Polymorphic Crystallization and Diversified Growth of CaCO3 in HPAM-HABS-Na2SiO3 Hybrid Solutions

CaCO3 crystallization is a controversial topic hampered in part by the lack of empirical evidence of the growth of polymorphic crystals. In this work, great effort has been made to investigate the polymorphic crystal growth mechanism and the diversified morphologies, including peanut, shuttle, worm-like and irregular cubic CaCO3 that occur in hydrolysed polyacrylamide (HPAM) - heavy alkylbenzene sulfonate (HABS) - Na2SiO3 hybrid system. It is verified that silica has an inhibition effect during the phase-transformation of CaCO3. With the addition of HPAM, a new morphology of CaCO3 composited with CaCO3 fibres was received in the HPAM-Na2SiO3 mixed solution. In the ternary additive system, the template effect of HPAM is undermined by HABS, and HPAM forms a new polymer-surfactant complex conformation. Meanwhile, the inhibition effect of silica is weakened with the increase of organics.