IMPROVEMENTS IN THE MANUFACTURE OF STEEL BY THE PNEUMATIC OR BESSEMER PROCESS AND APPARATUS THEREFOR
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, JOHN GJERS of the Ayrsome Iron Works, Middlesbrough in the North
Riding of the County of York, Ironmaster, do hereby declare the nature of said
invention for IMPROVEMENTS IN THE MANUFACTURE OF STEEL BY THE PNEUMATIC
OR BESSEMER PROCESS AND APPARATUS THEREFOR to be as follows:-
When steel is made by the Bessonier process (either by the acid or Basic method)
by blowing atmospheric air through or into a fluid mass of metal as is well known
all the impurities are oxidized by the oxygen in the air including the carbon which
is usually the last impurity that is acted upon in the acid method and phosphorous
which is the last acted upon in the Basic method. When the blow is fuished there
is usually a quantity of oxide of iron remaining in the bath and this quantity may
sometimes, (that is to say if the heat has been at all overblown, or in other words
not stopped at the proper moment) be very considerable It has been found by
experience that this oxide of iron must be got rid of or the steel will be red-short
and difficult to work and sometimes even rendered entirely rotten and useless.
Hitherto the principal means adopted in practice to deoxodize the steel has been to
add after the blow has been finished a proportion of Spiegel or Ferro-manganese
(combination of iron manganese and carbon) either in the fluid or solid state for
the double purpose of restoring a definite proportion or quantity of carbon and
manganese to the bath, and of clearing the bath of oxygen. When hard steel is
required, a larger proportion is added and thero results considerable ebullition,
which causes these added substances to become tolerably well mixed with the steel,
and thus to fairly well clear it of oxygen. But even with hard Bessemer steel it
has been difficult to get the mixture so intimate that the steel should be what is
called dead. When it has been poured into the moulds there has always been more
or less boiling in the moulds, the result being the production of unsound ingots
more or less full of blow holes. In this respect Bessemer steel has compared
somewhat unfavorably with steel made either by the Crucible process or by the
Open-hearth process, which has been more dead owing to its containing less oxygen.
The ebullition is caused by particles of carbon coming in contact with particles of
oxide of iron after the steel has been teamed, causing carbonic oxide or carbonic
acid gas to be given off.

page_text: The difficulty has been very much increased when making very soft Steel by the
Bessemer process, in consequence of the quantity of ferromanganese added being so
small that it has still less thoroughly permeated the bath and caused even less
oxygen to be removed than when making harder steel.
Attempts have recently been made to introduce a mechanical stirrer, and this has
produced a beneficial effect by bringing the particles of carbon and manganeso into
more intimate contact with the oxide of iron, but the application is difficult and
does not appear likely to secure extensive practical adoption.
Now the object of my invention is to apply a gaseous agitator, and one which
shall at the same time act chemically upon the oxide of iron and remove the oxygen
by means hereinafter to be described.
To this end when the ordinary blow is over I after blow through the ordinary
air passages or tuyeres carbonic oxide gas or a mixture of carbonic oxide and hydro-
carbon gases or other reducing or neutral gases, and continue the after blow until all
the oxide of iron in the bath is reduced by the carbon in the carbonic oxide gas
leaving carbonic acid gas which escapes. Thus by the reducing action of carbonic
oxide the oxygen is eliminated from the steel bath, and the result is a dead or a
comparatively dead steel, or soft ingot iron even without the use of spiegel or
ferromanganese.
Nevertheless, inasmuch as manganese in in small quantities may sometimes for
other reasons be desirable I may before I begin the after-blow of carbonic oxide,
or after I have completed such afterblow add spiegel or ferromanganese for the
purpose of giving a desired percentage of carbon and manganese to the steel, but in
this case a much-smaller quantity will suffice to produce the same final result, as
none of the carbon or of the manganese will be-waisted as is the case when it is
applied in the ordinary way.-It follows that exactitude of result may be attained.
I proceed to describe means for carrying my invention in to practical effect.
