Improvements in and relating to the Manufacture of Steel and Iron.
Year: 1888

page_text: Date of Application, 25th Sept., 1888
Complete Specification Left, 19th June, 1889-Accepted, 27th July, 1889
PROVISIONAL SPECIFICATION.
Improvements in and relating to the Manufacture of Steel and Iron.
I, HARRY JOHN SMITH, Ph.D. of Coltness Iron Works, Newmains, Lanarkshire,
do hereby declare the nature of my invention to be as follows:—
This Invention has reference to and comprises improvements in the manufacture
of steel and iron by the addition of a new or improved compound or substance for the
purpose of removing, or preventing the formation of oxide of iron in the metal, and
which will do so without incurring the deleterious effects caused by Ferromanganese
or Spiegeleisen heretofore used for this purpose. The new compound has also the
effect of removing carbon phosphorous and other impurities from the metal.
And the nature and novelty of my Improvements consist in using and mixing with
the molten steel or iron, soda-lime, or caustic soda, instead of Ferromanganese or
Spiegeleisen as heretofore. The proportions of soda-lime which I have found to act
well in steel manufactured according to the Siemens-Martin or Bessemer processes,
and in which 16 per centum of carbon is left, is 21 lbs. per 3 tons of metal, or 7 lbs.
per ton, but this proportion would vary according to the percentage of carbon desired
to be left in the metal.
The soda-lime or caustic soda, preferably in a granulated state, would be added to
the metal while in a molten state at any desired stage of the process, preferably in
the ladles after removal from the furnaces or convertors.
The soda-lime, when it is used, would preferably be obtained by evaporating down
pure caustic soda, with calcined or quicklimo in any desired proportions until this
forms a solidified or granulated mass, and heated to expel as far as possible water of
hydration.
Instead of soda, potash or any other of the allied alkalies or compounds of those
may be used either separately or mixed with the lime for treating the metal as
hereinbefore described.
Dated this 25th
- 1000
W. R. M. THOMSON & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in and relating to the Manufacture of Steel and Iron.
I, HARRY JOHN SMITH, Ph.D. of Coltness Iron Works, Newinains, Lanarkshire,
do hereby declare the nature of my said invention, and in what inanner the same is
to be performed to be particularly described and ascertained in and by the
following statement in writing, that is to say :-
This Invention has reference to and comprises improvements in the manufacture
of steel and iron by the addition of a new or improved compound or substance for
the purpose of removing or preventing the formation of Oxide of iron in the metal.
In the manufacture of soft steel and ingot iron either by the Bessemer or Siemens-
Martin processes, or by any of the oxidation processes, such as the Basic Bessemer
process, it has been found that the addition at a certain point in such processes of
Manganese in the form of Spiegeleisen or Ferro Manganese is for most purposes
indispensable. It is customary to add the Manganese alloys either to the converter
or ladle in the Bessemer process, or to the furnace or ladle in the Siemens-
Martin and like processes, and if this addition be omitted the iron or steel will be
"red-short
and unfit for manipulation and rolling. This addition of manganese
alloys however always entails an addition of carbon, as well as manganese and
"

page_text: frequently other impurities, to the steel or iron, and this addition is in certain cases
undesirable. By my invention however 1 am able to prevent the iron from becoming
"red-short" without the necessity of using Ferro Manganese or Spiegeleisen. It
has also the effect of removing Carbon and certain other impurities from the metal.
My said improvements consist in using Soda-Lime (or potash Lime as herein-
after set forth) and mixing the same with the molten steel or iron instead of Ferro
Manganese or Spiegeleisen as heretofore.used. Such compound I prefer to add at
that point in the process at which it is customary to add the manganese. If it is
added to the ladle Ladd it direct, and if to the converter or furnace I then make
use of "Tuyers" or tubes so that the. thorough incorporation with the molten metal
may be obtained. I prefer to add the compound to the ladles immediately after
removal from the furnace or converter.
In order to serve as a guide to the amount of the compound which should be used
I would say that under ordinary circumstances adding it to steel or ingot iron in a
state in which about decimal 16 per centum of carbon is left I should add about
twenty-one pounds per three tons of metal or seven pounds per ton, but this pro-
portion would vary somewhat according to the percentage of carbon desired to be
left in the metal. If a larger amount of carbon is desired to be left the proportions
used will be somewhat smaller, and if the iron has a larger percentage of carbon in
it when the compound is added some increase may be made in these proportions.
The soda-lime which may be prepared by any of the known methods is however
preferably obtained by evaporating down pure caustic soda with calcined, quick, or
slaked lime in any desired proportions until it forms a solidified or granulated mass
containing a percentage of water; or it may be heated to expel water and so far as
possible, water of hydration. As an example of the soda-lime that I use I give the
following analysis of such Soda-Lime and it will be found that with this approxi-
mate composition it will act well under such circumstances as I have described and
will eliminate approximately one half of the Carbon and a large percentage of any
silicon present from steel or ingot iron containing decimal 16 of Carbon.
I prefer to add the said Soda-Lime in a granulated state.
Instead of Soda, Potash may be used, in the preparation of the Lime compound,
this substance taking the place of a chemically equivalent weight of soda.
The lining of the furnaces or converters or ladles in these my processes may be
either what is technicallly known as "basic" or "acid.".
Although by my invention.I am able to dispense with the use of Ferro Manganese.
or Spiegeleisen or analogous substances such as Ferro Silicon Manganese as before
mentioned, these substances may also be added if for any reason it is desirable to do
so, as for instance if a certain percentage of Manganese or other metal is desired in
the resulting metal. Such addition will not however prevent the operation of my said
invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is :-
23
First. The use of Soda-Lime or Potash Lime in the process of manufacture of
steel or ingot iron, substantially as hereinbefore described.

page_text: Second. The improved processes for the manufacture of steel or ingot iron
herein before set forth.
Dated this 10th day of June 1889
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.