A NEW OR IMPROVED PROCESS FOR THE MANUFACTURE OF FERRO MANGANESE IN THE BLAST OR SMELTING FURNACE
Year: 1877

page_text: LETTERS PATENT to Gerard Wenzeslaus von Nawrocki, of the Firm of
J. Brandt and G. W. von Nawrocki, Civil Engineers and Patent Agents, of
No. 2, Koch Strasse, Berlin, in the German Empire, for the Invention of "A
NEW OR IMPROVED PROCESS FOR THE MANUFACTURE OF FERRO MANGANESE
IN THE BLAST OR SMELTING FURNACE." A communication by Caspar Stöck-
mann, of Hutte, Phoenix, near Ruhrort, in the German Empire.
Sealed the 18th December 1877, and dated the 11th July 1877.
PROVISIONAL SPECIFICATION left by the said Gerard Wenzeslaus von
Nawrocki at the Office of the Commissioners of Patents on the 11th July
1877.
GERARD WENZESLAUS VON NAWROCKI, of the Firm of J. Brandt and G. W. von
Nawrocki, Civil Engineers and Patent Agents, of No. 2, Koch Strasse, Berlin, in
the German Empire. "A NEW OR IMPROVED PROCESS FOR THE MANUFACTURE OF
FERRO MANGANESE IN THE BLAST OR SMELTING FURNACE." [A. communication by
Caspar Stöckmann, of Hutte, Phoenix, near Ruhrort, in the German Empire.]
The production of ferro manganese meets with two principal difficulties, which
up to the present time prevent its ready manufacture. These difficulties are of a
chemical nature, consisting firstly, in the great affinity between manganese and
oxygen, and secondly, in the, if possible, still greater affinity between manganic
protoxide and silicic acid.
#
If the manganese is present only in small quantities in proportion to the iron, the
manganic oxides are more easily reduced, and it appears in this case that a certain
affinity between the iron and the manganese operates against the above-named chemical
antagonistic forces. By means of this affinity and the reducing agents it is possible
to reduce small quantities of manganese tolerably completely; but it is otherwise
when the manganese is present in larger quantities. When a certain proportion
has been attained the manganese divides itself into two almost equal parts, of which
the one combines with the iron and the other with the slag, as the spiegeleisen
manufacture in Siegerlande proves.