I provide alongside the blastmain anywhere between the engine and the con-
verters, but by preference near the converters, a strongly plated, domed, vessel lined
throughout with refractory material, such as brick-work. This vessel is furnished
some distance above its bottom with a large fire grate in which is placed a deep fire
of, by preference, charcoal but it may be of coke, or anthracite, or of hydro-carbon
in admixture with carbonic oxide be required bituminous coal or other carbonaceous
matter may be used-The said vessel has an opening in the top of the dome
provided with a valve so that the opening may be kept open or closed. Also, there
is a pipe outlet near the top of the vessel communicating with the converter
Blastmain, and furnished with a valve so as to be capable of being opened or shut,
and a pipe inlet at, or near the bottom, also communicating with the Blastmain
and furnished with a valve. In the converter Blastmain itself is placed another
valve between the aforesaid two connections, so that by shutting this valve and
opening those of the inlet and outlet connecting pipes also closing the valves in the
top of the vessel the whole of the blast passing from the engine to the converters
can be caused to pass through the glowing charcoal (or other fire) in the grate of
the vessel whereby the whole of the oxygen in the air in combination with the
carbon will be converted into carbonic oxide gas which mixed with the neutral gas
nitrogen from the atmosphere will then pass into the converter acting as an efficient
agitator and at the same time deoxidizing the bath of steel. Thus during the time
of the ordinary blow in the converter the valve at top of dome and the valve in
the main blast pipe are to be kept full open, and the valves in the pipes leading to
the lower and from the upper parts of the domed vessel sbut so that the blast will
pass uninterruptedly to the converter, but when the ordinary blow is finished in
the basic acid converter or when the ordinary after blow is finished in the basic
converter I turn down the converter, close the valves in main blast pipe and top of
domed vessel open the valves in the pipes leading to the lower and from the upper
parts of the domed vessel, and after pouring off the slag in the case of a basic
converter turn the converter up again and let the blast pass through the fuel in
the domed vessel whereby carbonic oxide will be blown through the bath in the

page_text: converter. This after blow of carbonic oxide should be allowed to continue until
the bath has been completely deoxidized. Advantage of this may to some extent
also be taken to carbonize the bath.
That the nature of my invention may be better understood I append by way of
illustration two sheets of drawings wherein Fig 1, is a vertical section of the
apparatus. Fig 2 an elevation at right angles to Fig 1, and Fig 3 a plan A is the
domed vessel, B the fire grate, C the fire, D valve at top of vessel A; E outlet at
the top of A; F blastmain. G valve in the blastmain F, H pipe inlet at or near
the bottom of vessel A, and communicating with blastmain F, I valve in pipe H,
K valve in converter blastmain.

page_text: I, JOHN GJERS, of the Ayresome Iron Works, Middlesbrough, in the North Riding
of the County of York, Ironmaster, do hereby declure the nature of my invention
for "IMPROVEMENTS IN THE MANUFACTURE OF STEEL BY THE PNEUMATIC OR
BESSEMER PROCESS AND APPARATUS THEREFOR," and in what manner the same is
to be performed, to be particularly described and ascertained in and by the following
statement:-
When steel is made by the Bessemer process (either by the acid or basic method)
by blowing atmospheric air through or into a fluid mass of metal as is well
known all the impurities are oxidized by the oxygen in the air including the carbon
which is usually the last-impurity that is acted upon in the acid method and
phosphorus which is the last acted upon in the basic method. When-the-blow_is_
finished there is usually a quantity of oxide of iron remaining in the bath and this
quantity may sometimes (that is to say if the heat has been at all overblown or in
other words not stopped at the proper moment) be very considerable. It has been
found by experience that this oxide of iron must be got rid of or the steel will be
red-short and difficult to work and sometimes rendered entirely rotten and useless.
Hitherto the principal means adopted in practice to deoxidize the steel has been to
add after the blow has been finished a proportion of spiegel or ferro-manganese
(combinations of iron, manganese, and carbon,) either in the fluid or solid state for
the double purpose of restoring a definite proportion or quantity of carbon and
manganese to the bath and of clearing the bath of oxygen and hydrogen. When
hard steel is required a larger proportion is added and there results considerable
ebullition which causes these added substances to become tolerably well mixed
with the steel and thus to fairly well clear it of oxygen and hydrogen. But even
with hard Bessciner steel it has been difficult to get the mixture so intimate that
the steel should be what is called dead. When it has been poured into the moulds
there has always been more or less boiling in the moulds the result being the
production of unsound ingots more or less full of blowholes. In this respect
Bessemer steel has compared somewhat unfavourably with steel made either by
the crucible process or by the open hearth process which usually is more dead
mainly owing to its containing less oxygen. The ebullition is caused by particles
of carbon coming in contact with particles of oxide of iron causing carbonic oxide
or carbonic acid gas to be given off or by hydrogen gas which would have been
more likely to escape if the ebullition caused by the spiegel had been more
efficient.
