JMPROVEMENTS IN THE MEANS AND METHODS OF EXTRACTING PHOSPHORUS FROM IRON, STEEL, AND OTHER SIMILAR METALS
Year: 1877

page_text: LETTERS PATENT to Hermann Schulze-Berge and Julius Barnstorf, both of
Oberhausen, near Dusseldorf, Prussia, for the Invention of " JMPROVEMENTS IN
THE MEANS AND METHODS OF EXTRACTING PHOSPHORUS FROM IRON, STEEL,
AND OTHER SIMILAR METALS"
Sealed the 28th May 1878, and dated the 10th December 1877.
PROVISIONAL SPECIFICATION left by the said Hermann Schulze-Bergo
and Julius Barnstorf at the Office of the Commissioners of Patents on the 10th
December 1877.
HERMANN SCHULZE-BERGE and JULIUS BARNSTORF, both of Oberhausen, near
Dusseldorf, Prussia. IMPROVEMENTS IN THE MEANS AND METHODS OF EXTRACTING
PHOSPHORUS FROM IRON, STEEL, AND OTHER SIMILAR METALS.”
According to some experiments made by us for the purpose of dephosphorizing
iron, the use of chlorides and fluorides of the alkaline earths is most successful.
The following investigations, carefully executed by means of chloride of calcium,
will show this:-We prepared anhydrous chloride of calcium in the state of powder
dissolved, 15 grammes of borings of phosphorous foundry pig iron in muriatic acid,
which process left nearly all the phosphorous iron undissolved, then we purified the
residue by decantation, and dried it in a temperature of 100 degrees cont. A
sample weighing 0-1 grammes of the phosphorous iron prepared in this way, which
contained soine graphite and oxyde of silicum, was mixed with an excess of chloride
of calcium, and put in an iron crucible for melting, a layer of chloride of calcium
prevented any influence of the air. There escaped some protochloride of iron, which
by the influence of the air became perchloride of iron, and left at the same time
oxyde of iron in the crucible. The crucible being cool was put in a beaker filled
with water.
In dissolving the molten mass phosphoretted hydrogen was developed, which did
not burn, but it could be detected by its smell. There is no doubt that already in

page_text: consequence of the influence of the air nearly all the phosphide of calcium was
converted into phosphate of calcium during the process of melting.
In order to separate the phosphoric acid from the lime a small piece of tartaric
acid was dissolved in cold water, and then this solution put in the beaker containing
the iron crucible with the molten mass. After some stirring, the crucible was
removed, cleaned with water, and the contents of the beaker were immediately
filtered. The residue contained the iron not volatilized, the filtrate showed only
traces of it. For the purpose of comparison, another trial was made. Again 01
grammes of the phosphorous iron, combined with graphite and oxyde of silicium,
and prepared for this investigation, was weighed, and the phosphorous contained
in it, as well as in the above residue, and in the filtrate determined. The phosphorous
iron used showed 4.19 per cent. of phosphorus, the residue showed only traces of it,
which were difficult to detect, but the filtrate showed nearly the whole mass of the
phosphorous contained in the specimen. We found 3.91 per cent. of phosphorus,
and consequently 0.29 per cent. of phosphorus were volatilized as phosphoretted
hydrogen. Therefore it is evident that by means of chloride of calcium under the
influence of a red heat, the phosphorous iron was decomposed thoroughly. The same
result was obtained by means of chloride of barium, cloride of magnesium, chloride
of strontium, fluoride of calcium, and fluoride of magnesium.
