IMPROVEMENTS IN THE MANUFACTURE OF MALLEABLE IRON AND STEEL, AND IN THE PREPARATION OF THE MATERIALS USED FOR THE CONSTRUCTION OF THE FURNACES AND OTHER PLANT USED THEREIN.
Year: 1879

page_text: LETTERS PATENT to Carl Friedrich Claus, of 16, Mark Lane, City of London,
Chemist, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
MALLEABLE IRON AND STEEL, AND IN THE PREPARATION OF THE MATERIALS
USED FOR THE CONSTRUCTION OF THE FURNACES AND OTHER PLANT USED
THEREIN.'
"
Sealed the 25th July 1879, and dated the 10th May 1879.
PROVISIONAL SPECIFICATION left by the said Carl Friedrich Claus at the
Office of the Commissioners of Patents on the 10th May 1879.
"IM-
CARL FRIEDRICH CLAUS, of 16, Mark Lane, City of London, Chemist.
PROVEMENTS IN THE MANUFACTURE OF MALLEABLE IRON AND STEEL, AND IN THE
PREPARATION OF THE MATERIALS USED FOR THE CONSTRUCTION OF THE FURNACES
AND OTHER PLANT USED THEREIN."
When operating upon pig iron containing phosphorus with the view of con-
verting the saune into malleable iron or steel, and of freeing the same of the
phosphorus, I employ for the construction of the furnaces used in this operation,
that is to say, for the lining of the furnaces only, materials containing as little silica
as practically possible. I choose for this purpose materials such as lime, inagnesia,
and alumina, or mixtures of these; I use the lime in preference in the form of
burnt lime or burnt magnesian lime, but powdered limestone or magnesian limestone
will also answer the purpose, though not so well. I powder or otherwise des-
integrate these materials, and to give the particles of the powder sufficient cohesion
I mix thereto strong solutions, either of chloride of calcium or chloride of magnesium,
chloride of sodium, or metallic chlorides, such as chloride of iron or chloride of
manganese, or mixtures of any of these chlorides. I may also mix the chlorides
named to the lime or limestone or magnesian lime or limestone in a powdered or pul-
verized condition; I also treat desintegrated lime or magnesian lime or limestone
with muriatic acid, or I add to the lime or magnesian lime or limestone powdered
fluoride of calcium. The quantities of these substances to be added to lime or
magnesian lime or limestone powder should be regulated to be only just sufficient
to cause the particles of the powder to adhere to each other when subjected to a

page_text: heat exceeding that in which they are to be employed, so as to form a hard and
solid mass. If bricks are to be formed from these materials I either press the
mixture first, and then fire the the bricks, or I heat the mixture first and press it
whilst hot into bricks.
When operating upon iron containing phosphorus in furnaces constructed with
or lined with the materials named I add to the iron under treatment such substances
as a flux or slag forming material, for the purpose of taking up the phosphoric acid
and silicic acid, as are as free of silica as is practically possible.
I use therefore mixtures of lime or magnesian lime and chloride of sodium or
lime, or magnesian lime and chloride of calcium, or chloride of magnesium or
cloride of iron, or chloride of manganese, either alone or mixed with oxide of iron
(as free of silica as possible), I also use powdered fluoride of calcium instead of the
chlorides named, together with lime or magnesian lime with or without oxide of
iron.
I may however also use chloride of calcium or magnesium together with oxide of
iron only.
During the operation of puddling or conversion of pig iron into steel or malleable
iron the chlorides become either decomposed into hydro chloric acid or volatilised
as perchloride of iron, both or either of which may be absorbed in water, and may
be used over again.
The addition of chlorides or fluoride of calcium are made for the purpose of
inducing the fusion of the lime and oxide of iron so as to form a non siliceous
slag.
The linings described are equally applicable to the ordinary puddling furnace,
the rotatory furnace, as well as for Bessemer or other converters, or the Siemens
Martin, or similar furnaces. The material may be used either in the form of loose
fettling, or in the form of bricks
Powdered bauxit may also be formed into a cohesive or solid mass by mixing
thereto as a binding material a small quantity of the lime and chloride mixtures, or
some lime and fluoride of calcium.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Carl Friederich Claus in the Great Seal Patent Office on the 10th
November 1879.