The difficulty is much increased when making very soft steel by the Bessemer
process in consequence of the quantity of ferro-manganese added being so small
that it has still less thoroughly permeated the bath and caused even less oxygen
and hydrogen to be removed and less ebullition to have taken place than when
making harder steel.
Attempts have recently been made to introduce a mechanical stirrer and this has
produced a beneficial effect by bringing the particles of carbon and manganese into

page_text: more intimate contact with the oxide of iron and by driving off hydrogen by
the mere mechanical operation of stirring, but the application is difficult and does
not appear likely to secure extensive practical adoption.
Now the object of my invention is to apply a gaseous agitator or stirrer and
one which shall at the same time act both mechanically and chemically upon the
oxide of iron and remove the oxygen and hydrogen by means hereinafter to be
described.
To this end when the ordinary blow is over in the acid process and when the
ordinary after-blow is over in the basic process or when such blow or basic afterblow
has been continued longer than usual for the more thorough removal of impurities,
I further after blow through tho ordinary air passages or tuyeres carbonic oxide
gas or a mixture of carbonic oxide gas and nitrogen which is neutral and acts
chiefly mechanically as a stirrer. The carbonic oxide gas acting chemically as well
as mechanically-I continue this after blow until all the oxide of iron in the bath
is reduced by the carbon in the carbonic oxide gas, leaving a proportion of
carbonic acid gas which escapes together with intact carbonic oxide and nitrogen.
Thus by the reducing action of carbonic oxide the oxygen is eliminated from the
steel bath, and the hydrogen to a great extent removed by stirring, the result is a
dead or a comparatively dead steel or soft ingot iron (even without the use of
spiegel or ferromanganese) which iron may be made into a hard steel by simply
adding ordinary pure pig iron.
In my provisional specification I mentioned also that bydro-carbon gases or other
reducing or neutral gases might be combined with the carbonic oxide gas but I do
not now deem it advantageous to use hydrocarbon gases having found them
unsuitable, whereas the desired results are obtained by the use of the carbonic
oxide gas either unmixed or mixed with the neutral gas of nitrogen naturally
derived from the practical modle herein described of producing carbonic oxide.
Inasmuch as manganeso in small quantities may sometimes for other reasons be
desirable, I may bofore I begin the after-blow of carbonic oxide or after I have
completed such after-blow add spiegel or ferromanganese for the purpose of giving
a desired percentage of carbon and manganese to the steel, but in this case a much
smaller quantity will suffice to produce the same final result as none of the carbon
or of the manganese will be wasted as is the case when it is applied in the ordinary
way. It follows that exactitude of result may be attained but it will be noticed
that by the above described process it is possible to produce a soft and pure ingot
iron which is workable without addition of manganese.
Besides acting beneficially upon the steel as before stated the after-blow of
carbonic oxide has an important influence upon the slag in the converter. As is
well known this slag in the acid process but more particularly in the basic process
contains a considerable quantity of oxide of iron which at present not only
represents a loss of iron but in the case of the basic slag forms a large quantity as
also the principal obstacle to utilization of the slag (which is rich in phosphate of
lime) for manurial purposes.
Now the blowing of carbonic oxide through the basic slag will cause the
protoxide of iron to be reduced to metallic iron and thus will not only increase the
yield of ingot iron or steel but will leave the slag as comparatively pure phosphate
of lime
In the case of the acid process the action of the carbonic oxide on the slag will
be the same, but for the purpose of facilitating the operation and to leave a fluid
slag at the end I add during the blow say per cent or inore of lime.
I proceed to describe means for carrying any invention into practical effeet.
