Chloride binding behavior of monosulfate hydrate

Abstract

The chloride binding behavior of monosulfate hydrate (AFm) is investigated. The chloride binding curve of AFm can be represented by a Freundlich isotherm. The chloride binding of AFm mainly depends on the formation of Friedel' s salt by ion exchange between SO₄^2- and Cl^-. Theoretically, 1 mol of Friedel' s salt contains 2 mol of chloride ion. In this study, 1 mol of AFm bound 1.1 mol of chloride ion at a chloride concentration of 5mol/l. This is considered to be caused by the partial dissolution of AFm and the production of other hydrates such as ettringite.