CARBOCHLORINATION OF ARGENTINEAN TANTALO-COLUMBITES

The extraction of Nb and Ta from tantalo-columbites of San Luis, Argen tina has been studied at the laboratory scale. The ore mixed with carb on was chlorinated in a fixed bed reactor operated with downcoming flo w and pressures close to atmospheric. The variables investigated were: ore/carbon ratio, mixing time and procedure; temperature and reaction time; particle size and previous ore treatment with HCl, EDTA and NaO H solutions. The results obtained showed that: the optimum percentage of carbon varies with temperature; Nb and Ta recovery is hardly affect ed by the mixing time; the influence of the mixing procedure is import ant; recovery increases both with higher temperature and with longer r eaction times, and decreases with larger particle size; in general, or e leaching led to a decrease in the solid reactivity to the chlorinati on process. The solids were characterised by BET, XRD, XRF, SEM and op tical microscopy. Quantitative chemical analyses were carried out by X RF, ICPAES, gravimetry and UV-Visible spectrometry. (C) 1997 Published by Elsevier Science Ltd.