page_text: According to the present Invention one of the above forces inimical to the pro-
duction of ferro manganese, namely, the affinity between the manganic protoxide
and the silicic acid, is more or less completely neutralized by opposing thereto the
affinity between silicic acid and one or more other bases to such an extent that they
are held in equilibrio thereby; only a single force, namely, the affinity between the
manganese and oxygen, then requires to be overcome by means of the known
reducing agents, an operation which is readily performed. As bases for establishing
the above equilibrium are employed Ca O, Mg O and Al, O₂, and the former
generally in the form of limestone.
The question arising as to the extent to which the limestone has to be added to
establish this equilibrium, it was determined that such equilibrium must ensue
if the addition of limestone is such that in the slag the amount of oxygen of
Ca O+ MgO + Al. O, is greater than the oxygen of Si Oy.
1
= 42.12
Accordingly a furnace charge was prepared, having a proportion of Fe
per cent. and Mn 11.31 per cent. Under the tolerably correct assumption that
in spiegeleisen or ferro manganese, there are 94 per cent. of metal and 6 per cent.
of other substances, the theoritical yield of Mn is 19-89 per cent., that is, under the
assumption that all inanganic oxides are completely reduced, the spiegel. eisen pro-
duced should contain 1989 per cent. Mn; in reality it contained 17-67 per cent. Mn,
therefore 88.8 per cent. of the total quantity of manganese had been reduced,
and this with a slag in which the oxygen of the Si O. was to the oxygen of the
Ca O+ MgO + Al, O, as 10: 11.72.
The yield will not be capable of much increase owing to the fact that there
occurs at two places in the smelting process a small loss of Mn, which from technical
reasons is hardly to be obviated.
Firstly. Some Mn is carried away with the dust at the top of the furnace.
Secondly. Another portion of Mn is carried off with the slag, which is no longer
green but of a brownish colour. This is explained as follows The Mn is carried
with the slag, partly as metal, out of the furnace, and is then oxidised in the air.
The metal takes a certain time in the furnace to percolate through the slag on to
the hearth, and as the slag flows continuously out of the furnace, a portion of the
Mn can always be carried out of the furnace sooner than it can percolate through
the slag.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Gerard Wenzeslaus von Nawrocki in the Great Seal Patent Office on
the 10th January 1878.
GERARD WENZESLAUS VON NAWROCKI, of the Firm of J. Brandt and G. W. von
Nawrocki, Civil Engineers and Patent Agents, of No. 2, Koch Strasse, Berlin, in the
German Empire. "A NEW OR IMPROVED PROCESS FOR THE MANUFACTURE OF
FERRO MANGANESE IN THE BLAST OR SMELTING FURNACE." A communication by
Caspar Stöckmann, of Hutte, Phoenix, near Ruhrort, in the German Empire.
The important part which manganese plays at the present day in the form of
ferro manganese in the Bessemer and Siemens-Martin steel processes has caused iron
smelters to search for methods for preparing this alloy in a simple and cheap
manner in the blast furnace.
As my process, to be presently described, only relates to the preparation of ferro
manganese in the blast furnace, I will not refer to such processes as relates to its
preparation in crucibles or reverberatory furnaces.
Wedding gives in his work on iron smelting, vol. 3, p. 528, a list of the methods
at present in use.
Method I., proposed by Bessemer, relates to the manufacture in crucibles.
Method II., by Henderson, requires a reverberatory furnace.
Method III., of Terre Noire, requires a small shaft furnace, which is more similar
to a cupola than to a blast furnace, but to whichever it may be reckoned it does not
signify, as my process is entirely different from that of Terre Noire, which requires
a special preparation of the raw materials and does not mention the slag.
According to a report of Dr. Düře, Terre Noire now makes the ferro manganese in
reverberatory furnaces after Siemens' process, and this with a slag which only
consists of metallic oxides and lime, as the process requires the complete absence of
silica. How far this statement may be actual fact I cannot say, as according to my
experience there are no such slags, as with the usual temperatures they could not be
fused.
The process of William is carried out in crucibles; and lastly, a process of Thomson
is mentioned carried on in a reverberatory furnace. I believe that I have succeeded
in fulfilling the hope expressed by Wedding, at page 531, with reference to the future
method of producing ferro manganese; I having invented a process by which it is
possible, with a continuous daily working, to produce 20,000 to 25,000 kilogrammes
of ferro manganese per 24 hours, and this without the slightest difficulty.
PRODUCTION OF FERRO MANGANESE IN THE BLAST Furnace.
The reduction of manganese from its combinations with oxygen has always been
considered very difficult, as stated in Wedding, vol. 2, p. 582, and all other text
books.
After the many years experience of the iron smelters of Siegerland they assert.
(and it is a fact) that they cannot get more than 50 per cent. of the manganese out
of the ores into the spiegeleisen, the remaining 50 per cent. going into the slag.
At the same time the opinion is also held that, generally speaking, it is not possible
to raise the per-centage of manganese in spiegeleisen beyond a certain limit in the
blast furnace, because all added manganese goes into the slags.
.
Jordan, in Wedding, vol. 2, p. 584, speaks exactly to that effect as follows:-By-
increasing the proportion of lime and the temperature of the blast it is possible to
increase the proportion of Mn in spiegeleisen, but it must not be thought that the
proportion of Mn in the charge can be increased ad libitum. "With a small quantity.
"in the charge, it all goes into the iron; with a surplus of oxidised Mn it is divided
"almost equally between the iron and the slag, up to a certain limit, beyond which
"all additional Mn goes into the slag." These statements appear to be taken from
observations made in Siegerland,

page_text: The great resistance of the manganic oxides is due, firstly, to the great affinity between
Mu and oxygen, and, secondly, to the, if possible, still greater affinity between the
manganic protoxide and silica. In order to give an idea of the blast furnace slag, as
produced in the manufacture of spiegeleisen, I give below an analysis of the same. I
took the slag sample myself from one of the most noted spiegeleisen works of Sieger-
land, and added a piece to my collection. The spiegeleisen with this slag contains
on an average 11 per cent. manganese.

