日本金属学会誌

J. Japan Inst. Metals, Vol. 38, No. 7 (1974),
pp. 663-668

Anodic Reaction of Nickel Sulfide and Pyrrhotite in Acid Solution

Tokio Kato1 and Takeo Oki2

1Faculty of Engineering, Nagoya University, Nagoya. Present address: Semiconductor & Integrated Circuits Division, Hitachi, Ltd., Kodaira, Tokyo
2Faculty of Engineering, Nagoya University, Nagoya

Abstract:

To clarify the anodic dissolution mechanisms of nickel sulfide and pyrrhotite in acid solution, measurements of the electrode potentials and anodic polarization behavior, and galvanostatic anodizing were carried out.
(1) Nickel sulfide dissolved anodically in sulfuric and perchloric acid solutions through the following two simultaneous reactions;
(i)\phantom{i }NiS → Ni2++S0+2e,
(ii) NiS+4H2O → Ni2++SO42-+8H++8e.
(2) Pyrrhotite dissolved anodically with high current efficiency in perchloric acid solution through the following principal reaction: FeS → Fe2++S0+2e.
In sulfuric acid solution, however, an anodic film which consisted mainly of anodized elemental sulfur and iron compounds was formed. As a result, the anodic potential of pyrrhotite in galvanostatic anodizing was extremely unstable and the dissolution current efficiency was considerably lower than that in perchloric acid solution.


(Received 1974/02/28)

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