As it has been said already, the action of the air is to be prevented, because in
consequence of its action during the melting process the phosphide of calcium is con-
verted into phosphate of lime, the phosphoric acid of which is again reduced by the
iron when a sufficiently high temperature has been attained. For carrying the
process into practice on a larger scale, it is therefore necessary to prevent the action
of the air as far as possible, as is shown by the results of the following trials:-In
a wrought-iron tube of about 30 cents. long, and 5 cents. diameter, provided at one
extremity with a cap, about pound of chemically pure chloride of calcium was
melted, and white puddling pig iron taken from a blast furnace was slowly poured
upon it. A portion of the chloride of calcium, which had already fermented, pushed
itself up between the iron and the side of the tube. Taking into consideration the
quick cooling of so small a quantity of iron, as well as the small surface of contact
(and the short time of action) the following quantity of phosphoric acid found in
the chloride of calcium is a proof of energetic action:-The chloride of calcium
raised over the iron contained 1.15 per cent. of phosphoric acid, and the chloride of
calcium between the side of the tube and the iron on which the action of the air
was prevented contained 2.30 per cent. of phosphoric acid. This experiment, which
was repeated twice undor almost precisely similar conditions with puddling pig, was
also tried with foundry pig iron produced under a very hot blast. The result was
that in the chloride of calcium, which has cooled over the iron with access of air,
only traces of phosphoric acid were found, whilst that which had solidified between
the iron and the sides of the vessel contained 1-4 per cent. This unfavourable
result may perhaps be partly explained by the fact that the chloride of calcium in this
experiment was completely liquified when the iron was poured into it, so that the
chloride of calcium would be immediately lifted up without having to force itself
between the iron and the sides of the vessel. It may also be due to the fact that
foundry pig iron only contains the quantity of phosphorus which exists in puddling
量
pig.
In all the experiments sulphur and silicium were separated as well as phosphorous.
In order to make use of this action of chloride of calcium, and of the other above-
mentioned chlorides and fluorides of the alkaline earths, either alone or mixed
together, for the dephosphorization they must be driven in a fluid condition in
finely divided streams slowly, continuously, and regularly through the fluid metal
(pig iron, steel, &c.), air being rigidly, or as far as possible, excluded by suitable
precautionary measures. The process will progress the more favourably the less
the material of the vessel is allowed to act on the purifying medium employed, as
also on the new compounds formed during the operation. For this reason the
presence of slag is particularly injurious.

page_text: As the access of air, gases of combustion, slag, &c., are injurious to the process,it
is well, for example, to pour the fluid metal into a fore hearth similar to that of
"Krigar's" cupola, or into a receptacle similar to the converter used in the
Bessemer" process, taking care to warm the sides of such vessel beforehand, and
that it is properly protected from being cooled. The addition of the chloride of
calcium may take place through adjustable valves in the bottom like those shown
in the Drawing annexed.
In order to prevent the solidification of the chloride of calcium, the conducting
tubes, which are to be as short as possible, must be kept warmed to a sufficient
degree.
Radiation of heat from the surface of the metal may be prevented by a cover, and
the air above the fluid metal may be driven out, and entirely excluded by passing
in gas free from oxygen The chloride of calcium, driven by compressed air or by
compressed gases free from oxygen, flows off along with the phosphide of calcium
which is formed through an overflow aperture placed a little distance above the
surface of the iron. The chloride of calcium, which has not been decomposed either
by phosphorous, sulphur, or silicium, absorbs moisture, and thus separates itself from
the remaining phosphate of lime, &c., as we had an opportunity of proving during
the above experiments.
The novelty of our Invention therefore consists in the regular and continuous
forcing of fluid chlorides and fluorides of the alkaline earths in fine subdivision
through fluid iron, and in the complete, or as far as possible complete, exclusion of
atmospheric air during the process.
It is apparent that in carrying out the process the most varied constructions of
hearth and furnace are possible.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Hermann Schulze-Bergo and Julius Barnstorf in the Great Seal
Patent Office on the 5th June 1878.
HERMANN SCHULZE-BERGE and JULIUS BARNSTORF, both of Oberhausen, near
Dusseldorf, Prussia "IMPROVEMENTS IN THE MEANS AND METHODS OF EXTRACTING
PHOSPHORUS FROM IRON, STEEL, AND OTHER SIMILAR METALS."
As is well known, phosphorus may be separated from its combinations by the
action of the alkaline earthy metals. Doctor "Schönn," of Stettin, has utilized this
property for the qualitative analysis of phosphorus; and in Dr "Trisinius" Journal
of Analytical Chemistry, year 1869, p. 53, las especially recommended the use of
magnesium; his communications leave no doubt that even iron is separated from its
phosphunet by alkaline earthy metals at a red heat. What is known of the greater
affinity of the alkaline earthy netals for phosphorus, compared with that of the
heavy metals, leads to the belief that it need not be indispensable to use barium,
strontium, calcium, or magnesium, as simple bodies, but that they may on the
contrary be used in the state of chlorides.
