Green Electrorefining of Crude Lead with High-Quality Deposits in an Additive-Assisted Methanesulfonic Acid System

Abstract

The conventional electrorefining process of crude lead (Pb)�employing a bone glue (BG)-and calcium lignosulfonate (CL)synergistically assisted fluosilicic acid (H 2 SiF 6 ) system�suffers the undesired environment burden caused by the high saturated vapor pressure and low stability of H 2 SiF 6 . Herein, we propose an additiveassisted methanesulfonic acid (MSA) system for green and efficient electrorefining of crude Pb based on the low volatility and high stability of MSA. Combinations of MSA with additives are evaluated and screened using photographic images, SEM observations, XRD, white light interference, etc. The electrochemical analysis of cyclic voltammetry and chronoamperometry elucidates the Pb deposition behavior in the Lugalvan BNO12-assisted MSA system, in which a three-dimensional nucleation model is applicable. Using MSA as the solvent and β-naphthol ethoxylate (Lugalvan BNO12) as the assisted additive, the bench-scale operation of crude Pb electrorefining experimentally achieves an electric energy requirement (W) of 87 kWh e /t Pb and a cathodic current efficiency (η) of 99.6%. This is very competitive with the W of 120 kWh e /t Pb and η of 95.0% for the BG-CL-assisted H 2 SiF 6 system. Also, the bench-scale operation obtains a plat and dense deposit sample with a Pb purity of >99.99%. The distribution behavior of elements shows that most of the Pb element is recovered in the form of the cathodic Pb, elements Sn, Zn, and Fe mainly accumulate in the electrolyte, and elements As, Sb, Bi, Ag, and Cu remain in the anode slime. This work opens new directions for more technically and economically feasible Pb electrorefining.

Highly dispersed Ir/Fe nanoparticles anchored at nitrogen-doped activated pyrolytic carbon black as a high-performance OER catalyst for lead recovery

“…15 The hydrometallurgical process for high-purity Pb is based on electrochemical conversion, mainly including solid phase, chlorine salt, silicofluoric acid and MSA electrolysis, etc., in which the first three electrolytic methods for Pb recovery involve high energy consumption, long working time, serious equipment corrosion, and environmental pollution. 16 In contrast, the MSA electrolytic system is unanimously considered to have broad application prospects in the electrolytic Pb industry due to its excellent electrical conductivity, strong acidity, high boiling point, good stability, low toxicity, and high solubility of Pb. [17][18][19] However, during the current electrolytic recovery process in MSA, high-purity Pb metal can be recovered at the cathode, while there exists oxidation of both Pb and water in the anodic area, producing PbO 2 and O 2 , respectively, which will result in excessive operating voltages of the electrolyzer.…”

Electrochemistry of Tin Deposition from Methanesulfonic Acid

“…Kong et al [21] studied the effects of pH and cobalt concentration in an MSA system on the nucleation and growth of cobalt on a glassy carbon (GC) electrode via cyclic voltammetry and chronoamperometry, and clarified the electrocrystallization mechanism of cobalt on the GC electrode. Xiang et al [22] employed electrochemical analysis techniques such as cyclic voltammetry and chronoamperometry to investigate and understand the deposition behavior of lead, revealing the deposition mechanism of Pb and the nucleation and growth mode of deposition. The concept validation operation proves that the addition of β-naphthol ethoxylate to the MSA system is an effective and stable operation for Pb electrorefining, which has great advantages over H 2 SiF 6 .…”

Energy-Efficient and Green Extraction of Bismuth Metal in Methanesulfonic Acid-Based Membrane Electrochemical Systems

“…Due to its higher conductivity, larger metal salt solubility, and lower toxicity, MSA is widely used as an electrolyte in metal plating (Pb, , Sn, Cu, Ag, Zn, Ni, etc.) and crude metal electrorefining. − In recent years, MSA has also been used in the field of hydrometallurgy as a leaching agent to extract valuable metals from primary minerals (cerussite, chalcopyrite, , etc.) or secondary solid waste resources (zinc leaching residue, lithium-ion batteries, , coal ash, and spent lead-acid batteries, etc.).…”