Iron Ore Concentration No. 2. [Volume: 8, Issue: 2, 1888, pp. 97-111]

No. 2.1

CHARCOAL IRON WORKERS.

105

first convert its oxide into the magnetic oxide, and then put it
through his machine. One of his machines is now being operated up in Michigan, at the Humboldt Mine, and others have
been ordered for eastern mines.
The separation of the ore from the Cornwall hills, in Pennsylvania, attracted marked attention from the delegation of the United
States Association of Charcoal Iron Workers which visited the
Edison Laboratory. The sample separated was not specially
analyzed, but was of the average merchantable ore with iron about
48 per cent. and sulphur 2 per cent. An analysis of the concentrate showed iron 64.38, sulphur 0.90, phosphorus 0.03, silica 5.02.
THE WENSTROM MAGNETIC SEPARATOR has been in use for over
four years at Dannemora and at other mines in Sweden, and special
merit for it is based on its capability of taking ore in large sizes, so that
it is possible to eliminate by "cobbing" a good deal of waste rock
without the expense of crushing it to a fine size. The machine has a
stationary field magnet, A, plate VI and VII, and an armature barrel,
B consisting of a number of soft iron bars, E, separated from one
another by a non-magnetic material-in this case strips of wood.
The whole bound together by non-magnetic end-rings, F. The
bars E are cut away alternately on the inside to make one bar
project only towards the north poles of the magnet, and the next
only to the south poles, as is shown in plate VII at E and by dotted
lines. This gives each succeeding bar opposite magnetism. On
each of the four sections of the magnet are wound fifteen pounds
of copper wire. An Edison dynamo furnishes a current of ten
amperes and thirty-three volts. The ore is fed to the barrel by
means of a hopper, as shown in the engraving, the cylinder turning in the direction of the arrow on plate VII. The magnetic ore
adheres to the bars of the barrel and is carried downward past
the first delivery shute. Below the machine the bars, departing
from the influence of the electro-magnet, which is placed eccentrically, lose their power to hold the particles of magnetic iron ore
and they drop off. The particles of rock.in the ore, being nonmagnetic, drop from the barrel almost immediately and fall on the
NOTE.-For the cut of the Edison separator and also that of the Wenstrom
separator we are indebted to the courtesy of the Iron Age.
v