We have, in fact, assured ourselves of the possibility of this action by numerous
carefully conducted experiments. The iron is perfectly separated by the action of
an alkaline earthy chloride, with production of proto-chloride of iron, and an alkaline
earthy phosphuret. This double decomposition is easily verified by heating to a
red heat with exclusion of air, or in a current of azote, an intimate admixture of
phosphuret of iron, and of anliydrous chloride of calcium, until the fusion of
this latter takes place. This re-action is further demonstrated by the following test :-
A certain quantity of liquid forge pig, containing phosphorus, is placed in an iron
testing vessel, having an inner polished metallic surface; it is then turned over into
the metal bath, care being taken that the opening of the testing vessel remains
immersed, a piece of pure chloride of calcium is then placed under the opening,
through which it passes and rises within the testing vessel up to the inner level of
the bath, it being of less density than that of the metal bath After the iron has
cooled, there is found by the side of the non-decomposed chloride of calcium, proto-
chloride of ion, and phosphuret of calcium.
The alkaline earthy bromides, iodides, and cyanides may indiscriminately replace
the chlorides in the dephosphorization of iron; whereas the fluorides are preferable
when the iron coutains not only phosphorus but also silicium; in this case there is
simultaneous production of volatile fluoride of silicium and alkaline earthy
phosphuret. In the operation of dephosphorization, both the sulphur and the
silicium are completely eliminated while the carbon remains.
Taking for basis these properties of the haloid salts of the alkaline earthy metals,
amongst which the chlorides and fluorides are specially recommendable by reason
of their cheapness, we have adopted a new process of dephosphorization of liquified
or molten iron, whether pig iron, ingot metal, as Bessemer and Martin steel,
steel or wrought iron in a fluid state, which we will now proceed to describe in
detail.
Our process is as follows:-Fluid phosphorus containing iron, taken directly from
the blast furnace, or after remelting "Bessemer" steel from pig iron of inferior
quality after insufflation, "Martin" steel and malleable iron, also in a fluid state,
are received in a special apparatus, fixed or movable, and uniting the following
conditions, namely:-That of preventing, as far as possible, the cooling the molten
mass of also preventing any contact with air or other oxydizer; of permitting by
special arrangement the introduction into the inass, and from beneath, of the fluid
haloid salts with alkaline earthy base in the most divided state possible; or of
leaving it possible for the operator to mix intimately and continuously the
dephosphorizing agents and the impure iron. By oxydizers to be averted, we mean

page_text: those which in presence of the phosphurets of barium, strontuim, calcium, or mag-
nesium, might yield oxygen, such are besides atmospheric air, steam, carbonic acid,
the oxides and protoxides of iron, etc.
The oxygenation of the phosphurets of the alkaline earthy metals makes the
elimination of the phosphorus impossible, inasmuch that by the absorption of the
oxygen, the phosphuret of alkaline earthy metals produce phosphates, phosphites,
and bypophosphites, the acid of which will be reduced by the carburetted fluid iron,
so that the phosphorus returns to the iron, and that the alkaline earth (lime, baryta,
magnesia, strontiane) remains isolated. This re-action may be daily observed in
blast furnaces; it being proved that the phosphorus contained in the flux or castina
is absorbed by the iron.
It should be further observed, that by the access of even a very small quantity of
an oxydizing or oxygenating substance, a mass of alkaline earthy phosphates and
phosphurets of alkaline earthy metals is produced. Then only by the action of the
great heat there remains pure lime, while the free phosphorus returns to the iron.
Upon this point we refer to the qualitative analysis of "Rose and Finkener,"
6th edition, p. 648.
There may perhaps be another explanation of the prevention of the separation of
the phosphorus from the iron when the oxygenating bodios come into contact with
the alkaline earthy phosphurets, which have been produced. It is sufficient to
admit that the oxygen of these bodies allies itself directly with the alkaline earthy
metal, and forms with it an alkaline earth, so that, in the presence of iron in a fluid
state and at a high temperature, the phosphorus unites with this latter. Further,
the silicic acid acts very injuriously, because, when the fluorides of the alkaline
earths are used, its silicium volatilizes as fluoride of silicium, and its oxygen changes
into alkaline earthy oxide, the alkaline earthy metals liberated, which prevents the
action of a great mass of dephosphorizing agents. If other haloid salts are used the
silicic acid is still injurious, if only in contaminating the secondary products.
