Cinética de la Disolución de Columbo-tantalitas en Soluciones Acuosas de Acido Fluorhídrico

M. RODRIGUEZ; M. DEL C. RUIZ; O. QUIROGA

San Carlos de Bariloche (Río Negro)

Congreso; Jornadas SAM, Congreso CONAMET; 2003

Centro Atómico Bariloche

The dissolution rate of a columbo-tantalite of the San Luis Province in aqueous solutions of hydrofluoric acid has been studied. Experiments at different temperatures were carried out in a pressure reactor. The experimental results show that the mineral dissolution increases with the reaction time. This effect is greater when the temperature increases from 348 up to 396 K, but it is little 493 K. The experimental data were treated with different models, which have been deduced for the kinetic study of solid-fluid non-catalytic heterogeneous reactions. As a result, the better model that fit the experimental data is a model based on the "nucleation and growth" theory. This model is physically according to the attack observed by means of scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDXS) on the mineral residues. These residues show an irregular located-type attack. Keywords: Kinetic; Hydrofluoric acid; Columbo-tantalite; Leaching; Pressure