Tennom MUD MANURACEURE OR SODA AND SULPHURIC ACID
Year: 1863

page_text: LETTERS PATENT to James Bowron, of South Stockton, in the County
of York, Glass Manufacturer, and George Robinson, of Welbeck Street,
Cavendish Square, in the County of Middlesex, M.D., for the Invention
of Tennom MUD MANURACEURE OR SODA AND SULPHURIC ACID."
PROVISIONAL SPECIFICATION left by the said James Bowron and
George Robinson at the Office of the Commissioners of Patents, with
their Petition, on the 3rd December 1868.
We, JAMES BOWRON, of South Stockton, in the County of York, Glass
Manufacturer, and GEORGE ROBINSON, of Welbeck Street, Cavendish Square,
in the County of Middlesex, M.D., do hereby declare the nature of the
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF SODA AND SULPHURIC
ACID," to be as follows:-
This Invention has for its object improvements in the manufacture of soda
and sulphuric acid. For the purpose of manufacturing soda, sulphuret of
sodium is decomposed by bringing it in contact with metallic iron, zinc,
copper, manganese, or lead, or the oxide or oxides of any one or more of
these metals, or of any matter capable of yielding one or more of these
metals or oxides, the materials being heated to a red heat. The process
is conducted in one of the following modes:-The sulphuret of sodium is
reduced to powder, and then intimately mixed with the metal or metallic
oxide or substance containing one or both, with as little exposure to the air as

page_text: possible. The mixture is then placed in a retort or other vessel or furnace
where the mass is exposed to a red heat; on withdrawing the mass and
placing it in water, it will be found that the iron or other metal has taken the
sulphur from the sulphuret of sodium, and formed with it an insoluble
sulphuret, whilst the sodium has combined with oxygen and formed caustic
soda, which is dissolved in water. This solution is then to be drawn off, and
either evaporated at once to form caustic soda, or it may previously be car-
bonated and purified in any of the modes ordinarily practised for these
purposes. The residual insoluble sulphuret of iron or other metal or metals
after being washed with water and dried, is roasted in the presence of a
graduated current of air, and the resulting sulphurious acid gas passed into a
chamber or vessel for the manufacture of sulphuric acid. Instead of reducing
the sulphuret of sodium to powder, and then mixing it with the metal or
metallic oxide or substance, the latter may be heated to redness in a close
vessel or furnace, and the sulphuret of sodium then placed upon it and allowed
to melt, and so mingle with the metallic or metalliferous mass beneath, when
the same decomposition will occur; or the sulphuret of sodium may be formed
in the usual manner, and the metallic oxide or matter then mixed with it in
the same furnace, the object in all these cases being to effect the transfer of
the sulphur from the sodium to the iron, or other above-mentioned specified
metal or metals with as little exposure to the air as possible. In some
respects these two latter plans are preferable, and constitute part of our
Invention. In determining the relative quantities of sulphuret of sodium and
of the metal or metalliferous substance, regard should be had to the com-
bining proportions of the various elements, but it is always desirable to have
the decomposing metal in excess of the sulphuret of sodium. We would
remark that we are aware that sulphate of soda, charcoal, and a metallic
oxide have before been roasted together to produce soda, and also that
sulphuret of sodium has been boiled in water with a metallic oxide, also to
produce soda.
We do not therefore claim either of these processes, and they
are both of them more or less inconvenient; but this part of our Invention
consists in treating sulphuret of sodium (ready formed) with certain metals or
metallic oxides in any of the modes before mentioned.
Another part of our Invention consists in the use of a rotating retort or
furnace for effecting the decomposition of the sulphuret of sodium as above
described, and also for roasting, and thereby obtaining sulphurous acid from
the minutely divided metallic sulphuret resulting from the above process, or
from any minutely divided metallic sulphuret or sulphurets however obtained.
In the former case it is necessary to insure the intimate mixture of the

