Activity of ferrous oxide in ferromonticellite
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A c r o s s the i n t e r f a c e ( r = a) this r e d u c e s to a t e n s i l e s t r e s s " a i " given by:
-6gpe8 ai = 3Kp(1 + Vm) + 2Era The e x p r e s s i o n for a i i s i d e n t i c a l to the ones quoted by O r i a n i 7 and Speight and Lobb 5 and follows f r o m the o r i g i n a l d e r i v a t i o n of O l s e n et al.4 when the c o n t r i b u t i o n s of co0 and er162a r e included. W h i l e the e s s e n c e of the c o n c l u s i o n s of the o r i g i n a l p a p e r 4 r e m a i n s unchanged, we a p p r e c i a t e the effort of Speight and Lobb in b r i n g i n g to our attention a m o r e r i g o r o u s method for the a i d e r i v a t i o n . 4. R. J. Olsen, G. Judd, and G. S. Ansell: Met. Trans., 1971, vol. 2, p. 1353.
5. M. V. Speightand R. C. Lobb:Met. Trans., 1972,vol.3, p. 737. 6. N. F. Mottand F. R. N. Nabarro:Proc.Phys. Soc., 1960,vol.52, p. 86. 7. R. A. Oriani:Acta Met., 1964,vol. 12, p. 1399.
Activity of Ferrous Oxide in Ferromonticellite T . P . FLORIDIS AND W. S. MOSER FERROMONTICELLITE or iron-monticellite (CaO 9F e O . SiO2) i s a c o n s t i t u e n t of i r o n - o r e a g g l o m e r a t e s , t'2 The p u r p o s e of the work r e p o r t e d in this c o m m u n i c a t i o n w a s to d e t e r m i n e the a c t i v i t y of f e r r o u s oxide i n f e r r o m o n t i c e l l i t e , and thus e s t a b l i s h the c o n d i t i o n s for i t s reduction. The e x p e r i m e n t a l p r o c e d u r e c o n s i s t e d in e q u i l i b r a ting m i x t u r e s of s y n t h e t i c f e r r o m o n t i c e l l i t e and m e t a l lic i r o n with a t m o s p h e r e s having a c o n t r o l l e d oxygen p o t e n t i a l . F e r r o m o n t i c e l l i t e was s y n t h e s i z e d by m i x ing the p r o p e r q u a n t i t i e s of c a l c i u m c a r b o n a t e , f e r r i c oxide, and s i l i c a ; and by h e a t i n g the m i x t u r e s at l l 0 0 ~ for at l e a s t 200 h r u n d e r a c o n t r o l l e d a t m o s p h e r e c o n t a i n i n g n i t r o g e n , c a r b o n monoxide, and c a r b o n dioxide. T h e f o r m a t i o n of f e r r o m o n t i c e l l i t e was a s c e r t a i n e d by X - r a y diffraction and c h e m i c a l a n a l y s i s . A 1 g m i x t u r e of synthetic f e r r o m o n t i c e l l i t e and m e t a l l i c i r o n w a s p l a c e d in a c r u c i b l e m a d e f r o m thin A r m c o - i r o n sheet. The c r u c i b l e was placed in a v e r t i c a l f u s e d - q u a r t z m u f fle tube, and it was s u s p e n d e d with a thin p l a t i n u m w i r e f r o m the pan of a r e c o r d i n g b a l a n c e that was p l a c e d on top of the v e r t i c a l q u a r t z t u b e . The q u a r t z tube w a s s u r r o u n d e d by an e l e c t r i c a l l y - g r o u n d e d sheet of n i c k e l , and it was heated by a n e l e c t r i c a l - r e s i s t a n c e f u r n a c e . T e m p e r a t u r e s w e r e m e a s u r e d with a p l a t i n u m v s 90 pct P t - 1 0 pct Rh t h e r m o c o u p l e that was c a l i b r a t
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