AN IMPROVED PROCESS AND APPARATUS FOR TREATING SPENT OXIDE OF IRON TO EXTRACT SULPHUR AND AMMONIACAL SALTS THEREFROM, AND FOR PURIFYING THESE PRODUCTS, WHICH INVENTION IS ALSO APPLICABLE FOR THE EXTRACTION OF GREASE AND OIL FROM SEEDS AND OTHER MATERIALS." PRO SP
Year: 1873

page_text: LETTERS PATENT to Joseph William Freestone, of Dalston, in the
County of Middlesex, and John Humphris, of Little Ilford, in the
County of Essex, for the Invention of "AN IMPROVED PROCESS AND
APPARATUS FOR TREATING SPENT OXIDE OF IRON TO EXTRACT SULPHUR AND
AMMONIACAL SALTS THEREFROM, AND FOR PURIFYING THESE PRODUCTS, WHICH
INVENTION IS ALSO APPLICABLE FOR THE EXTRACTION OF GREASE AND OIL FROM
SEEDS AND OTHER MATERIALS."
PROVISIONAL SPECIFICATION left by the said William Freestone and
John Humphris at the Office of the Commissioners of Patents,
with their Petition, on the 18th August 1878.
We, JOSEPH WILLIAM FREESTONE, of Dalston, in the County of
Middlesex, and JOHN HUMPHRIS, of Little Ilford, in the County of
Essex, do hereby declare the nature of the said Invention for "An·
IMPROVED PROCESS AND APPARATUS FOR TREATING SPENT OXIDE OF IRON TO
EXTRACT SULPHUR AND AMMONIACAL SALTS THEREFROM, AND FOR PURIFYING THENS :

page_text: PRODUCTS, WHICH INVENTION IS ALSO APPLICABLE FOR THE EXTRACTION OF GREASE
AND OIL FROM SEEDS AND OTHER MATERIALS," to be as follows :-
Our said Invention is chiefly designed for treating the spent oxide of
iron which has been used in gas works, and consists,―
First. In an improved method of bringing the spent oxide of iron or
other substance to be treated into contact with a solvent.
Second. In a method of separating the said solvent from the products
extracted from the oxide of iron or other substance, and separating the
said solvent from the oxide of iron or other substance which has been
treated.
Third. In the use of oxidizing agents for removing the tar from the
solution of sulphur produced by treating spent oxide of iron.
Fourth. In the apparatus, herein-after described, for carrying our
said Invention into effect.
Heretofore in extracting sulphur and ammoniacal salts from spent
oxide of iron and in the treatment of various substances for the
extraction of grease, oil, and other products, the substances treated
have been subjected to the solvent in a dense mass, which it is difficult,
if not impossible, for the solvent to penetrate, and when the solvent has
been allowed to run off the dense form of the substance prevents the
last portions of the solvent coming freely away. It has therefore been
necessary to admit steam or hot water to vapourize and drive off the
remaining portion of the solvent, but the sulphur then forms a shell or
coat, which will not permit the heat to penetrate to the centre of the
mass, and the result of this process has therefore not been satisfactory.
Moreover the solvent containing the sulphur in solution has hitherto
been conducted into a still and subjected to heat, the volatile solvent
being driven off freely until sulphur is formed in lumps, absorbing and
retaining a quantity of the solvent which is thereby lost. The solvent
also extracts from the aforesaid oxide tarry matter which discolours the
sulphur.
In practising our said Invention we employ an apparatus wherein the
oxide of iron or other substance to be treated is brought into the most -
intimate contact with the solvent, that is to say, we place the said
substance and the required quantity of the solvent in a vessel which has
a perforated false bottom, and is provided with a stop-cock through

