Thermo–Kinetic diagrams: The Cu–H2O–Acetate and the Cu-H2O systems

Abstract

Abstract The thermo-kinetic (TK) diagram for the Cu–H2O system with and without acetate ions is developed and presented. The TK diagram, which is an Eh-pH-i contour map, can be used to evaluate the kinetics of the electrochemical processes occurring at the electrode/solution interface in the Eh–pH domain. Such a diagram can be used for corrosion engineering or for improved leaching performance in metal extraction and recycling processes. The TK-diagrams are developed based on experimental data collected under controlled conditions (298 ± 01 K, rotation at 500 rpm) and they do not require thermodynamic data or thermodynamic calculations. The electrochemical response of a pure Cu–Rotating Disk Electrode (Cu–RDE) was determined by linear sweep voltammetry scans and plotted as Eh vs. log i. The TK–diagram quantifies the rate of the faradaic process taking place on the Cu-RDE as a function of applied potential and solution pH. Based on the magnitude of current density, different regions in TK-diagrams can be differentiated similarly to those in the classic Eh-pH diagrams. TK-diagrams can be developed for other metals and minerals in aqueous media containing various ligands. The merits and disadvantages of using these diagrams are also discussed.