Paint casting: A facile method of studying mineral electrochemistry

Abstract

The electrochemical properties of minerals are often difficult to study due to the need to maintain an electrical contact with the current collector. In this study it is shown that a paste of the powdered mineral can easily be made by mixing it with an ionic liquid and painting this onto an electrode surface. This enables voltammograms with high resolution and relatively low resistive artefacts to be obtained. The oxidative and reductive charge can be correlated to the loading of mineral on the electrode.

Dissolution of pyrite and other Fe–S–As minerals using deep eutectic solvents

“…This technique has recently been demonstrated to be effective for the dissolution and electrochemical recovery of galena (PbS) and the signal was shown to be relatively independent of the mineral loading. 26 The use of a paste to dissolve and recover elements from ores ensures the minimum volume of solvent (lixiviant). The solute is processed from saturated solutions ensuring small distances over which mass transport occurs.…”

A Unified Method for the Recovery of Metals from Chalcogenides

“…The advantages of using lead are that Pb II is unlikely to be oxidized further to the unstable Pb IV within the potential window of ChCl:2EG, the redox potential of the Pb II/0 couple is likely to be sufficiently cathodic to the oxidation of the chalcogenide species, and the electrochemical behavior of lead is well-characterized. 28 To differentiate the redox processes associated with the chalcogenides from that of lead alone, CVs of the lead-free chalcogenide compounds were also measured (Na 2 S, Na 2 Se, and Na 2 Te), along with a chalcogenide-free Pb II compound (PbCl 2 ). The oxidation of chloride would take place alongside the anodic decomposition of the solvent and is not observed within the electrochemical window of the DES.…”

“…1.5 × 1.5 cm 2 ) bent at an angle of 90° that had been painted with a slurry of ca. 40 mg of material which had been ground to a paste with DES . For the semiconductor materials, it was important to ensure that the particle size was as small as possible and only the minimum amount of paste necessary was used on the working electrode, otherwise the resistive current was high and resolution of the redox peaks was poor.…”

“…40 mg of material which had been ground to a paste with DES. 28 For the semiconductor materials, it was important to ensure that the particle size was as small as possible and only the minimum amount of paste necessary was used on the working electrode, otherwise the resistive current was high and resolution of the redox peaks was poor. Cyclic voltammetry (CV) was performed using an IVIUMnSTAT multichannel potentiostat/galvanostat together with the corresponding Ivium software.…”

“…Other DESs made with either ethylene glycol or urea as the HBD component have been used to deposit films of lead selenide, lead telluride, copper telluride, and zinc telluride . During anodic dissolution, it has been shown that oxidation of metal sulfides can lead to the simple recovery of metals such as Pb, Fe, and Cu, − and this has recently been extended to oxides …”