Untersuchungen zum Einfluß der 1-Hydroxyethan-1,1-diphosphonsäure,HEDP, auf die Kristallisation von CaCO3 in Ca(HCO3)2-Lösungen

Studies about the Influence of 1-Hydroxyethane-1,1-diphosphonic Acid, HEDP, on the Crystallization of CaCO₃ in Ca(HCO₃)₂ Solutions When cleaned air at 40 °C is passed through solutions of Ca(HCO₃)₂ (4) mmol/l containing ≥5 μmol HEDP/1 x-ray-pure Vaterite crystallizes after a longer time. The reason of the delayed crystallization is not — as usual said in literature — a disturbed growth of the seed crystals of Calcite and Aragonite, but the changed conditions of the formation of crystal nuclei. This is demonstrated by measuring the scattered light, the pH-value and ionic balances. The most important factors of the stability of Ca(HCO₃)₂-solutions containing HEDP are characterized.