IMPROVEMENTS IN CONVERTOR FURNACES FOR METALLURGIC OPERATIONS
Year: 1884

page_text: I BENJAMIN JOSEPH BARNARD MILLS of the firm of Harris and Mills of
23 Southampton Buildings in the County of Middlesex, Patent Agent do bereby
declare the nature of the said Invention for IMPROVEMENTS IN CONVERTOR
FURNACES FOR METALLURGIC OPERATIONS to be as follows:-
This apparatus consists of a horizontal cylinder of wrought iron lined with
bricks of refractory earth acid or basic according to requirements, and supported
on rollers which permit it to turn around its axis.
The entire is carried by a carriage running upon rails which render the apparatus
transportable according to the requirements of the operations.
This cylinder is provided with a series of parallel tuyeres arranged in a horizontal
line and penetrating to the interior through the lining and following a conveniently
chosen inclination, the exterior orifices of these tuyeres open into a box external of
the cylinder, which receives the blast or the gases or vapours necessary for the
operation, these fluids are conducted by jointed tubes or by flexible tubes, which
allow the cylinder to oscillate around its axis.
The two circular bases of the cylinder are provided each with an opening
permitting on the one side the entrance of flames from any convenient furnace
independent of the apparatus, and on the other the exit of the products of com-
bustion which are directed into a chimney either directly or after passing through
condensation chambers for dust or through lead chambers for the utilization of the
sulphurous acid.
In the centre of the cylinder and the upper part is formed a third (rectangular)
opening by which the cylinder can be charged with the products to be treated and
the dross or slag and the finished products can be run off.
The furnace is also provided with a reservoir in which are placed various
pulverulent matters to be injected into the matters in fusion at the same time as
the air, gases or vapoure, for this purpose this reservoir communicates above with
the conduit under pressure which conducts these fluids, and below with the tube
which opens into the chamber communicating with the tuyeres, cocks placed on
these two communications permit of regulating at will the quantity of pulverulent
matters which will be drawn in by the gaseous current.
These matters are intended to produce in the mass in fusion the necessary
reactions and to preserve from wear the interior lining of the furnace, they will be
according to requirements, either silica in powder, or pulverulent basic substances,
lime, magnesia dolomite or other materials.
In order to enable the operation of this furnace to be understood I will describe,
as example, the treatment of a cupreous matte containing as is, habitually the

page_text: case, sulphur, iron and copper and in a small proportion lead, zine, tin, arsenic,
antimony and other metals."
After having heated the interior of the furnace to a red heat by placing it in
connection with an independent furnace, the flames from which traverse the
apparatus, it is wheeled to the fusion furnace of the mineral which produces the
matte, the cylinder is inclined in order to bring its upper opening opposite the
tapping hole and the apparatus is charged with the quantity desired of the material
in fusion. The apparatus is then raised and it is wheeled to the place prepared for
the blowing, where is provided the flexible tube which is fixed to the box of the
tuyeres, and a flue for carrying off the vapours. The blast is then given and the
apparatus is caused to oscillate until the tuyeres arrive at a certain depth below
the level of the liquid matte which depth is determined by the pressure of blast
in use.
The reactions immediately commence, the oxygen of the air blown forms, with
the sulphur of the sulphurous acid, and with the other bodies, oxides which are
drawn into the condensing chambers, the sulphurous acid can be recovered in lead
chambers or simply passed off by the chimney. With respect to the iron which
passes into the state of oxide and remains in the bath, it would soon eat into the
lining of the furnace if recourse were not had to the injection of silica, which is
commenced at the beginning of the blowing by causing the reservoir containing it
to communicate with the blast pipe, the latter diffuses it in the bath where by
contact with nascent oxide of iron it forms silicate of iron which melts and floats
at the top.
When it is known by the colour of the flames that all the iron is burnt, the
furnace is turned over to run off the slag which floats, and it is again put in work,
but the injection of silica which has no further utility is stopped.
