Process for the Direct Production of Iron and Steel and other Metals from their Ores.
Year: 1896

page_text: Date of Application, 10th Feb., 1896-Accepted, 28th Nov., 1896
.COMPLETE SPECIFICATION.
Process for the Direct Production of Iron and Steel and other
Metals from their Ores.
We, EMIL JOSEF MARIA SERVAIS, of Boulevard Royal, Luxemburg,
Engineer, and PAUL GREDT, of Esch on the Alzette, Engineer, both in the
Grand Duchy of Luxemburg, do hereby declare the nature of this invention
and in what manner the same is to performed to be particularly described and
ascertained in and by the following statement :-.
For the direct production of iron and steel from the ores it is necessary that the
reduction of the ores to metallic iron shall be effected in a different manner from
that usual with the iron smelting processes heretofore employed. For this purposė
the use of reducing agents are proposed which contain carbon not in a free but in
a combined state and which are either liquid of themselves, or which have so low
a melting point that when subjected to the heat of the smelting furnace they'
assume a liquid condition. Substances suitable for this purpose are oils either of
mineral or vegetable origin, fats or resins. By way of example, the use of
petroleum or petroleum residues has proved to be very suitable. The choice as to
which of the quoted substances may be used depends on the price of the material
as of course the cheapest will be used. The essential feature in the use of these
substances consists in the fact that they have a reducing action. They are not!
intended to serve as fuel or only to form a pasty mass.
Their reducing property is
the main point in view. The ore from which the metal is to be gained is mixed
with the reducing agent. The further method of treating depends on the cost of.
the process to be chosen and may therefore be determined according to general
conditions of wages for workmen &c. If the reduction is to be carried out with
the old generally known apparatus one may take the crucible or the open hearth.
The mixture of the ores and the reducing agents is brought in to the apparatus
and heated in the same way as usual. But in the-open-hearth one must take
precaution that the flames must not have an oxydising action during the reducing
period which may be effected by a suitable regulation of the admission of air.
Another manner for the production of iron in direct way is to introduce the
mixture of the reducing substance with the ore into the liquid iron in the melting
furnace obtained by a former charge. In this case the introduction is carried out
by means of one of the known mechanical devices such as feeding worms, pistons & c.
carrying the material into the interior of the bath. The proportions of the mixture
of reducing agents and iron ore must be made such as to correspond to the amount
of carbon necessary for reducing the iron ore which is determined by the
percentage of iron oxide contained in the ore. The advantage of using a fusible
reducing agent not consisting of pure carbon consists in that the reducing agent is
in intimate admixture with all parts of the ore and can consequently act in a
perfectly uniform manner, while a reducing action is exclusively obtained without
simultaneous carbonisation. For farther assisting the direct production of the iron
from the ore it is necessary that the iron sponge produced in the above described
manner or by the reduction by means of gases, shall be melted without any
oxydation being possible during this process, which oxydation would easily take
place without the use of special means. For preventing oxydation during melting,
I prcduce upon the surface of the mass of iron a skin of a protective combination
of iron with nitrogen or other suitable elements.

page_text: The production of the protective skin is effected by introducing ammonia gas, if
it appears necessary, previously dried by known means such as caustic alkalies or
lime. The production of the nitrogenous compound of iron can also be effected by
introducing into the furnace a mixture of ammonia salt, for instance carbonate of
ammonia, with lime in equivalent proportion. It will be found by experience
which of the methods is the cheapest and most suitable way in every case.
The main requisite of such a compound is that it shall have no tendency to
combine farther with oxygen, so as to prevent the formation of the oxygen com-
pounds and the access of oxygen to the mass of iron situated under the skin. The
same object, namely prevention of oxydation of the iron on melting, can be
attained, by introducing the spongy iron direct from the reducing furnace into the
liquid bath of the melting furnace, either continuously or intermittently, and
complete exclusion of the air... This is effected by introducing the spongy iron
under the skin of slags forming the surface of the bath. The said process is also
applicable to other metals besides iron, such as nickel, and is carried out in the
same manner as described for iron.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
. Process for the direct production of iron and steel and other metals from their
ores by smelting the latter under admixture of reducing, easily fusible, bodies, fats,
oils, resins, for example petroleum and petroleum residues, under partial or
complete exclusion of the air, or by the introduction of the mixture of the ores
with the reducing substances into the liquid bath in the melting furnace, or by
melting the spongy iron produced from iron ore by the reduction by means of oils
or reducing gases, such spongy iron being protected against oxidation by a coating
of a protective compound of iron with nitrogen or other suitable element, or by the
introduction of the spongy iron produced into the liquid bath of the smelting
furnace whether continuously by means of a feeding worm or intermittently by a
piston.
Dated this 10th day of February 1896.
ABEL & IMRAY,
Agents for the Applicants.