Attention must therefore be directed to freeing the iron, as much as possible, from
its slag. The object of melting the haloid salts of the alkaline earthy metals to be
used, is that they may not take too much heat from the fluid iron, but leave it
liquid as long as possible. It might for the same reason be desirable to superheat
the salts used.
We endeavour to attain the regulation and the fine subdivision of the dephos-
phorizing matters during their introduction, by the use of special valves at the
bottom of the apparatus. If it be found that the use of valves is not practicable,
the fine subdivision of the fluid alkaline earthy haloid salts might be obtained by
the aid of narrow twyers, or pipes, placed at the bottom, or in the lateral sides of
the apparatus, and the regulation by other efficient arrangements, or by a more or
less powerful pressure.
A fine subdivision or distribution, which is easily obtained in consequence of
the great fluidity of the liquid haloid salts is particularly desirable, because
thereby the most complete utilization and the most energetic action of the de-
phosphorizing agents is obtained.
In addition to the apparatus which receives the fluid iron, our system requires
another, intended for the fusion of the dephosphorizing matters.
In blast furnaces attention should also be directed to the utilization of the heat
of the slag which otherwise serves no purpose. To practically realize this idea, a
special furnace might be constructed of refractory materials in which the molten slag
would surround an iron vase. Such a receiver, if fixed, might be protected from
the corrosive action of the slag by a slight coating of refractory materials, while if
it is to be capable of being withdrawn, there should be no coating of its iron surfaces,
and its sides should be made to taper downwards. In the case that this style of
custing should be found objectionable in practice, or, if slag in fusion should be
wanting, an apparatus might easily be constructed in which the melting, which
takes place at a red heat, would be obtained without great expense,

page_text: It will, however, be difficult to have such an apparatus of sufficient strength to
resist, when at a red heat, the pressure required to drive out the dephosphorizing
agents in fusion, and force them through the mass of fluid iron.
It is therefore
necessary to have a third apparatus to receive the haloid salts of the alkaline earthy
metals in fusion before they are driven into the fluid iron, and capable of supporting
a pressure of several atmospheres. The inside of this receiver should be made of
matters having no decomposing action upon the dephosphorizing agents, and as this
apparatus should also not take too much heat from these latter, provision should be
made for heating it beforehand.
Finally, it is necessary that it should close hermetically, because the dephos-
phorizing agents are to be expelled therefrom by dry and compressed air, or other
dry and compressed gas which cannot oxydize the alkaline earthy metals. In blast
furnaces the compression may be obtained by a high column of water, which is made
to act from the top of the platform of the furnace upon air in close chambers or
compartments (gas holders such as are used in laboratories, air boxes, and similar
apparatuses). Wherever such a method of compressing air presents difficulties, a
force pump or analogous machine is quite as applicable.
In Bessemer" works a sufficient pressure of air is already available.
To set at work the above-described apparatuses for the dephosphorization of iron,
compressed air freed from its humidity is directed into the apparatus containing
the haloid salts in fusion. Here, the air pressing on the surface of the dephosphori-
zing agents, sends them, by a conduit adapted for this purpose, into the apparatus con-
taining the molten iron. The valves at the bottom of this apparatus open, and the
haloid salts of the liquified alkaline earthy metals, finely subdivided thereby, enter
the fluid iron, and rise to its surface by reason of their lessor specific gravity. Thus
they enter into perfect or nearly perfect contact with all parts of the iron, and
thereby produce its almost complete dephosphorization.
When a sufficient quantity of the haloid salts has penetrated into the mass of
iron the valves are closed, and the two apparatuses are separated. The purified iron,
whether liquid pig iron, liquid steel, or wrought iron, have been submitted to this
treatment, continuous to be worked by the "Bessemer" furnace, the puddling fur-
nace, "Siemens or Marpus" furnace, or is left in moulds or bars.
