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HPAM assisted controllable synthesis of peanut-like CaCO3 in fixed silicate solution A Physicochemical and engineering aspects

Shi, Weiguang, Ma, Zaiqiang, Wang, Yanling, Wang, Jun, Li, Benxian, Wang, Xiaofeng, Zhou, Wanfu, Cheng, Jiecheng
Colloids and surfaces 2017 v.535 pp. 34-40
adsorption, calcium carbonate, condensation reactions, crystallization, crystals, electrostatic interactions, energy-dispersive X-ray analysis, pH, peanuts, polyacrylamide, scanning electron microscopes, scanning electron microscopy, silica, silicates, temperature
Peanut-like CaCO3 was controllable synthesized in 150mg/L silicate solutions with the help of partially hydrolyzed polyacrylamide (HPAM). The polymorph, crystals structure and composition of CaCO3 under different conditions were characterized by scanning electron microscope (SEM), powder X-ray diffraction (pXRD), energy dispersive X-ray analyser (EDX) and so on. By varying the concentrations of HPAM, initial pH and reaction temperature, peanut-like, fusiform-like and hexahedral CaCO3 particles were prepared successfully. The mechanism of stable peanut-like CaCO3 crystallization induced by silica was proposed. It was found that the adsorption of silanol groups on CaCO3 surfaces played a key role during the condensation reactions of silanol groups, which resulted in the peanut shape of CaCO3 crystals. And as a morphological modifier HPAM led to the formation of specific fibrous surface with different shapes by electrostatic interactions.