CARL FRIEDRICK CLAUS, of 16, Mark Lane, in the City of London, Chemist.
"IMPROVEMENTS IN THE MANUFACTURE OF MALLEABLE IRON AND STEEL, AND IN THE
PREPARATION OF THE MATERIALS USED FOR THE CONSTRUCTION OF THE FURNACES
AND OTHER PLANT USED THEREIN."
In a Provisional Specification, No. 1074, dated the Thirtieth of March,
One thousand eight hundred and sixty eight, for improvements in the manu-
facture of malleable iron, I published the process by which, and the conditions
under which the phosphorus and sulphur contained in pig iron can be eliminated
during its conversion from pig into malleable iron. These conditions I stated
to be (1) the exclusion of all silicious materials, as far as practically possible
from the iron whilst under treatment. For this reason I proposed to construct
or to line the furnace with lime, magnesia, or alumina, and (2) the substitution
for the usual silicious slag by basic nonsilicious materials. In order to give to
such basic slag the necessary fusibility, and to bring it into intimate contact
with the iron under treatment, and so as to cause it to have the necessary washing
effect, I proposed the use of such nousiliceous materials which in point of cheapness
I considered to be the only practicable ones, I proposed for this purpose mixtures of
lime and salt, chloride of calcium, and chloride of magnesium. These I proposed to
mix with the usual quantity of nonsiliceous oxide of iron. An opportunity being
denied to me at the time of carrying out said process on a inanufacturing scale, the
application for Letters Patent was not proceeded with. The salient points of the
process are as stated, the use of nonsilicious basic materials for the construction of
the furnaces, together with the use of basic nonsilicious materials for the formation
of the slag. It is obvious that the nature of the process which effects the elimination
of the phosphors during its conversion from pig into malleable iron remains the
same, no matter what form or shape of furnace is used in the saine, that is to say,
whether the ancient force, the present puddling furnace, the revolving furnace, the
Siemens Martin, or the Bessemer furnace is used, so long as by the employment of
such process the result, viz., the elimination of the phosphorus, is the same."
It is further obvious that it remains the same also whether the dephosphorized
iron is used as such, or is converted into steel by the subsequent addition of
spiegeleisen or carbon iron, whether it is heated to fusion or used in the pasty
condition, whether the necessary heat during the conversion into malleable iron is
produced by extraneous furnace fires, or by the combustion of the metalloids con-
tained in the iron itself, so long as by maintaining during the process the conditions
of a nonsiliceous slag in a nonsiliceous furnace the phosphorus is eliminated from the
iron. The said process, as shown above, being now well known I wish it to be under-
stood that though it does not form part of my present Invention, still in carrying
out my present improvements I retain the main features or principles of the same,
that is to say, when it is a question of eliminating the phosphorus from iron during
its conversion from pig iron into malleable iron or steel, I use furnaces constructed
of nonsiliceous materials, such as lime, magnesia, or alumina, together with non-
silicious slag forming or purifying materials, such as lime and salt, lime or magnesia
and chloride of calcium, or chloride of magnesium, either alone or mixed with oxide
of iron, as will hereafter be further described.
As stated already I use in my present improvements furnaces or apparatus
constructed of nonsiliceous materials, viz., lime, magnesia, or alumina, or mixtures
of these, but instead of producing the cohesion of the particles of lime as has been
proposed by other, by the use of siliceous materials, such as clay or silicate of sode,
I use nonsiliceous materials, such as chloride of calcium, chloride of magnesium,

page_text: chloride of iron, or fluoride of calcium, and even chloride of sodium, either each
separate, or mixtures of two or more of these substances. The chlorides named I
use either in solution, or they as well as the fluoride of calcium may be added in
the form of fine powder, or the lime, magnesia, and alumina (or mixtures of alumina
with these) may be exposed to the action of liquid or gaseous hydrochloric acid
or chloride of iron. The treatment with gaseous hydrochloric acid I prefer to carry
out by passing the gas through these materials whilst in a highly heated state in a
kiln. The quantity of the chlorides or the fluoride of calcium to be added to the
other materials is easily found by experience, but I find that an admixture of about
ten per cent. is sufficient in most cases.
