Method for eliminating bismuth from molten lead by adding two different alloys of calcium and magnesium with control of the Ca/Mg ratio during treatment

摘要

A method for eliminating bismuth from molten lead consists of adding lumps of two Mg-Ca alloys, one containing predominantly Mg and the other containing predominantly Ca, each with a liquidus temperature below 650 deg C, and preferably less than 600 deg C. The liquidus temperatures of the two alloys are preferably within a range of less than 20 deg C to each other. A particularly effective treatment is obtained with a Mg-Ca alloy close to the eutectic alloy at 16.% by weight of calcium and containing 12 to 25% of calcium and a Ca-Mg alloy containing between 60 and 80% of calcium.