Cengiz Özmetin

Kinetic Investigation of Reaction Between Metallic Silver and Nitric Acid Solutions

In this study, the reaction kinetics between metallic silver and nitric acid solutions was investigated by taking into consideration the parameters of temperature, solid-to-liquid ratio, stirring speed, nitric acid concentration, particle size and addition of sodium nitrite. It was determined that the dissolution rate of the process increased with decreasing particle size and solid-to-liquid ratio, and increasing nitric acid concentration, reaction temperature and the amount of the sodium nitrite in the solution. In addition, it was observed that the stirring speed had more effect on the dissolution rate at low stirring speeds than at high stirring speeds. In the present study, the examination of shrinking core models of fluid-solid systems showed that the dissolution of metallic silver in the nitric acid solutions was controlled by the reaction on the surface. A semiempirical model, which represented well the process, was developed by statistical methods. The activation energy of the process was found to be 57.66 kJ mol–1.

Dissolution of Braunite in sulfuric acid solutions

Abstract In this investigation the dissolution of Braunite from Oltu, Erzurum-Turkey in sulfuric acid solutions was studied. In the experiments, particle size, acid concentration, solid-to-liquid ratio, stirring speed and reaction temperature were chosen as parameters. It was observed that the dissolution rate increased with increasing acid concentration and reaction temperature, and with decreasing particle size and solid-to-liquid ratio, while no pronounced effect of stirring speed was observed. The activation energy for this process was found to be 40.95 kJ mol−1.