IMPROVE- MENTS IN THE TREATMENT OF IRON ORES AND FERRUGINOUS SANDS, AND CERTAIN APPLICATIONS ARISING THEREFROM."
Year: 1858

page_text: LETTERS PATENT to Thomas Spencer, of No. 192, Euston Road, Euston
Square, London, Analytical Chemist, for the Invention of "IMPROVE-
MENTS IN THE TREATMENT OF IRON ORES AND FERRUGINOUS SANDS, AND
CERTAIN APPLICATIONS ARISING THEREFROM."
PROVISIONAL SPECIFICATION left by the said Thomas Spencer at the
Office of the Commissioners of Patents, with his Petition, on the
23rd June 1858.
I THOMAS SPENCER of No. 192 Euston Road, Euston Square London,
Analytical Chemist do hereby declare the nature of the said Invention
for IMPROVEMENTS IN THE TREATMENT OF IRON ORES AND FERRUGINOUS SANDO
AND CERTAIN APPLICATIONS ARISING THEREFROM," to be as follows, that is to say :-
This Invention consists in the first place of the production of a new
compound substance consisting of oxide of iron and carbon, And in
the second, of the application of the said substance to the useful pur-
poses named herein.
To produce this substance I mix ores of iron or ferruginous. sand with
carbonaceous matter, the proportions of which vary with the. nature
of the ore or sand employed. I then subject the mixture to heat-in
retorts such as are used in the manufacture of gas, but without limita
tion as to their size.
The carbonaceous matter employed in the operation may consist. of
charcoal, coke, coal, wood, or peat, or the dust of either of these; or
that of any other matter containing carbon. In conducting the process
care must be taken not to employ as much heat as will reduce tlie, oxide
of the ore or ferruginous sand to the metallic state.

page_text: I find in practice that by gradually increasing the temperature in the
retort until the mixture arrives at a low red heat the carbonic acid which
appertains to some ores is driven off, and in like manner a proportion of
the oxygen belonging to others. I further find that by the continuation
of a similar degree of heat the residual oxide of iron enters into com-
bination with the carbon in the retort at which stage I consider the
process to be complete.
The result of the operation I have briefly described is to produce a
solid compound of carbon and oxide of iron which substance is capable
of being usefully applied to the following purposes,
1st. When mixed with sand or other filtering media or alone, I find
that this substance effects the purification of water and other fluids by
depriving them of objectionable taste, colour or smell.
2nd. The same substance either alone or mixed with other well-known
materials effects the purification of illuminating gas by depriving it of
sulphur and ammonia.
3rd. I have further discovered that the same compound of oxide of
iron and carbon on being removed from the retorts in which it is pre-
pared and afterwards ground into powder may be advantageously used
in producing wrought iron or steel of a very superior character. The
mode by which these purifications are severally effected by this new
compound are in practice so similar to those already in use that they
need not be further described in this Provisional Specification.
4th. The same compound of oxide of iron and carbon may be used for
depriving atmospheric air of impurities contracted by admixture with
deleterious or offensive exhalations. The air to be purified being made
to pass over or percolate through moistened surfaces of the compound.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Spencer in the Great Seal Patent Office on the
23rd December 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I THOMAS
SPENCER of No. 192 Euston Road Euston Square London Analytical
Chemist send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent bearing date the Twenty-third day of June in the year of our
Lord One thousand eight hundred and fifty-eight in the twenty-second
year of Her reign did for Iferself Her heirs and successors give and
grant unto me the said Thomas Spencer Her special licence that I the