page_text: sulphuret of sodium with the decomposing metal or oxide, and this the
rotating retort or furnace effectually does, and in roasting the metallic
sulphuret or sulphurets when finely powdered it is essential to bring fresh
surfaces in contact with the air passing into the sulphuric acid chamber.
For both purposes a rotating cylindrical retort of iron or other material may
be used. It should have a door at one end, which may be wholly or partially
closed, to regulate the influx of air, and a pipe at the other end communicating
with the sulphuric acid chamber. Where natural pyrites is employed in the
manufacture of sulphuric acid, it may be prepared for use in our above-
mentioned process for the decomposition of sulphuret of sodium by allowing
it to fall while hot, and after the sulphur has been driven from it, into water,
when it will be easily reduced to a powder, so as to allow of its intimate
mixture with the sulphuret of sodium; and where the finely divided sulphuret
of iron obtained by our above-mentioned process, or otherwise, is roasted for
the purpose of manufacturing sulphuric acid, the resulting peroxide of iron is
available for the decomposition of fresh quantities of sulphuret of sodium.
Or the finely divided sulphuret of iron or other metal, or any artificial metallic
sulphuret however obtained, from sulphate of soda or sulphuret of sodium.
may be roasted with salt, so as to produce sulphate of soda, as has before
been proposed in respect to natural iron pyrites or sulphuret of iron; this
roasting also may be conducted in a rotating retort.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Bowron and George Robinson in the Great Seal
Patent Office on the 3rd June 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JAMES
BOWRON, of South Stockton, in the County of York, Glass Manufacturer, and
GEORGE ROBINSON, of Welbeck Street, Cavendish Square, in the County of
Middlesex, M.D., send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of December, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-seventh year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
us, the said James Bowron and George Robinson, Her special licence
that we, the said James Bouron and George Robinson, our executors,
administrators, and assigns, or such others as we, the said James Bouron
and George Robinson, our executors, administrators, and assigns, should at

page_text: ▸
any time agree with, and no others, from time to time and at all times there-
after 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 "IMPROVE-
MENTS IN THE MANUFACTURE OF SODA AND SULPHURIC ACID," upon the condition
(amongst others) that we, the said James Bowron and George Robinson,
our executors or administrators, by an instrument in writing under our or
their hands and seals, or under the band and seal of one of us or them,
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 James Bowron, on behalf of myself
and the said George Robinson, do hereby declare the nature of the said
Invention, and in what manner the same is to be performed, to be par-
ticularly described and ascertained in and by the following statement thereof,
that is to say:-
This Invention has for its object improvements in the manufacture of soda
and sulphuric acid. For the manufacturing soda we mix sulphuret of
sodium with oxide of iron, and heat the mixture to a red heat, at which
temperature we keep the mixture until it has been decomposed and converted
into soda and sulphuret of iron. The process may be conducted as follows:-
The sulphuret of sodium is to be reduced to powder, and intimately mixed
with the oxide of iron, and if it be desired to obtain caustic soda, we make
the mixture with as little exposure to the air as possible. The mixture is
then placed in a convenient retort, or other vessel or furnace, where the mass
can be exposed to a red heat. For this purpose an ordinary reverberatory
furnace may be employed, the mixture being placed in the bed of the furnace,
and the furnace heated in the usual manner. The material soon melts, and is
to be stirred about in the furnace with an iron rake until the sulphuret of
sodium has been desulphurized and converted into soda. This will generally
be effected in from half an hour to an hour after the mixture has been heated
red hot, the time varying according to the quantity of material operated
upon. If the object be to manufacture caustic soda, a reverberatory furnace
is not suitable, as a large proportion of the soda will become carbonated by
contact with the gases of the furnace. The contact of the mixture with the
gases of the furnace may be avoided by heating it in a rotating retort made of
fire clay, iron, or other proper material. We believe a cylindrical retort to be
the most convenient for this purpose, supported or mounted so as to be capable

page_text: f having rotary motion communicated to it, and heated by a fire beneath it
o a red heat. The retort should be caused to rotate continuously whilst the
charge is under operation. The retort should be furnished with a cover for
he opening at the end through which the charge is introduced and with-
drawn, in order to exclude the air and prevent the soda from being carbonated,
and the charge should be kept from the extreme ends of the retort (where it
would not be properly heated) by means of inclines formed or fixed within
the retort or other convenient means. On withdrawing the mass from the
retort after the completion of the process, and placing it in water, it will be
found that the iron contained in the oxide of iron, or a portion of it, has
become united with the sulphur of the sulphuret of sodium, and formed. with
it an insoluble sulphuret of iron, whilst the sodium has combined with oxygen
from the oxide of iron and formed caustic soda, which is dissolved in water.
This solution is then to be drawn off from the insoluble sulphuret of iron, and
either evaporated so that dry caustic soda may be obtained, or if desired, the
soda in the solution may be carbonated before evaporation. The caustic or
carbonated soda produced by our process may be purified in any of the modes
ordinarily practised for that purpose. The residual insoluble sulphuret of iron
formed by our process after the soda has been separated from it may be
washed with water, and dried and roasted in a current of air, and the resulting
sulphurous acid gas passed into a chamber or vessel for the manufacture of
sulphuric acid in the ordinary manner. Instead of reducing the sulphuret of
sodium to powder, and then mixing it with the oxide of iron, the latter sub-
stance may be heated to redness in a close vessel or furnace, and the sulphuret
of sodium then placed upon it and allowed to melt, and so mingle with the
oxide of iron beneath, and the mixture being then heated and treated in
A convenient
manner above described the same result will be obtained.
modification of our process is as follows:-In this modification of our process
we use a two-storied furnace, the upper bed of which is like that of an
In the upper
ordinary reverberatory furnace, and heated in a similar manner.
bed of this furnace sulphuret of sodium is produced in the usual way by
roasting sulphate of soda with carbonaceous matter. The furnace has also a
lower bed immediately under the upper bed, and the flue from the upper bed
passes down underneath the lower bed, which is thus heated by the flame
5 passing down from the upper bed to the under side of the lower bed. The
The
lower bed may, however, be heated in any other convenient manner.
space between the two beds is entirely enclosed, and there is at one side of the
furnace a charging door by which the oxide of iron is introduced into this
space or chamber, and laid upon the lower bed, where it is heated during the

