WHAT IS THE SOLUBILITY OF ZEOLITE-A

A meaningful solubility product of a zeolite should remain constant as composition of zeolite mother liquors varies at a given temperature. We identify a solubility product of zeolite A, Pi(s) = [Si(OH)(4)][Al( OH4-][Na+] = 1.2 x 10(-8) M-3, from experimental data in highly alkali ne aqueous solutions under conditions typical for zeolite A synthesis (1 M less than or equal to [Na] less than or equal to 4 M, 353 K less than or equal to T less than or equal to 363 K). To accomplish this we develop a thermodynamic model of dilute sodium aluminosilicate soluti ons representing mother liquors in equilibrium with zeolite A. Proper modeling of the liquid phase adjacent to a growing zeolite is necessar y to obtain meaningful supersaturation values and solubility products. Further quantitative modeling of solution mediated zeolite growth and dissolution should include a physically relevant model of aluminosili cate speciation in the liquid phase. (C) 1997 Elsevier Science B.V.