“…From a different point of view, many researchers have focused on the use of coal ashes for zeolite synthesis. Wide variety of zeolites including zeolite A (Rayalu et al, 2001), phillipsite and faujasite (Rujiwatra et al, 2005) and GIS-type zeolites (Mouhtaris et al, 2003) were synthesized from low-rank lignite fly ash containing high amount of amorphous phases. Whereas a group of zeolites including zeolite X (Font et al, 2009), phillipsite and hydroxylcancrinite (Nascimento et al, 2009) were synthesized from higher rank coal fly ashes.…”