The Roanoke times. [volume] (Roanoke, Va.) 1890-1895, 1890-10-22

one tiIne Drown ore was considered IN
dispensablc for the production of
foundry-iron. Prior to the development
of tho Lake Superior hematite regions,
brown hematite was the chief ore in use
in America. 1t occurs abundantly
throughout Germany. sit supplies by
far the greater number of French iron
| workers: and it occurs also in Spain,
| Russia, "(Crookcs and Rohrig, Treatise on
| Metallurgy, p. 332) etc. In England the
| famed Forest of Dean supplied great
abundance of it. There are still vast
bodies of the brown varieties unworlled
| in England, and in this country they oc-
cur in nearly every State in the union
| Since the advent of the rich Lake
| Superior hematite-ores, hundreds of pro-
| ductive brown hematite Gre. mines have
| been Abandoned; and there are still
numerous undeveloped beds too lean to
be handled profitably. In Pennsyl-
vania the mines of Lehigh and North
aInpton counties have furnished for
quarter of century the raw material of
| nearly half the iron made in the Lehigh
Valley.
With tho exception of the oolitic
varieties. the localities named may be
considered to represent all of the vari-
ties of brown-hematite ores. At pres
ent only tho better grades are in use,
and of these the supply is limited. An
investigation of the quality, product
and yield of thirty of these mines for
the year 1877, undertaken by the writer,
| showed that over 1OO,00O tons of this
orc, represented by fully 800 samples
and analyses, averaged only 81 per cent.
of metallic iron. Three-quartcrs of this
was wash-orc. The bulk of this ore, which
will fairly represent the majority of this
| class of mines in the United States,
will c1rrv abOut n nor oF ,,,otoll;,,
ron in the waSh-ore.
Examination of the iron oxide, or ore
proper, shows it to contain from As to
90 per cent. metallic iron, which, in the
wash-orc, is, in many instances, reduced
below marketable standard by the adj
mixture Of foreign material, chiefly
quartz-gravcl, states and clay.
Separation of the ore is problem
presenting many-sided difficulties that
have never been successfully overcome
Water-jigs and specific-grayity separa-
tors of innumerable designs have been
invented for the purpose all over the
world. But the very best results with
these machines fall short of obtaining
the ore entirely separated without loss
in the tailings. A concentrate
carrying AZ per cent of metallic
iron is a fair economical result from
these machines, and, except with I'M
usually rich ores, As per cent. of iron is
seldom obtained. The only satisfactory
solution of the problem lies in the re-
covery of all of the ore proper, entirely
FREQ from foreign material
Some experience few years ago with
a method of water-separation ac-
quaintcd me with the futility of at
tempting this result by that means or
any other at that time known. With the
modern demand for the rich material, it
Is easy to anticipate that the blast
furnace cannot exist among abandoned
ore-beds. And the fact must not be
overlooked that in this country nearly
all of the older blast-furnace plants
were located within or adjacent to the
brown-hematite regions. A perfect
method of concentrating would mean
survival of the brown-hematitc ore as a
source of supply.
On rapidly drying small sample of
llmonite over powerful Bunsen flame
on one occasion, I observed that the
smaller particles were magnetized
Could the ore be magnetizcd? A trial
on more practical scale convinced me
that such was the case. | then expert
mentcd with several different ores,
and found that all the ore
PARTICLES were so strongly affected as to
permit their complete separation by
means of magnet.
Naturally, series of experiments fol-
lowed, in every instance giving the same
results. My attention was then directed
toward finding out the conditions as well
as the cause of the phenomenon. This
led me to the conclusion that the agency
of heat in the presence of carbon or
carbon dioXide magnetizcs the hydrous
oxides of iron.
Further on will cndeavor to qualify
this statement; but before beginning ITS
discussion it may be interesting to
alludc to the practical method and the
results, from commercial standpoint.
of some OF the experiments.
The ore is placed in convenient re-
ceptaclc and merely roasted by the
usual process, using either solid or gas
fuel. 1T is undesirable to use much
heat, since at Il temperature of cherry
red augmentation is fully impaired.
The ore is drawn as fast as it reaches
this temperature, and is at once ready
for magnetic separation.
In the following list, for Obvious rca-
sons, the ores are designated alphabet
ically:
or Ore Re
Iron IN Conccn- Iron in Conc
Crude Orc trutc. Tnilings. tratc
Per cent. Per cent. Per cent. Per cent.
y, 1923 55.SS ..
4 ~