The lime should be burned at a very high temperature for the purpose of this
process. When alumina (in the form of bauxit) is to be used together with lime or
magnesia and the chlorides or fluorides I subject the mixture first to an intense
heat before mixing it with further quantities, in order to line out furnaces with it.
By doing so the material becomes much denser and more unalterable by heat or
exposure to air.
In making mixtures of lime, magnesia, and alumina (of either two or all of these)
together with chloride or fluoride of calcium, chloride of magnesium, or iron, I may
do so in any proportion thought best suited for the purpose, and to any such
mixture I may add the floride of calcium, or any of the chlorides named above, or
I may expose any of these materials or mixtures of materials to the action of
hydrochloric acid gas at ordinary or elevated temperature; or I may produce
mixtures of alumina and chloride of calcium in other ways, for instance, by decom-
posing chloride of aluminium by lime or mixtures of chloride of aluminium with any
of the other chlorides by lime, or mixtures of magnesia and chloride of calcium by
decomposing chloride of magnesium by means of lime and so forth, and such
decomposition may be either effected in solution or in the dry state, and by heat,
so long as they remain mixtures as aforesaid. The materials prepared as
described is best suited for what is termed " 'ramming," but it may also be
made in bricks or blocks in any suitable manner. Where the lime, magnesia,
or alumina mixtures are used for lining out furnaces, such as ordinary puddling
furnaces, the contact with brickwork should be avoided. When operating
upon iron containing phosphorus and sulphur in furnaces constructed of
or lined out with the materials named, I add to the iron under treatment
such substances as a slag forming material, as are as free as is practically possible
of silicic acid, for the purpose of taking up the phosphoric silicic acid formed
in the process of puddling or conversion, I therefore use mixtures of lime
and anhydrous or dry chloride of calcium, chloride of sodium, or chloride of
magnesium, or fluoride of calcium, either alone or together with oxide of iron.
I may however also use chloride of calcium or fluoride of calcium together with
oxide of iron only.
If the operation of converting pig iron into malleable iron is separated into two
parts, that is, if the solicion in the iron is separated first, and the slag containing it
is removed first, then I prefer to use the fluoride of calcium in the first operation,
although the chlorides may also be used. For the second part of the opera-
tion, that is, for the removal of the phosphorus, I prefer the use of the chlorides,
though the fluoride may be used also; what is intended to be conveyed by
the above is that I may use any or all of the materials named. By the addition
of the chloride or flueride of calcium to the other additions a fusion of these
materials is brought about, and a fluid nonsiliceous mass is produced, resembling
the ordinary siliceous slag, which like it enters into close contact with the
iron under treatment, and taxes up with acidity the impurities of the same.
The process or processes described above are equally applicable whether the
ordinary puddling furnace, the rotatory furnace, the Bessemer, the Siemens Martin,
or other furnaces are being used, and the effect of their application, namely, the
removal of the phosphorus sulphur from the iron under treatment will be the same
in all cases. By the exposure to heat of any of the chlorides named in contact

page_text: with iron chlorine is liberated principally as chloride of iron, and part as hydrochloric
acid, both of which may be condensed in water, or may be passed into a kiln filled
with heated lime to be again converted into chloride of calcium. Having now
described the nature of my Invention, I claim as new,-
I. The application of fluoride of calcium, chloride of calcium, chloride of
magnesium, chloride of iron, or chloride of sodium (either one, two, or more of
them), together with lime, magnesia, or alumina (either one, two, or all of thein) for
the preparation of materials for constructing or lining out furnaces.
II. The application of fluoride of calcium, chloride of calcium, or chloride of
sodium, together with lime, or together with oxide of iron, or together with lime
and oxide of iron, to produce a nonsiliceous slag forming material when iron is
being treated in furnaces lined out as above described with the view of removing
the phosphorus therefrom.
III. The recovery of the chlorine liberated in the process in various forms as
described.
In witness whereof, I, the said Carl Friedrich Claus, have hereunto set my
hand and seal, this Tenth day of November, in the year of our Lord One
thousand eight hundred and seventy nine.
CARL FRIEDRICH CLAUS. (L.S.)