page_text: which the solvent is permitted to escape. A perforated steam pipe
extends from end to end of this vessel. The said vessel also has an
agitator, preferably in the form of an archimedean screw. It is also
provided with a cover and with outlet and condensing pipes. The charge
of oxide of iron or other substance and the solvent are placed together
in the said vessel, the agitator is then set in motion and brings every
particle of the said substance into contact with the solvent. Then the
said stop-cock is opened and the solvent escapes into a second vessel, the
agitator preventing the solidifying of the mass. Then steam and hot
water are admitted into the vessel to volatalize the last traces of the
solvent. The agitator still prevents any solidification of the mass, and
the whole of the solvent is recovered.
The second or lower vessel is similar to that above described, except
that it has no false bottom. When the solvent from the upper vessel
is received into the lower vessel the screw or other agitator is set in
motion. A suitable oxidizing agent, preferably sulphuric acid, is admitted
to precipitate the tarry matter, which is drawn off through a cock at
the bottom of the said vessel. Steam or hot water is then admitted, the
solvent is volatilized and passes into a coil, wherein it is condensed for
future use.
The action of the agitator or stirrer prevents the formation of the
sulphur in a solid mass, and brings every particle of the same into
contact with the steam or hot water. The sulphur is therefore obtained
in a granular condition free from tar and from any traces of the solvent.
For the extraction of sulphur from the spent oxide the solvent we
prefer to use is bi-sulphide of carbon or a Hight hydrocarbon oil; when
the steam and hot water are admitted into the first vessel they form the
solvent for the extraction of ammoniacal salts. The said vessel has a
separate cock for drawing off the water, holding these salts in solution.
At one end of each of the said vessels there is a man-hole, through
which when it is uncovered the aforesaid screw delivers the solid contents
of the vessel. The said vessels are provided with condensing pipes,
and with a pump and fittings for supplying the solvent to them.

page_text: Patent, and of an Order of the Lord Chancellor, by the said William
Freestone and John Humphris in the Great Seal Patent Office on
the 18th March 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOSEPH
WILLIAM FREESTONE, of Dalston, in the County of Middlesex, and JOHN
Humphris, of Little Ilford, in the County of Essex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent bearing date the Eighteenth day of August, in the year
of our Lord One thousand eight hundred and seventy-three, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto us, the said Joseph William Freestone and
John Humphris, Her special licence that we, the said Joseph William
Freestone and John Humphris, our executors, administrators, and
assigns, or such others as we, the said Joseph William Freestone and
John Humphris, our 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 Inven-
tion for "AN IMPROVED PROCESS AND APPARATUS FOR TREATING SPENT OXIDE OF
IRON TO EXTRACT SULPHUR AND Ammoniacal Salts THEREFROM, AND FOR PURIFYING
THESE PRODUCTS, WHICH INVENTION IS ALSO APPLICABLE FOR THE EXTRACTION OF
GREASE AND OIL FROM SEEDS AND OTHER MATERIALS," upon the condition,
(amongst others), that we, the said Joseph William Freestone and John
Humphris, our executors or administrators by an instrument in writing,
under our, or their, or one of their hands and seals, 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 seven calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said Joseph William Freestone and
John Humphris, do hereby declare the nature of our said Invention,
and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement, refcrence

page_text: being had to the accompanying Drawing forming a part of this Speci- .
fication :-
Our said Invention is chiefly designed for treating the spent oxide of
iron which has been used in gas works, and consists,-
First. In an improved method of treating the spent oxide of iron or
other substance whereby the same is brought into intimate contact with
a solvent by the action of an agitator working in a closed vessel.
Second. In a method of separating the said solvent from the products
extracted from the spent oxide or other substances which are treated
and also separating the remaining portions of the solvent which are
absorbed in the spent oxide or other substances after the free portions
of the said solvent has run therefrom.
Thirdly. In the means for extracting the ammoniacal salts from the
spent oxide.
Fourthly. In the use of oxidizing agents for removing tar or other
impurities from the sulphur while dissolved in its solvent.
Fifthly. In the apparatus herein-after described for carrying our said
Invention into effect.
Heretofore in extracting sulphur from the spent oxide of iron, and in
the treatment of various substances for the extraction of grease and oil
in closed or covered vessels by a volatile solvent, the substances treated
have been subjected to the solvent in a dense mass difficult if not
impossible for the solvent to penetrate. When the solvent is allowed to
run off this dense condition has prevented the free coming away of the
last portions of the solvent. It has been the practice to admit steam or
hot water at this stage of the process to vaporize and drive off this
remaining portion of the solvent. But this method of working has been
found most unsatisfactory for the following reason, viz., the dense mass-
has not permitted the steam or hot water to penetrate through it
therefore it has been very difficult to drive off the last portions of
solvent, and in the treatment of spent oxide quite impossible to effect
this object, because so soon as the steam or hot water is admitted the
solvent on the outside of the mass is volatilized and driven off leaving.
a coat or shield of sulphur which it held in solution. This forms a wall
which will not permit the heat to penetrate to the centre of the mass, and
the result has been such a loss of the solvent as to render the operation ·

