Electrochemical evaluation of anodes in lead electrowinning

<p>"The recovery of lead from scrap batteries using hydrometallurigical techniques requires a chemically stable and electrochemically attractive anode in the electrowinning step. A high reaction rate of oxygen evolution and a low generation of lead dioxide are necessary to ensure a satisfactory efficiency. One way to inhibit the formation of lead dioxide is by employing additives, such as phosphorus or arsenic, in the electrolyte. The objective of this research was to produce and electrochemically characterize lead dioxide electrodes and study the effect of the different additives on the anodic reactions.</p> <p>Lead dioxide was plated on both graphite and titanium substrates using a nitrate solution. The deposits consisted primarily of β-Pb0₂ along with lesser amounts of α-Pb0₂ . The morphology of various lead dioxide coatings was dependent on the plating solution.</p> <p>Phosphorus and arsenic additions to a lead fluosilicate solution prevented the formation of lead dioxide while dramatically polarizing the overall anodic reactions. The cobalt additive catalyzed the oxygen evolution on lead dioxide. Phosphorus and arsenic were adsorbed in the lead dioxide electrode and modified the crystal growth and morphology. Electrochemical impedance spectroscopy tests revealed that the inhibition of the anodic reactions was related to the phosphorus and arsenic concentration. The adsorption of phosphorus or arsenic ions at the electrode during lead dioxide formation increased the charge transfer resistance for lead dioxide formation and polarized lead dioxide crystallization to overpotentials where the oxygen evolution reaction is dominant making lead electrowinning effective and efficient"--Abstract p. iv</p>

Name thesis:degree_name

Ph. D. in Metallurgical Engineering

Grantor

University of Missouri--Rolla

Year dc:date.available

2016

Author dc:creator

• Bemelmans, Christel

• Metallurgy

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/727

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-1729