Title

The Effects of Glue and Thiourea on the Electrodepostion of Bismuth and Copper from Acidic Sulfate Solutions

Abstract

The effects of commercial copper electrorefining additives (glue and thiourea) on the electrochemical removal of bismuth are of importance in copper production. It was found that Bi(III) electrodeposition occurs readily from acidic sulfate solution via a diffusion-controlled quasi-reversible reduction. The diffusion coefficient of Bi(III) was measured and found to be less than reported values of copper in similar solutions. The presence of thiourea and/or glue was found to accelerate or de-polarize Bi(III) reduction on stainless steel as compared to the inhibition or polarization of Cu(II) reduction. The additives also inhibited the dissolution of the Bi-Cu co-deposit during cyclic voltammetry. During short term deposition studies, the additives increased the concentration of Bi in co-deposited Cu-Bi products from solutions with low concentrations of Cu ( < 2 g/L). Bi deposition was significantly suppressed by increasing the Cu(II) concentration in the solution. The formation of a copper layer on the stainless steel electrode appeared to significantly suppress the reduction of Bi(III). This study demonstrates that glue and thiourea depolarize the deposition of bismuth on stainless steel. Therefore, the additives could be used to improve Bi impurity removal during third stage liberation.

Meeting Name

28th International Mineral Processing Congress, IMPC 2016 (2016: Sep. 11-16, Quebec City, Canada)

Department(s)

Materials Science and Engineering

Keywords and Phrases

Additives; Bismuth; Copper electrorefining; Glue; Liberation; Thiourea

International Standard Book Number (ISBN)

978-192687229-2

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2016 TAPPI Press, All rights reserved.

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