Application of chicken eggshell waste as a starting material for synthesizing calcium niobate (Ca4Nb2O9) powder

This study focused on the possibility of using CaCO3 from chicken eggshell waste as a starting material for synthesizing Ca4Nb2O9 powder via a conventional solid state reaction. The heat behavior of CaCO3 and Nb2O5 raw material mixture was studied by thermogravimetric analysis (TGA). Phase formation of Ca4Nb2O9 was studied as a function of calcination conditions by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and X-ray diffraction (XRD). The morphology and microstructure were charaterized via Scanning electron microscope (SEM). The X-ray fluorescence (XRF) results showed that the chicken eggshell contained more than 96.0% of CaCO3 by weight. The XRD pattern peaks matched the peaks of calcite CaCO3 ICDD No. 85-11108 very well. Furthermore, the XRD results and Rietveld refinement analysis confirmed that the purity and single phase of Ca4Nb2O9 corresponded to the monoclinic structure (ICDD: 49-0911) obtained after the calcination process. The non-isothermal kinetic of Ca4Nb2O9 also was investigated by the Ozawa methods. This study indicated that CaCO3 from chicken eggshell waste is an alternative starting material for synthesizing Ca4Nb2O9 powder. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.