page_text: said Thomas Spencer my executors administrators and assigns, or such
others as I the said Thomas Spencer my executors administrators and
assigns, should at any time agree with and no others from time to time
and at all times thereafter during the term therein expressed should and
lawfully might make, use, exercise and vend within the United Kingdom
of Great Britain and Ireland the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN THE TREATMENT OF IRON ORES AND FER-
RUGINOUS SANDS AND OERTAIN APPLICATIONS ARISING THEREFROM," upon the
condition (amongst others) that I the said Thomas Spencer my executors
or administrators by an instrument in writing under my or their or one
of their hands and seals should particularly describe and ascertain the
nature of the said Invention and in what manner the same was to be
performed and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Spencer do hereby declare the
nature of my said Invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the
following statement:-that is to say
DESCRIPTION AND MODE OF MANUFACTURING THE NEW COMPOUND
SUBSTANCE.
This Invention comprises the discovery of a method of treating iron
ores and ferruginous sands, so as to produce a new compound substance
composed of oxide of iron and carbon, together with the mode by which
the said substance may be applied to a variety of useful purposes.
In proceeding to manufacture this substance, it is necessary.
in. the
first place, to mix along with the ore of iron or ferruginous sand, or
oxide to be treated, certain proportions of matter which shall contain.
available carbon, the proportions of which are made to vary with the
nature of the iron ore, or ferruginous sand or oxide employed. The
mixture is then to be subjected to a low red heat in a closed fire-brick
chamber or oven, until the intended combination between the two sub-
stances (the oxide of iron and the carbon) is completed.
It is hardly necessary to say that the heat is obtained during the pro-
cess of combination by means of furnaces having the ordinary contact
with the floor or sides of the chamber or oven containing the mixture
to be operated on. Retorts.of metal or clay with furnaces such as those
used in the manufacture of illuminating gas, are also available for
every stage of the same process.
It is necessary to state that the door of the oven or retort employed,
must be closed or luted up during the process, as in the manufacture

page_text: of gas, but in this case to prevent the admission of atmospheric air.
It is at the same time necessary to state that there should be a small
aperture fitted with a stop cock in the door or other convenient part
of the oven or retort, to permit the escape of any of the gases, or steam
from moisture, proceeding from the mixture during the operation. The
same is also necessary as indicating the progress of the operation going
-on.within..
Though the compound substance which results at the close of this
operation is in itself new, yet according to the received opinions regard-
ing the chemical constitution of its ferruginous element, based on the
principles which govern chemical nomenclature, it may be properly
termed a ferroso-ferric carbide. In ordinary language however it is termed
by me magnetic carbide of iron;" or simply "magnetic carbide;" but
whether the carbon combines with the oxide in strictly atomic propor-
tions, or indefinitely, as the metal itself does in the case of cast iron, I
have as yet not had sufficient leisure to fully determine; though all the
-experiments I have been able to make lead to the latter conclusion. In
practice however it is immaterial.
*
33
Though this substance can be made directly (or by burning off the
sulphur in the first place indirectly) from any of the ores that are
ordinarily capable of being manufactured into iron, yet for obvious
reasons I prefer to employ those that are purest, and which contain
the least proportions of sulphur. The ores to which I give the preference
'are those known to mineralogists as "chalybite, or "spathose ores" and
also those equally well known as hematite ores or specular iron
ore." As already intimated, ferruginous sands or ordinary oxides of
iron may be converted into the same magnetic carbide by similar means.
'With regard to the necessary carbonaceous matter to be mixed along
with the ore, any substance readily carbonized at a low heat, such as
'wood chips, may be employed though as a rule, I prefer to use granulated
charcoal, sawdust, or granulated coke. At the same time, anthracite,
wood, or peat, in similar states, may be employed in making the new
substance; or even coal itself where other carbonaceous matter is incon-
veniently attainable. To prevent the reduction of the oxide to the
metallic state however, coal containing the least bitumen is obviously
preferable..
Having thus far described the nature of the raw materials proper to
'be used in this Invention, I have now to describe the details of the
process by which they are best made to unite. Should spathose ore
be employed, it is desirable in the first instance, to have it broken into
small pieces not exceeding an inch in diameter, or to shorten the
process it may be previously reduced to powder by grinding. It is then

