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: Al) in an attempt to synthesize zeolites from a highly alkaline waste stream. The reaction 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 degrees, 130 degrees, and 180 degrees C), X-ray diffraction analyse s of the products indicated that the fly ash and sodium aluminate had combined to form Zeolite A at 80 degrees C, and NaP1 (a gismondene-typ e) and an unnamed hydroxysodalite-type at 130 degrees and 180 degrees 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 t he bulk of the sodium had been incorporated into zeolitic phases, Beca use of the unique adsorptive and cation exchange capabilities of zeoli tes and the fact that some samples formed reasonably hard monoliths, z eolitic materials formed in this way might make excellent waste forms for ''mixed wastes'' which contain both radioactive and hazardous chem ical species.