In proportion as the level of the matte falls, in consequence of the disengage-
ments, the apparatus is caused to oscillate in order that the tuyeres may remain at
the same depth.
The matte is thus enriched more and more in copper, and a time arrives when
there remains only sub-sulphuret of copper, which is known by the colour of the
flames.
From this moment the sulphur continuing to burn, the copper is disengaged and
falls to the lower part, it is then necessary to raise progressively the tuyeres in
such manner as to blow only into the sub-sulphuret of copper which diminishes
more and more, until there remains only crude copper, which can be poured in this
state, or refined in the same furnace by known means, the heat of the above
mentioned independent furnace being employed when required.
If it is desired to treat phosphorous or sulphurous smelting the lining would be
made with lime, magnesia, dolomite and even with silica, and the sides would be
preserved by injecting lime, magnesia or other material.
This apparatus affords the possibility of working with precision all the chemical
reactions by the injection of air, gas vapours or matters in powder in the various
strata of the bath, to the precise point where it should be produced. It economizes
the plant and the operation by its mobility and the motive power of the blast
apparatus, as any pressure, however feeble it may be can be utilized, it permits of
treating very diverse quantities of materials, preserving the same pressure to the
blast. Lastly in consequence of the independent heating it permits of treating
matters which could not by themselves sustain a sufficient temperature.
Dated T
1001

page_text: I BENJAMIN JOSEPH BARNARD MILLS of the firm of Harris and Mills of
23 Southampton Buildings in the County of Middlesex, Patent Agent do hereby
declare the nature of the said Invention for IMPROVEMENTS IN CONVERTOR
FURNACES FOR METALLURGIC OPERATIONS and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:
This apparatus consists principally of a horizontal cylinder of wrought iron
lined with bricks of refractory carth acid or basic according to requirements,
turning around its own axis upon rollers which enable its position to be varied.
The apparatus is carried by two pairs of wheels running upon rails which
render the apparatus transportable at will according to the requirements of the
operations.
The convertor furnace is furnished with a series of tuyeres placed in a horizontal
line and penetrating through the lining and following a conveniently chosen
inclination and leading the compressed gases or air blast (hot or cold according
to requirements) or even superheated steam through the lining either on the
surface of the liquid metal contained in the apparatus, or into the mass itself of
the metal and at variable heights.
The two ends of the cylinder are each provided with an opening, permitting at
the one end the entrance of flames from any convenient furnace or of combustible
gases and at the other the exit of the products of combustion which are directed
into a chimney either directly or after passing through condensation chambers for
dust or through lead chambers for the utilization of the sulphurous acid.
The furnace is also provided with an apparatus intended to inject into the
matters in fusion submitted to the treatment either silica in powder, or basic
pulverulent substances, lime, magnesia, dolomite or other material, in view of the
reactions to be produced and to preserve from wear the interior lining of the
furnace.
The Invention is fully shown in the accompanying Drawings and described in
the following description. A. sheet iron casing forming the body of the convertor
furnace. B lining of bricks or refractory earth of variable composition. C blast
box into which is conducted the blast from the general conduit by means of jointed
metal tubes permitting the displacements of the blast box in the movement of the
cylinder around its horizontal axis.
These tubes can be replaced by a flexible tube of leather or caoutchouc.
D, D, exterior orifices of the blast box placed each in front and into the prolonga-
tion of the tuyeres, enabling their good working to be ascertained during the entire
continuance of the operations and of holding them always open, these orifices are
closed by stoppers of wood or metal.
E, E, tuyeres passing through the interior lining and conducting the fluids
injected at a certain inclination into the mass in fusion.
F, inlet for the flames of an independent furnace of any suitable description
burning either coke, or coal or gases.
G, exit for the flames or the products of combustion on their way to the chimney
and passing if necessary through condensation chambers.
H. central orifice serving for the charging of the matter to be treated and for the
outflow of the slags and finished products.

