Adds specified type and amount of reagent and agitates mixture to cause impurities, such as antimony, arsenic, bismuth, and tin to form into dross. Skims dross off mixture, using ladle, shovel, or perforated dipper. Throws zinc bricks into kettle and agitates mixture to desilverize lead. Skims crust of silver and gold content into basket of press, and compresses dross with air-driven ram. Pumps lead through reaction cylinder while chlorine is admitted to form zinc chloride slag. Skims slag after completion of reaction as indicated by color of slag and molten metal. Pours metal into molds or dips samples into cold water to prepare them for laboratory analysis. May hook pot to crane and signal OVERHEAD CRANE OPERATOR (any industry) 921.663-010 to transfer lead from one kettle to another. May crystallize zinc in water-cooled vacuum tank to remove zinc from desilverized lead. May produce antimony crystals from antimonial lead by mixing prescribed reagents with molten metal in kettle, by skimming dross, and by cooling bath to specified temperature. May be known according to specific duty performed as Desilverizer (smelt. & refin.).
