IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL FUEL, AND APPARATUS TO BE EMPLOYED THEREIN.
Year: 1875

page_text: LETTERS PATENT to Wilhelm Radeke, of No. 35, Gresham Street, in
the City of London, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF ARTIFICIAL FUEL, AND APPARATUS TO BE EMPLOYED
THEREIN.
"
Sealed the 10th August 1875, and dated the 19th March 1875.
PROVISIONAL SPECIFICATION left by the said Wilhelm Radeko at the
Office of the Commissioners of Patents, with his Petition, on the
19th March 1875.
I, WILHELM RADEKE, of No. 35, Gresham Street, in the City of
3 London, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL FUEL, AND APPARATUS TO
BE EMPLOYED THEREIN," to be as follows:-
The Specification of a Patent granted to me on the 24th of May,
A.D. 1873 (No. 1877) describes the manufacture of smokeless artificial
fuel by the aid of silicate of soda, lime, and soluble silica in a powdered
state.

page_text: The object of the present Invention is to dispense entirely with the
employment of a previously prepared solution of an alkaline or neutral
silicate, and thus not alone to modify considerably the cost of manu-
facture but also to improve the waterproofness of the fuel without
having to put necessarily into the compound any excess of powdered
soluble silica which was added, as described in the said Specification,
that it might combine with the caustic soda set free by the action of the
lime on the silicate solution, and thus form on the soda an insoluble
silicate. Now this is obtained by compounding the small coal or other
carbonaceous material with caustic lime, or substance containing lime,
as for example, Portland cement or a mixture of lime and cement,
soluble silica in a powdered state, or crushed limestone (carbonate of
lime) bitumen, and reducing the compound to a very thorough state of
plasticity by the addition of boiling water or steam. In the boiling
water or steam I dissolve sometimes so much of an alkali as is required
to produce a solution of from 5° to 10° of the acid gauge.
The bitumen is employed in the state of ordinary mineral pitch, cither
pure or prepared separately under heat by an admixture of from 3 to 8
gallons of oil of creosote to cach cwt. of pitch, and the soluble silica or
limestone, or it might be part of the lime, which is by preference
intimately mixed with the bituminous substance to which some coal dust
may also at once be added is again gauged proportionately to counteract
the softening properties of the bituminous matter. In this manner I
obtain an artificial asphalt which will set hard when cold, can thus be
reduced to finely divided powder by a suitable grinding apparatus, and
can so be more readily acted upon by boiling water or steam.
The proportions which I employ will necessarily vary according to the
nature of the carbonaceous material and of the fuel desired to be
produced, and will range from about 2 to 5 parts of the alkaline carths,
1 to 5 parts of bitumen, and to 5 parts of silica or limestone to every
100 parts of coal.
I also, according to my Invention, produce a waterproof artificial fuel
by compounding the small coal with the above named ingredients, except,
however, the bitumen, and sometimes also without the soluble silica or
limestone. By this process is produced what is commercially termed a
"smokeless fucl," and cold water might be used, but the resulting action
is by no means preferred, for firstly the subsequent formation of an

page_text: insoluble silicate of lime or a strong carbonate of that base, as the case
may be, depends, especially when formed by the carrying action of an
alkali in solution on the influence of heat; and secondly, by boiling the
water it is deprived of its carbonic acid gas in solution, the freedom
from which is, to a certain extent, a necessary condition for the ultimate
better concretion of the mass, hence when cold water is substituted it
should have been boiled previously.
The lime employed should be fresh ground and in a perfectly caustic
state. If it were hydrated or partially hydrated previously the resulting
action would not be a preferable one, since it should be used hot.
The small coal employed may be washed of carthy residue, but on no
account should all of it be in the state of fine dust nor be entirely
ground to dust (which is otherwise the general practice of the
manufacture) the object thereof being that the coal should offer on
crystallization to the surrounding particles of lime as many and as large
sided prisms as can conveniently be arranged.
The compounds, when worked by suitable mechanical means into a
very thoroughly plastic state, which is a most, essential condition, are
then very strongly compressed by a moulding machine, and are allowed
to set and harden gradually by the action of the atmosphere (not be-
artificial heat) resulting in the production of a very cheap and useful
fuel. I do however not follow the usually adopted and hitherto
generally practised mode of mixing, that is to say, of simply mingling
or mixing together the various ingredients which in its result I find to
be not only unreliable but almost invariably fatal to the requisite degree
of concretion, therefore to obtain the desired state of plasticity I first
reduce the lime, together with the silica or limestone when added, and
part of the coal into a thorough mortar, for which purpose I prefer to
employ such mixing mills or horizontal pans in which, by their alternate
revolutions, both vertical rollers and scrapers or blades, or it might be
rollers only, freely turn over and incorporate the various ingredients, and
such quasi-mortar is then mingled with the remainder coal, or coal and
cement if added.
For the purpose of grinding any of the materials I prefer to employ
a conc mill constructed on the principle described by me in the
Specification of a Patent, No. 1355, A.D. 1874, granted to myself and
S. R. Smyth.

