IMPROVEMENTS IN THE MANUFACTURE OF IRON
Year: 1879

page_text: LETTERS PATENT to William Thomas Lewis, of Neath, Glamorganshire, South
Wales, Analytical Chemist and Assayist, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF IRON."
Sealed the 22nd April 1879, and dated the 22nd January 1879.
PROVISIONAL SPECIFICATION left by the said William Thomas Lewis at
the Office of the Commissioners of Patents on the 22nd January 1879.
WILLIAM THOMAS LEWIS, of Neath, Glamorganshire, South Wales, Analytical
Chemist and Assayist. "IMPROVEMENTS IN THE MANUFACTURE OF IRON."
This Invention relates to improvements in the manufacture of iron, the object
being chiefly to eliminate phosphorous from iron, either as ore or pig iron. This I
effect by the agency or chemical action of sulphuret of carbon and chloride of
sulphur.
For convenience of description my process may be termed divisable into two
parts, though both theoretically and practically the Invention is the same in both
cases.
ore.
I will first describe my Invention as applied during the process of smelting the
In this case the source of sulphur I prefer is iron pyrites and of chlorine chloride of
sodium. The pyrites is first converted into sulphide and sulphate of iron, and then
decomposed by lime and dried. The dried mass is now a mixture of sulphide and
sulphate of lime and oxide of iron. The chloride of sodium used is common salt.
These compounds are introduced into the blast furnace along with the phosphoretic
ores, and in some instances, as when the ores are difficult to smelt, the said com-
pounds are first mixed with a proper proportion of argillaceous or clay iron stone
or red hematite ore. The result is the complete separation of the phosphorous
from the iron, and its elimination partly in the form of gas and partly in the
Blag.
The required proportions of my said compounds and of argillaceous or hematite
ore to the phosphoretic ores are determined by the composition of the latter, and in
practice have been found to vary from to 3 per cent. of the first, and from 0 to
10 per cent. of the second.

