IMPROVE- MENTS IN SHELFING AND PUDDLING IRON
Year: 1873

page_text: LETTERS PATENT to William Mickle, of Tynemouth, in the County
of Northumberland, Gentleman, for the Invention of "IMPROVE-
MENTS IN SHELFING AND PUDDLING IRON."
Sealed the 25th April 1878, and dated the 5th March 1873.
COMPLETE SPECIFICATION filed by the said William Mickle at the
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 5th March 1873, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
MICKLE, of Tynemouth, in the County of Northumberland, Gentleman,
send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
SHELTING AND PUDDLING IRON," and have petitioned Her most Excellent
Majesty Queen Victoria to grant unto me, my executors, administrators,
and assigns, Her Royal Letters Patent for the same, and have made
solemn Declaration that I am the first and true Inventor thereof.
4-

page_text: NOW KNOW YE, that I, the said William Mickle, do hereby declare
the nature of the said Invention to be as follows:-
In the modes of treatment in use of the fuel used in the smelting of
iron ore the waste is enormous, the waste of heat is also enormous, and
from the large quantity of iron made it is a matter of very great and
increasing public import to obviate or prevent, or materially reduce, this
waste of fuel, and also this waste of heat.
In the use of coal or raw fuel in the iron smelting furnace the
volatile combustible gases of such coal or raw fuel are by the heat in the
lower part of the furnace driven off unburnt or almost altogether unburnt,
and therefore wasted or almost altogether wasted, and the nuisance of
smoke is also caused. Where the coal is coked these gases which in
reality constitute the most valuable part of the fuel are altogether
wasted, and a considerable portion of the fixed carbon of the coal is also
altogether wasted, being burnt and wasted in the coke oven or open kiln,
generally at once, the coal being so treated immediately on being drawn
out of the pit. This utter waste or destruction, taking the calorific value
of the gas into account, being on the average fully one half of the
heating value of the coal, and a large proportion of the iron of the
country is made by coke fuel. When the coke is being drawn from the
oven or sow or open kiln it is cooled with water, and thus the heat
which if made available would be so valuable, and would so materially
aid in the smelting of iron, is lost, and the water used in cooling is to
some extent absorbed by the coke and requires to be evaporated by heat
in the iron furnace, requiring combustion of fuel to do so; and the
reheating of the coke before it can enter into combustion also requires
the consumption of fuel. By the present modes also the liquid hydro-
carbons obtainable from the coal are also lost.
The fuel also, from what is above stated, is not and cannot be used so
as to obtain the advantage that will arise from the concentrated heat;
and the immense reducing or smelting power arising from the con-
centrated heat of the gaseous or volatile and liquid combustible portion
of the coal, and the improvement in the quality of the iron from the
ore being reduced or smelted at a higher temperature from the consequent
more thorough separation of the earthy part of the ore or slag, and also
the improvement of yield in the ore as from the higher temperature, the
slag will not only be more thoroughly separated from the iron, but the
iron will be more thoroughly separated from the slag.

page_text: · In puddling furnaces the gas from the coal used contains a con-
siderable portion of the sulphur, generally contained in the coal which
passes off with the combustible gas to the iron being puddled, and a
considerable portion of the solid part of the coal is necessarily used in
the fires of the puddling furnaces simply to sustain the fire. There is
considerable diffusion and -consequent waste of heat from the fire to the
metal. The combustible gases of the coal partly pass off imperfectly
burnt, causing not only the nuisance of smoke but waste of carbon; the
black smoke being unburnt particles of carbon. There is also the
▸ expenditure of much heavy hot labour in firing.
In order to prevent the primary waste of coal or fuel above stated, and
also to carry out this Invention, it is requisite to treat the coal by dry
distillation in retorts similarly to gas works in use in towns, and have
1
the gas works contiguous to the smelting furnace; the works having
5 the usual plant of retorts, gas holders, &c. And I recommend that the
gas should also be purified as in ordinary gas works, and be thoroughly
purified.
My Invention or improvement is this, that to economise the heat as
above stated, and also to have the immense advantage for smelting the
ore of a body of fuel thrown into the furnace hot or red hot, or
approximating to red heat, I draw. the coke from the retort at the
red or white heat, or whatever it may be, into iron or other suitable tubs
'or carriages without having the coke made cold with water or without
cooling it with water, and convey it to the smelting furnace and
5 discharge it into the furnace as fuel, as the fuel is ordinarily charged; or
if requisite from the heat, by engine power. With this I combine the
use of the coal gas, and also the naptha or other combustible oil or spirit
obtained from the coal used for smelting, the gas being simply pumped
from the gasholder by engine power through pipes and tuyeres to and
) into. the furnace (in a similar way to the air pumped from the blowing
engine). If the said liquid hydrocarbons be used in the smelting
furnace they could be similarly pumped from a tank or receiver. I
recommend that the gas be well purified, and also that valves opening
to the furnace be fixed or joined into the pipes near the furnace, so as
5 to prevent any return of air getting mixed with gas in the pipes, causing
explosive mixture.

