r o c e s s e f f i c i e n c y and m a y give r i s e to the e m i s s i o n of c a r b o n soot. D e s p i t e m a n y a t t e m p t s at i n c r e a s i n g the e f f i c i e n c y , f o r e x a m p l e b y r e f o r m i n g the h y d r o c a r b o n s to c a r b o n monoxide and h y d r o g e n p r i o r to i n j e c t i o n , 4 o r in s i t u , s the h y d r o c a r b o n u t i l i z a t i o n e f f i c i e n c y r a r e l y e x c e e d s about 50 pct. W h e t h e r t h i s is due to a slow c h e m i c a l r e a c t i o n o r to a slow m a s s t r a n s f e r s t e p is u n c e r t a i n . The r a t e of d e o x i d a t i o n of c o p p e r b y c a r b o n m o n o x ide h a s b e e n i n v e s t i g a t e d b y T h e m e l i s and Schmidt, 6 and Nanda and G e i g e r . 7 In both s t u d i e s c a r b o n m o n o x ide was I n j e c t e d v e r t i c a l l y u p w a r d s through the c o p p e r . Nanda and G e i g e r w o r k e d at v e r y low j e t R e y n o l d s n u m b e r s in the r a n g e 1 < NRe < 90, and oxygen c o n c e n t r a t i o n s in the c o p p e r of 0.005 to 0.05 pct. Under t h e s e c o n d i t i o n s t h e y c o n c l u d e d that liquid p h a s e m a s s t r a n s f e r w a s c o n t r o l l i n g . T h e m e l i s and Schmidt a l s o o b s e r v e d liquid p h a s e c o n t r o l at t h e s e oxygen l e v e l s . H o w e v e r at oxygen c o n c e n t r a t i o n s of 0.1 to 1 p c t they c o n c l u d e d that the r a t e of d e o x t d a t i o n was c o n t r o l l e d b y m a s s t r a n s f e r in the g a s p h a s e . The p r o d u c t of the J. K. BRIMACOMBE is Assistant Professor, Department o f Metallurgy, University of British Columbia, Vancouver, British Columbia, Canada. E. S. STRATIGAKOS and P. TARASSOFF are Research Engineer, Department of Chemical Engineering, and Head, Process Engineering Division, respectively, Noranda Research Centre, Point Claire, Quebec, Canada. Manuscript submitted June 19, 1973. METALLURGICAL TRANSACTIONS
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