page_text: The analysis shew that the proportion of Mn increases to a certain limit, at which
the Mn goes in almost equal quantities into the iron and into the slag. With the
highest charge of limestone, which was 43 per cent, a ferro-manganese was produced
with 34 per cent. Mn, therefore somewhat over 30 per cent. of the theoretically
possible quantity. With this the oxygen of the silica was in proportion to the
Oxygen of.
The above analysis is in so far very instructive that it shews that the slag can
take up Mn far beyond the single silicate if the oxygen of the other bases be less
than the oxygen of the silica. This analysis is or will be published in the Journal
of the Iron and Steel Institute. Here again the Mn is to be found one-half in the
iron and the other half in the slag.
THEORY OF THE PROCESS FOR THE PRODUCTION OF FERRO MANGANESE IN THE
BLAST FURNACE ACCORDING TO THE PRESENT INVENTION.
The production of ferro manganese miccts with two principal difficulties, which up
to the present time prevents its ready, manufacture. These difficulties are of a
chemical nature, consisting, firstly, in the great affinity between manganese and
oxygen; and, secondly, in the, if possible, still greater affinity between manganic
protoxide and silica.
If the manganese is present only in small quantities in proportion to the iron, the
manganic oxides are more easily reduced; and it appears in this case that a certain
affinity between the iron and manganese operates against the above-nained
chemical antagonistic forces. "By means of this affinity and the reducing agents, it
is possible to reduce small quantities of manganese tolerably completely; but it is
otherwise when the manganese is present in larger quantities. When a certain
proportion has been attained the manganese divides itself into two almost equal parts,
of which the one combines with the iron and the other with the slag as the
spiegeleisen manufacture in Siegerland, England, and Reschitza proves. From a
number of phenomena which I had observed in the course of time in blast furnaces,
I determined a theory which led me to hope with certainty to be able to manu-
facture ferro manganese with facility.

page_text: My theory is as follows:-The two said inimical forces, the affinity between.
manganese and oxygen, and between manganić protoxide and silica, are together so
powerful that with the temperatures at present attainable in the blast furnace it is
not possible to reduce the manganic oxides. I had however found from my
collected observations that it is possible with ease to do away with and reduce
almost to nothing the one force, namely, the affinity between the manganic
protoxide and the silica by opposing thereto the affinity between silica and one or
more other bases to such an extent that they are held in equilibrio thereby. I
have then only to overcome a single force, namely, the affinity between the
.manganese and oxygen by means of the known reducing agents, an operation
which is readily performed. 1 employ as bases for establishing the above
equilibrium Ca Ó Mg'O and Al, Os, or other alkaline earths, and generally in the
form of limestone.
;
The question now arises as to the extent to which the limestone is to be added to
establish this equilibrium. According to my experience I determined that this
equilibrium must ensue if the addition of limestone in the slag is such that the
amount of oxygen of Ca O + Mg O + Al₂ 0, + alkaline earths is greater than the
oxygen of SiO2. I found in publications nothing that could discourage me, there-
fore I proceeded with confidence to trials which have confirmed my theory in the
most complete manner.
The commencement of my discovery dates several years back. A blast furnace at
the Phoenix Works was then producing white iron, which was puddled into puddle
steel and fine grained iron. The puddlers complaining that the steel did not shew
sufficient grain, but bad some fibrous parts, I endeavoured to give the pig metal a
higher degree of striation by increasing the charge of limestone; the striations
became in effect broader and broader, and were, to my astonishment, at last trans-
formed into complete spiegel, although the furnace charge only contained, about
3 per cent. of Mn. The slag was tolerably white, therefore the Mn was mostly sent
into the iron. I may mention that for the puddling process I obtained just the
contrary of what I wanted. With each increase of the limestone charge the iron
worked slower in the puddling furnace, the puddled slag became thicker (want of Si),
and the fibre in the puddled steel increased instead of diminishing.
A later experiment of mine (see Berg und Hüttenenännische Zeitung of 1876,
p. 244), showed that just the contrary process is the right one for this purpose; for
such iron the blast furnace must be worked with an acid (long glassy) slag, in order
that a certain quantity of Si, and not the maximum of carbon, may be sent into
the iron.
The first certain confirmation of the fact that a much greater quantity of Mn can
be sent into the pig metal than was hitherto considered possible was obtained by
me through the analysis of a slag which was produced at the Phoenix Works in the
manufacture of Bessemer pig. The slag was composed of―
The pig metal produced with this slag contained 2.85 per cent. Mn. As the
Bessemer pig at these works contained but little Mn, it was important to determine
how the Mn. behaved when present in the manufacture of Bessemer pig metal. For