In our process it is most important that the carbon remains in the iron, for other-
wise there would be no means of separating the phosphorus from the steel or fluid
ingot metals.
It is of equal importance that no separation of carbon takes place in the dephos-
phorized pig iron; because the continuation of its treatment permits obtaining with
sufficient certainty such steel or wrought iron as may be desired by the decarbu-
rating action of oxides of iron, or pure iron ore, in suitable furnaces. In short, every
known method for producing steel or wrought iron may be applied to the pig iron
dephosphorized by our process.
The phosphorets of calcium, magnesium, strontium, and barium, remain unattacked,
because they are protected from any oxydation on the surface of the iron.
When larger masses have become agglomerated, they run off with the haloid salts
of the alkaline earthy metals, which may remain undecomposed, into a receiver.
The engendered haloid salts of the iron are volatile and only become solidified in
a second receiver.
All the haloid salts of the alkaline earthy metals may be used separately or
mixed.
Perhaps the most advantageous way is to use a mixture of 2 or 3 of them. For
example, chloride of calcium with a slight per-centage of chloride of barium and
of fluoride of calcium might be employed more efficaciously than any chloride or
fluoride used separutely.
Nevertheless, we do not propose in any way to limit the choice of the dephos-
phorizing agents.
The haloid salts of the alkaline metals of the earthy metals, or of the heavy

page_text: metals, liquefied in presence of iron, also liquefied, do not give a dephosphorizing
action. They may, however, be employed if required to give by their adjunction
greater fusibility to the alkaline earthy salts used.
We have added to our description of our process Drawings of apparatuses which
permit its use, and we will now proceed briefly to describe them.
The first Sheet shows in section two vessels. The upper vessel resembles a ladle
(which primarily receives the fluid ingot metal) in the "Bessemer" process, and is
to receive the fluid iron; it is lined inside with a refractory mortar, the best adapted
to resist the attack of the haloid salts or of the products of decomposition Lime,
magnesia, graphite, coke, and other similar bodies bound with clay are suitable for
this purpose. The bottom of this crucible, the outer metal covering of which is
protected from the heat radiating from the lower crucible by a layer of refractory
materials, shows in section an open valve; this valve is for the introduction of
the haloid salts, and is self-acting, it opens or closes accordingly as the pressure is
greater upward or downward This self-acting valve may be replaced by a valvo
worked from the outside The cone which regulates the entrance of the dephos-
phorizing matters is then opened and closed, as is also the plug which regulates the
outflow of the iron
The number and the arrangement of the valves is regulated by requirement; the
Drawing shows three fixed to the bottom, each by three screws, and the removal of
which offers no difficulty.
The vertical section and plan also show an opening intended to permit the
dephosphorizing agents, mixed with calcium, phosphuretted, sulphuretted, or sili-
cated, to run off. The recipients intended to receive the products of decomposition,
whether liquid or volatile, are placed in communication with this opening. A. lid
or cover lessens the radiation of the heat, at the same time limiting the space above
the iron, which gives the possibility of protecting it from atmospheric air by gases
which do not oxidize the phosphiurets of alkaline earthy metals. These gases, car-
bonized hydrogen gases, for example, which are to drive out the air, are introduced
at the beginning of the operation by a conduit, shown on the Drawing, and may be
afterwards wholly or partly replaced by the steam coming from the ferruginous haloid
salts which are formed. The opening which must necessarily be made in the vessel
for the play of the plug is closed, as the best possible manner, by a sliding plate
attached to the stopper slide.
The second boiler serves to receive the purifying agents, and is also lined with
refractory materials having the same properties as those of the upper boiler. The
haloid salts are after their fusion introduced into the boiler, previously brought to a
red heat, by means of movable jointed tubes The narrowest tube has 2 branches,
and serves for the introduction or ojection of the compressed air or gas which is
used.
The vessels are fixed the one above the other, but isolated by a layer of mortar,
clay for example.
It need scarcely be observed that any other apparatus may be used for the dephos-
phorization of iron. We will simply state that, contrary to the arrangement shown
on the Drawing hereunto annexed, we might place the vessel containing the haloid
salts in fusion above that which contains the iron.
