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The electrochemical formation of Sc-Cu alloy was investigated in LiF-CaF2 eutectic molten salt employing various electrochemical methods. Cyclic voltammetry and square wave voltammetry indicate that the reduction of scandium(III) on the tungsten electrode is a one-step reduction process with three electrons transfer. As well as underpotential deposition of scandium on the copper electrode occurs owing to the depolarization effect, i.e., forming Sc-Cu intermetallic compounds. The thermodynamic properties of the Sc-Cu intermetallic compounds ScCu4, ScCu2, and ScCu in the temperature range of 1153–1223 K were estimated by open-circuit chronopotentiometry. Moreover, the Sc-Cu alloy were prepared by potentiostatic electrolysis and characterized by optical microscope, X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The results reveal that only Sc-Cu alloy composed of Cu-ScCu4 can be synthesized at low cathodic current density and above eutectic temperature.

In the present work, thermal decomposition of ASs in air was characterized by a combination of TG-DSC, XRD, and TG-FTIR. The treatment of generated toxic (CN)

The construction of a low-cost and green copper recovery method in gold plants is extremely important for treating CuSCN-containing refractory acidified sediments (ASs). In this work, an effective and environmentally-friendly hydrometallurgical process, consisting of thiosulfate leaching and protective electrodeposition, was proposed for selective copper recovering from ASs. The effects of leaching parameters on the leaching efficiency were systematically investigated. Subsequently, cyclic voltammetry, linear sweep voltammetry, and chronoamperometry were utilized to determine the predominant speciation and investigate the electrochemical behavior of the leachate. Eventually, the optimum electrolysis parameters for copper recovery were considered. The results demonstrated that the selective leaching efficiency of copper reached 99% under optimum leaching conditions, while no zinc and iron were leached, which coincides with the results of speciation calculations. Simultaneously, the kinetic analysis indicated that the leaching process exhibited a diffusion-controlled step with an apparent activation energy of 13.64 kJ/mol. Na2Zn3Fe(CN)6 as the main ingredient of the leaching residue was formed, which played a vital role in facilitating the copper leaching process. The electrochemical measurements indicated that the [Cu(S2O3)3]5- complex was the dominant species in the pH range from 7.0 to 11.0, and the mass transfer diffusion was the main resistance element for the cathodic reduction of the [Cu(S2O3)3]5- complex. Regarding the S2O32− stability, it decomposed more easily into S, S2−, S4O62−, and SO42− in the presence of Cu2+. However, the presence of SO32− significantly alleviated thiosulfate decomposition. The electrodeposition experiments showed that metallic copper was obtained with a recovery efficiency of 95%, current efficiency of 50%, and energy consumption of 1.25 kW h/kg Cu. This research developed an approach for the efficiently recycling ASs, yielding great economic results and more favorable environmental performance.