Визначення ефективністі та селективністі анодного розчинення жароміцного суперсплаву з ренієм у середовищах з хлорид-іоном та сульфатною або метансульфоновою кислотами

The object of this study is the electrochemical anodic dissolution of a heat-resistant nickel-based superalloy containing rhenium and other alloying elements in acidic electrolytes containing sodium chloride. The investigated alloy was obtained from scrap of high-temperature equipment. The anodic dissolution of the superalloy was studied in two acidic media: sulfuric and methanesulfonic acids. A comparative analysis of cyclic voltammetry and galvanostatic experiments was carried out. In sulfuric acid electrolyte, anodic processes proceed more vigorously, as indicated by higher current densities. However, this method records not only the dissolution currents of metals but also side processes such as anodic oxygen evolution and re-oxidation of dissolved ions. Under galvanostatic conditions, which allow direct determination of alloy mass loss, it was shown that methanesulfonic acid with sodium chloride provides a higher dissolution rate despite the medium's lower conductivity. This effect is explained by the higher solubility and stability of the methanesulfonates of the alloying components (Cr, Al, Nb, Ta, Re), which reduce the tendency of the surface to repassivate. In the H2SO4 + NaCl medium, dissolution proceeds more uniformly but at lower mass efficiency, attributed to the formation of poorly soluble sulfates. In the methanesulfonate electrolyte, within the current density range of 1.5–2.5 A·dm-2, the ratios of Ni, Cr, Co, W, and Re were closest to those in the original alloy, while rhenium was detected in solution, unlike in the sulfuric medium. The obtained results can be applied to optimize the initial stage of superalloy recycling and to develop electrochemical technologies for the recovery of strategically important metals from industrial waste