Abstract
Dissolution behavior of synthetic ettringite in an aqueous suspension containing a strongly acidic ion exchange resin, hydrogen-form (H-R) was investigated by monitoring the variations in pH and specific conductivity and by analyzing the fraction of dissolved ions using ion chromatography. The results obtained are summerized as follows;
(1) Initial cation exchange reaction between ettringite and H-R in aqueous media produces a hydrous alumina gel incorporated with small amounts of calcium and sulfate ions (Eq. 1).
Al2Ca6(OH)12(SO4)3+6(H-R)→3CaSO4(aq)+3(Ca-R2)+6H2O+2Al(OH)3 (1)
(2) In the final stage, the released H2SO4 produced by the subsequent ion exchange reaction between CaSO4 (aq) and H-R reacts with the gel to be dissolved accompaning with the complete dissolution of the ettringite.
