IMPROVEMENTS IN THE PURIFICATION OF STEEL AND IRON
Year: 1879

page_text: LETTERS PATENT to Peter Jensen, of 33, Chancery Lane, in the County of
Middlesex, for the Invention of "IMPROVEMENTS IN THE PURIFICATION OF
STEEL AND IRON." A communication from abroad by Alfred Krupp, of Essen,
in the German Empire, Cast Steel Manufacturer.
PROVISIONAL SPECIFICATION left by the said Peter Jensen at the Office
of the Commissioners of Patents on the 20th May 1879.
PETER JENSEN, of 33, Chancery Lane, in the County of Middlesex. "IMPROVE-
MENTS IN THE PURIFICATION OF STEEL AND IRON." A communication from abroad
by Alfred Krupp, of Essen, in the German Empire, Cast Steel Manufacturer.
The methods heretofore employed for producing iron and steel with the smallest
possible percentage of phosphorus from pig iron containing phosphorus have been of
twofold character. The pig iron was, according to one mode, purified by a peculiar
method, such as the purification process known as that of Alfred Krupp, in which
process the further products were made from this purified iron, or, according to
another mode, it was attempted to expose the pig iron to a purification during its
conversion into wrought iron or steel, such as by the puddling process, or, latterly,
by the process of S. G. Thomas.
This present Invention goes in a different direction from either of the aforesaid
modes, and is as follows:-From the pig iron containing phosphorus steel or fluid
iron is produced in any suitable manner, the product having the same, or even a
somewhat higher, percentage of phosphorus. This phosphor containing steel or
iron is in a fluid state conveyed into any suitable movable or stationary purifying
furnace while the slag is kept back; the hearth of the furnace has a basic or
neutral lining. In this furnace the steel is by means of basic iron or manganese
oxides, or by both together, purified in the same manner as the iron in the so called
Krupp process, but with the difference that it is not essential in the present
Invention to preserve the carbon. The loss of the whole of the carbon does not
injure the fluidity of the steel if it be conveyed into the purifying furnace sufficiently

page_text: hot; hence, one can go much further by the purification of steel than by the puri-
fication of pig iron, in which latter process the purification has to be interrupted
after the carbon has begun to oxydize.
Instead of the iron and manganese oxides, or together therewith, other basic
materials, especially lime and magnesia, may be used as additions; these may be
introduced into the purifying furnace in the solid or fluid state before or together
with the fluid steel or iron, or after the same.
For lining the hearth iron oxides, manganese oxides, bauxite, lime, magnesia,
carbon, and coal slate may especially be applied. In order to ensure greater
durability the hearth may be cooled by water.
The purifying furnace may be movable or stationary. All sorts of movable ovens,
rotary, oscillating, and reciprocating may be applied. With stationary furnaces the
intermingling of the fluid steel or iron and the basic materials may be produced or
furthered by stirring by hand or by mechanical appliances, or by the production of
currents; but even without such a purification takes place, though not so quickly
or so completely.
The process hereinbefore described may be used with every mode of steel or fluid
iron production, but it is of special importance with the Bessemer process.
It may, at first sight, appear that this mode of purifying Bessemer steel is more
complicated than the Thomas process, but the object in view is attained with greater
certainty and independently of accidental circumstances, and the process is also
materially cheaper.
Steel containing very little carbon, silicium, and manganese flows from the con-
verter into the purifying furnace. The action of the purifying materials can thus
be almost exclusively confined to the phosphorus, and will thus act much more
intensely thereon and be far better utilized than in Krupp's pig iron purifying
process in which the manganese and silicium have to be got rid of. By the con-
sumption of less purifying material the steel will be purified at less expense than
by the already cheap purification of melted pig iron.
It is quite the opposite in the Thomas process, which involves a very great con-
sumption of purifying material, and therewith necessarily great loss of heat; these
are weak points causing many difficulties and expenses. which are obviated in this
present Invention.
The Bessemer steel purified according to this Invention flows out of the purifying
furnace as a product similar to the Thomas steel from the converter. The addition
of inaterials for the purpose of giving the final product a certain percentage of
carbon, siliciun, and manganese offers no more difficulties than in the Thomas
process, and whether it be in the ladle or in a furnace with a peculiar lining.
If a steel or fluid iron of less phosphorus percentage is to be treated, or if a less
thorough purification be desired, then it is not necessary to use a special purifying
furnace. Instead of that the purification may be accomplished in a pan or in
gutters with basic or neutral lining, with addition of iron oxides or the other
inaterials named; the steel is conveyed into the pan or the gutters while the slag
is kept back. From this pan again the steel is let out into the ladle proper, the
slag being kept back for the addition of the iron oxides or other materials named.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Peter Jensen in the Great Seal Patent Office on the 29th January
1880.
" IMPROVE-
PETER JENSEN, of 33, Chancery Lane, in the County of Middlesex.
MENTS IN THE PURIFICATION OF STEEL AND IRON." (A communication from abroad
by Alfred Krupp, of Essen, in the German Empire, Cast Steel Manufacturer.)
The methods heretofore employed for producing iron and steel having the smallest
percentage of phosphorus from phosphoretic or phosphorus containing pig iron have
been of a twofold nature. According to one method the pig iron was purified by, a
peculiar purifying process, such, for instance, as that known as "Krupp's" process,
and from the so purified pig iron, steel or wrought iron were made according to
one of the usual processes for such purposes. According to another method the
pig iron was exposed to a purification during its conversion into wrought iron or
steel, such as in the puddling, or, latterly, by the process of "S. G. Thomas."
This present Invention goes in a different direction from either of the aforesaid
modes, and is as follows:-
From the phosphoretic pig iron a refined metal is produced in any suitable
manner, but especially by the usual "Bessemer " or "Sieinens-Martin process,
the product having the same, or, on account of the loss of iron, a somewhat higher
percentage of phosphorus than the original material, and containing from about one
half to about one per cent. of silicon and carbon together, these substances, with the
phosphorus, serving to keep the metal fluid.
This phosphoretic metal is, while in a fluid state, through a runner, or by a ladle,
conveyed into any suitable movable or stationary purifying furnace, while the
slag kept back the hearth of the furnace has a basic or neutral lining.
In this furnace the steel or iron is, by additions of certain materials hereinafter
to be named, purified in the same manner as the pig iron in the so called
"Krupp" process for the purification of pig iron, but with the difference that it is
not essential in this present Invention to preserve the carbon as it is with the fluid
pig iron in Krupp's process..
The additions aforesaid are basic iron or manganese oxides, or both together;
other basic materials, especially lime and magnesia, or mixtures or compositions of
same, such as magnesia or other limestone, should be used therewith. The pro-
portion of oxide may advantageously be about the same by weight as that of
the limestone or lime.
The additions may be introduced into the purifying furnace in the solid or fluid
state before or together with the fluid metal, or even after the same in some
cases.
For lining the hearth, lime, magnesia, magnesian limestone (dolomite), or carbon
may be applied, or magnesian lime bricks, or lime mixed with tar.
All sorts of movable furnaces, rotary, oscillating, and reciprocating, may be
applied. The "Pernot" furnace is especially suitable for the process. When using
stationary furnaces the intermingling of the fluid metal and the basic materials
may be produced or furthered by stirring by hand tools or by mechanical appliances
or by the production of currents, but even without such a purification takes place,
though not so quickly or so completely.
The process hereinbefore described may be practised with every kind of metal
refining furnace, but it is of special importance with the "Bessemer" converter.
When carrying out the first part of the process in a "Bessemer" converter the
blow is stopped from two to five ininutes before the drop of the flame so as to leave
from about one half to about one per cent. of carbon and silicon together in the
metal to be dephosphorized, as already stated. In the "Siemens or other refining
furnace the said part of the process is similarly stopped before the complete decar
buration and desiliconisation.
"

