A METHODOLOGY FOR ANALYZING Se IN Mn ELECTROLYTIC METAL AND Al MATERIALS COMING FROM THE CASTHOUSE

摘要

Production of Mn electrolytic metal can be improved by the addition of selenium derivatives. Se is then added to the production of aluminum when Mn compacts are added to the molten bath in the cast house. Problems related to Se toxicity during aluminum processing, and specially during the recycling of aluminum drosses, have been reported in the last years at different TMS conferences. In spite of this, actual content of Se is rarely certified or even reported in the documentation supplied by Mn electrolytic metal producers, although Se concentrations are essential to classify Mn lots. This work tries to solve controversies about real content of Se in Mn additives with the development of an analytical method based on the HG-ICP-OES technique (hydride generation-inductively coupled plasma-optical emission spectrometry) which is inexpensive, easy to handle and adequate in terms of high sensibility and repeatability for industrial metallic matrixes. A laboratory reference material (LRM) of Se in electrolytic Mn has been prepared to verify the goodness of the measurements performed. The new methodology allows to control precisely and accurately the Se concentration in Mn raw material lots, and in Al baths and drosses, thus a more adequate answer to issues of Se fate in aluminum production chain can be given.