Changes in structural parameters of different cokes during heat treatment to 2400 degrees C

This paper deals with the investigation of structural parameters of differe nt cokes: petroleum coke, pitch coke, pure metallurgical coke, and metallur gical coke produced from coal with the addition of atmospheric residue and coal tar pitch. Crystallographic parameters (crystallite height, L-c and in terlayer spacing, d(002)) were measured by X-ray diffraction after heat tre atment at 1200, 1600, 2000 and 2400 degrees C (heating rate 10 degrees C/mi n, heating time 4 h). Surface morphology was determined by means of scannin g electron microscopy (SEM analysis) at 1200 and 2400 degrees C. The result s show that temperature and the type of coke have an important effect on th ese structural parameters. Maximum L-c values and lowest d(002) values were obtained for the pitch coke and the coke produced from coal with 20 wt.% c oal tar pitch addition heated at 2400 degrees C. Differences in crystallogr aphic parameters of the cokes examined also become manifest through their s urface morphology. After heat treatment at 2400 degrees C, the pitch coke a nd the coke produced with addition of coal tar pitch brought about the deve lopment of more lamellar structural components. (C) 1999 Elsevier Science L td. All rights reserved.