IMPROVEMENTS IN THE TREATMENT OF CAST METAL FOR THE PURPOSE OF ELIMINATING PHOSPHORUS AND SULPHUR THEREFROM
Year: 1879

page_text: "
LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of IMPROVEMENTS IN
THE TREATMENT OF CAST METAL FOR THE PURPOSE OF ELIMINATING
PHOSPHORUS AND SULPHUR THEREFROM." A communication from abroad by
Auguste Ponsard, of Paris, in the Republic of France.
Sealed the 12th August 1879, and dated the 8th May 1879.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 8th May 1879.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN THE TREATMENT OF CAST METAL FOR THE
PURPOSE OF ELIMINATING PHOSPHORUS AND SULPHUR THEREFROM." A commu-
nication from abroad by Auguste Ponsard, of Paris, in the Republic of France.
This Invention relates to the treatment of cast or pig iron or other cast metal, for
the purpose of eliminating therefrom the phosphorus and sulphur which may be
contained therein.
In carrying out this Invention, the metal is melted in a cupola or small blast
furnace, the bottom and the whole of the lining of which are formed of lime stone,
dolomite, magnesia, or agglomerated materials, having a base of pure lime or
magnesian lime, or of magnesia, or the lining may be composed of pure carbon,
agglomerated by known processes.
The trough of the cupola or small blast furnace is of sufficient size to contain a
large proportion of molten metal and scoria.
In order to eliminate the phosphorus and sulphur contained in the metal, the
latter is melted in the cupola or in the small blast furnace according to circum-
stances, there being at the same time added to the charge a proportion of pure lime
stone mixed with a variable proportion of iron ore containing a small quantity of
silica, or with iron ore containing manganese, or with iron scales or other suitable
metallic oxides.
The proportion of limestone and ore will vary according to the quantity of
impurities contained in the metal. The metal when thus melted in presence of
lime, and of the metallic oxides hereinbefore described is purified from the

page_text: phosphorus and from the sulphur which it contained, these metalloids pass into the
scoria formed by the lime and metallic oxides which are incapable of being reduced
by the fuel employed for effecting the fusion, provided that the said fuel is not in
sufficient quantity to reduce the ore which remains but a short time in the cupola
or small blast furnace.
The scoria is withdrawn from time to time as in a blast furnace, and when a
sufficient quantity of metal has accumulated in the bottom of the furnace, it may
be run off into a ladle in order to be utilized (for example), for treating cast iron in
a Bessemer converter, or in a converter constructed according to what is known as
Ponsard's system, for the purpose of making steel, or in any other metallurgical
furnace, for the purpose of converting cast iron into malleable iron or steel..

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the 7th
November 1879.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN THE TREATMENT OF CAST METAL FOR THE
PURPOSE OF ELIMINATING PHOSPHORUS AND SULPHUR THEREFROM." A commu-
nication from abroad by Auguste Ponsard, of Paris, in the Republic of France.
The said Invention relates to the treatment of cast or pig iron or other cast
metal, for the purpose of eliminating therefrom the phosphorus and sulphur which
may be contained therein.
In carrying out the said Invention, the metal is melted in a cupola or small blast
furnace, the crucible or hearth, and the whole of the lining of which are formed of
lime stone, dolomite, magnesia, or agglomerated materials, having a base of pure
lime or magnesian lime, or of magnesia, or the lining may be composed of pure-
carbon agglomerated by known processes.
The fore part of the hearth of the cupola or small blast furnace is of sufficient
size to contain a large quantity of molten metal and scoria.
In order to eliminate the phosphorus and sulphur contained in the metal, the
latter is melted in the cupola or in the small blast furnace, according to circum-.
stances, there being at the same time added to the charge a proportion of pure
limestone mixed with a variable proportion of iron ore containing a small quantity
of silica, or with iron ore containing manganese, or with iron scales or other suitable
metallic oxides.
The proportion of limestone and ore, or its equivalent, will vary according to the
quantity of impurities contained in the metal, but as a general rule, it is found that
about eight parts by weight of limestone, and about eight parts by weight of
iron ore or its equivalent to every one hundred parts by weight of the metal to
be treated is sufficient when operating upon what is known as Cleveland iron of
an average state of impurity.
The metal when thus melted in presence of lime and of the metallic oxides
herein before described is purified from the phosphorus and from the sulphur which
it contained, these metalloids pass into the scoria formed by the lime and metallic
oxides which are incapable of being reduced by the fuel employed for effecting the
fusion, since the said fuel is not in sufficient quantity to reduce the ore which
remains but a short time in the cupola or small blast furnace.
The scoria is withdrawn from time to time as in a blast furnace, and when a
sufficient quantity of metal has accumulated on the hearth, it may be run off into a
ladle in order to be utilized (for example), for treating cast iron in a Bessemer
converter, or in a converter constructed according to what is known as Ponsard's
system for the purpose of making steel, or in any other metallurgical furnace for
the purpose of converting cast iron into metallic iron or steel.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original,
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is,-
The process of purifying cast metal by remelting the same in a cupola or in a
small blast furnace, the hearth and lining of which are composed of limestone or of
carbon, or of magnesia, or of agglomerated materials, having lime or magnesia as a

page_text: base in presence of a variable quantity of basic, cinder, or scoria, such cinder or
scoria being composed of limestone and iron ore, or any other suitable metallic
oxides, substantially as hereinbefore described.
In witness whereof, I, the said John Henry Johnson, have to this my Specifica-
tion set my hand and seal, the Seventh day of November, One thousand
eight hundred and seventy nine.
J. HENRY JOHNSON. (L.S.)