The leaching kinetics of gold from gold scraps in Cl-2-saturated HCl solutions

In order to explain the model of kinetics control on the leaching of gold in gold-bearing scraps, the effects of the reaction temperature, solid/liquid ratio, particle size and stirring speed and acid concentration are investigated. In the examination of the leaching kinetics of gold in Cl-2-saturated HCI solutions, Cl atoms occurring in the medium react more rapidly than Cl-2 molecules with gold scraps. This reaction takes place simultaneously with the reaction of dissolution and in situ-generated chlorine is called. Also, the method doesn't have some disadvantages such as the storage of generated chlorine. It is determined that the leaching rate decreases with increasing particle size and solid to liquid ratio while it increases with increasing reaction temperature, acid concentration and stirring speed. For fluid/solid systems, shrinking core models are analysed by using of experimental results. It is observed that the leaching of gold from gold-bearing scraps is chemically controlled. Also, the leaching rate controlled by the chemical reaction is supported by the relationship between the particle diameter and rate constant. The activation energy of leaching process by using Statistica Package Program is determined as 34.40 kJ/mol.