page_text: this purpose I applied to a blast furnace engineer who was producing pig metal
with more Mn. The slag analysis communicated to me is as follows:-
The pig metal contained 6 per cent. Mn. My friend wrote to me with this
analysis: "The above analysis proves that with from 5 to 6 per cent. Mn only
little Mn need go into the slag; but in my opinion this is the limit." Here the
above-mentioned opinion is again put forward by a practical smelter that only with
a low per-centage of Mu it is possible to send it entirely into the pig metal. My
opinion is that with the slag rendered basic by lime the Mn can be almost entirely
sent into the iron; even a proportion of 6 per cent. was confirmed, to my great
satisfaction, by the above analysis. Now I knew that in Siegerland with a higher
per-centage of Mn (10-12 per cent.) only about one half could be reduced, and I
very much doubted the fact that with the small difference between 6 and 10 per
cent. there should be such a great deviation, and I therefore concluded that either
the Mn must be of a very incomprehensible nature, or which seemed more likely,
that the operations in Siegerland were not carried on properly. I went to Sieger-
I first
land in order to study the manufacture of spiegeleisen carried on there.
observed the slag. This was rough on the surface, and crumbled to powder after
exposure to the air for a time; all together it appeared to the uninitiated to be of a
basic character. This shook my theory somewhat, but I informed myself of the
limestone charge and coke consumption, and both were, curiously enough, so small
that the slag could not possibly be basic through lime. I found, however, a further
fact which confirmed me to a certainty as to this last view. The furnace namely
gave off very little smoke; the gases burnt well in the hot blast stove and deposited
but little dust there. This was for me an unmistakable proof that the temperature
in the furnace could only be a low one, and that in consequence the slag could not
be basic through lime. The analysis made later of this slag confirmed this view
completely; the slag was composed as follows:-

