A unique pyrometallurgical lead refining process includes adding a Lewis acid component and an Arrhenius base compound to a molten lead bullion. The Lewis acid component and Arrhenius base compound are added in stoichiometric amounts that preferentially remove lighter amphoteric elements from the molten lead bullion, and promote reactions with amphoteric p-block elements in the lead bullion to form over the lead a slag of Lewis bases, thereby forming a slag layer incorporating the metal salts of the amphoteric p-block elements.