page_text: process of making the sulphuret of sodium on the bed above; when the sul-
phuret of sodium has been completely formed, then, by removing a plug
covering a hole made in the upper bed and leading into the chamber below,
the melted sulphuret of sodium is permitted to descend on to the heated oxide;
this process is that which we on the whole prefer for making caustic soda.
Another method of conducting our process is to produce sulphuret of
sodium in the usual manner by roasting sulphate of soda with carbonaceous
matter, and when the conversion is complete to add and mix the sulphuret of
sodium in the same furnace with the oxide of iron, and then proceed to heat
and treat the mixture as above described. The object in all modifications of
our process is to effect the transfer of the sulphur from the sodium to the
iron, and to do that with as little exposure of the mixture to the air as
possible. In determining the relative quantities of sulphuret of sodium and
oxide of iron to be used in performing our process, we believe that in order
to obtain a good result it is desirable to use an excess of oxide of iron beyond
the quantity necessary to decompose the sulphuret of sodium, and with that
object the proportions we prefer to employ are, two parts by weight of the
oxide of iron to one part by weight of the sulphuret of sodium. Peroxide of
iron, whether artificial or natural, if free from impurities which would injure
the soda, may be used in performing our process, but the material which we
have found to be the cheapest is the oxide of iron remaining after roasting
pyrites in the process of manufacturing sulphuric acid.
Having now described the nature of that part of our Invention which
consists of improvements in the manufacture of soda, we declare that what
we claim as respects this part of our Invention is, to obtain soda from
sulphuret of sodium by mixing it with oxide of iron and heating and treating
the mixture substantially in manner herein-before described.
Another part of our Invention consists of an improvement in the manu-
facture of sulphuric acid, by which we are enabled to operate upon iron or
copper pyrites, or sulphuret in powder or a minutely divided state, for
converting the sulphur it contains into sulphuric acid. When powdered or
minutely divided pyrites or sulphuret of iron or copper is roasted or heated
for the purpose of manufacturing sulphuric acid, there is great difficulty in
bringing the particles of the material sufficiently into contact with the air in
order to convert the sulphur it contains into sulphurous acid. For the
purpose of obviating this difficulty we introduce the powdered pyrites or
sulphuret into a rotating retort, which is kept rotating during the roasting or
heating process, so that the revolution of the retort causes every part of the
powder in the retort to be successively submitted to the action of a current of

page_text: air passing through the retort, by which the sulphur contained in the material
is gradually converted into sulphurous acid and carried away by the current of
air into the sulphuric acid chamber to be there converted into sulphuric acid.
A rotating cylindrical retort of iron or other material may be used. It
should have a door at one end by which it may be partially closed to regulate
the influx of air, and a pipe at the other end communicating with the
sulphuric acid chamber. The retort should be heated by an external fire and
mounted or supported in any convenient manner, so as to be capable of
rotating, and it may have rotary motion given to it by any convenient means.
The remaining part of the process of manufacturing sulphuric acid by
converting the sulphurous acid into sulphuric acid is conducted in the
ordinary way.
We claim, as respects this part of our Invention, an improvement in the
manufacture of sulphuric acid, by which we roast or heat pulverized or other-
wise minutely divided pyrites or sulphuret of iron or copper in a rotating
retort, so as to subject every part of the material to the action of the air
passing through the retort for the purpose of converting the sulphur it
contains into sulphurous acid, in manner above described.
In witness whereof, I, the said James Bowron, have hereunto set my
hand and seal, this First day of June, in the year of our Lord One
thousand eight hundred and sixty-four.
JAMES BOW RON. (LS.)