Pilot-plant testing at the Coleraine Research Laboratory
has indicated the potential benefits of dry magnetic separation
(cobbing) of Minntac rod-mill feed. Therefore, a prototype
commercial unit was installed on line 18 to establish the benefits
of dry cobbing. Line 18 was operated with and without dry cobbing
on alternate days. The initial test period indicated, that for a
short period and one splitter position, dry cobbing produced about
a 5 percent increase in the magnetic iron tons in the wet cobber
concentrate with a concurrent 2 percent loss in magnetic iron
recovery. About 25 percent of that iron loss was associated with
fine material being carried along with the dry cobber tailings. In
the second test period, a flow meter and density guage were installed
in the final concentrate line so that the actual long tons per hour
of concentrate produced could be measured. The second test period
ran for.about 2 weeks and showed a production increase of about 3
percent with essentially no loss in magnetic iron recovery.
While the tests are not totally conclusive they do indicate
potential benefits with dry cobbing. It is anticipated that with
the recommended optimization of the splitter position and with the
potential for increased iron recovery by screening the dry cobbing
tailings that production increases of greater than the observed
3 percent will be realized.
Prepared for: USX Corporation Technical Center, Monroeville, PA
University of Minnesota Duluth, Natural Resources Research Institute, 5013 Miller Trunk Highway, Duluth, MN 55811-1442
Benner, Blair R.
Dry Magnetic Separation of Rod-Mill Feed at Minntac: Progress Report No. 1.
University of Minnesota Duluth.
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