Zeolites Synthesized From Class F Fly Ash And Sodium Aluminate Slurry

A Class F fly ash was combined with a sodium aluminate slurry (3:1 Na:A1) in an attempt to synthesize zeolites from a highly alkaline waste stream. The rection was studied as a function of composition (3:2, 1:1, and 1:2 fly ash:slurry), time (1, 3 and 7 days), and temperature (80, 130 & 180 deg C). X-ray diffraction analyses of the products indicated that the fly ash and sodium aluminate had combined to form Zeolite A at 80 deg C, and NaP1 (a gismondene-type) and an unnamed hydroxysodalite-type at 130 & 180 deg C. The fact that the pH of the reactants decreased from initial values in excess of 13 to near neutral (7-9) after reaction signifies that the bulk of the sodium had been incorporated into zeolitic phases.