page_text: Finally I would wish it to be understood that my Invention in its
entirety consists not alone in the mere compounding of the various
enumerated ingredients but together therewith in the working of the
compounds into a very thorough state of plasticity as stated, which, in
conjunction with a subsequent strong compression I find to be an
essential condition for the requisite degree of concretion and solidification
of the blocks of fuel because naturally there is no great chemical
affinity of the coal (carbon) for the limes (calcium) nor the silica, but
by the mechanical action of a very thorough state of plasticity I find
such affinity to be artificially induced or enhanced, and it may be
considerably increased by the carrying action of an alkali in solution,
although its action is not a rapid one as compared with the action of a
previously prepared solution of silicate.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Wilhelm Radeke in the Great Scal Patent Office
on the 18th September 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILHELM
RADEKE, of No. 35, Gresham Street, in the City of London, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of March, in the year
of our Lord One thousand eight hundred and seventy-five, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Wilhelm Radeke, Her special license
that I, the said Wilhelm Radeke, my executors, administrators, and
assigns, or such others as I, the said Wilhelm Radeke, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF ARTIFICIAL FUEL AND APPARATUS TO BE EMPLOYED THEREIN,'
upon the condition (amongst others) that I, the said Wilhelm Radeke,
my executors or administrators, by an instrument in writing under
"

page_text: my, or their, or one of their hands and scals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Wilhelm Radeke, do hereby declare
the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say:-
The Specification of a Patent granted to me on the 24th of May, A.D.
1873 (No. 1877), describes the manufacture of artificial fuel by the aid
of silicate of soda, lime, and soluble silica in a powdered state.
Now the employment of silicate of soda, the principal binding agent
of that process, is objectionable in many respects, and it is the object of
the present Invention to dispense entirely with the employment of a
previously prepared solution of an alkaline or neutral silicate, and thus
not alone to modify, by at least one of the processes hereafter described,
the cost of manufacture, but also to improve or bring about the being
waterproof of the fuel without having necessarily to put into the
compound an excess of powdered soluble silica, which as described in
the said Specification had to be added that it might combine with the
caustic soda which is necessarily set free by the action of lime on the
silicate solution, and thus form on the soda an insoluble silicate.
In order that the nature of my Invention may be better understood I
will endeavour to explain what action the silicate solution has or is
believed to have when employed for the agglomeration of small coal.
Silicate of soda (or of other alkali), i.c., silica in solution, being a
liquid of glutinous nature serves when compounded with small coal as a
kind of mastic which gives plasticity to the compound, and when acted
upon by admixtures of alkaline earths (calcium) it forms insoluble
silicate of lime, which by the aid of pressure binds the coal firmly
together; when further more soluble silica in a powdered state is added
the hardness of the blocks is increased by the formation of other insoluble
silicate. Thus one action of silica in solution is to form the small coal
into hard solid shapes.
Another action of equal importance in connection with the employ-

page_text: of temperature at which most other known substances would melt or
become otherwise decomposed, therefore the minute blending of silicate
through a mass of small coal has the effect of holding the fuel together
when undergoing combustion. Now to effect both these results and to
render the fuel sufficiently waterproof, I found it necessary as described.
in the recited Specification to employ proportions of silica both in solution
and in a powdered state which are objectionable on account of the excess
produced, and the rapid action of silica in solution on lime is also some-
times a source of inconvenience. I have consequently arrived at the
conclusion that some other cementing material might advantageously be
employed to serve as a mastic in the place of silica in solution provided
it were itself unlike a silicate insoluble in water, and that the required
contraction during the process of combustion might nevertheless be
effected and maintained by the simple, but judiciously proportioned
admixture of a soluble silica in the state of a finely divided powder.
On account of their great binding power bitumen or bituminous
cements have since long been employed for the consolidation of small
coal, and were it not that this class of cements is liable to the great
inconvenience of melting into a semi-liquid state when the fuel undergoes
combustion, especially when the heat is high, their adoption might have
been more generally approved of; but at a temperature lower than that
of boiling water they begin to soften, and thus frequently deposit the
conglomerated fuel in a semi-liquid state on the fire-bars. Silica
however is capable to resist a degree of heat above 2000° F, therefore a
judiciously proportioned mixture of bituminous matter and silica should
furnish both the gluten or mastic to bind the coal together, and the
contracting medium to hold the conglomerated small coal together until
the mass has become sufficiently ignited to form a coke.
For some purposes it may however be desired to produce a so-called
"smokeless fuel" when a smokeless or non-bituminous binding material
must be employed. I find that for such purpose a prepared solution of
silicate may be substituted by a weak dissolution of alkali in boiling
water, which in order to prevent the inconvenience of obtaining an excess
of free alkali should not contain more of the latter than would readily
combine with the lime employed, or such proportion thercof as might be
deemed requisite to serve as the carrier between the base (lime) and the
powdered soluble silica, it being well understood that the alkalis serve as
the carrier between those substances, and are believed to give thus rise