page_text: I, I, hooks by which the upper part of the furnace can be raised to permit of
important repairs of the lining.
J, J, J, J, rollers upon which the furnace oscillates.
K, K, half rings fixed to the cylinder and running upon the rollers.
L, toothed sector fixed to the cylinder to cause it. to oscillate.
M, pinion gearing into the sector L.
N, handle keyed upon the shaft of the pinion M, serving to cause it to turn.
O, framing carrying the bearings P, P, of the rollers J, J, and resting upon the
axles of the two pairs of carrying wheels R, R, which enable the furnace to be
moved about the works.
S, S, toothed wheels fixed upon the carrying wheels and taken into by two
pinione.
T, T, double handles keyed at right angles to each other and operating the
toothed wheels of the carrying wheels through the intervention of the pinions
above referred to.
U, sheet iron reservoir containing the pulverulent matters injected to facilitate
the reactions and to preserve the lining of the furnace.
V, tube conducting pressure from the reservoir of compressed fluids.
X, cock for transmitting or cutting off the upper pressure.
Y, cock for transmitting or cutting off the lower pressure.
Z, rod for opening or closing the outlet orifice for the powders.
W, plug for the introduction of the powders.
The following are the details of the working of the convertor furnace.
The convertor furnace is previously heated to a more or less elevated tempe-
rature by causing the flames of an independent furnace to enter by the lateral
orifice F.
When the temperature is considered sufficient it is brought opposite the blast
furnace or any other furnace which contains the matter to be treated, it is inclined
by causing it to oscillate on its rollers in such manner as to bring it into the
position indicated in the Drawing at Figure 1 the matter is run into the furnace
either by the aid of a conducting trough, or by the aid of a ladle; the metal can
also if required be melted in the apparatus itself by flames entering by the lateral
opening F, as has been above described for the heating.
The furnace having received its charge of matters to be treated, is brought either
to a special place where it will deliver the products of combustion into lead
chambers, or before-the independent furnace which is the source of heat as above
described.
In one or other of these positions the workman will commence by putting the
blast box in communication with the reservoir of compressed fluids (by fluids it is
intended once for all to designate the hot or cold gases, hot or cold air, or super-
heated steam, according to requirements). Then the furnace will be caused to
oscillate upon its rollers in order to bring it into the position shown at Figure 2
or into that indicated at Figure 3. or into an intermediate position between these
two extreme positions according as it is desired to cause the compressed fluids to
impinge upon the surface of the bath or to pass into the interior of the liquid mass
at different heights, either in view of the reactions to be produced, or consequent
upon the pressure in use, or again to cause the fluids to penetrate into such parts
of the bath of which the matters are superposed in order of density or lastly to
enable very variable quantities of metal to be always treated with the same
pressure and in the same conditions.
During the continuance of the operation of blowing, the level at which the fluids
enter into the metal is varied, and by the effect of these variations the method is
known in which they should be effected, for according to the point at which the
fluids act, the nature of the fumes and the color of the flames are found to be
modified as also the pressure indicated by the manometer which is placed for this
purpose upon the conduit of the fluids blown,

page_text: During one part of the operation or during its entire continuance, according to
the case the communication is opened which permits the pulverulent matters
contained in the reservoir U, to descend to the conducting tube for the fluids
blown which draws them into the substance of the melted matter under treatment.
These pulverulent matters are of character adapted to the reactions to be
produced and preserve the lining of the convertor furnace. During the operation,
the furnace can be inclined on its rollers and the slags which would be generated
are run off by the orifice H, to finish then the apparatus is again raised and
the reactions terminated.
Lastly the operation completed the furnace is inclined in order to run the
product obtained either in mixture with the slags into a vessel where they separate,
or directly into the ingot moulds, after having removed the slags from its surface
by a suitable raking.
