15 Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on February 26, 2018 | https://pubs.acs.org Publication Date: April 14, 1986 | doi: 10.1021/bk-1986-0303.ch015
Granular Graphitic Carbon 1
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W. M. Goldberger , P. R. Carney , R. F. Markel , and F. J. Deutschle 1
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Superior Graphite Company, 120 S. Riverside Plaza, Chicago,IL60606 R . F. Markel & Associates, 14 Gallery Center, Taylors, SC 29678 Superior Graphite Company, 4021 Calvin Drive, Hopkinsville,ΚY42240
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Desulco is a granular graphitic carbon made by desul furizing petroleum coke at temperatures approaching 2500C. Desulco meets a sulfur specification of 0.03 percent sulfur maximum as required for use of the product as a recarburiser for production of ductile iron. A highly advanced continuous electrothermal furnace process was developed by The Superior Graphite Company for production of Desulco. Commercial opera tion was first begun in 1977 at Hopkinsville, Kentucky. Plants with total capacity of 30,000 metric tons are in operation in the U.S. and Europe. Desulco is characterized by its high purity, relatively low particle density and very high degree of microporosity. In addition to use worldwide as a carbon additive to molten iron, Desulco is finding increasing use in special graphite products such as lubricants, coating agents and electrically conductive fillers.
Commercial c a s t i r o n s a r e a l l o y s c o n t a i n i n g 2-4 p e r c e n t d i s s o l v e d carbon. On c o o l i n g and s o l i d i f i c a t i o n , t h e d i s s o l v e d carbon p r e c i p i t a t e s as c r y s t a l l i n e g r a p h i t e . I n " g r a y " i r o n c a s t i n g s , the g r a p h i t e has been p r e c i p i t a t e d i n s p h e r i c a l o r n o d u l a r f o r m . Ductile or n o d u l a r c a s t i r o n has e x c e l l e n t m e c h a n i c a l w o r k i n g c h a r a c t e r i s t i c s and i s f i n d i n g i n c r e a s i n g m a r k e t s . S o l i d carbons a r e added t o i r o n m e l t s to a d j u s t t h e carbon c o n t e n t b e f o r e c a s t i n g . A l i s t i n g and a n a l y s i s of t h e v a r i o u s carbon s o u r c e s used i s g i v e n i n Table I . S u l f u r p r e s e n t i n the carbon a d d i t i v e w i l l be r e t a i n e d by t h e i r o n . T h i s i s n o t c r i t i c a l i n making gray i r o n s c a s t i n g s because the s u l f u r content of t h e m e t a l i s r e l a t i v e l y h i g h , i n t h e range 0 . 0 4 - 0 . 1 2 p e r c e n t ( 1 ) . However, f o r p r o d u c t i o n of d u c t i l e i r o n , i t i s e s s e n t i a l to m a i n t a i n s u l f u r i n t h e range 0 . 0 0 5 - 0 . 0 1 5 p e r c e n t . For t h i s reason, synthetic 0097-6156/86/0303-0200$06.00/0 © 1986 American Chemical Society
Bacha et al.; Petroleum-Derived Carbons ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
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GOLDBERGER ETAL.
Granular Graphitic Carbon
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g r a p h i t e , w h i c h i s v i r t u a l l y s u l f u r f r e e , i s used to a v o i d a s u b s e quent need to d e s u l f u r i z e the hot m e t a l b e f o r e c a s t i n g . Synthetic g r a p h i t e has been a p r e f e r r e d " r e c a r b u r i s e r " i n d u c t i l e i r o n f o u n d r i e s a l s o because i t c o n t a i n s no v o l a t i l e s and almost no a s h .
Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on February 26, 2018 | https://pubs.acs.org Publication Date: April 14, 1986 | doi: 10.1021/bk-1986-0303.ch015
Table I .
T y p i c a l A n a l y s e s of V a r i o u s R e c a r b u r i s e r M a t e r i a l s
Carbon Type Metallurgical Coke Brown C o a l Char Calcined Anthra cite P i t c h Coke Natural Graphite Calcined Petro leum Coke Synthetic Graphite
Analyses, Percent Volatile Matter Sulfur Nitrogen
Hydrogen
1.60 2.90
0 .93 0 .28
1. 00 0. 60
1.10
10. 0 0.55 13. 2
0.4 0.50 0.44
0 .35 0 .45 0 .35
0. 10 0 . 60 0. 06
0.013 0.20 0.20
99,.6
0. 4
0.4
1 .8
0. 60
0.15
99,.5
0. 5
