Publication: Extraction of silica and alumina from coal fly ash for the synthesis of zeolites
Date
2009
Authors
Kamarudin R.A.
Matlob A.S.
Jubri Z.
Ramli Z.
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Abstract
This paper reports the extraction of soluble silicates and aluminates from coal fly ash using microwave irradiation from a domestic microwave oven. Fifteen experimental conditions for the extraction were obtained using Box-Behnken design through manipulation of three variables namely sodium hydroxide (NaOH) concentration, power level of microwave irradiation and exposure time; each variable has three values. The variables with their values were; NaOH concentration (2, 4 and 6 M), exposure time to microwave irradiation (1, 3.5 and 6 min) and power level of the irradiation (10, 50 and 100 Watts). Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) was used to study the amount of silicon and aluminium in the extracts. The extracted silicates and aluminates (after the molar ratio of SiO2 to Al2O 3 was adjusted to unity by adding aluminium foil) were further incubated at 95�C for 72 hours. The products isolated from the 14 experiments were characterized by their XRD images and found to be Na-A zeolites, gibbsite and sodalite octahydrate. �2009 IEEE.
Description
Keywords
Fly ash , Microwave , Silica , Zeolites , Aluminum , Aluminum foil , Coal ash , Emission spectroscopy , Fly ash , Inductively coupled plasma , Irradiation , Metal recovery , Microwave devices , Optical emission spectroscopy , Silica , Silicate minerals , Silicon oxides , Sodium , Stoves , Sustainable development , X ray diffraction , Zeolites , Box-Behnken design , Coal fly ash , Experimental conditions , Exposure-time , Gibbsites , Inductively coupled plasma-optical emission spectroscopy , Molar ratio , NaOH concentration , Power levels , Silica zeolites , Sodium hydroxides , XRD , Microwave irradiation