Process for the removal of bismuth from a quantity of molten lead by the addition of calcium, magnesium alloys - -

摘要

The invention concerns a method for eliminating bismuth from molten lead with magnesium and calcium, which consists in inputting magnesium and calcium in the form of lumps of two Mg-Ca alloys, one containing predominantly Mg, the other containing predominantly Ca, each having a Liquidus temperature lower than 650 °C, and preferably less than 600 °C. The Liquidus temperatures of the two alloys are preferably close to less than about 20 °C. A particularly efficient treatment is obtained with a Mg-Ca alloy close to the eutectic alloy at 16.2 wt. % of calcium and containing 12 to 25 % of calcium and a Ca-Mg alloy containing between 60 and 80 % of calcium. The invention enables fast elimination of bismuth and adjustment of the Ca/Mg ratio during treatment.