Rimozione dell’arsenico dalla soluzione di lisciviazione di un concentrato enargitico-aurifero

Leaching a enargite-gold concentrate using sodium hypochlorite alkaline solutions, As is selectively dissolved in the form of arsenate AsO4(3-). In order to reuse the solution in the process, the arsenic was precipitated with ferric cloride and separated by filtration. In the study has been investigated: the influence of the method adoptated; pH; molar ratio Fe/As and reaction time. The obtained results evidenced that As has been precipitated almost completely in the form of an amourphous mixture of arsenate, ferric hydroxide and ferric oxyhydroxide(ferrihydrite), whic have a good stabilility, with small releases of arsenic on the long time in the storage ponds