For the introduction of the dephosphorizing agents into the fluid iron we provide
iron pipes starting from the bottom of the upper vessel, and descending nearly to
the bottom of the lower one. These pipes, covered with refractory materials, should
carry near the lower end subdividing or separating valves, or other suitable
mechanism, which may be regulated and closed from the outside This alteration
has the advantage that by employing it the violent penetration of the iron into the
lower vessel need no longer be feared, and that the movements of the vessel itself
are freer.
Our process may be applied with more or less advantage to any furnace per
mitting permanently or from time to time the retirement of oxydizing agents, such
as air, the gasses from combustion, and the oxide and protoxide of iron.

page_text: The moveable and transportable vessel which receives the iron may be replaced
by a fixed furnace, such, for example, as the "Swedish Bessemer" furnace, or by a
fore hearth, such as that of "Swam's" or "Krigar's" cupola; and instead of the
channel for the outflow of the iron which is at the bottom and closes from the
inside with a plug, a simple tapping hole may be placed at the side in the aforesaid
apparatuses. The regular introduction of the dephosphorizing agents may also be
operated laterally by twyers, or by narrow, oblong, and horizontal slits. The outlets
of these twyers or of these conduits into the iron may be narrowed or widened by
conical or cuneiform stoppers or mouth-pieces.
Instead of using valves and twyers any suitable arrangement may be adopted which 1
will secure the fine subdivision of the haloid salts of the alkaline earthy metals to
be introduced into the iron; consequently the use of rotary furnaces is not excluded,
provided that it is possible to prevent the introduction of air or any other oxydizer to
operate the continuous and intimate admixture of the dephosphorizing agents with
the fluid iron, and eject secondary products. "Siemens" " rotatory furnace, for example, 1
with the slight alterations resulting from what we have just set forth, might serve
perfectly for the dephosphorization of iron.
A suitable rotatory furnace should be capable of being separated from the regene-
rator after being brought to the greatest white heat possible, that the entrance of the
gazogene as well as the opening for admission of fluid iron and haloid salts may be
closed. The isolation of the atmospheric air takes place as in the apparatuses herein-
before described.
For driving out the gases one face of the rotatory furnace is provided in the middle
with an opening, to the inside of which is fitted a pipe; in this pipe is a second
narrower pipe, through which, in case of necessity, there may be introduced into the
apparatus gases which may come out of the first.
Sheet II of the Drawing shows a rotatory furnace uniting these conditions. The
intimate and continuous mixing produced by the rotation of the furnace may be
obtained in fixed furnaces by the agitation of the fluid masses by means of special
apparatuses The same action is also produced when the fluid iron filters through
a somewhat thick layer of dephosphorizing agents, or falls through it in fine sub-
division.
Sheet I. shows a furnace intended for the melting of the dephosphorizing agents
with utilization of the heat of the molten slag. The arrows represented show the
ascent and descent as well as the distribution of the slag.
The melting apparatus is composed of a vertical oval boiler, made, suitable
proportions being preserved, to give an extended heating surface, and that the
fusion of the haloid salts may be uniform at the edges and in the interior. The
boiler is protected from the corrosive action of the slag by a thin coating of
refractory materials The fusion may be continuous or intermittent, according to
the arrival of the slag, as the feeding, which takes place by the upper opening,
which may be closed, may occur at any moment.
The dephosphorizing agents after their fusion are driven out by air, or any other
suitable compressed gas, and then led into the vessel intended to receive them by
shifting jointed tubes.
To stop the furnace, provision must be made to remove the slag therefrom, which
is done by the opening in the masonry shown on the Drawing.
By the various arrangements which we propose means is given on the one hand
for the purification at once of a great mass of iron containing phosphorus, and on
the other hand for collecting in an undecomposed state, as we have already set
forth, all the secondary products of the dephosphorization of the iron by our
process. Our process thereby developing 3 great advantages:
1. All the haloid salts employed may be reproduced at a trifling cost.
2. With the phosphorus taken from the iron there may be manufactured without
difficulty either acid phosphate of lime or phosphoric acid.
