Individual and synergetic effect of EDTA and NTA on polymorphism and morphology of CaCO3 crystallization process in presence of barium

Abstract

The effect of different chelating agents on the crystallization of CaCO3, polymorphism and morphology of CaCO3 in the presence of barium were studied at 100 °C. The samples were characterized using FTIR, Raman spectroscopy, XRD and FESEM techniques. The study revealed that without any chelating agents, in the presence of different volumes of 0.1 M Ba2+ ion solution, stabilization of a binary mixture of rhombohedral calcite and flower-like vateritewas facilitated. In the presence of EDTA, the phenomenal transformation of calcite to vateritewas observed. Pure calcite has resulted in the presence of Nitrilotriacetic acid (NTA) in the presence of Ba2+ ions. Blending EDTA with NTA favored a binary mixture of spherical vaterite and calcite. The probable mechanism for stabilization of various polymorphs by the additives and effect of blending of additives for better scale inhibition efficiency has been discussed.