The effect of nascent calcium carbonate inhibiting the flotation behavior of calcite

Abstract

• Specifically, SEM, XRD, and FTIR were used in this study to confirm that the recrystallization process of newly formed CaCO 3 was consistent with the flotation behavior of calcite and the mesophase of CaCO 3 was ACC and vaterite . This work is the first of its kind, and could provide a reference for further research. • The intensity of the chemical reaction between ACC–vaterite–calcite and SH was shown to be gradually weakened with recrystallization process progression. • The high solubility and instability of vaterite/ACC can improve the adsorption capacity of SH and weaken the ability of OL − in collecting the mineral. • In solution, vaterite/ACC is more soluble than calcite, and its active sites are more exposed. Furthermore, vaterite/ACC reacts with SH, resulting in the removal of a large amount of Ca atoms on the surface of calcite, which reduces the adsorption sites of OL − and weakens the collection capacity. Recent studies on calcite have shown that newly precipitated clusters of amorphous calcium carbonate (ACC) and vaterite in pulp change the inherent reactivity of the calcite surface. The flotation recovery and surface zeta potential of calcite undergo rapid changes during the initial reaction time but are slightly altered after 60 min. In order to further understand the adverse effects of newly precipitated CaCO 3 on the flotation of calcite, the relationship between the recrystallization process of nascent calcium carbonate (CaCO 3 ) and the flotation behavior of calcite was explored under different time conditions in this study. Accordingly, during the recrystallization process, the intensity of the chemical reaction between ACC–vaterite–calcite and hexametaphosphate (SH) was found to gradually weaken through the flotation test, SEM, XRD and FTIR. Furthermore, due to the difference in crystal structure, ACC and vaterite were shown to strengthen the reactivity of SH and Ca 2+ on the surface of calcite in flotation through the zeta potential test and X–ray photoelectron spectroscopy (XPS), thereby weakening the ability of oleate (OL − ) in collecting the mineral.