The Roanoke times. [volume] (Roanoke, Va.) 1890-1895, 1890-10-16

dispcnsablo for the production of
foundry-iron. Prior to the development
of the Lake Superior hcmatitc regions,
brown hematitc was the chief orc i'll use
in America. 1t occurs abundantly
throughout Germany. sit supplies by
far the greater number of Frcnch iron
workers: and it occurs also i'll Spain,
Russia, " lCrookes andRohrig. Treatise on
Metallurgy, p. 1922 etc. In England the
| famed Forest of Dean supplied great
abundance of it. There are still vast
bodies of the brown varieties unworkcd
! in England. and in this country they oc-
cur in nearly every State in the union.
! Since the advent of the rich Lake
Superior hcmatitc-ores, hundreds of pro-
| ductive brown hcmatite Orc-mincs have
been abandoncd: and there are still
numerous undcveloped beds too lean to
DO handled protitably. In Pchnsyl-
vania the mines of Lehigh and North
ampton counties have furnished for
quarter of Il century the raw material of
nearly half the iron made in tho Lchigh
Valley.
Win the exception of the oolitic
varieties. the localities named may be
considered to represent all OF the vari-
ties OF brown-hcmatitc ores. At pres
ent only the better grades arc i'll 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 100000 tons of this
ore, represented by fully 800 samples
and analyses. averaged only 81 per cent.
of metallic iron. Thrcc-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 carry about "A per cent. of metallic
iron in the wash-ore.
Examination of the iron oxide, or ore
proper. shows it to contain from A. to
60 per cent. metallic iron. which, in tho
wash-orc. is, in many instances, reduced
below q marketable standard by the ad-
mixture OF foreign material, chiefly
quartz-gravel, states and clay.
Separation of the ore Is problem
presenting many-sided difficulties that
have never been successfully overcome.
Water-jigs and specific-gravity separa-
tors of innumerablc designs have been
invented for the purpose all over the
world. But the very best results with
these machines fall short of obtaining
the orc entirely separated without loss
in the tailings. A concentrate
carrying ~ per cent. of metallic
iron is a fair economical result from
these machines, and, except with M
usually rich ores, IS per cent. of iron is
seldom obtained. The only satisfactory
covcry of all of the ore proper, entirely
free from foreign material.
Some experience few years ago with
method of watcr-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 tho rich material. it
is easy to anticipate that the blast
furnac. cannot exist among abandoned
Ore-bcds. And tho 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-hcmatitc regions. \ perfect
method OF concentrating would mean Il
survival of the brown ematitc ore as ii
source Of supply.
On rapidly drying small sample of
limonitc over powerful Bunscn flame
on one occasion, l observed that the
smaller PARTICLES were magnet zed.
! Could the orc be magnetized? trial
] on a 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 a magnet.
Naturally, Il series of experiments fol-
/ lowed in every instance giving the same
results My attention was then directed
toward finding out the conditions as we'll
as the cause of the phenomenon. This
led me to the conclusion that the agency
of heat i'll the presence of carbon or
carbon dioxidc magnctizcs the hydrous
I oxides Of iron.
Further on will cndcavor to qualify
I this statement: hut before beginning its
discussion it may be interesting to
alludc To tho practical method and the
results. from commercial standpoint,
of some of the experiments.
The orc is plac d in Il convenient re-
ccptaclc and merely roasted by the
/ usual process. using either solid or gas
fuel. 1t is undesirable to use much
/ heat. sine. at Il temperature of cherry
rcd imagine that ton is fully impaired.
The ore is drawn Az fast as it reaches
this temperature. and is at oncc ready
for magnetic separation.
: In the following list. for Obvious rca-
sons. ,hc ores are designated alphabet t.
ically:
or Orc Re
IrOnin covered as
! Iron n COaccIi- iron II COnccn-
Crude Ore trae. 'Tuilngs. tlTtc.
Per cent. Per cent Per cent Per cent.
~, IO.9S BOSS
Il, 34.32 jl.72 80.