Permeability, diffusivity, and solubility of oxygen gas in liquid slag
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An e x p e r i m e n t a l p r o c e d u r e f o r m e a s u r e m e n t of the p e r m e a b i l i t y of d i s s o l v e d oxygen g a s in liquid s l a g h a s b e e n d e v e l o p e d using an oxygen c o n c e n t r a t i o n c e l l . The s m a l l a m o u n t of o x y gen gas which p e n e t r a t e d through the liquid oxide f r o m a p u r e oxygen c o m p a r t m e n t to a p u r e a r g o n c o m p a r t m e n t was d e t e r m i n e d b y the g a l v a n i c c e l l . The p e r m e a b i l i t i e s of oxygen t h r o u g h liquid PbO-StO8 and F e O - I ~ b O - S i O 8 w e r e found to be in the r a n g e 3 • 10 -8 to 3 • 10 -7 m o l e s / c m 9s. The p e r m e a b i l i t i e s w e r e l i t t l e influenced b y t e m p e r a t u r e but m o r e influenced b y the c o m p o s i t i o n . In s e p a r a t e e x p e r i m e n t s , the oxygen p r e s s u r e change at the b o t t o m of a c o l u m n of s l a g was d e t e c t e d b y a n o t h e r g a l v a n i c c e l l . By t h i s method, it is not n e c e s s a r y to quench the s p e c i m e n to d e t e r m i n e the c o n c e n t r a t i o n p r o f i l e of d i s s o l v e d oxygen and to d e t e r m i n e i t s diffusivtty. Liquid o x i d e s in the l ~ O - S i O s , CaO-SiO2-AI~O ~ and FeO-l~oO-SiO2 s y s t e m s w e r e studied. The oxygen d i f f u s i o n c o e f f i c i e n t s (5 • 10 -s to 3 • 10 -~ c m S / s ) w e r e found to i n c r e a s e with t e m p e r a t u r e f o r a f i x e d c o m p o s i t i o n of s l a g , and with an i n c r e a s e of n e t w o r k - m o d i f i e r oxide content at c o n s t a n t t e m p e r a t u r e . The s o l u b i l i t y of oxygen gas in PbO-SiO8 m e l t s was e s t i m a t e d to be 2 • 10 -4 to 2 • 10 -s m o l e s / c m s f r o m the d e t e r m i n e d d i f f u s t v i t i e s and p e r m e a b i l i t i e s . The s o l u b i l i t i e s d e c r e a s e d with i n c r e a s i n g t e m p e r a t u r e in the c o m p o s i t i o n r a n g e studied. P h y s i c a l s o l u b i l i t i e s of g a s e s and m e t a l s in s l a g s d e t e r m i n e d by o t h e r i n v e s t i g a t o r s a r e c o m p a r e d with the p r e s e n t r e s u l t s .
IN 1959,
G r e e n e and his c o - w o r k e r s p u b l i s h e d two p a p e r s , ~'8 in which t h e y m e a s u r e d the r a t e of a b s o r p tion of p u r e oxygen gas b u b b l e d into liquid a l k a l i a l u m i n a s i l i c a t e g l a s s . T h e s e s t u d i e s a r e a m o n g the v e r y few d i r e c t m e a s u r e m e n t s of oxygen gas a b s o r p t i o n into liquid oxide m i x t u r e s containing no t r a n s i t i o n m e t a l s . H o w e v e r , only the p r o d u c t of the oxygen d i f f u s i v i t y and s o l u b i l i t y was a p p r o x i m a t e l y obtained. In the p r e s e n t work, the p e r m e a b i l i t y and d i f f u s i v i t y of oxygen g a s through oxide m e l t s have b e e n i n d e p e n d e n t l y m e a s u r e d , and f r o m t h e s e two q u a n t i t i e s the s o l u b i l i t y is e s t i
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