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Vortex capture in high gradient magnetic separators at moderate Reynolds number
No full textThe authors report on an experimental investigation of the effect of increasing the slurry velocity in a single-wire cell to achieve a working-wire Reynolds number, Re, in the range 4-30. Attention is focused on this range because the slurry velocities are high enough for the boundary layer to have detached itself from the wire and for stable standing vortices to have formed at the rear of the wire. The particle-wire interaction and the flow domain around the wire are considered. The possibility of a turbulent contribution to rear wire capture due to the introduction of turbulence generators in the flow regime is explored. The interaction studied is basic to high-gradient magnetic separation<br/
Extraction of heavy metals using microorganisms and high gradient magnetic separation
No full textIt is pointed out that a large number of microorganisms have affinity to ingest or precipitate ion species onto their surfaces. In the case of magnetic ionic species, magnetic separation methods could be applied to remove the ion-loaded organisms from the surroundings. A wide range of metal ions were studied in the experiments described. The results show that the microorganisms developed an appreciable magnetic moment which lends to their removal by magnetic separation. The biomagnetic separation process was shown to be effective in reducing the concentration of a large number of ions either in multi-ion solutions or in a single metal ion solution. Reduction in most instances was from 10-100 p.p.m. to 10-100 p.p.b., a 90% removal. The single wire technique proved useful in the magnetic characterization of the microorganisms. The results indicate that this procedure is effective in estimating the magnetic susceptibilities of individual particles. The process described will have applications in the mineral processing industry, in the treatment of effluents from the nuclear industry, and in the recovery of precious metals<br/
Theoretical calculations and experimental results pertaining to a permanently magnetised filter
No full textThe evaluation of HGMS for mineral processing with a single wire
Full text linkIn this short communication it is shown that it is possible to undertake inexpensive but useful preliminary mineral studies using single–wire HGMS. Such studies enable an assessment to be made of the viability of HGMS as a large-scale processing technique for particular mineral slurries.<br/
The adsorption of heavy metals by tochilinite, an iron sulfide material produced by chemical precipitation: analysis using a simple theory of chemisorption
No full textThis paper describes the adsorption of heavy metals Cd, Ph, Cu, and Zn by a tochilinite-like material composed of alternating layers of Fe1-xS and Fe(OH)(2). The layers are thin, being of atomic dimension. The material was produced by chemical precipitation together with some magnetite, Fe3O4, which renders the material magnetic. The results were analyzed with a simple chemisorption model which contained two parameters g(=mass of the heavy metal adsorbed/mass of adsorbent added) and C, a kinetic term with dimensions, 1.mg(-1).h(-1)., h is the time elapsed in hours. The fitting procedure works well with values of g > 1, in some cases. However, according to the simple theory g and C should be constant independent of M-A, the mass of adsorbent added: the constancy predicted was not observed. From the variation of g and C with M-A the conclusion was that for a more complete understanding of the adsorption process, in addition to chemisorption adsorption-desorption processes must be included
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