Non-isothermal decomposition of NiC2O4-FeC2O4 mixture aiming at the production of NiFe2O4

• Published in: The Journal of physics and chemistry of solids Vol. 64; no. 8; pp. 1375 - 1385
• Main Author: GABAL, M. A
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier 01.08.2003
• Subjects: Chemistry; Condensed matter: structure, mechanical and thermal properties; Elements and non-metal compounds (oxides, hydroxides, hydrides, sulfides, carbides, ...); Exact sciences and technology; Inorganic chemistry and origins of life; Inorganic compounds; Physics; Preparations and properties; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Water, oxides, hydroxides, peroxides; Reaction intermediate; Moessbauer effect; Iron oxide; Thermal decomposition; Crystal chemistry; Experimental study; X ray diffraction; Chemical reaction kinetics; Inorganic compound; Characterization; Infrared spectrometry; Ferrites spinels; Transition metal compounds; Chemical preparation; Non isothermal condition; Crystallographic site; Activation energy; Nickel oxide
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/S0022-3697(03)00163-X

The non-isothermal decomposition of NiC2O4 2H2O-FeC2O4 2H2O (1:2 mole ratio) mixture was studied on heating to the formation of NiO-Fe2O3 mixture at 350 C in air atmosphere using thermogravimetry. Kinetic analysis of data according to the integral composite method showed that the oxidative decomposition of FeC2O4 and NiC2O4 are best described by the three-dimensional phase boundary model. The activation parameters were calculated and discussed. The solid products at different decomposition stages were identified using XRD, Mossbauer and FT-IR spectroscopic techniques. Some characteristic XRD lines of NiFe2O4 start to appear at 800 C beside the characteristic lines of NiO and Fe2O3, whereas at 1000 C, only the characteristic lines of single phase cubic NiFe2O4 appeared. The Mossbauer spectrum at 1000 C fitted into two Zeeman sextets characteristic of Fe3+ on the tetrahedral (A) and octahedral (B) sites of NiFe2O4 inverse spinel. Consistent results were obtained using FT-IR where the absorption bands appeared at 602 and 407 cm-1 for the mixture calcined at 1000 C. These can be assigned to the intrinsic vibrations of tetrahedral and octahedral sites of NiFe2O4, respectively. 32 refs.