page_text: so much limestone that the O of the bases (exclusive of Mn O), becomes greater
than that of Si O₁, they will at once get 16 to 17 per cent. Mn in their spiegel-
eisen instead of only 11 per cent. as at present, and instead of only 50 per cent.
they will reduce from 75 to 90 per cent. An of the charge, as was proved so clearly
by my trials, even after only a few days. It may well be asked how it is possible
that this discovery was not made long ago in Siegerland. The explanation is
tolerably simple. There have been up to the present time few or no chemists at
the works there; only few analysis were made, and these mostly had only for their
object to determine the commercial value of the manufacture. It was, I believe,
never imagined that by means of chemical analysis the metallurgical processes could
be followed out and cleared up in a most perfect manner. The endeavour of such
works is always to produce a fine large spiegel, therefore the temperature of the
furnace must be so regulated that the slag shall have a particular colour. If the
temperature accidentally becomes higher the appearance of the slag changes, it
becomes lighter and more basic by means of the reduced silica, the spiegeleisen no
longer has the fine spiegel but has a seam, that is, the upper part of the fracture of
a pig has a small spiegel, or even fine granular appearance. If the temperature
should rise still higher, the seam would eventually become grey, and with a still
greater heat the entire fracture would become grey.
If the proportion of oxygen indicated by me be established in the slag, the seam
does not appear, and it is not possible to make the iron grey; it remains white at
the highest temperatures; the seam of the Siegerland metal therefore at once points
towards the ferro manganese structure. But as a spiegel eisen with scam only has a
small value for Siegerland, they endeavour, as quickly as possible, to change the
conditions of working.
.
I would remark here that in my experiments it was not my object to produce
spiegeleisen, but to reduce the Mn as much as possible. The products obtained by
me had from the first more the appearance, of ferro-manganese, and not the fine large
spiegel surfaces. In fact, while 1 operated upon the chemical composition by means
of a lime-basic slag, Siegerland has been operating with an acid slag merely for the
appearance to the eye.
DESCRIPTION OF MY EXPERIMENTS FOR THE PRODUCTION OF FERRO MANGANESE.
The principle of my method for the production of ferro manganese is, as already
stated, as follows:-I take the proportion of limestone to the charge of ore so high
that in smelting in the blast furnace a slag is formed in which the O of all bases
(exclusive of Mn O, and Fe O) is greater than the O in the Si O. By this means
I am enabled to reduce and send into the ferro manganese 75 to 100 per cent. of the
total Mn present. With this it is according to experience quite immaterial how
much Mn is present in proportion to Fe, so that a charge might be used containing
only Mn and no Fe, if such a material could be found.
My experiments for the production of ferro manganese have been so conducted
that I commenced with a proportion of Mn similar to that of the Siegerland spiegel
eisen manufacture, namely, 11 per cent. in the charge, and then increased the Mn
in the following charges. For this purpose I made three descriptions of charges;
the first contained 42-12 per cent. Fc, 11:31 per cent. Mn; the second 30-36 Fe,
18.12 Mn; and the third 2361 Fe, 27.08 Mn. The proportion of Mn was therefore
increased from 11:31 to 27.08, while the Fe was decreased from 42.12 to 23.61. .1
have employed four descriptions of ores for the experiments, namely:-
1. Auxbach; roasted spath-iron ore from the Auxbach mine at Linz a Rhine,
belonging to the Phoenix Company.
2. Eisengarten; roasted spath-iron ore from Siegerland.
3. Heinrich; sphärosiderite mixed with manganic ore from the Heinrich mine at
Diez, belonging to the Gutehoffnungshütte in Oberhausen.

page_text: From this the chemical composition was calculated as follows:-
Fe
41. 1
+102
Mn
11
3
+ 0.01
Fe
Mn
from the coke ash
:-
42 12 Fe
11 31
Mn
"
دو
"
"
Ca O
Mg O
173
+025
Ca O
"
1 98
Ca O
.
2. 73
+ 0
03
Mg ọ
>>
"
"
>>
Al, O
3. 57
+1 53
A1, 0,
"
"3
"
"
2 76
5. 10
Mg O
Al₂ O
Si O, 15 53
+2
84. Si O,
"
"
"
"
P
0 0530 007 P
"
"
"
"3
18 37 Si O₂
0. 060 P.
With the tolerably correct assumption that in the spiegeleisen and ferro man-
ganese there are 94 per cent. metal, and 6 per cent. other substances (C, Si, &c.), the
theoretical quantity of Mn sent into the spiegeleisen is 19.80 per cent. I have
actually produced a spiegel eisen with 17.67 per cent. Mn, therefore 88.8 per cent.
of the existing Mn was reduced, or 949 per cent. of the 1131 per cent. in the
charge, 182 per cent. Mn having consequently gone into the slag.
According to calculations, this charge gives, with a limestone charge equal to 45
per cent. to 100 parts ore, 58.52 slag-yielding ingredients, and as to this must be
added 182 parts of Mn; the slag contains, according to calculation, about 3.02 per
cent. of Mn, while the analysis gives 3.28 per cent. Mn, which two results are
sufficiently in accordance with each other.
The first charge was placed in the blast furnace on the 23rd April of this year,
with a quantity of ore equal to 2300 kilos. and 34 per cent. limestone. The coke
charge was in this and in all other experiments constant, namely, 1400 kilos. The
limestone charge was gradually increased from 34 to 45 per cent. These figures of
the limestone charge always relate to the moist charge. As this contained about 16
per cent. moisture the limestone charge amounted to about 53 per cent. with the