page_text: In the second part of my Invention, in which it is desirable to employ the sulphur
in a purer form, the best source of the sulphur is sulphate of iron (common copperas)
and sulphate of lime (common gypsuin), the chlorine being obtained from the same
source as in the first part. The sulphates and sulphides or sulphurets of any or all
of the alkalies and alkaline earths may be resorted to as a source of the sulphur
or the form in which it may be used. In dealing in this part of the process with
some qualities of the phosphoretic iron (such as those not highly carbonised) it has
been found necessary to add carbon in small proportions, the best and cheapest form
of carbon being pulverised anthracite.
The process here consists in the introduction into the iron in a molten state of a
properly prepared mixture, in various proportions, of the above named ingredients.
This mixture is introduced by being fixed in the casting bed into which the molten
iron is run. This bed may be the ordinary sand bed, or a series of cast iron cells or
moulds, which latter I prefer.
In ordinary cases one hundred weight of the prepared mixture is found sufficient
to dephosphorise, and, where necessary, to decarbonize a ton of pig iron. The pro-
portion of carbon (when necessary) to the sulphate is determined by the quality of
the iron operated on, the iron in the majority of cases being sufficiently carbonised
to supply all the carbon required in the operation, and its abstraction thus is
essential to the success, and forms part of the operation.
In this part of the process the phosphorus, in the form of phosphoric acid, or
otherwise, being exposed to the strong action of the chloride of suphur and sulphuret
of carbon, produced by the chemical changes taking place under the high temperature
of the iron, is withdrawn from the iron and entirely eliminated, chiefly in the form
of gas, while in some instances it has been found in small quantities in the thin slag
formed on the upper surface of the ingot.
The great elevation of temperature produced by the liberation of oxygen in the
cells also contributes to the purification of the iron.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
Baid William Thomas Lewis in the Great Seal Patent Office on the 19th July
1879.
WILLIAM THOMAS LEWIS, of Neath, Glamorganshire, South Wales, Analytical
Chemist and Assayist. "IMPROVEMENTS IN THE MANUFACTURE OF IRON."
This Invention has for its object improvements in the manufacture of iron by its
purification from all foreign matters, but chiefly from phosphorus. This I accom-
plish as follows:-The process is divisible into two applications, but the principle is
the same in both.
In the first division, which is applicable during the operation of smelting the ore,
the process consists in the introduction into the furnace along with the ore of a
compound or mixture of sulphate and sulphide of lime, chloride of sodium, and oxide
of iron. This compound or mixture is prepared by first converting, by exposure to
air and moisture, iron pyrites into sulphide and sulphate of iron, and then mixing
them with lime and common salt, in proportions varying according to the quality
of the ore to be smelted. For ordinary ores the best proportions are lime 80, con-
verted pyrites 12, salt 8. Where the ore is rich in phosphorus the proportions of
the limo to the other ingredients should be reduced accordingly. The above mixture
is to be used in addition to the usual flux in the proportion of from to 3% of the
ore, according to the quantity of phosphorus in the ores to be eliminated. In some
instances, as where the ores are difficult to smelt, it is advantageous to mix this
preparation with either argillaceous or hematite ores, in proportions varying
according to the work to be done, but not exceeding 10%. The use of argil-
laceous or hematite ores in such cases is not new, except in combination with my
Invention.
°
The second division of the process is applicable to the iron after its reduction
from the ore. It consists in the introduction into the iron in a molten state of a
properly prepared mixture of sulphates, sulphides, and chlorides, with carbon in
various proportions. This mixture is prepared by the admixture of solutions of
iron persulphate and the chlorides of iron and sodium, and the absorption and
partial decomposition thereof by hydrate of lime and pulverized charcoal, coke,
anthracite, or coal. This mass is to be intimately mixed and then carefully dried.
The proportions most suitable in ordinary case are two parts of the iron persulphate
and one part of each of the chlorides, with from 1 to 8 per cent. of carbon, the
proportion of carbon being regulated by the proportions of that element known or
estimated to exist in the iron operated on. Some irons have been found to be
sufficiently carbonised to supply all the carbon necessary in the process, and its
abstraction is thus essential to the success, and forms part of the operation. The
lime is used as a medium to fix the other ingredients in the moulds or ladles into
which the iron is run, also to ensure their gradual decomposition when in contact
with the molten iron, and to assist in the absorption and separation from the iron
of the impurities dislodged in the operation. This it effects by gradually forming
a slag with the said impurities, and carrying them with it as it rises to the surface.
The proportion of lime will be governed by the size of the mould or ladle and the
rapidity with which it is desired the operation should proceed, as, when large, the
mould or ladle generally takes a considerable time in filling, and the chemical
action should therefore be retarded, and when it is desired that this action should
be still more slow and prolonged or retarded, a small proportion of argillaceous
clay, in addition to the lime, may be advantageously mixed with the said ingredients.
From the foregoing it will be seen that the above described mixture of substances
or ingredients is to be placed on the bottom, and sometimes on the lower part of
the sides of the mould or ladle. The molten iron is run on this in the proportion
of oue ton of iron to from a half to a hundredweight of the preparation, and
allowed to remain undisturbed until all ebulition or boiling has subsided. If in

page_text: moulds the slag on the surface of the iron should now be removed, but if in a ladle
the iron may be run off by a tap-hole at the bottom into sand or iron moulds (the
latter being preferable when making pig or ingot iron), the slag being removed either
from the surfaco of the iron before, or from the bottom of the ladle after tapping.
The above described mixture or preparation of ingredients may be used also for
purifying iron in the puddling furnace and in the blast furnace, and may be
introduced into the latter at the tuyer holes, or in any other suitable way.
I claim as my Invention to be secured by the hereinbefore in part recited Letters
Patent, improvements in the manufacture of iron, substantially as hereinbefore set
forth and described.
In witness whereof, I, the said William Thomas Lewis, have hereunto set my
hand and seal, this Nineteenth day of July, A.D. One thousand eight hundred
and seventy nine.
W. THOS. LEWIS. (L.S.)