page_text: to be subjected to as much heat in the oven or retort already referred
to, as shall be sufficient to "drive off" the carbonic acid which naturally
belongs to this ore. In this preliminary part of the process, the ore
itself need not be brought beyond a dull red heat, and half an hour's
continuance of the same will be generally found sufficient to eliminate
the whole of the carbonic acid belonging to the ore. When it has
assumed a coal-like blackness in the course of the process, it may be
safely assumed to have parted with all its carbonic acid. At the termi-
nation of this stage, any of the above-named carbonaceous matters such
as sawdust or granulated coke, is to be added to the black oxide and
the door of the retort or oven again tightened to prevent the admission
of air. The retort and its contents are now to be brought to a dull
or "cherry red" heat, being a little in excess of that employed in the
previous operation. The mixed mass is to be kept at this temperature
from two to six hours this difference of time depending on the original
state, or granulation of the ore. For example, if the ore is of the purest
description, and has been reduced to powder in the first instance, the
shorter period named will be found ample to effect its carbonization.
The rest will be the result of experience.
It may be set down as a rule with regard to this ore, or any of the
others which it may be found convenient to employ, that care should
be taken that the heat should not be so great at any stage of the
operations, as to cause the reduction of the oxide to the metallic state.
On the completion of the process, the newly formed compound may
either be suffered to cool before removing the door of the retort for
the admission of air, or it may be discharged into water whilst red hot,
in the manner practised at gas works in discharging the residual coke
from the retorts whilst in a state of redness.
In manufacturing this substance from the oxide of the spathose ore,
it ought to be accompanied, in the retorts, by any of the substances
named which will produce on being heated about twenty parts by
weight of carbon, for although the whole of this quantity is not
necessarily absorbed yet I find it desirable in practice to have an excess
of carbon present. In complying with this, not absolutely necessary
condition, however as to carbon no waste need ultimately accrue, as
the unabsorbed portion may be readily sifted out from the carbide, and
used in succeeding operations.
In operating directly with peroxide or hematite ores, I would
recommend an increase of about five per cent. to the latter amount of
carbon. An increase in such cases is required because the extra portion
of oxygen belonging to these ores can only be separated from them at
this temperature, in combination with an equivalent of carbon.

page_text: The oxygen and carbon when thus combined, form the well-known
carbonic oxide gas, which is allowed to escape from the retort by means
of the stop-cock already referred to. The heat being continued the
oxide of iron left in the retort then combines with the residual carbon,
and thus forms the new substance embraced in the first part of this
Invention, and which I have termed "ferroso-ferric carbide," or "carbide
of magnetic oxide of iron, or, indifferently "magnetic carbide" each
term implying the same substance. When made from the stoney
hematite ores, this compound substance is perfectly black and hard.
If however it is slaked in water on being drawn from the retorts,
it becomes brittle and easily reduced to the condition of powder by
grinding.
As regards the chief physical and chemical properties of this sub-
stance I may remark, that in all ordinary temperatures, or in moisture,
though it attracts oxygen, it resists ordinary oxidation equally with
gold or platinum; but on the other hand it attracts and absorbs sulphur.
On each of these properties are founded the useful applications to be
presently described, and which form the second part of this Invention.
I may state also that this compound substance is attracted by the
magnet, though not in equal degree with the black oxide itself previous
to its admixture with carbon. In addition to these, it possesses several
other highly interesting physical properties, some of which are peculiar
to itself but as they have no practical bearing, that I am at present
able to see, on any of the processes to be referred to in this Invention,
they need not be described here.
I have already found by the results of numerous practical experiments,
that this new compound is capable of being applied to several useful
purposes, most of which are of a sanatory nature, and are of so easy
and obvious application in themselves, that any lengthened or technical
description is unnecessary. Amongst the most important of the uses
to which I apply the new substance is, the purification of water, and
gas, the modes of operation in these and some other cases I shall proceed
to describe briefly.
PURIFICATION OF WATER.
For the purification of water I proceed as follows: Should the
magnetic carbide which I have described, not be previously in a state
of granulation arising from the original condition of the ore or oxide,
it is to be reduced by grinding to the condition of ordinary sand. It
is then to be placed in the filtering reservoir, tank, or smaller vessel;
the size of which in each case, being regulated by the quantity of water
requiring purification in a given time. The water is then allowed to
percolate through the mass, in the mode usually practised in filtering,

