Magnetization as an Effective Tool for Kinetics Evaluation in Mechanochemical Synthesis of Chalcopyrite CuFeS2

Abstract

Copper, iron, and sulphur in elemental form were applied for mechanochemical synthesis of chalcopyrite CuFeS2. Products of synthesis were characterized by XRD method and evaluated by Rietveld analysis. A mixture of cubic (JCPDS 75-6866) and tetragonal (JCPDS 37-0471) phases of chalcopyrite with almost identical diffractograms were identified. Both phases are nanocrystalline with sizes 13 nm and 7 nm for laboratory and industrial milling, respectively. For determination of iron consumption during the synthesis, method of magnetometry has been applied. Based on magnetization data reflecting time dependent incorporation of elemental iron into chalcopyrite nanostructure, the kinetics of the synthesis was evaluated. From kinetic data the rate constant of reaction k, as well as the conversion degree R were determined. High conversion degree of mechanochemical synthesis performed in a laboratory mill (R = 100%), as well as in an industrial mill (R = 96%) offer the possibility to scale-up the process of synthesis in preparation of this perspective magnetic semiconductor. The method of magnetometry was proved to be an effective tool for following the processes of synthesis where iron particles are incorporated.