Purpose of Purifying, Hardening, and Improving the same.
Year: 1887

page_text: Date of Application, 20th Sept., 1887
Specification Accepted, 27th Jan., 1888
Purpose of Purifying, Hardening, and Improving the same.
1, GEORGE GATEWOOD MULLINS, of No. 406. North Second Street, St. Louis in
the County of St. Louis, and State of Missouri, in the United States of America,
Gentleman, 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 :-
This invention relates to a process of purifying, hardening, and otherwise greatly
improving iron, all of which will be more fully hereinafter described and pointed
out in the claims.
This invention consists essentially in the use of Silica (Si O₂) in the treatment of
iron.
Silica in the form of a very pure quartz or in the form of nearly pure silicious sand
is or may be found in nearly all parts of the globe. .
By a large number of experiments, I found that silica in this common form, after
being crushed to a powder, and fused to a liquid state has a strong affinity for sulphur,
phosphorus and arsenic and as a physic and detergent carries off these enemies from
the molten and thoroughly worked or well puddled iron; leaving the iron purer than
that produced in any other manner.
I also found that the silica, being to some extent reduced in greater or less degree
combined with the purified liquid iron, and in some way acted upon the iron, so as to
change its quality, greatly improve its character, rendering it a hard, tough steel-like
iron; which for want of a better name I venture to call "Silicated iron.*
The process is as follows:-
The puddling furnace is charged with the ores, or with east or pig iron of commerce;
it is reduced to a molten state and brought to the highest white heat possible; and
when in that condition the powdered silica, in weight from (5 to 25) five to twenty
five percent of the weight of the iron, varying according to the known impurity of
the iron, is introduced; the mass is most thoroughly puddled, allowed to boil or
simmer a few minutes until certain blue and greenish flames are emitted from the
boiling mass,
when the metal is worked out and manipulated in the usual manner.

page_text: To make a still more highly improved product, I repeat the same process upon the
iron already having been once subjected to the treatment.
It has been found in actual practice that when the powdered silica is introduce.}
while the mass of iron is boiling and at most intense heat, not only are the sulphates,
phosphates and other impurities removed with the scoria; but, beyond doubt during
the puddling of the mass at highest possible temperature (and the more powerful the
furnace the better) the silica is to some extent reduced and in greater or less degree,
is combined with the purified liquid iron.
The result is, not pure "silicide of iron" but possibly a
"silicated
or whatever it may be styled ; certainly a hard tough steel like iron, or semi-
steel which by numerous working tests has been proved to have many valuable
qualities.
iron
The principal features of this invention are:-
"Silicide
"
ог
1st. The simple use of powdered silica; 2nd. When the silica is to be introduced;
and 3rd. How it may thus be readily fused and melted, and made to combine with the
molten mass of iron to eliminate therefrom the impurities, and at the same time
imparting in some way (professedly not understood) such quantity of itself and such
properties as to form the product Silicated Iron ""Semi-Steel or greatly improved
metal, above referred to.
I do not claim the use of "Silica" in combination with any other substances, such
as have been heretofore employed, as physic, flux, detergent or alloy.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what we
claim is
The process of purifying and improving iron by the introduction to the melted mass
of iron, at the proper heat, of pulverized silica, which consists in adding silica when
the iron is at a suitable white heat, subsequently puddling the charge until blue or
green flames are emitted; then finally working the metal in the usual manner, sub-
stantially as and for the purpose described.