Comparativeanalysisof_省略_l_FeCl_3andHCl_.pdfVIP

International Journal of Minerals, Metallurgy and Materials Volume 18, Number 1, February 2011, Page 9 DOI: 10.1007/s12613-011-0393-1 Comparative analysis of the dissolution kinetics of galena in binary solutions of HCl/FeCl and HCl/H O 3 2 2 Alafara A. Baba and Folahan A. Adekola Department of Chemistry, University of Ilorin, P.M.B 1515, Nigeria (Received: 30 November 2009; revised: 10 January 2010; accepted: 19 April 2010) Abstract: A comparative study of the dissolution kinetics of galena ore in binary solutions of FeCl /HCl and H O /HCl has been undertaken. 3 2 2 The dissolution kinetics of the galena was found to depend on leachant concentration, reaction temperature, stirring speed, solid-to-liquid ratio, and particle diameter. The dissolution rate of galena ore increases with the increase of leachant concentration, reaction temperature, and stirring speed, while it decreases with the increase of solid-to-liquid ratio and particle diameter. The activation energy (Ea) of 26.5 kJ/mol was obtained for galena ore dissolution in 0.3 M FeCl3/8.06 M HCl, and it suggests the surface diffusion model for the leaching reaction, while the E value of 40.6 kJ/mol was obtained for its dissolution in 8.06 M H O /8.06 M HCl, which suggests the surface chemical reaction model a 2 2 for the leaching reaction. Furthermore, the linear relationship between rate constants and the reciprocal of particle radius supports the fact that dissolution is controlled by the surface reaction in the two cases. Finally, the rate of reaction based on the reaction-controlled process has been described by a semiempirical mathematical model. The Arrhenius and reaction constants of 11.023 s−1