ABSTRACT

This work, entitled “A study on the recovery of hexavalent chromium by an electrochemical reactor with compartments separated by ceramic separators”, is focused in the possibility of recovering hexavalent chromium from the “mordentado” solutions of the plastic metallization industries by using an electrochemical reactor with compartments separated by ceramic separators. These separators were prepared at different pressure and with different starch composition. The recovery of these metals produces a decrease in the environmental pollution beside a save in raw materials, since the metal may be reused in the “mordentado” process.

The electrochemical study of the “mordentado” baths allows the analysis of the optimum working conditions for the ceramic separators of the electrochemical reactor at constant electrode potential and at constant intensity. The objective is to select the ceramic separator that shows the minimum ionic migration, but that presents the maximum resistance to convection ant to diffusion. The selected ceramic separator should avoid the pass of the Cr (III) towards the anodic compartment, where the Cr (III) would be oxidized to Cr (VI) producing a decrease in the process yield.

The effect of the applied current and the electrode potential on the main “figures of merit” of the electrochemical reactor and on the metal deposits, has been evaluated. The “figures of merit” evaluated are the fractional conversion, the current efficiency, the space-time yield and the specific energy consumed in a theoretical time t100.

Finally with the studies made with the pilot plant electrochemical reactor, a mathematical model for the residence time distribution and to optimize the parameters of the new configuration has been proposed with real solutions in order to recover the hexavalent chromium.