Optimization of the leaching conditions of an autoclave: Application to the dissolution of ferrocolumbite from san luis province, Argentina

摘要

The optimum working conditions of a Parr laboratory autoclave for minerals dissolution were studied and the results obtained were applied to the leaching with HF of a Nb and Ta mineral, from the San Luis, Argentina. The optimized variables were heating rate, liquid volume, stirring speed, inert solid addition and cooling rate. Changes in the liquid volume, stirring speed and presence of an inert solid did not produce modifications in the actual heating rate. The optimum heating programs ranged between 5 and 100C/min and depended on the programmed final temperature. The cooling period was 25 min. The results indicated that, using the optimum working conditions, more than 90% of mineral might be dissolved at 2200C. It was also observed that the dissolution of mineral was slightly affected by the stirring speed and the particle size whereas temperature, HF concentration, solid-liquid relation and reaction time strongly influenced the extraction of elements.