Highly efficient separation of Ag, Cu and Sn by vacuum cracking to prepare ultra-pure energy metal lead materials

Abstract

Ultra-pure lead has been confirmed as an irreplaceable metal material that is employed for new energy storage batteries, aerospace, nuclear industry. Ultra-pure lead has been scarcely produced because of the lack of large-scale low-cost production techniques, such that the development of the lead industry is significantly hindered. To develop a clean and efficient deep purification technology, a novel process invented preferentially employed vacuum dissociation as the core and cracks intermetallic compounds (e.g., PbnAgn and PbmCum) in metallic lead lumps in a low-pressure system. Subsequently, the main metallic lead volatilized based on the difference in gasification characteristics. Impurities (e.g., Ag, Cu, and Sn) are separated and then enriched as residues. The contents of impurities (i.e., Cu, Sn, and Fe) in the vacuum gasification volatiles only reached 0.004 ppm, 0.012 ppm, and 0.006 ppm, and the impurity content of Ag was obtained as 0.06 ppm. Besides, the product lead conformed to the 6 N Pb standard, and the direct recovery rate of metallic lead exceeded 90%. Furthermore, metallic lead can be deeply purified by single vacuum gasification, which serves as a novel, clean, efficient, energy-saving, and low-carbon method for the preparation of ultra-pure lead.