Kinetic modeling of CuO chlorination with C2Cl4

Chlorinating roasting is a well-known process devoted manly for the extraction of metals as volatile chlorides from oxidized minerals and residues. Experience has shown that the use of a gaseous chlorinating agent, Cl2, for example, and the incorporation of a reducing agent, charcoal, for example, stimulate, respectively the kinetics and thermodynamics of the desired reactions. In this scenario, organo-chlorinated molecules, such as, CCl4 and C2Cl4, appear as potential candidates for Cl2 replacement, as they can be easily volatilized and bear in the same molecule the chlorinating and reducing agents. In order to support reactor sizing, however, reliable kinetic data is needed, which are scarce regarding both mentioned chlorinating agents. In present work, chlorination of pure CuO samples with diluted C2Cl4 (P(C2Cl4)=0.0307atm) has been quantitatively appreciated in the range between 923 and 1173K. The kinetic data were modeled according to the Shrinking-Core model (SCM) and a quantitative agreement between experimental and calculated data has been found for all temperatures. Finally, a global activation energy of 117.9±10kJ/mol has been determined, which is close to earlier literature values for similar systems. A significant reduction of the form factor with temperature (3 to 1.5) has been detected, which, can be correlated to the partial sintering of the remaining CuO crystals.