Dressing Weakly Magnetic Iron Ores by Dry Magnetic Separation Process
Dressing Weakly Magnetic Iron Ores by Dry Magnetic Separation Process
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Date
2015-05-03
Authors
Abdalla, Mohamed Abdelmonem Mohamed
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Journal ISSN
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Publisher
UOFK
Abstract
Iron ore samples were obtained from El Bajrawiya iron ore deposits in order to beneficiate these
ores. Chemical analyses and microscopic examination have shown that these ores mainly
contain valuable mixtures of weakly magnetic iron oxides; (goethite, limonite and hematite), and
non magnetic gangue materials; (silica), and clay minerals as major impurities. These materials
were prepared to be beneficiated by dry high intensity magnetic separation process, by crushing
and grinding to liberate the iron oxide grains from the cement of the ore matrix. Crushing and
grinding processes produced significant amounts of fine materials (-53μm), which could not be
treated by the available machine within the Central Petroleum Laboratories (dry high intensity
magnetic separator). Hence, all ground samples materials were washed to remove the fines by
wet screening on the 53 micron sieve. The portions of each sample coarser than 53 μm were
dried and screened on a nest of sieves to yield four size fractions each having closer ranges for
the magnetic separation in order to avoid the gravity effect on the process.
The Frantz Magnetic Barrier Laboratory Separator Model (LB-1) was used to conduct the
separation tests on each size fractions of the washed various ores. Recovery of iron values and
the separation efficiency were assessed by determining the percentages of Fe in the concentrates
and tailings by Atomic Absorption Spectrometry (AAS) techniques..
The separation process was applied on four mixtures of iron oxides as feed for the process. They
were having average grades 32.94, 41.43, 17.00 and 48.00% Fe. The process of treatment gave
concentrates having average grades from the feed 39.79, 49.82, 47.67and 52.76 % Fe and
average iron recoveries were 86.83, 87.63, 76.32 and 83.51 %, respectively. The flow rates of the
feed into the separator were: 19.63, 20.32, 25.66 and 12.37 g / minute, respectively. These results
were achieved when the Frantiz separator was operated at 0.8 ampere. However, when the
ampere of the separator was increased to 1.0 ampere, the recoveries were increased on the
account of the grades which were decreased remarkably
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Keywords
Dressing,Weakly,Magnetic,Iron,Ores,Dry,Magnetic,Separation,Process