Dissolution kinetics of hemimorphite in trichloroacetic acid solutions

摘要

In this study, the dissolution kinetics of hemimorphite in the presence of the organic reagent, trichloroacetic acid (TCAA), was investigated. Experimental variables such as reaction temperature (293–323K), TCAA concentration (0.084–0.184mol/dm3), particle size (0.081–0.214mm), and stirring speed (200–650rpm) were studied to determine the influence on the zinc dissolution rate, and a kinetic model was developed to represent the relationship. The results demonstrated that during the leaching process, zinc was rapidly dissolved in TCAA and the zinc leaching rate increased as a function of increased reaction temperature, TCAA concentration, and stirring speed, and decreased particle size. Among the kinetic models of the porous solids tested, a new variant of the shrinking-core model well described the zinc leaching kinetics. The activation energy was determined to be 54.94kJ/mol, and the rate of reaction equation [1?(2/3)x?(1?x)2/3]2=[11.24(C)3.80946(PS)?2.00833(SS)1.62147exp(?54.94/RT)]twas also obtained to describe the process.