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High Gradient Magnetic Separation of Iron Oxides and other Magnetic Minerals from Soil Clays
Author(s) -
Schulze D. G.,
Dixon J. B.
Publication year - 1979
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1979.03615995004300040036x
Subject(s) - hematite , magnetic separation , magnetic mineralogy , fraction (chemistry) , chlorite , vermiculite , materials science , particle size , magnetite , kaolinite , goethite , mineralogy , analytical chemistry (journal) , remanence , chemistry , quartz , magnetic field , environmental chemistry , metallurgy , adsorption , chromatography , magnetization , composite material , physics , quantum mechanics , organic chemistry
A filter of ferromagnetic stainless steel wool, placed in a strong magnetic field, provides the magnetic field gradients necessary to trap weakly magnetic clay size particles from a flowing suspension. Of the total dithionite‐citrate‐bicarbonate extractable Fe 2 O 3 in the 2–0.2 µm size fraction of six soils, 70 to 94% was recovered in the magnetic fraction which consisted of 1.6 to 27.7% free Fe 2 O 3 by weight. For the <0.2 µm size fraction, 11 to 40% of the total free Fe 2 O 3 in the size fraction was recovered in the magnetic fraction which contained 2.8 to 53.1% free Fe 2 O 3 by weight. Larger particles are captured more efficiently because of their greater overall magnetic attraction. Goethite, hematite, lepidocrocite, and anatase are concentrated in the magnetic fraction, while quartz is concentrated in the tailings. Chlorite is effectively concentrated in the magnetic fraction. Although mica, vermiculite, and smectite are often found in both the tailings and the magnetic fraction, vermiculite and mica appear to be more concentrated in the magnetic fraction. The concentration effect on kaolinite appears to be dependent on the particle size and rate of flow through the magnetic filter.