EDTA HYDROXYLAMINE SULFATE FE2- AN EFFICIENT CORROSION-INHIBITOR SYSTEM FOR AN INDUSTRIAL CRYSTALLIZATION PLANT( )

Unexpected corrosion problems that arose in a crystallization plant wi th evaporators made entirely of type 316L (UNS S31603) stainless steel (SS) were solved using a corrosion inhibitor system of ethylenediamin etetraacetic acid (EDTA)-hydroxylamine sulfate (Sl)-iron anions (Fe2+) . An experimental statistical plan reduced the number of experiments n eeded to optimize the concentration of EDTA-Sl-Fe2+. Moreover, the pla n allowed more rapid and economical study of the action of each compon ent in the inhibition mechanism. Statistical processing of the data co llected from the potential-vs-time anodic, and cathodic potentiodynami c measurements permitted estimations of the influence of each independ ent variable (EDTA, Sl, and Fe2+ concentrations). Voltammetric, polaro graphic, anodic potentiodynamic curves, and Flade potential measuremen ts helped further understanding of the inhibiting system.