Year: 1899

page_text: Date of Application, 11th Feb., 1899-Accepted, 1st Apr., 1899
I, OTTO THIEL, Engineer, of Theaterstrasse, 18, Kaiserslautern, in Austria, 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 follow-
ing statement:-
-
The present invention relates to a process of producing iron directly from the
ore, as follows:-
In an apparatus provided with a gas-generator furnace (as for instance a
Martin-furnace as represented in the accompanying drawing) with tightly closing
doors a, a, and constructed of as solid or impermeable masonry as possible and
the air and gas chambers of which can be securely closed so that no air may
reach the furnace, the front wall is provided with a preferably circular opening
instead of a door, as usually placed there fitted with a tube 6 set in the masonry
and continued in a gas conduit also laid in masonry to a heat-reservoir. In this
the gas passing from the generators to the furnace are heated to a temperature
of 1000° C. or more. The inlet b is placed at such an angle that the issuing gas
is obliged to pass downwards and over the furnace.
wall
The gas outlets cc are arranged in the rear wall r of the furnace one at each
side of the top hole and of such cross sections that their total area is equal to or
preferably a little in excess of, the cross sectional area of the inlet in the front-
Both out-lets are connected by means of short connections with tubes
through which the gases resulting from the reduction as well as the injected gas
the temperature of which has become partly reduced, are carried away for further
treatment. Part of it will serve to supply heat for the purpose of heating the
heat-reservoir in which the gas to be introduced into the furnace is to be brought
to the required temperature. Both in the inlet and outlet tubes valves are
arranged for the purpose of regulating the pressure in the furnace chamber, inas-
much as there always ought to be a slight excess of pressure to prevent air pass-
ing inwards should there be any leakage or irregularity in the surrounding
masonry.
The process is carried out as follows:-
Suppose the above described Martin-furnace is at full heat as for instance
after the tapping of the metal. The furnace is at once charged with about two-
thirds of the flux and full heat applied. The gas-generator heating is then sus-
pended and now the charge, consisting of a mixture of ore, carbon and the
remaining portion of the flux all broken to the side of nuts is introduced as
rapidly as possible. The ore, heated previously is introduced eventually directly
from the roasting kiln into the Martin-furnace. The quantity of
might become excessive, but this is prevented by withdrawing the flue slides
gas evolved
or dampers. The furnace being thus charged the doors are tightly closed. "The
gas-generator heating having as has been said been suspended; an equalization
of temperature takes place between that of the charge and the temperature of the

page_text: surrounding masonry, during which time carbonic oxide gas is evolved which
has the effect of reducing some of the ore. This process, however, will soon
slacken and the temperature in the furnace chamber will grow less. At this
moment the highly heated gas is admitted, raising the temperature and rendering
the process of reduction so energetic and rapid that the whole charge will be
reduced in from 2 to 3 hours.
It is within the power of the workers to carry the process of reduction as far
as may be required, continuing it until eventually the iron becomes carbonized;
as a rule, however, the reduction is not quite carried through.
As soon as the required degree has been reached, the gas is shut off, and molten
metal is run into the furnace. The furnace is closed again the hot gas re-
admitted until all the reduced iron has been dissolved in and taken up by the
molten metal, so that the possibility of the reduced iron re-oxidising is prevented.
After this the gas is completely shut off and gas-regenerator firing instituted the
remainder of the process closely following the lines of the Martin process.
In this manner it is possible to get 50 per cent. or more of iron from a full
charge, directly from the ore, according to the quality of the ore.
Ores with a greater quantity of slagging impurities are somewhat differently
treated inasmuch as after the reduction of the ore and the dissolution in molten
iron the slag is entirely melted and the mass tapped into a second furnace care
being taken to retain the slag on the way to the second furnace in which then
the remaining operation is carried out.
In preparing the charge the apparatus described in Patent Specification
No. 10923 of 1894 would be of great advantage.
It has been stated above that the reduction of the ore, should not be completed
entirely and for this reason that, when the molten metal is run in a strong
reaction sets in, which has been found to powerfully aid the slagging and the
dissolving power of the molten metal.
To know to what extent reduction has taken place it is only necessary, from
time to time, to take samples of the out-coming gas and compare them with the
constitution of the in-going gas; by which means it will be possible to form a
sufficiently accurate estimate.
The advantages and novelty of the invention, as compared with others of a
somewhat similar character are that in apparatus provided with a gas regenerator
furnace.
(1). The reduction of ores is carried out in a manner whereby the heat required
for the reduction of the ore is not produced by the gas regenerator furnace, but
by the introduction of a highly heated current of reducing gas, which is produced
independently of the said gas regenerator furnace.
(2). The reduced ore is not placed in a bath of molten cast-iron but on the
contrary molten cast-iron is poured on the reduced ore, effecting a complete dis-
solution by providing a constant current of a highly heated, reducing gas whereby
reoxidation is prevented.
(3). That the gas regenerator furnace becomes absolutely independent of the
process of reduction, so that its action can be effectively employed without any
regard to the latter.
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
1. A process of producing iron directly from ore in which a blast or highly
heated reducing gas is passed through an apparatus provided with a gas regener-
ator-furnace charged with a mixture of ore, carbon and flux which blast is entirely
independent of the gas-generator furnace said highly heated gas in passing
through while creating a thoroughly reductive atmosphere in the furnace chamber
parts with some of its heat thus heating the walls of the chamber and the charge

page_text: and compensating for the loss of heat produced in the reduction process substan-
tially as described.
2. In the manufacture of iron, heating a regenerative furnace by the introduc-
tion of heated reducing gas adding part of the flux to be employed and heating
same, shutting off the gas supply and adding the charge of ore, carbon and the
remainder of the flux, readmitting the gas and then cutting it off to allow of an
equalization of the temperature of the apparatus, then readmitting the gas until
the desired degree of reduction is obtained and afterwards adding molten iron
to take up the reduced iron substantially as described.
Dated this 11th day of February 1899.
BOULT & WADE,
Agents for the Applicant.