In order the better to understand the advantage which can be obtained from
this new furnace, I will describe as example the treatment of a cupreous matte,
containing as is habitually the case, sulphur, iron, and copper, and in much weaker
proportions, lead, zinc, tin, arsenic, antimony and other metals.
The furnace running upon rails, is brought, after having been heated to a red
heat by the independent furnace, which has already been mentioned, before the ore
melting furnace which produces the matte it is inclined in such manner that the
orifice H, may occupy the position shown at Figure 1; into this orifice is
introduced one end of a sheet iron trough lined with refractory earth the other
end of which is placed under the pouring hole of the furnace where the matte
is produced, the pouring hole is pierced and the matte runs directly into the
convertor furnace.
When the charge is judged sufficient the pouring hole is closed, the trough is
removed and the furnace is lightly lifted around its rollers, but without allowing
the matte to cover the tuyeres and the whole apparatus is made to run to the
precise point of the works where the blowing should be effected and where tlie
pipe leading the fluids to be blown is situated and the outlet carrying away
the fumes, which communicates or not with chambers of condensation or of
utilization of these fumes, the blast is given and the furnace is raised until the
blast penetrates the liquid matte at a certain depth underneath its surface, a depth
which depends on the pressure of blast in use.
The re-actions commence directly the oxygen of the air blown combines with
the sulphur to form sulphurous acid, and with all the other bodies, to form oxides
which are drawn along by the gaseous current into the condensation chambers
where these oxides are collected; the sulphurous acid can then be received into
lead chambers to be transformed into sulphuric acid or into any other product or
simply thrown away in the elevated parts of the atmosphere by a high chimney.
With regard to the iron which passes to the state of oxide, the greater part
remains in the bath, and would not take long to redden the lining of the furnace
and to put it quickly out of use, if recourse were not had to the injection of
silica.
For that purpose, from the beginning of the blowing, the reservoir of silica is
made to communicate with the blast pipe and this draws it into the bath where it
arrives in contact with the nascent oxide of iron and forms silicate of iron, which
melts and floats in the bath of matte.
The level of the matte lowers in consequence of the giving off of sulphur and of
other bodies, in consequence the furnace is turned sucessively and slowly in order
that the blast which arrives may penetrate always into the matte to the same
extent.
The matte is thus more and more enriched with copper by the loss of the two
other elements iron and sulphur as also by the combustion and volatilization of all
the metalloids and metals more oxidisable than copper.
At a given moment there remains absolutely nothing in the furnace but sub-
sulphuret of copper, this moment is seen very clearly by the colour of the flames. -

page_text: After this moment the oscillating movement should be reversed, that is to say,
instead of causing the tuyeres to plunge more and more into the bath, they will be
again raised in a continuous way.
In effect from this moment, the sulphur continuing to be burnt, the copper is in
excess and becomes disengaged from the combination.
It descends, because of its greater density, below the remaining sub-sulphuret,
the tuyeres are then given an ascending motion, slowly progressing in a direction
reverse to that given during the first part of the operation so as only to blow into
the sub-sulphuret of copper and to raise the level at which the blast acts, according
as the height of the reduced copper augments and the working is thus continued
until all the sub-sulphuret is decomposed.
At this moment there only remains raw copper in the furnace, it is run out in
this state by turning the furnace as shown at Figure 4 or the refining process is
proceeded with in the converting furnace itself by the processes usually employed
in this operation.
In case the temperature of the furnace should not be sufficiently elevated at the
end of the blowing to effect the refining, the furnace is brought in front of the
independant furnace to reheat the apparatus and the copper that it holds and after
the refining the pure copper is run out directly into ingots or into plates to be
rolled.
In the middle of the operation when it is seen by the colour of the flames that
all the iron has been burnt, the furnace is turned over into the position shown at
Figure 1 and the slag which floats is run off if it is sufficiently fluid, the blast
which strikes at its surface and at the posterior part of the bath suffices to chase
it away.
