MOSSBAUER ANALYSIS ON THE MICROWAVE—MAGNETIC DESULFURIZATION OF RAW COAL

MOSSBAUER ANALYSIS ON THE MICROWAVE—MAGNETIC DESULFURIZATION OF RAW COAL Weng Sihao 1 first-author China Center of Advanced Science and Technology, World Laboratory, Beijing 100080, and East China Normal University, Shanghai 200062, China China Center of Advanced Science and Technology, World Laboratory, Beijing 100080, and East China Normal University, Shanghai 200062, China The selective dielectric heating of microwave energy to convert a portion of each pyrite particle to moderately magnetic pyrrhotite has been suggested to enhance the magnetic separation of inorganic sulfur from coal. The results for Mossbauer analyses show that the considerable amount of pyrrhotite produced during microwave irradiation, carrying with it some of non-magnetic pyrite (unconverted), ferrous sulfate, and troilite, is completely removed from coal after magnetic separation. The optimum desulfurization efficiency can be attained by appropriately controlling the irradiation time to maximize the amount of pyrrhotite formed pyrite decomposition. Excessive irradiation would be disadvantageous for improving magnetic separation due to the further decomposition of pyrrhotite to antiferromagnetic troilite. Coal desulfurization Microwave irradiation Magnetic separation Mossbauer spectroscopy REFERENCES Jacobs I S , Levinson L M , Hart H R , Jr . J Appl Phys , 1978 ; 49 : 1775 J Appl Phys Ergun S , Bean E H . Magnetic separation of pyrite from coals, USBM-RI-7181 , 1968 Magnetic separation of pyrite from coals, USBM-RI-7181 Zavitsanous P D , Bleiler K W , Golden J A . U. S. Patent 4076607 , 1978 ; 4152120 , 1979 Fanslow G E , Bluhm D D , Nelson S O . J Microwave Power , 1980 ; 15 : 187 J Microwave Power Nelson S O , Fanslow G E , Bluhm D D . J Microwave Power , 1980 ; 15 : 277 J Microwave Power Jacobs I S , Zavitsanous P D , Golden J A . J Appl Phys , 1982 ; 53 : 2730 J Appl Phys Bluhm D D , Fanslow G E , Nelson S O . IEEE Trans Magn , 1986 ; MAG-22 : 1887 IEEE Trans Magn Kelland D R , Lai-Fook M , Maxwell E et al . IEEE Trans Magn , 1988 ; MAG-24 : 2434 IEEE Trans Magn Russell P E , Montano P A . J Appl Phys , 1978 ; 49 : 1573 J Appl Phys Gupta V T , Singh A K , Chandra K et al . Phys Status Solidi A , 1984 ; 81 : 281 Phys Status Solidi A Schwarz E J , Vaughan D J . J Geomag Geoelectron , 1972 ; 24 : 441 J Geomag Geoelectron Bertaut E F . Acta Crystallogr , 1953 ; 6 : 557 Acta Crystallogr Bommannavar A S , Montano P A . Fuel , 1982 ; 61 : 523 Fuel 1993-04-25 1994-02-01 2021-02-05 1994 Nuclear Science and Techniques 01 05