page_text: giving the proportion of:
O in Si O, O in Ca O + AlĘ O
:
10 11 76.
In order to determine how these figures agreed with the actual facts, I made an
analysis of the slag with the following result:
This proportion therefore agrees pretty well with the calculation.
As already stated the composition of the slag is of the greatest importance in the
smelting process.
The appearance of the slag in the fracture is very characteristic for this com-
position, particularly in respect of the proportion of oxygen.
An experienced eye can tell with considerable certainty the approximate Mu per-
centage in ferro-manganese from the appearance of the fracture of the slag.
The surface is less characteristic, though even here there are definite indications.
On the surface, the slag always has a basic appearance, whether there be much or
little limestone in the charge. With a small charge of limestone the fracture is
dark green, and has a certain wax-like fatty lustre. With the increased limestone
charge, this lustre disappears, and the slag is less green, and assumes more and more
a stony character.
It will be seen that in this basic condition the MnO is hardly combined with
the Si O, where the slag comes in contact with the atmosphere, the metal is at
once oxidized to Mn, O,. It is however not at all improbable that the Mn is carried
by the slag in metallic shape out of the furnace. In the air the slag assumes a
brownish colour; if it cools slowly in the air it falls to powder, but if it cools some-
what more quickly, for instance, by allowing it to run on thin sheet metal, it does
not fall to pieces.

page_text: I have nerem-before given the analysis F
of phosphorus of the spiegeleisen of this first charge was calculated at 0.105 per
cent. The second description of charge was composed by weight of,
Spanish haematite 40-1°
Auxbach
-
26.3
"
Heinrich
33.6 "
100.0
from this the chemical composition is calculated as follows:-
Fe
29. 8
Fe
+1 16
Out of coke ash
-
Mn
18. 1
+ 0.02
Mn
30 96 Fo
18 12
Mn
"
"
Ca O
3.
1
+ 0.28
Ca O
3. 38
"
"
Mg O
1.
5
+ 0.03
Mg O
-
"
"
Al, O
6*
0
+1.75
Aly Os
=
"
"
1 53
7. 75
Ca O
Mg O
Al₂ 0,
Si O₂
14 2
+ 3.25
P
0. 072 0008
Si O₂
P
=
うう
"
رو
"
17. 45 Si O.
•O• 080 P
With the previous assumption the theoretically possible Mn per-centage of the
ferro manganese from this charge is calculated at 347 per cent.
I have in reality produced a ferro manganese from it with 30.07 per cent. There-
fore 867 per cent. of the total Mn were reduced, or of the above 18.12 parts Mn
15.71 were reduced and 2.41 went into the slag. As these 2.41 parts Mn are
combined with 56-42 parts slag-producing substances.
The charge II. was introduced into the furnace on the 1st May 1877, with a
weight of ore equal to 1,750 kilos. and 29 per cent. limestone; the latter was
increased to 39 per cent. As the charge had about 16. per cent. moisture, the
oxygen proportion is as above.
From this the proportion of the
O in Si O, O in Ca O + Mg O + Al¸ O¸ = 10 12:41.
This slag has not yet been analysed, but its appearance would seem to prove the
correctness of the above figures.
The phosphorus per-centage of this ferro manganese is calculated at 0.153 per
cent., but as will be presently shewn, it is probably less.
What was stated about the slag of Charge No. I. also applies here.
CTTT concintail of

