Leaching kinetics of Chevreul's salt in hydrochloric acid solutions

The aim of this study was to investigate the dissolution kinetics of Chevreul's salt in hydrochloric acid [HCl] solutions in a mechanical agitation system and to precipitate Chevreul's salt [Cu2SO3·CuSO3·2H2O] using ammonium sulfide [(NH4)2SO3] solutions at various concentrations from synthetic aqueous copper(II) sulfate [CuSO4] solutions. Reaction temperature, concentration of HCl, stirring speed and solid/liquid ratio were selected as parameters. The experimental results were successfully correlated by linear regression using Statistica Package Program. Dissolution curves were evaluated in order to test shrinking core models for solid–fluid systems. It was observed that increase in the reaction temperature and decrease in the solid/liquid ratio causes an increase the dissolution rate of Chevreul's salt. The dissolution extent is highly increased with increase the concentration of HCl solutions in the experimental conditions. The activation energy was found to be as 57 kJ/mol. The leaching of Chevreul's salt was controlled by diffusion through the ash or product layer.

Graphical abstractVariation of 1 − 3(1 − X)2/3 + 2(1 − X) with time for reaction temperatures.Figure optionsDownload full-size imageDownload as PowerPoint slide