page_text: useless. Moreover the solvent containing the sulphur in solution has
hitherto been conducted into a still and subjected to heat, the greatest
portion of the solvent being vaporized until sulphur begins to form in
lumps, absorbing and retaining a quantity of the solvent which is
thereby lost, the sulphur also adheres firmly to the sides of the vessel,
necessitating the uncovering of the same, so that the sulphur may
be removed by digging it out, which is a most difficult operation to
perform.
. In practising our said Invention we employ an apparatus constructed
as shown in the accompanying Drawing, in which,-
Figure 1 is a side elevation, partly in section, of one form of our
apparatus; Figure 2 is a side elevation, partly in section, illustrating a
modification of the same; Figures 3 and 4 are sections on the lines x, x,
and y, y, Figure 1. Like letters indicate the same parts throughout the
Drawings.
-
A is the extractor which is made of iron as shown in Figure 2, or
of wood and lead lined as in Figure 1; a is the cover of extractor
fastened down with clamps; b, b, are perforated plates with a filtering
medium between them to prevent the passage of any solid material from
the extractor into the still; c is an arm or shoot for introducing the
charge of material into the extractor; the lid of this shoot is clamped
down; d is a vapor pipe leading to its condensing coil; e is an
overflow pipe leading into the still; fis an outlet cock for the same;
g is a pressure gauge connected with the vapour pipe; h is a driving
wheel connected with the shaft which passes through a stuffing box and
driven by the worm and wheel shewn.
The agitator is shown in Figure 1 in the form of an archimedean
screw i, but in Figure 2 it consists of stirring and ejecting blades j, k;
Z-is a man-hole in the extractor for discharging its contents; m, m, arc
perforated plates with the filtering medium between them to prevent
solid matter passing through the man-hole; n is a steam jacket ;
o, p, are perforated steam pipes; q is a steam pipe for jacket; is an
outlet cock between extractor and the still B. The said still as shown
Figure 1, it is made of
B³ fastened down with
in Figure 2 is made of iron, but, as shewn in
wood and lined with lead. It has a cover
clamps; C, C, are perforated plates with filtering medium between them
to prevent the passage of sulphur from the still into the condensing

page_text: worm; D is a vapour pipe leading from the still to its condensing worm;
E is a pressure gauge connected with the vapour pipe.
"
In Figure 1 the still is shown provided with a screw agitator i similar
to the screws in the extractor in the same Figure.
In Figure 2 the still has agitating, scraping, and ejecting blades j, k,
similar to the blades j, k; l' is a man-hole at the bottom of the still to
discharge the grain sulphur. The covers of the man-holes F, F, are
provided with levers and weights to hold them; m² is a perforated
steam pipe at the bottom of the still; n¹ is a steam jacket on the still;
o' is the steam inlet for the same; ³ is a cock for drawing off fluid from
the still; is a cock with funnell for introducing into the still the
oxidizing agent; is a cook for drawing from the extractor the
ammoniacal salts in solution.
The said apparatus is mounted upon a frame or staging F; G is the
tank containing cold water for condensing vapour from the extractor
and still, and which passes into coils in the said tank; G³ is a large coil
for condensing the vapour from the still; G³ is a small coil for con-
densing vapour from the extractor; G³, Gʻ, are the outlets of the coils
for conveying the condensed vapour to the receiver; G³, G³, are test
cocks for ascertaining when the running of the solvent is finished;
G³, G³, are vapour pipes from the outlet of the coils to convey vapour
which does not condense in the lower coils to the upper one; G³ is a
tank containing water for condensing vapour passing through the coil in
the same; G is a coil for condensing all vapour escaping from the
lower coil; G is an outlet pipe from G" for conveying condensed vapor
to the store tank; G₁is a gas pipe to permit the escape of all uncon-
densable gasses into the atmosphere; G is an overflow pipe from the
top tank for conveying water to lower tank; Lis a pump for raising
the solvent from the store tank into the extractor; L' is a cock for
admitting the solvent into the extractor; I is a cock in a pipe for
drawing off solvent from the extractor; It is a cock for shutting off the
solvent from the pump; L' is a cook for. admitting water to the said
pump; E is the store tank under ground and containing the solvent;
E' is a frame or staging for supporting the said tanks and pumps.
In working with our improved apparatus we open the cover of the
inlet shoot c, which admits the charge of oxide or other substance into
the extractor A under the perforated plate b. The said cover is then
clamped down. We then open the cook D₁ at the bottom of the