I provide alongside the Blastmain anywhere between the engine and the
converters but by preference near the converters a strongly plated domed rossel
lined throughout with refractory material such as brickwork. This vessel is
furnished some distance above its bottom with a large fire grate in which is placed
a deep fire of, by preference, charcoal, but it may be of coke or anthracite or other
carbonaceous matter may be used. The said vessel has an opening in the top of

page_text: the dome provided with a valve so that the openrug may
Also there is a pipe outlet near the top of the vessel communicating with the
converter blastmain and furnished with a valve so as to be capable of being opened
or shut and a pipe inlet at or near the bottom also communicating with the blast-
main and furnished with a valve.
In the converter blastmain itself is placed another valve between the aforesaid
two connections so that by shutting this valve and opening those of the inlet and
outlet connecting pipes and also closing the valve in the top of the vessel the whole
of the blast passing from the engine to the converters can be caused to pass through
the glowing charcoal (or other fire) in the grate of the vessel whereby the whole of
the oxygen in the air will be combined with carbon and will be converted into
carbonic oxide gas which mixed with the neutral gus nitrogen from the atmosphere
will then pass into the converter acting as an efficient agitator and at the same
time deoxidizing the bath of molten metal and slag. Thus during the time of the
ordinary blow in the converter the valve at the top of the dome and the valve in
the main blast pipe are to be kept full open and the valves in the pipes leading to
the lower and from the upper parts of the domed vessel shut so that the blast will
pass uninterruptedly to the converter but when the ordinary blow is finished in the
acid converter or when the ordinary afterblow is finished in the basic converter or
after such blows have been more than usually over-blown for the purpose of freeing
it as much as possible from impurities. I turn down the converter, close the valves
in the main blast pipe and top of the domed vessel, open the valves in the pipes
leading to the lower and from the upper parts of the domed vessel and after
pouring off the slag or not as may be deemed desirable in the case of a basic
converter I turn the converter up again and let the blast pass through the fuel in
the domed vessel whereby carbonic oxide and neutral nitrogen will be blown
through the bath in the converter. This afterblow of carbonic oxide should be
allowed to continue until the bath has been completely deoxidized or the slag
completely freed of oxide of iron. Advantage of this may to some extent also be
taken to carbonize the bath, but this will only take place to a very limited extent.
In the apparatus for producing carbonic oxide just described it will be seen that
the gases will leave the producer at a higher temperature than that at which it is
advisable they should enter the converter at this stage of the process. To avoid
this I pass them after they leave the producer through a regenerator of brick which
will absorb sufficient heat to reduce them to a moderate temperature of say 500
or 600° Fahrenheit before they enter the converter. At the commencement of the
next blow I pass the blast through the said regenerator to absorb its accumulated
heat and carry it into the converter. It will thus be seen that in the beginning of
each blow when heat is most needed the charge in the converter will get the
advantage of heat derived from the production of carbonic oxide in the previous
blow. During the afterblow it is usually desirable that the temperature of the
molten metal should be reduced and to this end I continue longer than is necessary
for the mere deoxidizing of the bath, the action of the cooled carbonic oxide.
Referring to the accompanying three sheets of drawings, Fig 1 is a vertical
section of an apparatus according to my invention. Fig 2 an elevation at right
angles to Fig 1 and Fig 3 a plan. A is the domed vessel, B the fire grate, C the
fire, D valve at the top of vessel A. E outlet at the top of A. F blast-main. G
valve in the blast main F. H pipe inlet at or near the bottom of vessel A, and
communicating with the blast-main F. I valve in pipe H. K valve in converter
blast main.
During the usual blowing operations the blast proceeds through the main F, F
direct from the engines to the converter.
When carbonic oxide and nitrogen are to be forced through the molten metal in
lieu of atmospheric air the valve K is closed and the valves H and C opened, and
thus the blast is directed through the vessel A.
Fig 4 is a vertical section and Fig 5 a plan of a modified form of apparatus
according to my invention wherein the gases are cooled after they leave the pro-

page_text: ducer. D 18 the blast main from the blowing engines and F the main to the
converters; M is the producer and E the regenerator. There are two courses for
the blast according to the way the valves are set it can either pass first through
the producer and then through the regenerator, or it can avoid the producer and
go through the regenerator only. It can also be cut off entirely.
