Journal article

A modification of the zeta potential of copper sulphide by the application of a magnetic field in order to improve particle settling

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Publication Details

Author list: Gqebe S, Rodriguez Pascual M, Lewis A


Publication year: 2016

Journal: Journal of the Southern African Institute of Mining and Metallurgy

Journal name: Journal of the Southern African Institute of Mining and Metallurgy

Volume number: 116

Issue number: 6

Start page: 575

End page: 580

Total number of pages: 6

ISSN: 2411-9717

eISSN: 2411-9717



Gravitational sedimentation of suspensions in various precipitation
processes is hindered by colloidal stability. This is due to the high surface
charge of the suspension and results in strong attraction/interaction
between the ions on the particle surface and counter-ions in solution.
Moreover, this strong interaction results in a charge build-up that renders
the suspension stable. In order to induce gravitational sedimentation of
these particles, a redistribution of ions close to the particle surface is
required. We therefore sought to redistribute ions close to the particle
surface by applying a magnetic field. This results in the reduction of
interparticle electrostatic repulsive forces and a subsequent increase in the
zeta potential of a suspension. For the purpose of this study, a copper
sulphide suspension was used. Copper sulphide particles were exposed to a
range of field strengths for set exposure times and their zeta potential was
measured before and after exposure. All particles had an initial zeta
potential value equal to or less than –40 mV prior to magnetic field
exposure. A significant increase in zeta potential was observed, with
values reaching a maximum of –16.5 mV when exposed to a 2 T field
strength for 40 minutes. This is due to Lorentz ion shifts resulting from the
Lorentz force exerted by the magnetic field on the particle surface.


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Last updated on 2017-28-04 at 15:59