page_text: extractor connected with the pipe from the pump; then the cock D* is
opened, and the pump is worked, forcing the solvent from the store
tank E into the extractor through perforated plates or false bottom m,
and into the charge of oxide in the extractor. Steam is now admitted
into the jacket, and the agitator is set in motion, the cock fis opened,
the pump continually forcing solvent through the oxide in A while it is
in motion. This solvent becomes charged, and passes through the per-
forated plates b, b, flows down through the pipe e into the still B, while
all vapour of the solvent passes through d into the condensing coils G³,
and condenses therein, and runs from outlet G into the store tank E.
Steam is now admitted into the jacket of the still B, the solvent is
thereby driven off in vapor, and passing through perforated plates c, c,
out of pipe D into condenser coil G¹ it is then condensed, and runs out
at g³ into the store tank E. The test cock connected with pipe e is
now opened; and a small portion of solvent let out. We thereby
ascertain how much sulphur is being washed out of the extractor. If
the washing out with solvent has proceeded far enough the pump is
stopped. The cock r is then opened, and the solvent allowed to drain
from the oxide in the extractor A through the perforated false bottom m
into the still B while the agitating screw or the agitator j, k, is
revolving. The perforated steam pipes are opened, the remaining
solvent is volatilized from the exhausted oxide in the extractor A, the
solvent vapor and steam passes out through the vapor pipe d, and are
condensed in the coil G³, thence flowing into store tank E.
The solvent in the store tank has a layer of water over it, an overflow
pipe is arranged at the top of the same to allow the condensed water
from the steam used to flow over as it accumulates. When all traces of
the solvent are driven from the oxide in the extractor A. the cock D³ is
opened, water is sent to the pump through the cock L³ and the steam
cock at the bottom of the extractor. Steam plays therein, and the a
agitator revolving, all ammoniacal salts are dissolved, while every trace
of volatile solvent is driven off. Steam is now shut off, and the cock 7+³
is opened, allowing the solution of ammoniacal salts to run into vessels
ready for concentration. The man-hole at the lower end or bottom of
the extractor A is opened, the agitator or stirrer ejects the oxide that has a
been treated, and the extractor A is ready for a fresh charge.
During the working of the said extractor steam has been kept to the
still by passing into the jacket n¹, the solution of sulphur and solvent

page_text: has therefore become concentrated; the cook ³ is now opened, and the
oxidizing agent poured therein; the agitator or stirrer is now revolved
rapidly; the tar and impurities are thrown down; the agitator is stopped
for a time, and this tarry fluid drawn off through the cock ¹; the
agitator or stirrer is set revolving again, and free steam allowed to play
through the perforated pipe m³. As the solvent is driven off sulphur
forms in grains, being broken up by the movement of the agitator or
stirrer, when every trace of solvent is driven off. The man-hole at the
end or bottom of the extractor is opened, and the agitator then ejects the
solid grain sulphur. The vessel is now ready for a repetition of the
process.
During the concentration of the sulphur solution in the vessel B the
vapor escapes through the pipe D into the coil condenser G², and runs
out as fluid at G³ into the store tank. It therefore follows that the same
solvent may be used repeatedly, in fact until all traces of the material
to be solved out of the extractor are exhausted. During these operations
the solvent is kept out of contact with the atmosphere, nor can any
vapor escape, as all the joints of the apparatus are plumber's joints, and
all cocks are fitted with water packing.
The above described working is applicable to the treatment of spent
oxide for the extraction of sulphur and ammoniacal.salts.
For seeds and grease refuse the same operation is required in the
extractor, and still with this difference, that no oxydizing agent is
required, nor is the man-hole required to be opened in the still, because
the grease or oil is liquefied by the free steam admitted to drive off
solvents therefrom. It is only necessary to open the cock v³ to draw off
the grease or oil from the still. The exhausted seed or grease refuse in
the extractor A should at last be steamed therein, while the agitator or
stirrer is revolving, for the purpose of driving off every trace of solvent.
keeps the
When the
When the agitator is in motion it brings every particle of the oxide or
other substance into contact with the solvent, the agitator during the time
it is kept in motion, and as it passes over the false bottom
mass moving, thereby assisting the solvent to run off freely.
solvent ceases to flow the steam or hot water is admitted into the vessel
to volatilize the last portions of solvent which is retained or absorbed in
the material that has been acted upon. The agitator being set in motion
brings every particle of the material acted upon into contact with the
steam and hot water, which prevents the solidification of the mass.

