IMPROVEMENTS IN SEPARATING SULPHUR FROM COAL AND COKE
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by Christopher Binks at the Office of
the Commissioners of Patents, with his Petition, on the 1st December
1864.
I, CHRISTOPHER BINKS, of No. 13, Rue Gaillon, Paris, in the Empire of
France, Chemist, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN SEPARATING SULPHUR FROM COAL AND COKE," to be as
follows:-
The principal object of my Invention is to purify coal and coke from
sulphur, with the view of applying such desulphurized coal and coke as fuel,
and in manufacturing and metallurgical and other separations wherein the
presence of sulphur is injurious. A subordinate object in some cases is the
utilization of the sulphur or sulphur compounds obtained through these opera-
tions for desulphurizing the coal and coke,
When the sulphur in the coal which is intended to be desulphurized exists
in the form of iron pyrites, that is, bisulphuret of iron, I proceed to effect its
separation from the coal by one or other or a combination of the following
methods, namely:-
First method. I reduce the impure coal to a fine powder, and mix this powder
with water; preferably I grind or levigate the impure coal in water, and then I
pass atmospheric air, either of ordinary temperatures or artificially heated, into
and through this mixture, in order, thoroughly to agitate the mixture and
suspend in or diffuse the mixed particles of coal and pyrites throughout the
water. I then cease to agitate the mixture by staying the admission of the

page_text: atmospheric air, and leave the mixture to rest until the particles of pyrites
by reason of their superior gravity shall either wholly or partly have sepa-
rated from the coal and settled to the bottom of the reservoir or apparatus in
which this operation is carried on. I use an agitating and settling apparatus
so constructed that the deposited pyrites can be flushed or carried off from the
bottom, leaving the coal either still suspended in the water, or lying in a
deposited stratum above the pyrites, or otherwise so constructed that the sus-
pended coal, or, when it has been deposited, the stratum of coal can be washed
off from the deposited pyrites. This operation of alternately agitating the
impure coal pulp by currents of air, and leaving the pulp to stand till its
heavier constituents separate by subsidence, I repeat as often as necessary
(when one such operation is not sufficient) till the whole or the greater por-
tion of the pyrites is thus mechanically separated from the coal. I do not
confine my Invention to the use of air as the agitating agent, but, at pleasure,
I apply any other convenient mechanical agency fór alternately agitating the
mixture of pulverized impure coal and water, and leaving it at rest to effect
the separation of the pyrites from the coal.
Second method. The above or first method I use to separate pyrites from
coal when it is desired that this operation shall be accomplished by mere
mechanical appliances as herein above specified; but by this, my second
method, I bring into action the aid of certain chemical agencies to be used
conjointly with the mechanical appliances just above described, namely, 1
expose the pulverized impure coal mixed with water to the action of atmo-
spheric air, so applied and continued as to oxidize all or a portion of the pyrites
mixed with the coal, and because of such oxidation, to convert the previously
insoluble bisulphuret of iron into soluble sulphate of iron and free sulphuric
acid, which products are capable of being separated from the residual coal by
washing or lixiviation. In this operation I prolong the aërating and agitating
action obtained by passing atmospheric air at ordinary temperatures into and
through the impure coal pulp till the oxidation of the pyrites (or of such a
portion of it as it may be desired to oxidize) be completed; but I prefer, in
place of applying the air at its ordinary atmospheric temperatures, to employ
heated air, or air mixed with ordinary steam or superheated steam in order to
accelerate the natural oxidizing action of air and moisture on the pyrites.
The products of this oxidation, consisting chiefly of proto-sulphate of iron and
free sulphuric acid, are then removed by washing or lixiviation, and the pre-
viously impure coal is thus left either completely or partially desulphurized,
and any unoxidized portion of pyrites can be removed by the mechanical
action of subsidence as described above..

page_text: Third method. I reduce the impure coal to the condition of a fine powder,
and the more impalpable its particles the better, and expose this pulverized
coal, made into heaps or beds, to the natural oxidizing action of air and
moisture till the particles of pyrites have been transformed into sulphate of iron
and sulphuric acid. I then wash out these soluble products, and thus effect
the desulphurization of the coal. I prefer to use a covered shed on the floor
of which to spread the coal, and when the natural moisture in the coal, or the
hygrometric water of the atmosphere are not sufficient to supply the water of
composition requisite to the formation of hydrated sulphuric acid, I then add
such water to the coal. I so construct the under ground of the floors of the
sheds that any water thrown upon the beds of coal and made to percolate
through them can be drained off, and the products of the oxidation of the
pyrites be conveyed to suitable reservoirs for after treatment in utilizing them.
But I prefer to aid the natural oxidizing action of atmospheric air and
moisture on the iron pyrites in the coal by the application of artificial heat to
the heaps or beds of impure coal, and for this purpose I throw heated air into
the sheds, either by currents passing over the surface of the coal or by means
of flues constructed below the floors and conveying heated air beneath or
through the beds, or conveying thereto a mixture of heated air and steam.
The sulphur compounds so produced are then separated from the coal by
washing them out or by lixiviation by any convenient arrangements. These
compounds are of themselves valuable products, but can be further utilized in
the manufacture of other products. The washed and desulphurized coal can
be air dried or kiln dried, or in its wet or pasty condition be used as fuel, or
for the manufacture of coke or of gas, and in most kinds of metallurgical and
manufacturing operations.
My improvement in desulphurizing coke is as follows:-To coke which has
been manufactured from coal contaminated with iron pyrites I apply water
acidulated with some kind of acid capable of forming, with the proto-sulphuret
of iron left in the coke, a soluble salt of iron, and at the same time of
liberating the sulphur in the form of gaseous sulphuretted hydrogen, which is
expelled and escapes. The residual salt of iron I at pleasure either separate
from the coke by lixiviation or leave it mixed with the coke, when its chemical
composition makes its presence to be harmless or advantageous in the. after
applications of the desulphurized coke.