3. The volatilized iron may be collected in the state of oxide of iron.
To recover the haloid salts of the alkaline earthy metals, with the exception of

page_text: the fluorides or cyanides, we mix in equivalent proportions the engendered haloid
salts of iron with alkaline earthy carbonates, ground or pulverized, or alkaline
earths. Thus proto-chloride of iron is mixed with limestone (carbonate of lime),
and left exposed to the air. The protochloride of iron then changes into oxide and
perchloride of iron; this latter is also by means of the carbonate of lime or burnt
lime transformed into oxide, with simultaneous formation of chloride of calcium ;
and if the decomposed mass be then lixiviated, the chloride of calcium and the
oxide of iron are obtained separate.
The process of reproduction which we have just described is accelerated if the
mass of protochloride of iron and carbonate of lime or burnt lime is introduced
into a cupola, and a current of hot air and steam is then passed through it.
The production of hot air may be obtained by an apparatus similar to those used
in blast furnaces.
The furnace may also be so arranged that at the side beneath the mixture of
protochloride of iron and calcareous matter there may be a fire-place heated by coal
or gas. The passing air is then heated by the fire and ascends through a grating
into the furnace along with the gases froin combustion. When all the iron is super-
oxidized the furnace is emptied, to be charged or fed again. If required, a con-
tinuous working might be easily established.
When chloride of calcium is used, after cooling, water is poured upon the chlorido
of calcium soiled by phosphuret, silicide, or sulphuret of calcium. The result is a
transformation of the phosphuret of calcium, partly into hypophosphite, and phosphate
of lime partly into phosphorized hydrogen This latter volatilizes, whilst the first
remains undissolved; the chloride of calcium dissolves, and may be recovered after
evaporation to dryness. But in this way a part of the phosphorus would be lost
as it escapes in the state of phosphorated hydrogen. If only a slight quantity
of this combination is produced, by reason of the soluble haloid salts, its recovery
may be neglected; but if the contrary is the case it becomes necessary to inject
water into the close vessel and to drive out the phosphorus hydrogen produced
through pipes. It is then easy to find an arrangement which will give the
phosphorus in a useful form. For example, it may be changed into phosphoric acid
by burning it exposed to the air, or it may be transformed in presence of chlorine,
or finally be made useful in any form.
We will give a short calculation of the probable consumption of chloride of lime,
assuming it alone to be employed for dephosphorization of iron by our process.
We assume in this calculation that the iron operated upon is forge pig iron, and
contains 15% of phosphorus, 0.5% of silicium, and 0.3% of sulphur, and that
the mass of chloride of calcium required must be quadrupled in order to obtain
complete dephosphorization. 1000 kilogrammes of forge pig contains 15 kg. of
phosphorus, 5 kg. of silicium, and 3 of sulphur.
According to the formula Ca² P* 15 k. of phosphorus require 53-7 k. of chloride
of calcium, which decompose in 344 kg. of phosphuret of calcium, and 61.5 of
protochloride of iron. 5 kg. of silicium require, according to the formula, Ca 2 Si,
39-6 kg. of chloride of calcium, which decompose in 19-3 kg. of silicide of calcium,
and in 454 of protochloride of iron 3 kg. of sulphur require, according to the
formula Ca S 104 kg. of chloride of calcium, which decompose in 675 k. of
sulphuret of calcium, and in 11-9 of protochloride of iron. The decomposition of
at least 103.7 kg. is therefore required to liberate these 1000 kg. of forge pig
from its phosphorus, silicium, and sulphur. Assuming it to be necessary to melt
and inject four times the quantity of chloride of lime required we arrive at
4148 kg. But in reality it is only necessary to use 2 times the quantity, that is
to say, 259 k. 25 of chloride of calcium, as we have ascertained by experiments on
a small scale.
According to our first hypothesis the 3/4 of the 414 kg. 8 would pass through the
mass of fluid iron without being decomposed If we admit that 5% is lost in the
operation of recovery we arrive at 2955 kg, with 15-6 kg. of loss. Theoretically
the 118 k. of protocbloride of iron produced should yield by recuperation exactly

page_text: the fourth. But in practice there is a loss, and if we take it at 10% we arrive at
93 32, with a loss of 104 k. of chloride of lime. Therefore for 1000 kg. of forge
pig containing 1·5% of phosphorus, 0·5% of silicium, 0.3% of sulphur, the loss by
our process, taking the most unfavorable view, is only 26 k. of chloride of lime.
