STUDY OF THE INFLUENCE BETWEEN BARIUM IONS AND CALCIUM IONS ON MORPHOLOGY AND SIZE OF COPRECIPITATION IN MICROEMULSION

Abstract

In this paper, we systematically drew a series of inverse-microemulsion quasi-ternary system phase diagrams of OP -10+ C8H17OH + C6H12+ brine ( CaCl2/ BaCl2) by adjusting the ratio of CaCl2and BaCl2. On this basis, microemulsions have been prepared with seven different molar ratios of Ca2+/ Ba2+, and calcium carbonate and barium carbonate coprecipitation products were obtained by reaction with an equimolar amount of sodium carbonate. The influence of barium ion to morphology and composition of nanometer calcium carbonate were studied. These samples were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The SEM photographs indicated that when the content of Ca2+was higher, some incomplete large cube of coprecipitation particles were formed in solution, but with the content of Ba2+increased gradually, they formed a large number of small spherical particles, with the further increase of Ba2+concentration, the particles mainly had structures of irregular polyhedron eventually. The measurement results of FTIR and XRD indicated that CaCO3coprecipitation products gradually changed from calcite to the vaterite, eventually turned into being aragonite with the further increase of Ba2+concentration.