IMPROVE- MENTS IN THE MANUFACTURE OF IRON AND STEEL
Year: 1876

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, for the Invention of "IMPROVE-
MENTS IN THE MANUFACTURE OF IRON AND STEEL."
abroad by Siegfried Stein, of Bonn, Prussia.
A communication from
aled the 23rd September 1876, and dated the 17th April 187€
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 17th April 1876.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN THE MANUFACTURE OF IRON
AND STEEL." A communication.
The said Invention of improvements in the manufacture of iron and steel
consists in the production and application of cyanide of ammonium in blast furnaces,
the so called "Siemens Martin "furnaces, "Bessemer" converters, puddling furnaces,
and the like, for the purpose of removing phosphorus and sulphur from iron or steel
during the process of manufacturing the same."
In applying this Invention to blast furnaces the cyanide of ammonium is produced
by mixing with the charges of ore, coal, coke, and limestone a certain proportion
of titanic iron, or carbonate of potash, or any other suitable compounds of potassium,
either separately or combined, while at the same time at a suitable height above the
tuyeres a jet of steam, carburetted hydrogen, petroleum vapour, or other hydro-
carbon, either separately or combined, and by preference at a high temperature
is forced into the furnace.
In the application of the said Invention to "Siemens Martin" furnaces, "Bessemer"
converters, and puddling furnaces the cyanide of ammonium is produced and applied
by introducing at the proper period into the molten metal a mixture of sal ammoniac
and dried yellow prussiate of potash, or any other suitable mixture that gives off
cyanide of ammonium at a high temperature.

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 17th
October 1876.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Fatent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN THE MANUFACTURE OF
IRON AND STEEL." A communication from abroad by Siegfried Stein, of Bonn,
Prussia.
My said Invention relates to the manufacture of iron and steel, and consists in
the production and application of cyanide of ammonium in blast furnaces, Siemens
Marten furnaces, Bessemer converters, and puddling furnaces for the purpose of
removing phosphorus and sulphur from iron and steel during the process of
manufacture.
In blast furnaces the cyanide of ammonium is produced by mixing with the
charges of ore, coal, coke, and limestone a certain proportion of titanic iron ore,
carbonate of potash, or any suitable compound of potassium, either separately or
combined, while at the same time at a suitable height above the tuyeres a jet or
jets of steam, carburetted hydrogen, petroleum vapour, or other hydrocarbon, either
separately or combined, and by preference at a high temperature, are forced into the
furnace..
In carrying this part of my Invention into practice I prefer mixing the titanic
iron ore, which is mostly found in the state of fine sand, in the proper proportion
with the crude coal before coking the same in the ordinary way, so as to have the
ore in most intimate mixture in the coke.
If carbonate of potash is used I prefer dissolving the necessary quantity in water,
thus forming a solution which the coke is made to absorb, being dried afterwards
before use.
In both cases the coke so prepared is charged in the ordinary manner along with
the impure iron ore, limestone, and the like at the top of the furnace.
It is not necessary that all the coke used should be prepared as above, it is
sufficient if only a portion of the coke required for the furnace is so prepared, always
provided that the quantity of titanic ore, or carbonate of potash, or of both com-
bined, necessary for the purification of the impure materials used in smelting is
regularly added to each charge.
The quantity of titanic ore or carbonate of potash required will depend entirely
on the quantity of phosphorus and sulphur to be eliminated, and the correct pro-
portion must be ascertained by actual experiment, but as a guide to those using
this Invention it may be stated that in practise about 10 lbs. of carbonate of potash
- or a proportionate quantity of titanic iron ore will be required for every 1 per cent.
of sulphur and phosphorus and per ton of iron made.
•
For forcing the superheated steam or hydrocarbon into the furnace I prefer to
arrange a second tier of smaller tuyeres above the blast tuyeres, at such a height
where all the oxygen contained in the atmospheric air of the blast has been practi-
cally consumed, and reduction of the ore by the action of the carbonic oxide has
commenced. The proper height I ascertain practically by inserting bars of wrought
iron for a short time through the tuyere box at different angles into the furnace,
and placing the steam tuyeres a little above the line where the iron bars begin to
burn away.
In practice this height varies a good deal according to the quantity
and pressure of the blast, but. 12 to 18 inches above the centre of the blast tuyeres
will be found in all ordinary cases the proper height for the steam tuyeres.
In using superheated steam alone it will be found sufficient to take the steam
direct from the boiler, passing it through a series of pipes heated by part of the
waste gases similar to those used for heating the blast, but if hydrocarbons are to
be mixed with the superheated steam (which I prefer doing) a modification of the
steam blower can be advantageously employed for taking up the vapor of the
hydrocarbons that are to be mixed with the steam.