page_text: to the formation of silicates, although such action is a slower one than
that of a prepared solution of silicate.
By the adoption of these modes I purport to obviate the employment
of a solution of silicate, and having thus stated the nature of my
Invention I will proceed to describe how it is to be carried into effect,
that is to say, I compound the small coal or such like carbonaceous
material which is better when ground with bitumen or bituminous sub-
stance, which I prefer to use in the state of mineral pitch, soluble silica,
lime, limestone, (carbonate of calcium), and reduce the compound to as
plastic a state as can be readily effected. To effect it the compound
must in all cases be acted upon by heat, that the bituminous matter may
become thoroughly liquified; this is well understood and what mode may
best suitably be adopted for the purpose must be governed by the
already existing appliances or means at command of the various
established fucl works. Steam (or it might be superheated steam) or
waste heat will all effect the purpose, and as such modes have all since
long been successfully employed, and are well understood in their
various and separate effects, it would not appear necessary that I should
proceed to a more detailed description thereof.
For a small mode of manufacturing where it may possibly be difficult
to introduce the use of steam or high heat on account of the frequently
experienced difficulty of procuring suitable mixing apparatus for such
smaller purposes, I have sometimes employed the aid of boiling water,
that is to say, I firstly preparo in a separate vessel a species of artificial
asphalt by mixing about one-twentieth part of the small coal with the
silica and lime, and part of the bitumen (pitch), the vessel is kept over a
good bright heat, and the mixture agitated until it forms itself into one
mass, it is then allowed to cool, when it sets hard. This artificial
ashphalt is ground into a fine powder by a suitable grinding apparatus,
and is mingled with the remainder coal and bituminous matter, boiling
water sufficient to moisten it having been added; it is kept over a fire
until steam is generated; when the greater part thereof has escaped the
compound is compressed in moulds by suitable pressing appliances.
Sometimes I also add to the boiling water or water used for generating
steam, so much of an alkali (soda ash preferred on the ground of
economy), as would bring the dissolution to from 5° to 10° of the acid
gauge; I find that the addition of alkali has a tendency to render the
compound somewhat more plastic for moulding.

page_text: The object of putting into the compound admixtures of calcium (lime,
limestone, calcareous stone, carbonate of lime), is to counteract if
necessary a possible additional formation of solid incombustible residue
on the fire-bars, an excess of which might occur if the soluble silica were
employed in a form where it is chemically largely combined, or in close
union with substances such as for example, alumina, protoxide, or
peroxide of iron, etc., and which would flux under high heat. In nature
however soluble silica occurs in so many states of variable combination
with substances such as afore-named, that it would be difficult to state
the exact requisite proportionate admixtures of lime or its carbonate,
which might be universally applicable to counteract the said excess of
additional formation of incombustible residue; therefore a careful
analysis should in all cases be made of the silica intended for use, and
this obtained the equivalent of calcium required to produce a more
perfect combustion will soon be determined by the chemist.
Soluble silica in such form as is known by the various denominations
of infusorial silica, or fossil silica, or kieselguehr, or porous silica, has
been employed by me in its pure state without any admixtures of
calcium; it analyses about 96% of silica, and offers furthermore the
advantage of being of a very low specific gravity, and can thus readily
be reduced to a very finely divided powder of which in so minute a state
of division, a smaller quantity will suffice for a thorough blend through
the coal than would have to be used of a substance of higher specific
gravity and of less purity of state. The advantage of this is evident,
therefore the purer the state of the silica, and the lower its specific
gravity the more is it to be preferred for use. Experience then must
be the guide and will soon point to the most suitable substance of all
soluble silicas which have come under my notice; I give the pre-
ference to such substance as the above referred to, kieselguehr or
infusorial silica; I prefer to employ the bituminous matter in the state of
coal tar, pitch, or at least the solid coal tar, pitch (asphaltum bitumen), to
be proportionately predominating to ensure a rapid hard setting of the
compressed blocks; this would not be the case if it were used in the
state of liquid coal tar alone, which as is well understood invariably
requires a subsequent baking of the fuel to set equally hard, nevertheless
coal tar alone may be used and possibly even to advantage in districts
where it can be cheaply obtained, or where established fuel works are
provided with appliances suitable to its usage.

