AN IMPROVED PROCESS FOR THE MANUFACTURE OF IRON
Year: 1879

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
and Co., Patent Agents, Southampton Buildings, London, for the Invention of
"AN IMPROVED PROCESS FOR THE MANUFACTURE OF IRON." A communication
from abroad by Siegfried Stein, of Bonn, Prussia.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 12th August 1879.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, and Co., Patent Agents,
Southampton Buildings, London. "AN IMPROVED PROCESS FOR THE MANUFAC-
TURE OF IRON." [A communication from abroad by Siegfried Stein, of Bonn,
Prussia.]
This Invention relates to an improved process for the manufacture of iron, and
whereby I eliminate the phosphorus from the pig iron and transfer the same to the
slag, as hereinafter described.
When in a blast furnace which is being charged with coal or coke it is required
to remove the phosphorus from the pig-iron and transfer it to. the slag, the latter
will have to be made basic by the addition of a flux of alkaline earths or their
compounds to such a degree that for every 100 parts of oxygen in the silicic acid
which is contained in the slag the total amount of oxygen in the base will be at
least 120 parts.
But this increased proportion of the base in the blast furnace slags can not be
obtained by an increased addition of lime-stone fluxes alone but necessitates a
corresponding addition of a flux consisting of a mineral or minerals containing
magnesium with lime-stone, such as bauxite, witherite dolomite, bitter-spar, and
magnesite, which are introduced at the top of the furnace, with or without the
addition of the lime-stone usually employed.
The above specified minerals may be used separately, the choice being determined
by their relative cost, but I prefer that several or all of them should be used toge-
ther. The more polybasic the slag is the more easily will it melt and thus fuel is
saved. It is desirable, not to use these minerals in too large pieces; they may
advantageously be powdered or roasted before putting them in the furnace.

page_text: But for the purpose of this Invention the use of the basic slag, as above described
would not alone produce the desired result; the phosphorus would remain in the
pig-iron and would not be transferred to the slag. I therefore employ the process
described in the Specification of Letters Patent dated 17th April, A.D. 1876,
No. 1609, wherein the phosphorus is liberated by means of cyanide of ammonium
generated in the blast furnace, but used separately from the iron ore, the coals, the
coke, and the lime-stone, that is to say, from the materials usually employed in the
blast furnace. The phosphorus thus liberated by the above process then exists
in the blast furnace in a gaseous condition, and if the ordinary slag is used the
greater portion of this phosphorus returns to the iron and only a small quantity
combines with the slags.
But if the slags are made basic to the extent above specified then all the
phosphorus which has been liberated by the cyanide of ammonium from the mate-
rials placed in the furnace euters into the highly basic slag and runs with the same
out of the blast furnace.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent Office on the 12th
February 1880.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "AN IMPROVED PROCESS FOR THE MANUFAC-
TURE OF IRON." A communication from abroad by Siegfried Stein, of Bonn, Prussia.
This Invention relates to an improved process for the manufacture of iron
whereby I eliminate the phosphorus from the pig iron and transfer the same to the
slag, as hereinafter described.
When in a blast furnace charged with coal or coke it is required to remove the
phosphorus from the pig iron and transfer it to the slag, the latter will have to be
made basic by the addition of a flux of alkaline earths or their compounds to such
a degree that for every 100 parts of oxygen in the silicic or other acid contained in
the slag the amount of oxygen in the base will be at least 120 parts.
But this increased proportion of the base in the blast furnace slag cannot be
obtained by an increased addition of limestone fluxes alone but necessitates a
corresponding addition of a flux consisting of a mineral or minerals containing
magnesium or magnesia with or without limestone, such as bauxite, witherite,
dolomite, bitter-spar, or magnesite; these minerals are introduced at the top of the
furnace, with or without the addition of the limestone usually employed. The
above specified minerals may be used separately, the choice being determined by
their relative cost, but I prefer that some or all of them should be used together.
The more polybasic the slag is the more easily will it melt, and thus fuel will be
saved. It is desirable not to use these minerals in large pieces and they may
advantageously be powdered or roasted before putting them in the furnace.
But for the purpose of this Invention the use of the basic slag, as above described
will not alone be sufficient, that is to say, it will not effect the result of eliminating
the phosphorus from the pig iron and transferring it to the slag. I therefore
employ, in addition to or in combination with the means above described, the
process described in the Specification of Letters Patent dated 17th April, A.D. 1876,
No. 1609, wherein the phosphorus is liberated by means of cyanide of ammonium
generated in the blast furnace but used separately from the iron ore, the coals, the
coke, and the limestone, that is to say, separately from the materials usually
employed in the blast furnace. The phosphorus thus liberated then exists in the
blast furnace in a gaseous condition, and if the ordinary slag is used the greater
portion of this phosphorus returns to the iron and only a small quantity combines
with the slag. But if the slag is made basic to the extent above specified all of
the phosphorus which has been liberated by the cyanide of ammonium from the
materials placed in the furnace enters into the highly basic slag and runs with the
same from the blast furnace.
Having thus fully described the said Invention, as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it under-
stood that I claim,―
The improved process consisting in the employment of a mineral or minerals
containing magnesium or magnesia, with or without limestone, in a blast furnace
wherein the phosphorus is liberated by means of cyanide of ammonium from the
materials in the furnace, as and for the purpose specified.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Twelfth day of February, in the year of our Lord One
thousand eight hundred and eighty.