page_text: The charge No. III. was introduced on the 6th May 1877, with a weight of ore
equal to 1850 kilos. and 16 per cent. limestone. The latter was increased to 24. per
cent.
The theoretical yield of Mn from this charge was about 54 per cent. and a ferro
manganese was produced with 4513 per cent. Mn, therefore 83.6 per cent. Mn
were reduced. The slag had not reached the highest degree of basic nature, and
could have borne an increase of the limestone charge without becoming infusible.
The increase could however not be effected because the charge was consumed.. The
basic condition will have been about 10: 12.5. An accurate calculation could not
take place, because the composition of the slag was not accurately known.
The ferro manganese produced with 24 per cent. limestone contained,—

page_text: UNCITO manganese producee
cent. limestone gave :-
Mn
= 45 98 per cent.
P
= 0.101 "
Si
= 1. 17 "
"
рек
The above Mn determination was made as follows:-After Fe and Mn had been
twice separated by acetate of soda, the Mn. was precipitated by bromine and filtered;
then dissolved in hydrochloric acid, completely reduced with some sulphide of soda,
and then according to Fanmm, precipitated with carbonate of ammonia. After
standing for 12 hours it was filtered, well washed, dried, calcined, and weighed
as Mn, O.
With the other Mn determinations, the manganic peroxide, precipitated with
bromine and well washed, was calcined and weighed as Mn, O.
From the foregoing it will be seen that the novelty of my process for the manu-
facture of ferro manganese consists in producing the before-mentioned high
yield of manganese from charges having a high per-centage of this substance
by means of a slag, in which the oxygen of Ca O + Mg O + Al O, is
greater than the oxygen of Si O. Up to the present time no smelting works
are known to do anything of the kind, nor is any description of the kind contained
in any published work. On the contrary, it is the general view that it is impossible
to attain a similar yield of Mn, and that it is not possible to reduce much above
50 per cent of the total quantity, whereas by my process I am enabled to reduce
from 75 to 100 per cent of the total manganese.
The discovery of my process arose principally from an observation made by nie,
as before stated, in the manufacture of Bessemer pig metal, and from the com-
parison of this observation with the manufacture of spiegeleisen. From the
comparison of these two methods of manufacture my theory and the discovery of
my inethod of producing ferro manganese originated, neither of the two methods is
the same as mine, and from neither alone can ny process be developed.
In the manufacture of Bessemer pig metal a totally different product is aimed at,
a product which is a grey, and therefore of a graphitic nature in its fracture..
In the manufacture of spiegeleisen the method of smelting is totally different.
With this, one half of the Mn goes into the slag, even with ever so high a per-
centage of the Mn in the charge, as shewn by the analysis of John Brown and Co.,
and Reschitza.

page_text: Having thus described the nature of this Invention, and in what manner the same
is to be performed, as communicated to me by my correspondent, 1 claim,-
First. The method substantially as herein described of manufacturing ferro
manganese, whereby from 75 to 100 per cent. of the manganese contained in the
blast furnace charge are reduced, by so proportioning the charge of alkaline sub-
stances as to produce a slag in which the oxygen of,- Ca O + Mg 0 + Al, 0, +
alkaline earths is greater in quantity than the oxygen of the silica.
Second. The use of ferro manganese containing from 75 to 100 per cent. of the
total quantity of manganese contained in the furnace charge from which it is smelted
in the manner substantially as herein described.
In witness whereof, I, the said Gerard Wenzeslaus von Nawrocki, have here-
unto set iny hand and scal, this Twenty-eighth day of December, in the year
of our Lord One thousand eight hundred and seventy-seven.
GERARD WENZESLAUS V. NAWROCKI. (L.S.)