page_text: resulting action is not preferred, for the carrying action of an alkali in
solution is assisted by the influence of heat, and by boiling the water it
is deprived of its carbonic acid gas, the freedom from which in solution
it is believed is to a certain extent a necessary condition for the ultimate
better concretion of the mass; hence when cold water be substituted it
should have been boiled shortly before being used.
The lime employed should be fresh, finely ground, quick slacking,
and in a perfectly caustic state, that it may be used hot. Any substance
containing lime, such as for example Portland cement, may be used.
The small coal employed may be washed of earthy residue, but on no
account should it in this smokeless process be entirely ground to dust,
the object thereof being that the coal should offer on crystallization to the
surrounding particles of lime as many and as large sided prisms as can
conveniently be arranged. In this process the action of the soluble
silica may be explained as follows:-Lime is the binding agent forming
carbonate of lime which consolidates the fuel by the action of the alkali
which is in aquous solution; the soluble silica is slowly carried into
chemical combination with the lime and so gives rise to the formation
of silicate; if the alkaline solution is limited to a strength equal to about
5° to 8° of the acid gauge there will be no free alkali in excess, as so much
of it is taken up by the lime. If limestone or calcareous stone (car-
bonate of lime) is used in place of or in addition to soluble silica, an
action of similar nature takes place, and such addition to the compound.
serves to give substance to the fuel.
The compound, after having been worked by suitable mechanical
means into a very thoroughly plastic state, which is a most essential
condition, is then very strongly compressed in a moulding machine, and.
allowed to set and harden gradually by the action of the atmosphere,
but never in this process by the aid of artificial heat. I do however not
follow the hitherto usually adopted and generally practised mode of
mixing, that is to say, of simply mingling or mixing together the various
ingredients which in its result I find to be not only unreliable but almost
invariably fatal to obtaining the requisite degree of concretion. To
obtain then the desired state of plasticity I first reduce the lime together
with the silica or limestone when added, and about one-fourth part of
the coal into a thorough mortar, for which purpose I prefer to employ
such imixing mills or horizontal pans in which a quasi-mortar can be

page_text: prepared on the ordinary mortar making principle by revolving rollers
and scrapers. Such quasi-mortar is then mingled with the remainder
coal or coal and cement, if this be added.
Useral commonations would be with every about 100 parts of north
5 country coal,—
22 parts of caustic lime,
to 1
soluble silica or limestone
دو
"
(or mixture of both),
or 21
or 2
1
"
,, caustic lime,
all by weight.
وو
,,
caustic lime,
"
"
soluble silica,
1
وو
دو
Portland cement.
The compound in every case to be reduced to the greatest possible
state of plasticity by the addition of boiling water or boiling water
charged with alkali (say soda ash) sufficient to produce a dissolution
equal to from 5° to 8° of the acid gauge.
For the purpose of grinding any of the materials (but limestone only
if previously crushed into small lumps) I prefer to employ a cone mill
constructed on the principle described by me in the Specification of a
Patent (No. 1355, A.D. 1874), granted to myself and Samuel Richard
Smyth. The roller cutters R & R' in the hopper B, therein described
as being "simply strong barrels with projecting knives or cutters fixed
therein," should be suitably altered into like barrels with projecting
beaters or feeding fingers to move the material downwards in place of
the said cutters or knives.
Finally, I would wish it to be understood that my Invention in its
entirety consists not alone in the mere compounding of the various enumer
ated ingredients, but together therewith in the working of the com-
pound sinto a very thorough state of plasticity, which, together with a
subsequent strong compression, I find to be an essential condition for the
requisite degree of concretion of the fuel blocks, because naturally there
is no great chemical affinity of the coal (carbon) for the lime (calcium),
nor the silica, but by the mechanical action of a very thorough state of
plasticity I find such affinity to be artificially induced or enhanced, and
it may be considerably increased by the carrying action of an alkali in
solution, although its action is not nearly so rapid as that of a previously
prepared solution of silicate.

page_text: Having now stated the nature of my Invention, and particularly
described in what manner the same is to be performed, I would have it
understood that what I claim in the manufacture of artificial fuel from
small coal or such like carbonaceous matter is,―
First. The firstly described process of manufacturing artificial fuel
substantially as herein described.
Second. In combination with and for the counteracting of bituminous
cements the use of soluble silica in a finely powdered state, and in as
pure a form as procurable, such as for example infusorial silicas like
kieselguehr, substantially as herein described.
Third. The production of a so called "smokeless" fuel, substantially
in the manner described.
Fourth. The use of a cone mill for grinding the materials, substan-
tially in the manner described.
In witness whercof, I, the said Wilhelm Radeke, have hereunto
set my hand and seal, this Eighteenth day of September, in the
year of our Lord One thousand eight hundred and seventy-five.