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Dissolution of nickel ferrite in aqueous solutions containing oxalic acid and ferrous salts

Journal Article · · Journal of Colloid and Interface Science
The dissolution of nickel ferrite in oxalic acid and in ferrous oxalate-oxalic acid aqueous solution was studied. Nickel ferrite was synthesized by thermal decomposition of a mixed tartrate; the particles were shown to be coated with a thin ferric oxide layer. Dissolution takes place in two stages, the first one corresponding to the dissolution of the ferric oxide outer layer and the second one being the dissolution of Ni{sub 1.06}Fe{sub 1.96}O{sub 4}. The kinetics of dissolution during this first stage is typical of ferric oxides: in oxalic acid, both a ligand-assisted and a redox mechanism operates, whereas in the presence of ferrous ions, redox catalysis leads to a faster dissolution. The rate dependence on both oxalic acid and on ferrous ion is described by the Langmuir-Hinshelwood equation. In the second stage, Langmuir-Hinshelwood kinetics also describes the dissolution of iron and nickel from nickel ferrite. It may be concluded that oxalic acid operates to dissolve iron, and the ensuing disruption of the solid framework accelerates the release of nickel.
Research Organization:
Comision Nacional de Energia Atomica, Buenos Aires (AR)
OSTI ID:
20080255
Journal Information:
Journal of Colloid and Interface Science, Journal Name: Journal of Colloid and Interface Science Journal Issue: 2 Vol. 225; ISSN 0021-9797; ISSN JCISA5
Country of Publication:
United States
Language:
English