Impurities and oxygen control in lead alloys

Abstract

The control of the impurities is of major interest for ensuring adequate and safe operation of lead alloys facilities from the viewpoint of the corrosion phenomenon. Specific methods have to be implemented for effective control of the liquid lead–bismuth eutectic quality to the required specifications, as for instance: dissolved oxygen monitoring, dip sampling system, analytical techniques for impurities measurement. Even though the oxygen control in the static facility BIP proved difficult, a better knowledge of kinetics behaviour of the oxygen is acquired. Oxygen sensors gave results in agreement with the theory during the tests achieved on the BIP and on the COLIMESTA facilities. The dip sampler was validated on static device: it allows an effective sampling of the liquid metal melt and an easy separation of the melt from the sampling device when cold. The set of analytical techniques for the measurements of metallic impurities is efficient as well, except for the nickel element, for which the method of analysis with atomic absorption spectroscopy coupled with spiking method should allow the lower detection limit to be decreased below the 5 μg/g as for the iron impurity.