ELECTROLYTE ADDITIVES FOR IMPROVED BEHAVIOR OF ANODES IN ELECTROWINNING OF METALS

Citation
Pr. Ramachandran et al., ELECTROLYTE ADDITIVES FOR IMPROVED BEHAVIOR OF ANODES IN ELECTROWINNING OF METALS, Transactions of the Indian Institute of Metals, 49(6), 1996, pp. 789-794
Citations number
6
Categorie Soggetti
Metallurgy & Metallurigical Engineering
Journal title
Transactions of the Indian Institute of Metals
ISSN journal
09722815 → ACNP
Volume
49
Issue
6
Year of publication
1996
Pages
789 - 794
Database
ISI
SICI code
0972-2815(1996)49:6<789:EAFIBO>2.0.ZU;2-Q
Abstract
Compounds of arsenic, phosphorous and cobalt have been investigated as additives to the electrolyte for the Improvements of anodes used in t he electrowinning of metals. Corrosion of lead anodes, anodic depositi on of PbO2 in lead electrowinning and poisoning of electrocatalytic an odes are some of the problems discussed. Addition of cobalt salt in sm all amounts to the electrolyte reduces anodic corrosion of lead anodes employed in the electrowinning. Corrosion in terms of PbO2 is largely avoided and instead oxygen evolution is promoted. Anodic formation of PbO2 from lead fluoborate electrolyte is controlled by the addition o f soluble compounds of P or As or Co to the electrolyte. Arsenic is fo und to he more effective even at a concentration of 500 ppm and prefer ential adsorption of these species on the electrode surface is the pro bable reason for the inhibition of PbO2 formation. Electrocatalytic an odes employed for the reduced cell voltage in the electrolytic cells g et poisoned by the presence of manganese in the electrolyte. Arsenic o r phosphorous compounds added in small amounts to the electrolyte, eff ectively controls anodic deposition of MnO2 prolonging the effective u se of the expensive electrocatalyst employed.