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is a s s u m e d where L is the f a i l u r e load, d is p e l l e t d i a m e t e r , and n = 2. This t r e a t m e n t of p e l l e t strength data, h o w e v e r , a s s u m e s a u n i f o r m r a d i a l distribution of bonds within the a g g l o m e r a t e s . It has been d e m o n s t r a t e d , 1 u s i n g a s i m ple g e o m e t r i c m o d e l , that the exponent n in Eq. [1] would be expected to be equal to 1 for the c a s e in which the s t r e n g t h - f o r m i n g bonds are concentrated in an outer s h e l l and equal to 2 only if t h e r e is a uniform bond d i s tribution. Other bond d i s t r i b u t i o n s b e t w e e n t h e s e e x t r e m e s lead to v a l u e s of n i n t e r m e d i a t e between 1 and 2. Thus in c a p i l l a r y state wet a g g l o m e r a t e s , the e x p o nent n g e n e r a l l y has a v a l u e c l o s e to 22'3 s i n c e the liquid binder f o r m s a continuous network and acts u n i f o r m l y a c r o s s the whole p e l l e t c r o s s - s e c t i o n . In the e a s e of dry a g g l o m e r a t e s held together by r e e r y s t a l l t z e d salt b r i d g e s , n is often c l o s e r to unity 4 s i n c e the salt a c c u m u l a t e s in the s u r f a c e l a y e r s due to the action of c a p i l l a r y f o r c e s during drying. The influence of t h e s e f a c t o r s in s i z e - s t r e n g t h r e l a t i o n s h i p s for iron o r e p e l l e t s m a y be d e m o n s t r a t e d by c o n s i d e r i n g the data of Urieh and Han. 5 T h e s e data for different a g g l o m e r a t e d i a m e t e r s w e r e n o r m a l i z e d by G r e a v e s and E n g l i s h 6 by a s s u m i n g n = 2 in Eq. [1]. If this a s s u m p t i o n is not made and the data a r e fitted to Eq. [1] by a l e a s t s q u a r e s procedure, the r e s u l t i n g k and n v a l u e s are shown in Fig. 1 and 2 for wet and dry p e l l e t s , r e s p e c t i v e l y , as a function of the percentage of m i n u s 325 m e s h p a r t i c l e s . It is evident that the i n dex n is not equal to 2 in m o s t of the c a s e s , even for the wet p e l l e t s which as noted a l r e a d y might be e x pected to be of uniform r a d i a l strength. Although a n u m b e r of explanations m a y be advanced to account for the n o n - u n i f o r m i t y of wet, dried or fired p e l l e t s , the " c o n c e n t r i c s k i n " concept of Cohen 7 would s e e m to be one of the m o r e l i k e l y explanations. Cohen noted that p e l l e t s m a y be made up of c o n c e n t r i c l a y e r s due to prolonged r o l l i n g at i n t e r m e d i a t e s t a g e s in their growth or due to drying of the p e l l e t s u r f a c e during d e l a y s in the growth p r o c e s s . The bonding of s u c c e s s i v e l a y e r s i n s i d e the p e l l e t s is thus quite v a r i a b l e l e a d i n g to n o n - u n i f o r m r a d i a l bond distribution and v a l u e s of n which are not equal to 2. It should b