Recovery of antimony from acidic and alkaline leaching solution of low-grade antimony ore by electrowinning process.

With regards to the global continuous growth in consumption of base metals such as antimony (Sb), mining companies are currently looking to improve the productivity and extraction of Sb from low grade ore in order to economically process it. With this aim, in this study, an efficient protocol was developed to recover metallic Sb from the low grade FeSiO(OH). SbO(OH). SbO ore of the Sefid-Abe mine in Zahedan province, Iran, utilizing selective acidic or alkaline leaching followed by Sb electrowinning. A process was developed to recover antimony from an SbO ore source, using selective acidic or alkaline leaching followed by antimony electrowinning. Sb could be leached with an efficiency of 85 % using 5 M NaOH and 87 % using 5 M hydrochloric acid/5 M sulfuric acid as the digestion solution at 80 °C for 8 h. The electrowinning process plays a significant role in recovery of highly pure Sb metal. Relying on this approach, a high deposition rate and current efficiency have been generated at a deposition potential 2 V at 30 °C (80 °C for alkaline medium). This was achieved by using anode electrode made of graphite and cathode electrode made of steel (two steel electrodes were used for alkaline electrowinning). Additionally, for acidic electrowinning, exploitation of Sb from the electrolyte solution was achieved by applying a current of 0.1 A, resulting in the highest yield equal to 89 %. On the other hand, for alkaline electrowinning, the highest efficiency corresponds to the current intensity of 0.5 A, which resulted in 97 % Sb extraction from the electrolyte solution. The XRD and ICP analysis performed for samples obtained from the electrolysis confirmed that the resulting antimony ingot has an exceptionally high purity.