Efficient separation of lead and antimony metals from the Pb-Sb alloy by super-gravity technology

The Pb-Sb alloy was obtained during the pyrometallurgical processing of jamesonite (Pb4FeSb6S14). To effectively separate lead and antimony metals from the Pb-Sb alloy, an innovative approach of super-gravity technology was introduced in the current study. The super-gravity technology plays a significant role in enhancing mass transfer and phase migration of heterogeneous phases as the interfacial tension between different phases will become insignificant. The theoretical calculation of separating efficiencies based on the lever principle of Pb-Sb phase diagram was investigated. The effect of the super-gravity field on Pb-Sb alloys and the corresponding mechanism of filtrating were discussed. With the help of scanning electron microscopy-energy dispersive spectroscopy, metallographic microscopy and X-ray diffraction methods, it demonstrated that the lead phase migrated to the bottom of the sample along the super-gravity direction, whereas almost all of the antimony-rich phase accumulated along the opposite direction. As a step further, the Pb-Sb alloy was separated effectively by the filter in the super-gravity field, and the separating efficiency increased with the increasing of the gravity coefficient (G) within the range of G ≥ 50. With an optimized separation condition T = 533K (260 °C), G = 450, d pore  = 48 μm and t = 210 s, the mass fraction of Pb in the filtrated lead phase reached 85 wt%, which was close to the theoretical separation value 88.8 wt% based on the phase diagram of the Pb-Sb alloy, and the mass fraction of Sb in the residue antimony-rich phase exceeded 91 wt%.