MICROSCOPIC STUDY OF SPHERES AND MICROSPHERES IN FLY-ASH

Spherical particulates in fly ash from two bituminous coals, two subbi tuminous coals and one lignite have been studied by interference contr ast polarized light microscopy (ICT-PLM) and scanning electron microsc opy with energy dispersive X-ray spectroscopy (SEM-EDS). Most of the g lassy spheres were between 8 and 50 mu m in diameter. Second phase mat erial was seen on many of the solid sphere surfaces. Microspheres atta ched to the surfaces of larger spheres were found to have different co mpositions from that of the host sphere. Microparticulate capture by t he larger spheres is a phenomenon that needs more study before the cap ture mechanism and its efficiency can be understood.