page_text: The gas not used in the smelting furnace can be appropriated to
the usual lighting and heating purposes, that is, for houses, shops,
cooking, &c. The liquid hydrocarbons can be used for general purposes.
In puddling iron I distil the coal in the same manner, and pump the
coal gas as fuel from the gas holder through pipes, and also the air 5
required for combustion through pipes from ordinary blowing apparatus
similarly to that for smelting into the puddling furnace to puddle the
metal. I recommend the gas to be thoroughly purified, and the pipes,
jets, tuyeres, or orifices of the air and gas to be conveniently small and
numerous, and well mixed together, so that the air and gas may be well 1
mingled for the purpose of obtaining thorough combustion. Or the air
may be supplied as at present, but I recommend it to be pumped
through pipes. The gas coke can be used for smelting or any other
useful purpose. This mode will prevent or greatly diminish the labour
of stoking or firing, and the impurity from the coal and the smoke, and 1
also the waste before named.
The heating of the air blast may be continued as at present, but I do
not believe that with the use of the coke put into the smelting furnace
hot or red hot, and the coal gas pumped in as above, it will be found
needful, as the heat will independently of the air being heated be so
great that the heating of the air may be dispensed with. The air
might be heated at option, and where esteemed convenient by the
air blast pipes being passed along or round the retort furnaces or
flues or chimneys, in such a manner as to get the benefit of the waste
heat from them.
The coal gas will for pumping require to be cleared of the tar, and
should be well purified; but after allowing for what condensation these
require, it will save heat by pumping it into the furnace as nearly
to the temperature the gas leaves the retort as may be, and the gas
holder and the pipes from the retort could, if thought desirable, be
covered with felt or other covering.
The retorts may at option be heated with the smelting furnace waste
gases, or the carbonic oxide hydrogen, &c., and heat of such waste gases.
As to puddling, the retorts may also be so heated with the puddling
furnace waste gases. The gas engine boiler fires if the air blast engines

page_text: be not used for pumping the gas as to smelting, or if pumps be not
attached to other engines at the puddling works can also be so heated.
The coal gas pumped into the smelting furnace. I so pump all or
any part of it in close proximity to the air pumped in so as to be most
powerful gas blow pipes, and to obtain a most intense concentrated heat
in the hearth or crucible.
And I believe that from the use of coke put into the smelting furnace
hot, and the use of the gas as before named, the increment of heat in the
furnace will be very great, and that consequently on this the flow of
metal will be rapid, and the produce from the furnace much increased.
The calcining of ore may be continued as at present; but with the
charging of hot coke into the smelting furnace, which will at once as
soon as thrown in act in driving off the moisture and carbonic acid of
the oro, I do not believe it will be found requisite.
After allowing for the fuel required for the deoxidation of the ore, and
the carbon of the fuel necessary for the carburization of the metal, I
believe that with the intense concentrated heat from the gas blow pipes
as above, and the use of coke put in hot as above, much weight of fuel
may not be needed, and that therefore the enormous weight of air at
present used for combustion will be greatly diminished, and therefore a
great saving of the engine power and blowing apparatus for pumping
the air, and the fuel and labour used for such engines will be effected.
And I believe also that although it be found advantageous to have
large furnaces, yet from the use of a mass of coke thrown into the
furnace hot, or red hot, or approximating to red heat, the coke being a
mass or column of heated fuel from the very top and the heat from the
gas, that the produce of metal from the furnace will be so large that in
future the iron smelting furnaces need not be erected so large and
costly as at present; smaller and cheaper ones yielding metal in large
quantities.
I believe indeed that the use of fuel hot or red hot or approximating
to red heat as drawn from the retort and put into the iron smelting
furnace, together with such potent gas blow pipes will cause most rapid
production of metal, and that it may reduce the consumption of fuel in
iron smelting practically to a minimum.

page_text: The intensity and increment of heat by this process will more highly
liquify the metal and slag in the iron smelting furnace, thus more
thoroughly separate the metal and slag, and I believe as result the iron
will be purer and better in quality, and more yield from the ore than as
at present; the iron will contain less admixture of slag, and the slag t
of iron.
I believe it will be found that under this process a great deal of
small and inferior coal, hitherto found unsuitable for iron smelting, and
until of late worthless, or nearly so, or altogether cast aside and wasted,
will be rendered available for smelting where it contains gas and cokes ]
in the retort.
Supposing that there be used in the iron smelting furnace to make
a ton of metal, twenty-five hundredweights of coke, and five hundred-
weights of this coke be absorbed or required in deoxidising the ore
and carburizing the metal, there will be twenty hundredweights of 1
coke for combustion with the air pumped in, and about eight tons, or
about two hundred and forty thousand cubic feet of air pumped into
the furnace for combustion with the coke, about three-fourth parts, or
six tons of such air will be nitrogen, which is not only noncombustible
but requires heat, and consequently the consumption of fuel in the
heating stoves, if hot air be used, and in the blast furnace to licat it to
the temperature in the furnace or the hearth of the furnace; thus about
six tons or about one half of the whole of the materials put into the
furnace being not only useless (excepting perhaps as to cyanogen) but
detracting from the heat of the furnace and requiring fuel to raise its 5
temperature. The use of coke put into the furnace hot, which heat
assists in the smelting of the metal, diminishes the air, and consequently
the nitrogen required, and lessens the detraction from the heat in the
hearth caused by the nitrogen.
I think it will be found that on smelters becoming familiar or
thoroughly conversant with the process before named in their furnaces,
that the use of coke put in hot or red hot, or approximating to red heat,
and coal gas, will from the intense heat give so much and so potent a
command over the reduction or smelting of the ore, that eight to ten
hundred weights of the gas produced and heated coke may be found;
sufficient in the furnace for fuel, inclusive of what is required for
deoxidation of ore and carburization of metal; if so, it will only require