At the beginning of the ordinary Bessemer blow the valves A and B are closed,
and the valve C is opened. The blast then passes direct from the main D through
the regenerator E and on to the converters through the branch F and the blow is
effected in the ordinary way. The blast in going through the regenerator E takes
up the heat which the brickwork has absorbed during the previous carbonic oxide
after-blow and this heat increases the temperature of the iron in the converter.
As soon as the ordinary Bessemer blow is finished the converter is turned down,
the valve C is closed and at the same time the valve A is opened. This arrangement
turns the blast through the carbonic oxide producer M and the valve B is raised
automatically by the
pressure. As soon as it lifts it is drawn tight up against the
seat to prevent gas froin passing into the pipe between the valves B and C.
The blast then passes from the blast main through the valve A into the blast box K
through the tuyeres L and into the producer M escaping through the connection O
past the valve B through the regenerator E on to the converters.
The regenerator E which is cold from the previous blow-through of blast,
absorbes all the heat in the carbonic oxide blast and delivers it comparatively cool
to the converters.
Any dust passing from the generator M is collected in the dust box P.
Fig 6 is a longitudinal section of another modified form of apparatus according to
my invention-Fig 7 is an elevation at right angles to Fig 6 and Fig 8 is a plan.
In this arrangement a reversible system of double regenerators is employed in
which the blast is not caused to absorb heat on its way to the converter during the
ordinary blow. On the other hand the carbonic oxide is not reduced to so low
a temperature. The blast from the engines comes by the main 4 and can be either
directed through the producer 10 and the two regenerators 9 and 11, to the main 5
or through the inverted U shaped pipe (Fig 7) direct to the main 5 and thence to
the converters.
At the beginning of an ordinary Bessemer blow the valves 1 and 2 are closed and
the valve 3 is opened. The blast is then directed from the main 4 up through the
valve 3 and down to the converter through the main 5.
As soon as the ordinary blow is finished the converter is turned down, the valve
3 is closed and the valves 1 and 2 are opened. The blast then proceeds from the
inain 4 through the valve 1 to the reversing valve 6 which turns it into the pipe 7.
It then passes into the chamber 8 through the regenerator 9 into the producer 10;
then through the regenerator 11 into the chamber 12 and from there by the pipe 13
to the other side of the reversing valve 6 through the valve 2 into the blastmain 5
and along into the converters.
The blast in going through the regenerator 9 cools it and after passing through
the producer 10 gives up its heat again to the regenerator 11. For the next blow
by means of the reversing valve 6 I reverse the current and blow through the
regenerator 11 first, cooling it and transferring the heat to the regenerator 9. By
this means supposing both regenerators to be slightly warm, warm blast is always
delivered into the producer 10 and the heat is given up again to the opposite
regenerator, the position of the valve 6 being reversed at every blow. The blast
first goes from 1 to 7 through the producer and back from 13 to 2 or in the other
position of this valve it proceeds from 1 to 13 and back from 7 to 2.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be perforined, I declare that what
I claim is
1. In the manufacture of steel by the pneumatic process, treating the molten
metal, after the ordinary blow or the ordinary after-blow, with carbonic oxide gas,

page_text: or a mixture of carbonic oxide and a neutral gas the same being blown through the
molten metal substantially as described.
2. In the manufacture of steel by the pneumatic process reducing the oxide of
iron in the alag to metallic iron by after blowing with a reducing gas, such as
carbonic oxide, substantially as described.
3. In the manufacture of steel by the pneumatic process agitating or stirring the
molten metal by the use of a gaseous agitator or stirrer produced and acting as
described.
4. In the manufacture of steel by the pneumatic process the continuing the
ordinary blow or after-blow longer than hitherto has been practised so as to effect
more thorough removal of impurities and then restoring the bath with an afterblow
of carbonic oxide such as described.
5. The manufacture or production of steel and ingot iron by the pneumatic
process in the manner and by the means hereinabove described dispensing with the
ordinary use of spiegel or ferro-manganese.
6. The use in the manufacture of Bessemer steel as above set forth of apparatus
arranged and operating substantially as described with reference to and shewn
respectively in Figa 1, 2, and 3, Figs 4 and 5, and, Figs 6, 7, and 8 of the drawings,
so that the charge can be blown at will either by atmospheric air or by carbonic
oxide and nitrogen gas substantially as described.