GIS-type zeolite synthesis from Greek lignite sulphocalcic fly ashes promoted by NaOH solutions

Bench-scale synthesis of zeolite A from subbituminous coal ashes with high crystalline silica content

“…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.…”

Properties and microstructure of lightweight aggregate produced from lignite coal fly ash and recycled glass

“…This work has characterized FA (Filippidis and Georgakopoulos 1992;Georgakopoulos et al 1994;Sakorafa et al 1996;Fytianos et al 1998;Georgakopoulos et al 2002;Arditsoglou et al 2004;Karangelos et al 2004;Koukouzas et al 2006;Skodras et al 2007) and assessed potential applications including use in cement and concrete (Papayianni and Valiasis 1991;Kouloumbi and Batis 1992;Papayianni 1993;Kouloumbi et al 1994;Malami et al 1994 FA in zeolite production (Mouhtaris et al 2003;Moutsatsou et al 2006) and road construction (TEE 1988;AUTH 1994;Mouratidis 2001;Kehagia and Tsoxos 2005) have been reported. The potential for using FA in cement production, brick manufacture and construction of road embankments in Greece has also recently been investigated (Skodras et al 2007).…”

Processing of mesoporous silica materials (MCM-41) from coal fly ash

“…Owing to the high content of useful silica and alumina in CFA, it makes perfect economical sense to recover these minerals for useful industrial applications. Several studies based on the hydrothermal method were employed to convert CFA to mesoporous silica such as faujasite, zeolite P, zeolite X, hydroxysodalite and gismodinee [15][16][17][18]. Although this effort was successful, the abundance generation of liquid waste during hydrothermal treatment and the high ratio of solution to CFA as well as the difficulties to obtain single-phase zeolite, make this method less favourable.…”