page_text: about one-fourth of the air, or about two tons, thus diminishing the
available air blast power required three-fourths; and' as before named I
believe that previous calcining and heating stoves may not continue to
be used, and the engine boilers and retorts may be heated with the
furnace waste gases; the general result would be that the metal may be
Emelted with the total consumption of about half a ton of coal. And
supposing that on the average there be now used to make a ton of metal
for calcining engine power for pumping the air, heating the air, and
smelting the ore about three and a half tons of coal, the net saving would
be about three tons of coal in making a ton of metal, and as there are
now making in this country nearly or about seven million tons of pig iron
annually, the saving at the present rate of make would be nearly twenty
million tons of coal annually, which is a matter of very great and
increasing importance. I do not bind myself to the extent of saving
above named, but I thoroughly believe it will be so, that is, the reduction
of consumption of fuel to about ten hundredweights, or the .general
saving of twenty million of tons of coal on the present make of pig iron
annually, more or less, or approximating to it.
From what is before stated I consider that by this process very much
of the hard and dangerous labour and drudgery in mining for coal and
other labor for smelting or making iron will be saved.
I believe that this process will enable iron to be produced much
cheaper, and thus stimulate the building of iron ships, railways, &c., and
generally foster the staple industries of the country as well as free a
large quantity of coal for domestic use which is much needed, and
which would be a great boon to the poor and to the public generally..
I think when convenient it will be desirable for the puddling furnaces
to be near the smelting furnace, so that the heated coke made in
distilling coal for the gas for puddling may be used in the smelting
furnace, and thus save the heat of the heated coke; and also that the air
blowing apparatus attached to the smelting furnaces may be available
for pumping air to supply the combustion at the puddling furnaces.
: Where the coal gas is well purified I believe it to be a very pure or
fine and superior description of fuel, and independently of what is before
named as to deeper liquifaction, will aid in making higher class iron.
I believe that the coal gas. purified as ordinarily, and used as before
named for puddling, will tend to make better malleable iron, and that

page_text: both as regards smelting and puddling there will be much more com-
mand over the heat of the furnace, as the force of gas and air and
consequent instantaneous heat can be increased when desirable by accele-
rating the motion of the engine and pumping.
Where there are beds of iron ore at a distance from coal, as for
instance those in the oolites and lias, I consider that this process as to
the fuel will be of great value in developing them, and may be of
essential import where the ore is at present considered too poor to smelt,
because I believe that the quantity of fuel required will be relatively so
small, and therefore the cost of carriage so, and the power of heat so 1
great over inferior ores.
In using peat wood or other fuel which yields on distillation solid and
gaseous combustible products economically, and in sufficient quantity
for iron smelting and puddling, I subject it to dry distillation, and then
treat and use the combustible products for the purposes of this Patent as 1
before named in the same way that I do coal for iron smelting and
puddling.
Having thus described the nature of my said Invention, and the
manner in which the same is performed,—
I claim, firstly, and as a distinct and separate claim, so as to greatly 2
economise heat and consequently fuel, and also to have a mass of hot or
red hot fuel or fuel approximating to red heat at such heat from the
very top of the column of fuel, and the consequent immense power for
reducing or smelting the ore from such heat, and the consequent increase
of quantity of metal smelted on a given weight of such fuel put in so 2
heated, the use of heated coke or other solid carbonaceous fuel as before
named conveyed hot as drawn from the retort directly to the iron
smelting furnace, and thrown or put into the furnace and used as fuel
to smelt the orc.
I claim, secondly, for the consideration before stated the use of the 30
combustible gas as before stated, together with or combined, or in con-
junction with such solid heated fuel in the iron smelting furnace as fuel
to smelt the ore to assist in its rapid reduction or smelting, and so obtain
greatly increased quantity on a given weight of fuel, to improve the
quality of the iron from the coko being used hot as before named, and the 3
gas, and otherwise for the objects of this Patent as before named.

page_text: And I claim, thirdly, for the considerations before stated the carboni-
zation by dry distillation or in retorts, and treatment of coal, peat wood,
or other such fuel as before named, and the use of the combustible gas
as before named as fuel to puddle the iron, and this in mode as herein-
before named.
In witness whereof, I, the said William Mickle, have hereunto set
my hand and seal, this Third day of March, in the year of our
Lord One thousand eight hundred and seventy-three.