Interaction of anhydrite and melamine-formaldehyde polycondensates in aqueous suspensions

The interactions of molecules of melamine- formaldehyde (MF) polycondensate s in aqueous suspensions with synthetic anhydrite were studied. The sorptio n is selective. The medium molar fractions of additives are preferably sorb ed on the surface of anhydrite and its product of hydration after 10 and 30 min of interaction. After 180 min, all high molar fractions are sorbed out . The results indicate that molecules of polycondensate tested interact wit h calcium ions in suspension and have a tendency to transform from R-SO3Na to R-(SO3)(2)Ca form. Any other changes in the structure of molecules after interaction in aqueous suspension of anhydrite were not proved by the test s carried out. (C) 2000 Elsevier Science Ltd. All rights reserved.