METHOD OF REFINING LEAD TO REMOVE ANTIMONY, TIN, AND ARSENIC IMPURITIES Russian patent published in 2003 - IPC

FIELD: nonferrous metallurgy. SUBSTANCE: method comprises preliminary treatment consisting in addition of aluminum to lead melt at temperature not exceeding 680-750 C, stirring, settling, and subsequent final refinement. The latter operation ensuring production of high-grade lead is accomplished via cooling melt at velocity 10 deg/min to 350 C, while simultaneously removing solid takeoffs, followed by anodic polarization in sodium hydroxide at 360-380 C during no longer than 2 h. EFFECT: increased degree of refinement, reduced process time, and avoided use of expensive and dangerous reagents. 1 tbl