page_text: by means of sand or any other ordinary media. The thickness of the
layer of magnetic carbide is made to vary with the quality of the water
intended to be purified. For example, to thoroughly deprive very
brown bog or peat water of its colour, from six to eight inches of the
ferruginous media is required; but where the colour is relatively less,
half this thickness will be found ample though in each case, a previous
experiment is desirable.
Where water requires to be freed from turbidity arising from
suspended matters, as well as colour or disagreeable taste, it is then
necessary to add a considerable thickness of fine sand to the magnetic
carbide; the sand being intended to act along with it as an ordinary
filter. Where filtration is required on a large scale, I prefer as a rule
to have the magnetic carbide mixed with sand, but the proportions of
each are made to vary with the circumstances of the water, and the
texture of the sand itself. As a consequence of the peculiar attractive
force exercised by the magnetic carbide independently of its power of
decolouring water, a layer comprised of eight or ten inches composed
equally of sand and carbide frees water from suspended impurity, more
effectually than three or four times as much sand, if used alone; whilst
in the rarer quality of depriving water of organic or gaseous impurity,
or of ill flavour arising therefrom, the carbide itself by far exceeds all
other substances known. Not only do its initial powers of purification
exceed those of charcoal, but unlike that substance, they are capable
of maintaining themselves for far longer periods with undiminished
vigour. Moreover, with colored water which happens to be not other-
wise very impure, the powers of the new substance may be indefinitely
sustained, with slight trouble, though constantly in use. This is effected
on exposing its surface to the atmosphere, by leaving it uncovered with
water for a few minutes of each day; whilst the egress of the purified
water need not be interrupted. The oxygen acquired during these
few minutes effects if required, the complete revival of the whole mass.
Though on the other hand, should the impure surface water of a rural
district be operated on, which naturally contains plenty of air, the
oxygen found in it is usually sufficient to effect its entire purification
without any exposure. In such cases, the ferruginous media as a con-
sequence of its attractive power, forces the oxygen into chemical com-
bination with any impurities that may be present in the water, and
thereby renders them perfectly innoccous and tasteless.
In a word, purification by these means is effected on the same
principles of oxidation, as in the ordinary process employed by nature,
though in the presence of the carbide the same takes place in much
shorter periods.

