Sedimentation acceleration of remanent iron oxide by magnetic flocculation--颗粒学报PARTICUOLOGY

Stolarski, M., Eichholz, C., Fuchs, B., & Nirschl, H. (2007). Sedimentation acceleration of remanent iron oxide by magnetic flocculation. China Particuology, 5(1), 145–150. https://doi.org/10.1016/j.cpart.2007.01.005

Sedimentation acceleration of remanent iron oxide by magnetic flocculation

Mathias Stolarski ^a *, Christian Eichholz ^a, Benjamin Fuchs ^b, Hermann Nirschl ^a *

a Institute of Mechanical Process Engineering and Mechanics (MVM), University of Karlsruhe, 76131 Karlsruhe, Germany
b DuPont, Experimental Station, Building E304 Wilmington, DE 19880, USA

10.1016/j.cpart.2007.01.005

Volume 5, Issues 1–2, February–April 2007, Pages 145-150

Received 14 June 2006, Accepted 17 January 2007, Available online 6 June 2007.

E-mail: mathias.stolarski@mvm.uni-karlsruhe.de; hermann.nirschl@mvm.uka.de

Highlights

Abstract

Sedimentation based processes are widely used in industry to separate particles from a liquid phase. Since the advent of the “Nanoworld” the demand for effective separation technologies has rapidly risen, calling for the development of new separation concepts, one of which lies in hybrid separation using the superposition of a magnetic field for magnetic particles. Possible product portfolio of such separation consists of pigment production, nanomagnetics production for electronics and bio separation. A promising step in that direction is magnetic field enhanced cake filtration, which has by now progressed from batch to continuous operation.

In sedimentation processes in a mass force field the settling behaviour of particles strongly depends on physico-chemical properties, concentration and size distribution of the particles. By adjusting the pH, the interparticle forces, in particular the electrostatic repulsion, can be manipulated. For remanent magnetic particles such as magnetite, pre-treatment in a magnetic field could lead to a change of interparticle interactions. By magnetizing the particles apart from van der Waals attraction and electrostatic repulsion, an additional potential is induced, the magnetic attraction, which could easily dominate the other potentials and result in agglomeration in the primary minimum. By sedimentation analysis, a wide spectrum of parameters like pH, magnetic field strength and concentration have been investigated. The results show a strong increase of sedimentation velocity by magnetic flocculation of the raw suspension. This leads to a rise in throughput due to the acceleration of sedimentation kinetics by imparting a non-chemical interaction to the physico-chemical properties in the feed stream of the separation apparatus.

Graphical abstract

Keywords

Magnetic flocculation; Field enhanced separation; Cake filtration; Magnetic structuring; Magnetic separation

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