In the contrary case this slag is raked off by known means. Afterwards the
apparatus is again raised in order to reduce, as has been described the subsulphuret
of copper.
It is well understood at this part of the operation, the injection of silica is
stopped because there is no more iron to be scorified and in consequence no more
wear to be feared for the sides of the converting furnace.
It is seen that with this furnace, one can at will, in treating poor and impura
mattes, obtain either absolutely white matte except from iron and other substances
more oxydizable than copper either raw copper or refined copper ready for rolling
and that less than an hour after having taken it from the crucible of the blast
furnace and without consumption of fuel.
If phosphorous or sulphurous cast iron be treated in this convertor furnace the
lining is made of lime, magnesia, dolomite or even of silica and the sides are
preserved by injecting lime, magnesia and so on.
These appropriate substances in a pulverulent state, mixed thus intimately with
the metal and mingled with it by the blast, react energetically upon the substances
which it is required to eliminate from the fluid mass, the operation is more rapid
and does not take place at the expense of the lining, which consequently lasts
longer and so much the more as its composition having less influence it can be
rendered as solid as is wished by the addition of silicate of alumina which causes a
very notable economy.
Whatever kind of metal is treated the convertor furnace presents the advantage
of requiring a blast pressure relatively small because it can at will be caused to
enter into the matter in fusion at a height corresponding to the pressure of the
Llast in use, thus the necessity is avoided for a large and costly moving force,
which in certain localities is almost impossible to procure.
The advantages of the improved apparatus are therefore the following
1st The possibility to moving the convertor furnace, which instead of being fixed,
is moveable, and can be transported easily from one furnace to another to take
therefrom substances to be treated; which avoids an intermediate remelting by
means of the cupola or the employment of ladles...

page_text: :
Secondly Economy of plant and of hand labour, because oscillating freely and
without effort upon its rollers, being symmetrical in all its heavy parts, it needs
only an insignificant force to pass from one of its positions to another.
Thirdly Considerable economy in the motive power of the blast apparatus
because one can at will and by the simple inclination of the apparatus cause the
blast to plunge into the matters in fusion at as slight a depth as may be desired.
Fourthly Facility to operate with precision all the chemical re-actions necessary
in such parts of the bath where they are useful consequent upon the possibility of
causing the blast to enter at the precise point where these reactions should be
produced which permits the doing in a single operation that which needs many
with the apparatus hitherto employed, whence arise an economy of time and
of fuel.
Fifthly Drying and heating of the apparatus by means of an independent
furnace or even by means of the waste flames from any convenient furnace.
Sixthly: Considerable economy in the maintenance of the apparatus by the
injection of pulverulent matters suitable for this purpose according to the case;
these new principles and applications constituting essential features of the
Invention, whatever may be the apparatus employed to effect this injection.
:
Seventhly The possibility of treating any given weight of matter within very
extended limits, which is of a great practical advantage, and of acting nevertheless
always in the same conditions of pressure in the tuyeres.
:
Eighthly The possibility of treating matters and meltings which would not of
themselves contain sufficient body, capable by their intermolecular combustion of
maintaining by themselves a sufficient temperature in the bath, thanks to the
heating which can be carried on even during the entire time of the operation of
blowing by means of an independent furnace in front of which the apparatus can
be placed.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that what
I claim is:
:
First The application to metallurgic operations of a moveable, oscillating
convertor furnace the tuyeres of which can carry the air blast or the gases to the
desired depth into the matters in fusion by the simple inclination of the apparatus
substantially as herein shown and described.
:
Second The injection into the matters in fusion by the same tuyeres of
pulverulent matters suitable to the re-actions desired to be produced and to the
preservation of the lining substantially as herein shown and described.
Third: The arrangement by which the said furnace can receive when required
the heating of an independent furnace substantially as herein shown and described.
AU
1
100
B. J. B. MILLS.
By Harris & Mills,
23, Southampton Buildings,
Agents.