The 344 kg. of phosphuret of calcium containing 15 kg. of phosphorus may give
34.4 kg. of phosphoric acid, or 75 k. of phosphate of lime, and from the 118.8 k. of
protochloride of iron we get 74.8 k. of oxide of iron. The value of these secondary
products is not insignificant, and may sensibly diminish the cost of our process of
dephosphorization. An important consumption of chloride of lime results from the
separation of the silicium, and it is evident that still more favorable results may be
obtained by the use of a slight per-centage of fluoride of calcium, because the fluor
contained in this latter volatilizes the silicium, while at the same time the calcium
decomposes phosphuret of iron.
In conclusion we will again set forth the points of novelty in our process; they
are,―
1. The continuous and regular introduction, as herein-before fully described, of
fluid haloid salts of the alkaline earthy metals in a state of fine subdivision into
the fluid iron and the intimate and continuous mixing of this latter with the salts
in rotatory furnaces.
2. The complete, or as nearly complete as possible, exclusion of atmospheric air
or other oxydizer from the fluid iron or from the fluid haloid salts, or the phos-
phides of the alkaline earthy metals which are to come into contact with the
iron.
3. The extraction of the phosphorous from the fluid iron as phosphuret of the
alkaline earthy metals, and its recuperation or recovery in a useful form
4. The recuperation or recovery of the haloid salts of the alkaline earthy metals,
provided they are soluble in water.
5. The recuperation or recovery of the volatilized iron in the state of proto-
chloride or of oxide of iron.
6. The apparatuses above described and represented in the accompanying Sheets
of Drawing, as also the modifications made therein and in other known appa-
ratuses.
Having now described and ascertained the nature of our said Invention and in
what manner the same is to be performed, we claim as secured to us by the herein-
before in part recited Letters Patent,-
The exclusive use of any operation whereby a fluid alkaline earthy haloid salt,
of any kind, or any mixture of fluid alkaline earthy haloid salts, is as a dephos-
phorizing agent to obtain the elimination of phophorus sulphur and silicium,
brought into contact with fluid iron, whether pig iron, steel, or wrought iron, or
any other similar liquid metal, protected from the influence of air or other
oxydizing agents acting upon the phosphuret of alkaline earthy metals.
The establishment and utilization of the necessary apparatuses explained in the
above description and shown on the Drawings, with the modifications made in these
apparatuses, and in other apparatuses already known.
And, finally. The use of our processes by which it is possible to obtain the
eliminated phosphorus in a useful form, as well as the recuperation of the volatilized
iron as oxide of iron, and the partial recuperation of the dephosphorizing agents,
whether the dephosphorizing agent employed contains as impurity, or as addition,
haloid salts of alkaline metals, earthy metals, or heavy metals, or presents an
additional mixture of other substances having no injurious action, and which cannot
oxydize the phosphuret of alkaline carthy metals, lime for example, whether the
phosphorus, the sulphur, and the silicium be eliminated from the iron issuing
directly from the blast furnace or from iron remelted from steel or from malleable
iron in fusion at the temperature obtained during the production without the
necessity of having recourse for the exclusion of air and other oxydizing bodies to
the use of gas deprived of oxygen, but obtaining the same results by means of
volatile haloid salts and other bodies which volatilize, whether other apparatus be

page_text: used constructed upon the same principles as the apparatuses and the modifications
of known apparatuses described by us; also if the phosphorus be obtained in a
useful form, together with a recuperation of the volatilized iron and agents
employed in the dephosphorization, according to the principles described by us for
this obtention and recuperation, and especially if the dephosphorization is effected
according to the principles set forth in this Specification
In witness whereof, we, the said Hermann Schulze-Berge and Julius
Barnstorf, have hereunto set our hands and seals, this Twenty-seventh day
of May, in the year of our Lord One thousand eight hundred and seventy-
eight.
Witness,
HERMANN POTHMANN,
Oberhausen.
HERMANN SCHULZE-BERGE. (L.S.)
JULIUS BARNSTORF.
(L.S.)