page_text: The material purified according to this Invention flows out of the second or
purifying furnace as almost free from phosphorus, sulphur, silicium, and manganese;
the amount of carbon, manganese, and silicium which it is desired should be con-
tained in the finished product may be given by suitable additions of spiegeleisen,
ferromanganese, &c., as is well understood; these final additions may be made in
the purifying furnace itself, or in a ladle, or in another special vessel or furnace
into which the purified material is conveyed for this purpose.
If a less phosphoretic metal is to be treated, or if a less thorough purification
be desired, then it is not absolutely necessary to use a special purifying furnace ;
instead of that the purification may be accomplished in a previously heated ladle
having a basic or neutral lining with addition of the iron oxides or other afore-
said materials; the metal is conveyed into such ladle while the slag is kept back.
From this ladle again the metal is let out into the ladle proper.
Having now described the nature of the said Invention, and in what manner the
same is to be performed, I declare that I do not claim producing iron or steel in
which, practically, no carbon or silicon is left in a "Bessemer," or << Siemens," or
other furnace, and then transferring the metal (practically completely decarbonized
and desiliconized) to a second basic lined ladle or furnace with a view to dephos-
phorizing it, as the communicator has found the presence of a certain amount of
silicon and carbon in the transferred metal to be necessary for success; he, therefore,
does not complete the said desiliconizing and decarbonizing operation in the first
converter, as has been heretofore proposed; but I claim,―
The manufacture of steel or steely iron from phosphoretic pig iron by a combined
process consisting of a preliminary metal refining operation conducted in a silicious
lined "Bessemer" converter or other suitable refining furnace and an immediate
subsequent treatment of the fluid partly refined metal containing a total amount
of silicon and carbon of from about one half to about one per cent., and containing
also the phosphorus in a basic lined "Pernot," or "Siemens," or other purifying
furnace or heated ladle with basic additions, all substantially as hercinbefore
described.
In witness whereof, I, the said Peter Jensen, have hereunto set my hand
and seal, this Twenty eighth day of January, in the year of our Lord
One thousand sight hundund and sight.