Study of a titaniferous magnetite chlorination at high temperature
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P~ MEUBUS,
AND
M. PAQUET
The c h l o r i n a t i o n of a t i t a n i f e r o u s m a g n e t i t e with low content in T i and F e has b e e n s t u d i e d b e t w e e n 1273 and 2273 K. Most of the h e r c y n i t e and i l m e n i t e i n i t i a l l y p r e s e n t a r e d e c o m posed d u r i n g the g a s - s o l i d phase r e a c t i o n b e t w e e n 1273 and 1823 K. C o n s i d e r a b l e i l m e n ite d e c o m p o s i t i o n and FeC13 evolution a l r e a d y o c c u r at 1273 K, leaving a r e s i d u e c o n s i s t ing of TiO~, Fe203-TiO2 (pseudobrookite), and about 50 pct of each of the C r and Mg i n i t i a l l y p r e s e n t . X - r a y d i f f r a c t o g r a m s shown the f o r m a t i o n of A12TiOs which c o n t r i b u t e s to the s t a b i l i z a t i o n of TiO2 up to 1773 K, above which t e m p e r a t u r e s i g n i f i c a n t d e c o m p o s i tion of A12TiO~ is o b s e r v e d . At the m e l t i n g point of the t i t a n i f e r o u s m a g n e t i t e s a m p l e (around 1823 K), the p r e s e n c e of both solid and liquid p h a s e s r e s u l t in a c o n s i d e r a b l e d e c r e a s e in the c h l o r i n a t i o n r a t e . In this r e s p e c t , heating the s a m p l e u n d e r h e l i u m up to the m e l t i n g point, so that liquid and solid p h a s e s a r e obtained at e q u i l i b r i u m , y i e l d s two s t r u c t u r e s r e p l a c i n g the m a g n e t i t e p r e s e n t just p r i o r to m e l t i n g . One of t h e s e s t r u c t u r e s is of the s p i n e l Fe2TiO4 type, while the o t h e r is a c o m b i n a t i o n of the s p i n e l types MgA1204, FeA1204, and MgCreO4. When the s a m p l e is c h l o r i n a t e d , a high p r o p o r t i o n of the i n i t i a l C r (90 pct) and T i (80 pet) a r e found in the c h l o r i n a t i o n r e s i d u e at the e a r l y s t a g e s of fusion, t o g e t h e r with 13 pct of the i n i t i a l F e . C h l o r i n a t i o n of the liquid phase b e t w e e n 1823 and 2273 K shows a steady d e c r e a s e of T i and C r in the c h l o r i n a t i o n r e s i d u e , a s s o ciated with an i n c r e a s e of F e content.
THE
t i t a n i f e r o u s m a g n e t i t e s t u d i e d here is of the Magpie type (P.Q., Canada) which r e p r e s e n t s a supply of F e a n d T i e s t i m a t e d at 109 t o n s . B e s i d e s F e and T i , this m i n e r a l ore also c o n t a i n s , for i n s t a n c e , v a l u a b l e e l e m e n t s like C r . T a b l e I g i v e s the c o m p o s i t i o n of the s a m p l e used in this study. T h i s type of t i t a n i f e r o u s m a g n e t i t e has b e e n c h a r a c t e r i z e d and the s u b j e c t of phase e n r i c h m e n t by m e t a l l u r g i c a l t r e a t m e n t has b e e n studied. 1 Some p r o m i s i n g p r e l i m i n a r y r e s u l t s show that a r e d u c i n g fusion leads to a r e d u c e d i r o n c o n t a i n ing V as well as a t i t a n i f e r o u s s l a g . C h l o r i n a t i o n p r o c e s s e s have b e e n used for the b e
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