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Kinetics of sulfation of nickel and cobalt ferrites with sodium sulfate melt containing iron(3+) ions

Jacob, KT (1987) Kinetics of sulfation of nickel and cobalt ferrites with sodium sulfate melt containing iron(3+) ions. In: Transactions of Indian Institute of Metals, 40 (2). pp. 383-388.

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Abstract

$Ni$ and $Co$ were extd. from their ferrites by using $Na_2_S_O_4$ melts contg.$Fe^3^+$. The kinetics of extn. from synthetic ferrites using an $Na_2_S_O_4-Fe_2(S_O_4)_3$ eutectic melt were studied as a function of ferrite particle size and temp. at 900-1073 K. The divalent ions in the ferrite exchanged with $Fe^3^+$ in the melt to leave a hematite residue. The rate of reaction conforms to that of the Crank-Ginstling-Brounshtein diffusion model (1950, 1957). The reaction rate is governed by the counter diffusion of $Fe^3^+$ and $Ni^2^+$ or $Co^2^+$ in the hematite lattice. Anal. expressions for the rate consts. were derived from the exptl. data as a function of particle size and temp. Activation energy for the extn. of $Ni$ from $Ni$ ferrite is 154 kJ/mol, and the corresponding value for $Co$ is 142. In sulfation roasting of minerals contg. $Ni$, the yield of $Ni$ is generally limited to 75% due to the formation of sol. ferrites. Use of melts based on $Na_2S_O_4$ provides a possible route for enhancing $Ni$ recovery to .apprx.98%.

Item Type: Journal Article
Additional Information: The copyright belongs to The Indian Institute of Metals
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited: 28 Feb 2008
Last Modified: 07 Oct 2010 09:39
URI: http://eprints.iisc.ernet.in/id/eprint/12438

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