page_text: Where it is found necessary to operate on very impure or foul water,
such as that which issues from common sewers, purifying filters com-
posed of this substance become ultimately covered with a deposit of
slimy matter, though not nearly so soon as if ordinary mechanical
filtering media, were employed. This may be got rid of however, by
the removal of a thin layer from the surface of the filter.
The matter
so removed is then to be washed in the manner ordinarily practised
with similarly fouled sand, or, in cases where it has become extremely
foul, it may be thoroughly revived by subjecting the same to a relatively
slight heat in a retort or oven, similar to that used in its preparation.
In such a case, exposure for a few minutes to a heat equal to 400
Fahrenheit is sufficient. On withdrawal from the retort the magnetic
carbide will be found completely revived with a proportionate addition
of free carbon arising from the carbonization of the foul matters during
the process. Advantage may be taken of this circumstance to prepare
at the same time an additional portion of the carbide itself, by mixing
along with the foul mass a small proportion of fresh ore, or oxide on
the same being placed in the retort for renovation.
It is obvious that the excess of carbonaceous matter accruing from
the charred impurities, will be sufficient to convert a fresh portion of
ore thus introduced into the retort, into the state of magnetic carbide.
I may add in conclusion that filters composed of this magnetic media,
are as effective on a small scale for domestic use, as they are on one
sufficient to supply the wants of the largest towns.
PURIFICATION OF SACCHARINE FLUIDS.
I have discovered in the course of experiment, that, for the purification
of saccharine fluids, such as those derived from beet-root, or the sugar-
cane, the magnetic carbide also effects their complete purification. To
effect this object it is only necessary to substitute this ferruginous
compound in lieu of the animal or other charcoal used in the refinement
of sugar.
When the powers of the magnetic carbide are expended in
the course of the process of refinement, they are to be revived by
reheating in a retort or oven, in the manner just stated as regards the
same substance when fouled by water. A similar process of reheating
is now adopted for the revivification of the animal charcoal used in the
manufacture of sugar.
PURIFICATION OF ALCOHOLIC FLUIDS.
It is known that alcoholic fluids such as brandy, rum, whiskey and
others of a like character, are frequently impure and unwholesome, by
reason of the presence of certain volatile, or essential oils which arise
from the nature of the organic materials used in their distillation. To
remove these I find as in the preceding cases, that the magnetic carbide

page_text: acts most effectually. Should it be required to render the spirit pure
during the actual process of distillation, it is only necessary that it
should be distilled, or received upon the carbide in the first instance,
in the manner usually practised with charcoal to effect the same purpose.
If the spirit is required to be purified after distillation however, it is
to be passed through a filter composed of this ferruginous substance in a
granulated state, adopting at the same time the obvious precautions
necessary to avoid loss by reason of evaporation. In either case this
substance is to be employed for the purification of spirit in the manner
at present practised for the purification of the same fluids by means
of charcoal. For the purpose of this part of the Invention the magnetic
carbide may, or may not be mixed with other filtering media, as in
the manner described as regards water. I find as a rule that the
purification of alcoholic spirits subsequent to distillation, is best effected
by a filtering media composed of the magnetic carbide, and perfectly
clean sand, in equal parts, or, a mixture of pounded glass in lieu of the
sand will answer the same purpose. In such cases the thickness of the
media will altogether depend on the amount of impurity present in the
spirit; but where the first filtration is found insufficient, the impure
spirit may be passed through the media a second, or even a third time.
I find also, that the spirit to be purified should not be allowed to pass
through the filter continuously, but at intervals; that is to say, as soon
as the filtering media becomes saturated with the spirit to be purified,
no additional quantity ought to be added until the first charge has
reached within an inch of the bottom of the filtering layer. This pre-
caution promotes the accession of oxygen. At the same time to prevent
loss by evaporation the process ought to be conducted in covered vessels.
FOR THE PURIFICATION OF GAS.
The purification of illuminating gas from sulphur and ammonia, forms
another important application of this ferruginous compound. A detailed
description of the mode of its application however will not be necessary
to those at present engaged in the manufacture of gas, because the same
mode of application, and apparatus, is required in operating with this
substance that is at present used in the purification of gas by ordinary
methods, especially by that termed the "dry lime process" which is so
well known. In operating with the carbide it is to be kept slightly
moist in the purifying apparatus during the process of purification. It
may also be mixed with any other substance such as sand, sawdust,
lime or gypsum, to allow greater freedom of access to the gas. When
the carbide has become in some degree inert, by reason of its partial
absorption of sulphur, and other impurities from the gas it is to be

