Improvements in the Purification of Iron for Casting and General Foundry Purposes, as also in the Production of Steel and Wrought Iron.
Year: 1893

page_text: Date of Application, 14th June, 1893
Complete Specification Left, 7th Mar., 1894-Accepted, 12th May, 1894
PROVISIONAL SPECIFICATION.
Improvements in the Purification of Iron for Casting and General
Foundry Purposes, as also in the Production of Steel and
Wrought Iron.
We, JOSEPH BRAMAH COCHRANE, of Pedmore Hall, Stourbridge, Worcester-
shire, and THOMAS HENRY TAYLOR, of No. 63 King Street, Dudley,
Worcestershire, do hereby declare the nature of this invention to be as
follows:-
Our invention has for its object the purification from sulphur of cast iron when
used either for casting or foundry purposes or for the production of steel or
wrought iron.
Very great trouble is experienced with cast iron owing to the sulphnr contained
therein, and up to the present time its effectual removal has not been accomplished
by any of the processes heretofore proposed.
The sulphur present in the metal is due not only to that contained in the crude
pig iron but also to a further quantity taken up from the coke used in remelting
through the cupola.
According to our invention we effect the removal of the sulphur from the iron
by treating it with a compound by preference formed into lumps or balls, composed
of a mixture of fluor spar, lime or limestone, and iron or steel drillings or turnings
or scrap, a little sal ammoniac being added for binding the other ingredients
together.
The said substances are used in such proportions that by merely running the
molten metal upon the compound, whether in the form of compact balls or
otherwise, and allowing them to rise with the metal, the sulphur is to a very great
extent removed.
The proportions employed may be considerably varied according to circum-
stances; compounds formed of from 35 to 60 p.c. of iron or steel borings,
36 to 21 p.c. of lime, 28 to 17 p.c. of fluoride of calcium, and 1 to 2 p.c. of sal
ammoniac have been employed with advantage.
The great advantage of using the compound in an agglomerated form with iron
borings and sal ammoniac as described is, that while the lumps have a tendency to
float and consequently to rise with the metal. as this is poured into the ladle, the
metallic iron added tends to keep as large a proportion as possible of the mass
submerged and thus causes the compound to operate very effectually on all parts
of the molten metal with which it comes in contact this action being so perfect
that no stirring or rabbling is required. Owing to this effectual action of the
compound only a comparatively small proportion thereof is required, as compared
with the proportion of similar desulphurizing materials employed in other
processes.
Thus the metal treated may be in the proportion of from 500 to 1000 times the
weight of the said desulphurizing balls, the treatment being. so effectual as to
reduce the sulphur in the metal from 12.p.c. to .04 p.c. and from 072 p.c.
to 024 p.c.
The chemical reaction produced is very energetic, causing the evolution of
considerable heat in the ladle.
If it be desired to remove silicon with the sulphur, we employ oxide of iron
in the form of iron ore, or otherwise, in lieu of or together with the iron turnings
or borings.

page_text: The said desulphurizing and desiliconizing process is comparatively rapid, as
the time required is only that occupied in filling the ladle with molten metal from
the cupola.
When applying the said compound in the manufacture of steel or wrought iron
it would be added either in the ladle receiving the molten cast iron for transference
to the converter, or in the converter or steel or puddling furnace itself.
The said purifying process has the advantage of materially increasing the
strength of the metal, both tensile and transverse, as also its elasticity. The
castings produced are stronger and exhibit a marked freedom from blow holes.
In place of fluor spar or fluorides may be used chlorides or other suitable
halogen compounds, although such is not desirable, and in place of the lime may
be used a hydrate such as sodium hydrate. Also, other materials may be used in
place of chloride of ammonium, for rendering the balls compact.
In preparing the compound care must be taken that the materials be well
incorporated by grinding with water, the mass being subsequently dried.
Dated this 14th day of June 1893.
ABEL & IMRAY,
Agents for the Applicants.
Improvements in the Purification of Iron for Casting and General :
Foundry Purposes, as also in the Production of Steel and
Wrought Iron.
We, JOSEPH BRAMAH COCHRANE, of Pedmore Hall, Stourbridge, Worcester-
shire, and THOMAS HENRY TAYLOR, of No. 63 King Street, Dudley, Worcester-
shire, do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :—
Our invention has for its object the purification from sulphur of cast iron when
used either for casting or foundry purposes or for the production of steel or
wrought iron.
We have found that the element may to a very large extent be removed at a
trifling cost by the use of a mixture of fluoride of calcium and lime together with
metallic iron or steel, applied in the special manner which we have discovered as
being both the most effectual and economical.
The fluoride of calcium and lime are mixed with iron or steel borings or filings or
any small scrap and made into a pasty condition with water, a little sal-ammoniac
being added to facilitate the adhesion of the mass.
The mixture is made of such proportions, varying according to the quality of
metal to be treated, that when moulded into bricks, balls, or masses, they will float,
while being to a large extent submerged in the molten metal.
The following proportions have been found to answer very well with a moderately
sulphurous iron :
Iron
Fluoride of calcium
Lime
Sal ammoniac
35 to 70 per cent.
28 12
"
"
"
36 16
"
"
"
1
2
"
"
"
The proportions having, with water, been thoroughly ground or mixed together,
are moulded into bricks, balls, or any other desirable shape.

page_text: In treating the iron for foundry purposes the brick or ball is thrown into the ladle
at the commencement of or during the filling, the metal being desulphurized by the
floating body as rapidly as it rises.
In converting iron into steel the iron may be treated in a similar manner, as it is
received from the blast furnace, and before transference to the converter, or it may
be treated in the converter or furnace direct.
The great advantage of using the compound in an agglomerated form with iron
borings and sal-ammoniac as described is, that while the lumps have a tendency to
float and rise with the metal (as this flows into the ladle) the iron borings added
tend to keep as large a proportion as possible of the mass submerged, and thus cause
the compound to operate very effectually on all parts of the molten metal, this action
being so perfect that no stirring or rabbling is required.
Owing to this effectual action of the compound only a comparatively small
proportion thereof is required as compared with the proportion of similar
desulphurizing materials employed in other processes.
Thus the metal treated may be in the proportion of from 250 times to 750 times
the weight of the desulphurizing materials proper, the treatment being so effectual
as to remove the sulphur in the metal to the extent of from 50 to 75 per cent.
Silicon may also be removed from the metal by the use of oxide of iron in the
form of iron ore or otherwise, in lieu of or together with the iron borings or
turnings.
In place of, or together with the fluorides may be used chlroides or other suitable
halogen compounds such as calcium, sodium, or ferric chlorides although such is not
desirable, and in place of lime may be used a hydrate, such as sodium hydrate or
an alkaline oxide or carbonate.
We are aware that fluorides together with lime have already been proposed for
the purification of iron from sulphur, and we do not claim the use of these substances
generally.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In treating iron for foundry and general casting purposes, the use, for
purifying it from sulphur, of a floating ball or brick composed of calcium fluoride or
other halogen compounds such as calcium, sodium or ferric chlorides together with
an oxide, carbonate or hydrate of an alkali, metallic iron and chloride of
ammonium.
2. In treating iron for its conversion into steel, the use for purifying it from
sulphur of a floating ball or body such as is referred to in the first claim, either in
the ladle or vessel of crude iron, or in the furnace or converter.
3. In converting crude pig iron into wrought iron the use for purifying the same
from sulphur of floating brick or ball such as is referred to in the first claim at the
melting or other period of the conversion.
Dated this 7th day of March 1894.
ADEL 0. IMD AV
ABEL & IMDAY
Agents for the Applicants.