A REVIEW OF SULPHUR IN COAL: WITH SPECIFIC REFERENCE TO THE TELKWA DEPOSIT, NORTH-WESTERN BRITISH COLUMBIA
The Jura-Cretaceous coal seams of the Currier, Mist Mountain, &thing and Gates formations generally formed in delta or strand plain environments with little marine influence. The sulphur contents of coal from these formations is therefore generally low, nearly always less than I % and often less than 0.5 %. Coalbearing formations of the Cretaceous Nanaimo and Skeena groups were deposited in coastal areas with more marine influence. Consequently sulphur contents are more variable and tend to be higher. It is therefore important to study aspects of sulphur in Cretaceous coal seams such as the seams in the Skeena Group at Telkwa (Figure I).
An experimental study of sulphate transformation during pyrolysis of an Australian lignite
Abstract The transformation of sulphate minerals during pyrolysis of an Australian lignite has been studied using pure sulphates (CaSO 4 , FeSO 4 and Fe 2 (SO 4 ) 3 ), a high mineral (HM) lignite sample and a low mineral (LM) lignite sample collected from different locations of the same deposit, and samples of acid-washed LM doped with sulphates (CaSO 4 + LM and FeSO 4 + LM), respectively. Thermogravimetric analysis and fixed-bed reactor techniques were used for the pyrolysis experimentation and the lignite samples and their chars were analysed using FTIR and XRD. The TGA experiments showed that CaSO 4 decomposes between 1400 and 1700 K in nitrogen and a 50/50 N 2 /CO 2 mixture, while in air CaSO 4 decomposes between 1500 and 1700 K. Using a TGA–MS it was found that only a small fraction of CaSO 4 in CaSO 4 + LM decomposed at 653 K, releasing SO 2 . CaSO 4 was still observed in the char recovered at 1073 K as confirmed by the FTIR and XRD analysis. FeSO 4 ·7H 2 O released the bound water below 543 K and the remaining FeSO 4 decomposed between 813 and 953 K. FeSO 4 in FeSO 4 + LM decomposed at 500 K to release SO 2 . The inherent sulphates in HM were dominated by iron sulphates which started to decompose and release SO 2 at around 500 K and all sulphate had been decomposed at 1073 K. It was observed that during the fixed-bed pyrolysis at 1073 K in nitrogen, approximately 36% of the total sulphur in the CaSO 4 + LM decomposed, 88% of the total sulphur in the FeSO 4 + LM decomposed and around 76% of the total sulphur in HM decomposed. It was also confirmed that FeSO 4 + LM produced more volatile sulphur than CaSO 4 + LM during pyrolysis.
Is the Benussi Effect a Kinetic Depth Effect?
Rapid, successive presentations of an eccentric circle pattern and its mirror-image elicited apparent depth and, as has been previously demonstrated for the Benussi effect, there was an increase in apparent depth with an increase in circle eccentricity. Taken together, these data were interpreted as contravening Wallach, Adams, and Weisz's account of the Benussi effect as an instance of the kinetic depth effect.