page_text: During the time the agitator in the still is kept in motion it prevents
the formation of sulphur in a solid mass; it brings the particles of
sulphur as it forms into contact with the steam or hot water, and
prevents its adhering to the sides of the vessel. The sulphur is therefore
obtained in a granular condition free from tar and all traces of the
solvent. All the operations are performed while the vessels are closed,
'the only outlet being vapour pipes, which condense anything entering
into the same.
For the extraction of sulphur from the spent oxide the solvent we
prefer to use is bi-sulphide of carbon or a light hydrocarbon oil. When
the steam and hot water are admitted into the first vessel they form the
solvent for the extraction of the ammoniacal salts.
Having thus fully described our Invention, and the manner of
performing the same, we wish it understood that although two forms of
apparatus shewn in the Drawings with the agitator constructed and
operating in each as described are the most convenient for carrying the
said Invention into practice, yet we do not limit ourselves to any
particular form or construction of the said agitators or the vessels in
which they are enclosed, but may use any form or construction thereof
which will serve for effecting the purposes of the said Invention; and
we claim,-
First. The herein described method of treating the spent oxide of iron
or other substances, whereby the particles of these substances are brought
by agitation into intimate contact with the solvent for the purpose
described.
--
Second. The breaking up of the mass of oxide or other substance in
the extractor to prevent the solidification of the same, as herein set forth
and for the purposes specified.
Third. The keeping of the sulphur mass in the still broken up during.
the working of said apparatus by means of an agitator to permit the
escape of the solvent, and for the production of grain sulphur, as herein
set forth.
Fourth. The employment of an oxidizing agent or substance for
precipitating the tarry impurities while the sulphur is held in solution.
Fifth. In the process herein described the direct use or application of
hot water in the extractor for the purpose of solving out the ammoniacal
salts after the extraction of the sulphur.

page_text: Sixth. The construction of an agitator to be employed in our improved
process in the form of an archimedean screw, or in the form of a series
of blades and beaters arranged spirally or otherwise around a rotating
shaft for the purpose of beating up the mass being treated, and
discharging the solid portions from the extractor or the still, as herein
set forth.
Seventh. The apparatus consisting of the two closed or covered vessels,
each of which is fitted with a screw or other agitator, and which are
constructed and arranged in connection with each other, as shewn in
Figure 1, or in any other suitable relative positions, and provided with
the appliances necessary for working our improved process, as herein
set forth.
Eighth. The apparatus consisting of two closed or covered vessels,
each of which is fitted with an agitator or series of agitating or stirring
blades, and which are constructed and arranged as shown in Figure 2,
or in any other suitable relative positions, and which are provided with
the necessary appliances for working our improved process, as herein set
forth.
Ninth. The combination of the two vessels A, B, constructed and
arranged either as in Figure 1 or in Figure 2, with the other apparatus
shewn in Figure 1, as herein set forth and for the purpose specified.
In witness whereof, we, the said Joseph William Freestone and
John Humphris, have hereunto set our hands and seals, this
Eighteenth day of March, in the year of our Lord One thousand
eight hundred and seventy-four.
TANDDT
PARRAMATH
Witness,
H. J. NOONE,
30
JOSEPH WILL
JOHN HUMPHRIS.
8, Southampton Buildings,
London.
FREESTONE. (L.8.)
(L.S.)