Year: 1888

page_text: "
I THOMAS TWYNAM of 54 Minford Gardens West Kensington Park in the County
of Middlesex, Metallurgical Chemist, do hereby declare the nature of this invention
to be as follows:-
This invention relates to an improved process for the direct reduction of iron
ores or iron slag or scale into ingot iron or steel.
For this purpose I employ
an open hearth steel melting furnace provided with a basic or neutral lining.
The iron oxide to be reduced may be a natural ore of iron (not highly silicious)
or it may be iron cinder or scale. The ore or scale in a sufficiently fine state of
division is mixed with a carbonaceous matter (such as fine coal or coke) to effect its
reduction.
The basic open hearth furnace is brought to a white heat and the mixed oxide
and carbon thrown in on the bed of the furnace. Upon the top of this, limestone or
lime is charged and then some pig iron which I prefer should be rich in phosphorus,
the amount of pig iron charged may be about one third or more of the iron in the
oxide charged.
The whole is melted down and when melted well rabbled for a time until the slag
becomes clear and the metal boils, the operation is then continued, more oxide and
lime being added as required until the metal is purified. The ingot iron or steel
produced is then tapped in the usual manner.
Instead of adding all the ore to be reduced when charging the furnace, part
of. it may be conveniently added when the charge is completely melted, in the
form of briquettes composed of ore or scale and carbon agglutinated together with
pitch or tar.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London,
Applicant's Agent.

page_text: Improvements in the Manufacture of Ingot Iron and Steel.
1, THOMAS TWYNAM of 54 Minford Gardens West Kensington Park in the County
of Middlesex, Metallurgical Chemist, 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 an improved process for the direct reduction of iron ores,
or iron slags or scale into ingot iron or steel. For this purpose I employ any
suitable open hearth steel melting furnace which must be provided with a basic or
neutral lining.
The iron oxide to be reduced may be any natural ore of iron, phosphoric or other-
wise, it must not however be high in sulphur, nor should it contain any excessive
percentage of silica. Mill or roll scale or other finely divided form of iron oxide is
especially suitable for direct reduction by this process. Such iron slags as are rich
in oxides of iron and not two high in silica may also be employed, the presence of
phosphoric acid in them not being disadvantageous. If the ore or slag is not in
powder, it should be reduced to at least nut size. The ferruginous material to be
reduced is first mixed with a sufficient amount of any suitable carbonaceous material
(small coal or coke dust being very convenient) to effect the reduction of the oxides of
iron. The mixture when made is placed on the bed of a basic or neutrally lined
open hearth furnace which has been previously brought to a high heat. The mixture
should be placed evenly over the bed of the furnace and covered with a layer of lime
or limestone, on the top of which pig iron (preferably phosphoric pig low in silicon)
is charged.
The pig iron may be run in molten, but I prefer to charge it cold and place the
pigs evenly over the surface of the mixture, the amount of pig charged may vary at
pleasure, but it is convenient to charge not less than one third as much pig as there is
iron in the oxide to be reduced. The amount of lime or limestone added will vary with the
composition of the pig iron charged and with that of the oxide or slag to be reduced, it
should be sufficient to combine with any silica in the oxide or slag and to form a basic
slag with the oxidized phosphorus in the pig iron charged. Some of the lime or
limestone may be conveniently charged in among the mixture of ore and carbon.
The proportion of pig iron and oxide used varies with the composition of the oxide to
be reduced, but with a rich oxide of iron or pure iron scale, about two tons of pig iron
may conveniently be charged to every five tons of oxide to be reduced. The lime-
stone added when the charge is put in the furnace should be about twelve to fifteen
per cent. of the weight of phosphoric pig iron charged, more limestone will generally
have to be added to finish the purification of the charge. The amount of pig iron
introduced should always be sufficient to well cover the bath of oxide and so prevent
reoxidation of the reduced metal.
The charge is melted down in the furnace and allowed to remain quiescent for
some time to allow of the reaction between the carbon and ore to take place more

page_text: gradually. When it is well melted a rabble or other suitable tool is introduced and
the mixture of ore &c. remaining on the bottom of the furnace is stirred up into the
bath. When the slag becomes clear and the carbonaceous matter has all been burned
off, the charge is worked down into ingot iron or steel in the usual way and tapped
when ready.
Instead of charging all the ore or scale to be reduced on the bottom of the furnace
as described, part of it may be conveniently added when the charge is completely
melted in the form of briquettes composed of the ore or scale and carbonaceous matter
agglutinated together with pitch or tar or other suitable binding material. It is not
essential that these briquettes sink into the bath of metal, it is sufficient that they
are worked well into the phosphoric slag on the surface. The reaction in this"
case may be looked upon as a reduction of the phosphate by the added
carbon and a reoxidation of the phosphorus by means of the oxygen in the ore
added.
The same reaction also takes place to a certain extent in the former case in
which the ore and carbon are placed in the bottom of the furnace, a continual
oxidation and deoxidation of the phosphorus of the pig iron added taking place
alternately by means of the oxide and carbon so long as any free carbon remains.
Having now particularly described and ascertained the nature of my said.
invention, and in what manner the same is to be performed, I declare that what
I claim is :-
The improvements in the manufacture of ingot iron or steel hereinbefore set
forth which consist in effecting the direct reduction of oxides of iron or rich iron
slags by mixing them with carbonaceous matter and submitting the mass to a
suitable heat in a basic or neutrally lined open hearth furnace in the presence of
pig iron preferably phosphoric, substantially as described.
1000
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London,
Applicant's Agent.