Electrochemical stripping of gold from Au-Ni-Cu electronic connector scrap in an aqueous solution of thiourea

J. C. Lin, J. J. Huarng

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

The electrochemical behaviour of a gold-plated connector from electronic scrap in aqueous thiourea solution has been investigated. An attempt was made to recover gold from scrap in a nontoxic thiourea medium by an electrochemical method rather than the traditional cyanide process. Linear sweep voltammetry indicated that thiourea extraction of gold is more efficient in acidic solution than in neutral and alkaline. Hydrochloric acid is preferable to control the pH of the solutions; the optimum concentration of thiourea is 2.5% (0.33 m). Analysis of voltammetric data yielded a critical potential (0.40 V vs SCE), which is the upper limit for significant extraction of gold from scrap. Higher potentials should be avoided in practice to prevent decomposition of thiourea and its passivation of the scrap. Electrolysis at constant potential indicated that gold was extracted selectively in the range 0.20-0.30 V vs SCE. Electrolysis at potentials either less than 0.15 V vs SCE or greater than 0.40 V vs SCE is not recommended, because of slow dissolution in the former and severe passivation in the latter.

Original languageEnglish
Pages (from-to)157-165
Number of pages9
JournalJournal of Applied Electrochemistry
Volume24
Issue number2
DOIs
StatePublished - Feb 1994

Fingerprint

Dive into the research topics of 'Electrochemical stripping of gold from Au-Ni-Cu electronic connector scrap in an aqueous solution of thiourea'. Together they form a unique fingerprint.

Cite this