page_text: removed from the purifying apparatus, and exposed to the atmosphere
for a day, or two until it has become revivified. It may thus be used
repeatedly for several times in succession until it is ultimately found
to have become fully saturated with sulphur. At this stage it is to
be placed in an ordinary gas retort and heat applied as in its previous
preparation when the whole of the sulphur it has absorbed will be
distilled off and may be collected in a molten state, by means of a
tubular aperture fitted to the retort. For this operation retorts of clay
or brick are preferable to those of iron. As some portions of the carbide
may have become peroxidižed in the course of the operation, as soon
as the sulphur has been distilled off it is always well to add to the
retort containing the residual carbide a small proportion of carbonaceous
matters, which on reheating the mass to redness, has the effect of
carrying off any surplus oxygen, whilst it leaves the carbide fully
restored to its former vigour.
The same magnetic carbide of iron may be advantageously used for
depriving atmospheric air, as it enters buildings, of any of the noxious
impurities which it may have contracted by admixture with deleterious
or offensive exhalations. To accomplish this object the air to be purified
is made to pass over, or percolate through, moistened surfaces of the
ferruginous compound. For this purpose of purification I prefer to
have the magnetic carbide reduced to a state of granulation equal to
coarse gunpowder, and then placed in flat boxes, or trays, not exceeding
two or three inches in depth. When in operation they ought to be
inclined at a slight angle. An intermittent drip of water let in at the
upper edge of the box, or tray, is also necessary to insure the constant
moisture of the carbide. In this operation the carbide may be mixed
with any other substance, though, not necessarily so.
APPLICATION OF THE MAGNETIC CARBIDE TO THE MANUFACTURE OF
IRON AND STEEL.
For most of the preceding purposes I have preferred to manufacture
the magnetic carbide from peroxide or hematite ores by reason of their
abundance. These ores however have been at all times found exceed-
ingly difficult of reduction by themselves, when required for the manu-

page_text: facture of iron and steel. To effect their reduction to the metallic state
with economy, it has therefore been found necessary to mix them with
poorer, but at the same time, the almost necessarily, less pure ores
found in other districts. But by the method described by me in the
first part of this Specification for reducing the hematite ores at a
relatively low heat to the state of magnetic carbide in the first instance,
their subsequent reduction from this to the metallic state, becomes
easy and economical. To effect this purpose it is necessary to mix the
granulated carbide when cool with an additional 10 or 15 per cent. by
weight of pure coke or granulated charcoal, and, on being placed in
any of the ordinary reducing furnaces, the remaining oxygen is driven
off as carbonic oxide by the application of the necessary amount of heat.
By this treatment the mass, becomes reduced to the state of pure
metallic iron from which, it is obvious, may be manufactured steel of
the best quality.
As regards this primary step in the manufacture of iron or steel from
the magnetic carbide herein described, no claim is made by me for any
mode beyond that which necessarily arises out of my having shown in
this Specification how an ore, or oxide, of iron, may be converted into
the state of magnetic carbide. As my claim ceases at the convertion
of the ore into this compound (which as regards the manufacture of iron
may be considered as a raw but easily converted substance) it is there-
fore not incumbent on me, further to describe any of the well-known
processes connected with its subsequent manufacture into iron or steel.
I have to add in conclusion that the magnetic carbide, if mixed with
lime, sand or clay, forms a cement or mortar capable of being applied
advantageously under water.
Having to the best of my knowledge thus described the nature of my
said Invention I shall now proceed to state the nature and extent of
my claims in the present Patent.
In the first place I claim to make or manufacture by the application of
heat or as better understood by chemists, I claim to manufacture in the
"dry way," the compound of oxide of iron and carbon, described by
me to the best of my knowledge-for the first time.
I have entitled this compound "ferroso-ferric carbide," or indifferently
"oxy-carbide" or magnetic carbide," each term implying the same
substance.
"
In the second place I claim the applications of this substance, to the
several purposes herein described for the full term of this Patent

page_text: irrespective of how the substance itself by possibility may be manu-
factured hereafter.
In witness whereof I the said Thomas Spencer have hereunto set
my hand and seal this Twenty-third day of December in the year
of our Lord One thousand eight hundred and fifty-eight.
THOMAS SPENCER. (L.S.)