A Method for Producing Iron or Steel from Ores and other Materials Containing Iron.
Year: 1890

page_text: COMPLETE SPECIFICATION.
A Method for Producing Iron or Steel from Ores and other
Materials Containing Iron.
I JOSEF VON EHRENWERTH of Leoben Sitererinark, in the Empire of Austria,
Professor of a Mining Academy 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 consists in a method or process for the production of iron of all
kinds, soft iron, soft steel or pig iron in a liquid state direct from the ores.
Iron containing carbon when in a highly heated liquid state reacts upon iron con-
taining slag melted iron ores by the carbon in the said iron reducing the iron from the
slag, the iron so reduced mixing with the metal already free. This process continues
until the carbon in the metal used for the reduction is exhausted. On the other hand
liquid iron takes up carbon very freely again and becomes more or less saturated
therewith according to temperature up to the maximum of 5% so that the metal from
which the carbon has been used may be recarbonized.
As such carbon-containing metal is capable of reducing iron from ores it is evident
that by repeating these alternately succeeding processes of the reaction of liquid carbor.-
containing metal upon liquidfied ores etc. and the recarbonization of the metal from
which the carbon is exhausted any desired quantity of iron in a liquid state can be
obtained. In order to carry out the process a metal bath if possible highly carbonized
at the commencement is required. This may be produced by the melting or addition
of molten pig iron or of other kinds of iron over a foundation of coal, it may however
be made by the reduction and fusion of a mixture of ores with suitable reducing
agents or fluxes. In order that the processes may take place quickly, very high
temperature is required so that for the purpose of carrying out the system furnaces
suitable for producing such temperatures are necessary (such as a Siemens furnace
and combustibles such as generator gases watergas etc.).
As the slag when deprived of its contents of iron is useless in the furnaces and a
large quantity of slag is only a hindrance it is advisable to remove the spent slag as
much as possible.
Tho process is performed as follows:-
On the hearth of a reverberatory furnace with deepened sole and lateral outlet and
constructed of a basic or neutral or other material effectually resisting the slag for
instance on the hearth of a Martins furnace is placed in the first instance a highly
carbonized metal bath. On the latter are placed iron ores or matters containing iron
to be reduced either cold or preferably after previous heating or best of all in a hot
liquid condition. As soon as the bath is suitably hot the above mentioned reaction of
the metal upon the ore bath begins and when the temperature has become very high
said reaction proceeds very energetically and speedily ceases.
When this point is reached the metal bath relieved from carbon by the reluction
process is to be recarbonized. This is done by the insertion of solid coal, charcoal,
coke or other carbonaceous solid matter into the metal bath in the furnace or by
running off the bath into a pan containing these carbonizing substances or it may be
in a small shaft furnace filled with said substances and provided with an outlet for
the metal.
For the same purpose one may also line the hearth of the reverberatory furnace with
substances containing carbon or introduce such substances previous to the re-insertion
of the metal therein. For the purpose of quickening the process it is well that the
carbonizing substances should be previously heated.

page_text: In the meantime one can provide the hearth with the next batch of ore which how-
ever is placed upon the metal only after pouring back the latter.
After the metal bath is carbonized again in this manner it is again caused to
act upon the ore or slag and further quantity of metal of this obtained.
When the recarbonization has been done by running off the bath the metal is
poured back again into the furnace whilst the slag containing as little iron as possible
is detained, the ores being added again and the process repeated until the desired
quantity of metal has been obtained.
This at last will be recarbonized either in part or the whole and cast in the usual
manner. A part or also the whole quantity may be also highly carbonized (made into
pig iron) and thus be made into a foundation metal for subsequent charges or pig iron
for other purposes.
Instead of proceeding with the carbonization of the reaction metal and with the
reaction upon the ores in an alternate manner one may also go on continually and
simultaneously with both processes until one obtains a certain quantity of metal by
inserting carbonaceous matters continually into the metal bath whilst adding repeatedly
fresh ore.
In this case the process is only interrupted when the slag is removed.
Carbonizating and reaction take place in the furnace which for the purpose of
practical work is provided with openings at the side or in the dome as well as a
vertical shaft from the dome into the metal bath through which shaft the carbonaceous
matter is thrown in.
In order to carry out the method with transfusion in a simple manner it is
advisable to provide the furnace with an inlet (receiving orifice or receiving channel)
on the same side as the outlet or to arrange the outlet and the working door on the
same side, to use a pan with a pouring hole and to arrange suitable mechanical lifting
devices for said pan. For this manner of carrying out, one may also employ several
furnaces so that the metal is transferred from one to the other in series and the first
one always begins afresh.
In place of the ordinary construction of furnace of Martin's system it is preferable
to use a furnace with which the escaping gases may be used for preheating, or
even for the smelting of the ore. For this purpose whilst adhereing to the usual
arrangement or construction, preheating hearths are added on both sides or one of
said hearths is arranged at the side and heated with a part of the waste gases which
are admitted to the same through a channel from the furnace or with furnaces with
lateral flame-stream a preheating hearth may be inserted between the smelting hearth
and the gas escape towards the regenerators, or such a preheating hearth or a pre-
heating shaft furnace is connected through a separate channel with the outlet side of
the smelting furnace and thus a part of the escaping gases from the latter furnace are
carried into the former one.
The metal may also be run through a shaft furnace for the purpose of utilizing the
superfluous heat from recent reaction or to transfer the metal into such a furnace and
then re-insert it into the reaction furnace within which the ores have been preheated
or smelted; by which modification the cost of fuel may under certain circumstances
be reduced.
The quantity of ore added in each case must be of course in proportion to the
quantity of carbon in the metal.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
For the purpose of reducing iron direct from the ores or slags.
1. The method or process consisting in the repeated or continuous carbonization
to the highest point of metallic iron in a liquid state by means of solid carbonaceous
matter as set forth by the insertion of the latter into the former or by pouring the iron
over the carbonaceous matter or by lining the reaction furnace therewith and the

page_text: alternate or continuous use of the carbonized metal for the reduction and obtaining of
a metallic iron from liquefied ore or slag brought into counteraction with said metal
substantially as set forth.
2. In said process the method of employing the waste gases from the reaction
furnace for the purpose of preheating the ores or also the carbonaceous matter or
also for use in smelting the ores substantially as and for the purpose described.
Dated this 20th day of March 1890.
HERBERT & Co.,
18, Buckingham Street, Strand, London, W.C., Agents to Applicant.