page_text: By adding titanic ore or carbonate of potash to the charge cyanide of titanium
or cyanide of potassium are produced as soon as the charges reach the reception
basin in the furnace, while the superheated steam and hydrocarbons meeting
the nitrogen and carbonic oxide of the reducing zone produce compounds of
ammonium (probably carbonates), which meeting the cyanides above mentioned in
statu nascendi form cyanide of ammonium in the very zone of the furnace most
suitable for the climination of phosphorus and sulphur from the materials used in
smelting iron by the action of cyanide of ammonium, and experience has proved
that the phosphorus and sulphur thus eliminated do not recombine with the cooler
portions of the charges above, but escape in the form of gases (the nature of which
has not been as yet fully ascertained), burning away at the mouth of the furnace,
or are consumed under the boilers or other apparatus heated by the waste gases
of the furnace.
It is thus obvious that my Invention can be easily applied to any existing blast
furnace, and that the great advantage of the said Invention consists, first, in the
application of cyanide of ammonium for the purification of the ores; limestone, coke,
or other material employed for smelting iron without interfering with the proper
working of the furnace, and then in producing the cyanide of ammonium in the
very zone of the furnace when its purifying power is most effectual in the
moinent of its production.
Applied to "Siemens Martin" furnaces, " Bessemer" converters, and puddling fur-
naces, the cyanide of ammonium is produced and applied by introducing at the proper
period into the molten metal a mixture of sal-ammoniac, and dried yellow prussiate
of potash or any other suitable compound that gives off cyanide of ammonium at
a high temperature.
To carry this part of my Invention into effect I use a mixture of three parts of
dried yellow prussiate of potash and two parts of sal-ammoniac in a finely powdered
state, or if Berlin blue or Turnbull's blue is preferred, I use two parts of either of
these to one part of sal-ammoniac at the rate of about 5 to 6 lbs. of the mixture
for every 1 per cent. of phosphorus and sulphur per ton of iron or steel.
In the Siemens Martin furnace I prefer to introduce the necessary quantity of
any of the above mixtures in small doses immediately before a fresh quantity of
iron is added to the bath in the furnace, but it can also be added in larger doses
just before the final heating of the bath before tapping the metal.
In the application of this Invention to the "Bessemer" converter I prefer to
employ a closed hopper large enough to contain the required quantity for one
charge of any of the above mixtures, and communicating with the blast pipe as near
to the converter as can be conveniently arranged by a suitable stop cock, by turning
which a portion of the mixture is dropped at each revolution into the blast pipe,
and is carried by the blast through the tuyeres into the metal. A small quantity
of charcoal dust may be usefully mixed with the compound to prevent caking, and
to facilitate the carrying of the powdered materials by the blast through the tuyeres
into the molten metal. A flat bar of iron placed in a slanting direction across the
centre of the tuyere box will also be found useful in causing a rotary motion of
the blast in the box, thus sweeping up any particles of the mixture that may have
settled there.
In the application of this Invention to the "Bessemer" converter the cyanide
of ammonium in a gaseous form may also be introduced directly into the blast,
but in this case care must be taken that the whole of the apparatus is thoroughly
air-tight, and provision must be made to ensure that any escaping gas shall be
carried away by the draught up the chimney, where it is burned in passing
the mouth of the converter. In the puddling furnace any of the above mixtures
are introduced as soon as the iron is melted, and as the quantity required is only
small, I prefer to use a shallow wrought-iron trough with a long handle which can
be easily introduced into the hole in the furnace door: The mixture is put into
the trough, the latter is introduced at the said hole in the furnace door, inverted
with a sharp jerk, and moved about in the molton iron in all directions, the

page_text: gas escaping all round the edges of the said trough and passing through the iron.
When the escape of gas ceases the handle is depressed, the residue removed from the
trough by a sinart blow against the handle, and after cooling the trough in water
the operation can be repeated if the iron requires a second operation to free it
sufficiently from phosphorus and sulphur.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner in which the same may be conveniently and
advantageously carried into practise, I wish it understood that I do not confine myself
to the precise details herein specified, provided that the peculiar features of my
said Invention be retained, and I claim in and for the manufacture of iron or steel-
First. The removal of phosphorus and sulphur from iron ores, limestone, coke,
coal, or other materials usually employed for smelting iron by passing cyanide of
ammonium over these materials at a high temperature such as is usual in blast
furnaces.
Secondly. The production of cyanide of ammonium in blast furnaces for the pur-
pose above stated by mixing with the charges of ore, coal, coke, and limestone a
suitable quantity of titanic iron ore, carbonate of potash, or other suitable compounds
of potassium, either separately or combined, while at the same time at a suitable
height above the tuyeres a jet or jets of steam, carburetted hydrogen, petroleum
vapour, or other hydrocarbon, either separately, or combined, and by preference at
a high temperature, are forced into the said furnace.
Thirdly. The removal of phosphorus and sulphur from iron or steel by passing
cyanide of ammonium through the molten metal.
Fourthly. The production of cyanide of ammonium by introducing a suitable
mixture of either dried yellow prussiate of potash, Prussian blue, or Turnbull's blue
in combination with sal ammoniac (chloride of ammonium) into the molten metal
be purified or freed from phosphorus and sulphur.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Seventeenth day of October, in the year of our Lord
One thousand eight hundred and seventy-six.
W. ROB LAKE. (L.S.)